The aims of the study were to investigate the incidence of C-shaped root canal systems in mandibular second molars in a native Chinese population using radiography and clinical examination under microscope and to comp...The aims of the study were to investigate the incidence of C-shaped root canal systems in mandibular second molars in a native Chinese population using radiography and clinical examination under microscope and to compare the relative efficacies of these methods. For the recognition of C-shaped root canal system, 1 146 mandibular second molars were selected and examined. Teeth with C-shaped canal systems were categorized by using the radiographic classification criteria and the modified Melton＇s method. C-shaped canals were identified in 397 （34.64%） mandibular second molars by radiography （type I, 31.23%; type II, 38.29%; type III, 30.48%）. Clinical examination showed that 449 （39.18%） cases exhibited C-shaped canal systems （C1, 22.94%; C2, 48.11%; C3a, 15.59%; C3b, 13.36%）. As for the result of the radiographic and clinical combined examination, C-shaped root canals were found in 473 （41.27%） mandibular second molars （C1, 21.78%; C2, 45.67%; C3a, 16.70%; C3b, 15.86%）. The incidence of C-shaped root canal diagnosed by radiographic method was statistically different from that by clinical examination and the combined examination （P〈O.05）. The study indicated a high incidence of C-shaped canal system in a Chinese population. The combination of microscopic and radiographic examination is an effective method in identifying the C-shaped root canal system.展开更多
BACKGROUND Odontogenic maxillary sinusitis,often triggered by dental issues like periapical periodontitis,significantly contributes to chronic sinusitis,mainly affecting adults around 50 years old,emphasizing the need...BACKGROUND Odontogenic maxillary sinusitis,often triggered by dental issues like periapical periodontitis,significantly contributes to chronic sinusitis,mainly affecting adults around 50 years old,emphasizing the need for a multidisciplinary diagnostic and treatment approach.AIM To investigate the therapeutic effect and clinical value of root canal therapy combined with nasal endoscopic surgery compared with simple root canal the-rapy in the treatment of severe odontogenic maxillary sinusitis caused by peria-pical periodontitis.METHODS The clinical data,diagnosis,and treatment of 200 patients with severe odonto-genic maxillary sinusitis caused by periapical periodontitis from October 2020 to October 2021 were analyzed retrospectively.Among them,63 patients were treated with simple root canal therapy as the control group,and 137 patients were treated with root canal therapy combined with nasal endoscopic surgery as the observation group.The therapeutic effect,Lund-Kennedy endoscopic score,paranasal sinus Lund-Mackay score,complication rate,recurrence rate,and patient satisfaction were compared between the two groups.RESULTS First,we compared the effective rates:23 cases were cured,22 were improved,and 8 were ineffective in the control group,yielding a total effective rate of 84.90%.Meanwhile,97 cases were cured,34 improved,and 6 were ineffective in the observation group,resulting in a total effective rate of 95.62%.The observation group had a higher total effective rate compared with the control group(P<0.05).Second,we compared the Lund–Kennedy endoscopic score.Before treatment,no significant difference(P>0.05)was observed in this score between the two groups.After treatment,the Lund–Kennedy endoscopic score decreased in both groups.The Lund–Kennedy endoscopic score of the observation group at 3 and 6 mo after treatment was lower compared to that of the control group(P<0.05).Third,we compared the Lund–Mackay score of paranasal sinuses.Before treatment,there was no significant difference in this score between the two groups(P>0.05).After treatment,the Lund–Mackay scores of paranasal sinuses decreased in both groups.The Lund–Mackay scores of paranasal sinuses in the observation group at 3 and 6 mo after treatment were lower compared to those of the control group(P<0.05).Fourth,we compared the incidence and recurrence rate of complications.Three months after treatment,no significant difference was found in the incidence and recurrence rate of complications between the observation group(6.56%)and the control group(9.52%)(P>0.05).However,6 mo after treatment,the incidence and recurrence rate of complications in the observation group(2.91%)was significantly higher compared to that of the control group(12.69%)(P<0.05).Fifth,we compared patient satisfaction.Six months after treatment,the patient satisfaction of the observation group(93.43%)was significantly better than that of the control group(84.12%)(P<0.05).CONCLUSION Root canal therapy combined with nasal endoscopic surgery has a good therapeutic effect on severe odontogenic maxillary sinusitis caused by periapical periodontitis,and it can reduce the injury of maxillary sinus mucosa and bone,and significantly reduce the incidence of complications and recurrence rate.Meanwhile,it has high patient satisfaction and remarkable therapeutic effect,which is suggested to be popularized and applied in clinic.展开更多
The Suez Canal is a unique sea-level waterway between northern Africa and southern Asia that connects the Mediterranean Sea to the Red Sea via the Isthmus of Suez. The canal’s artificial navigation route substantiall...The Suez Canal is a unique sea-level waterway between northern Africa and southern Asia that connects the Mediterranean Sea to the Red Sea via the Isthmus of Suez. The canal’s artificial navigation route substantially reduced the sailing distance between countries in Europe and East Asia and offered a more direct route between the North Atlantic Ocean and the Indian Ocean through the Mediterranean Sea and the Red Sea. The primary objective of this study is to document the historical, economical, and environmental impacts of connecting the Mediterranean Sea and the Red Sea via a canal. After the completion of the Suez Canal in 1869 the canal became an economically lifeline for Egypt. However, the economic gains were partially offset by negative environmental impacts. The impact of port activities on the environment depends on their cargo volume and location, seaports can have an impact on the air quality and therefore on the health of the communities along the Suez Canal. The salinity barrier to migration was removed and animals and plants from the Red Sea began colonizing the eastern Mediterranean. Since the 1880s, species from the Indo-Pacific Ocean have been introduced, via the canal, into the Mediterranean ecosystem. They are endangering some local and endemic species and impacting the ecology. The results showed significant changes in the shoreline and land cover due to climate change and anthropogenic activities that necessitate the implementation of adequate protective measures. The findings of this study may assist policymakers in formulating adaptation plans to protect this crucial area, the communities along the Suez Canal and the Red Sea and Mediterranean ports, from climate change and human activities.展开更多
The North Crimean Canal is a watercourse originating from the Kakhovka Reservoir and flowing into the Crimean Peninsula.The canal is an important source of drinking water supply and is also used to irrigate agricultur...The North Crimean Canal is a watercourse originating from the Kakhovka Reservoir and flowing into the Crimean Peninsula.The canal is an important source of drinking water supply and is also used to irrigate agricultural lands and fillfish farms.Due to its location,in recent years its functioning has not been stable,and the processes occurring along the canal have been poorly studied.In this study,we determined the content(with a safety assessment),features of spatial and seasonal distribution,and potential sources of hydrocarbons in the water of the North Crimean Canal,Crimea.During the study period(from March to November 2023)in the primary canal,the content of aliphatic hydrocarbons did not exceed sanitary standards(0.05 mg·L~(-1)).Their increased concentrations in the secondary canals could be associated with the input of organic substances into the canal water as it moves across the Crimean Peninsula.The composition of n-alkanes had temporal and spatial variability.In the period from spring to autumn,the content of autochthonous compounds decreased sharply.The share of allochthonous compounds increased as a consequence of the natural processes.The analysis of biogeochemical markers showed that autochthonous compounds produced by phytoplankton predominated in the spring–summer period.Subsequently,they had less importance,and the main share was accounted for allochthonous n-alkanes.展开更多
BACKGROUND The numbers of mandibular first premolar roots and root canals vary,and the incidence of three roots and three canals is 0.09%.CASE SUMMARY In this article,we review the root and root canal conditions for t...BACKGROUND The numbers of mandibular first premolar roots and root canals vary,and the incidence of three roots and three canals is 0.09%.CASE SUMMARY In this article,we review the root and root canal conditions for the mandibular first premolar and report the case of a mandibular left first premolar with three roots and three canals in a male patient,with suggestions for clinical diagnosis and treatment.The patient was referred by an orthodontist for the extraction of the tooth.Preoperative cone-beam computed tomography examination revealed that it had three roots.Under local anesthesia,the extraction socket was carefully expanded,and the tooth was successfully removed intact using forceps.The procedure was uneventful,with no root fractures,postoperative bleeding,or sensory abnormality observed.CONCLUSION The mandibular first premolar is characterized by multiple roots and canal variations that can increase the difficulty of treatment.展开更多
BACKGROUND Early anal canal cancer is frequently treated with endoscopic submucosal dis-section(ESD)to preserve anal function.However,if the lesion is in the anal canal,then significant difficulties such as bleeding a...BACKGROUND Early anal canal cancer is frequently treated with endoscopic submucosal dis-section(ESD)to preserve anal function.However,if the lesion is in the anal canal,then significant difficulties such as bleeding and challenges associated with scope manipulation can arise.CASE SUMMARY A 70-year-old woman undergoing follow-up after transverse colon cancer surgery was diagnosed with anal canal cancer extending to the dentate line.The patient underwent a combination of ESD and transanal resection(TAR).The specimen was excised in pieces,which resulted in difficulty performing the pathological evaluation of the margins,especially on the anal side where TAR was performed and severe crushing was observed.Careful follow-up was performed,and local recurrence was observed 3 years postoperatively.Because the patient had super-ficial cancer without lymph node metastasis,local resection was performed again.The second treatment attempt was improved as follows:(1)TAR and ESD were performed appropriately based on the situation by the same physician;(2)A needle scalpel was used during TAR to prevent tissue crushing;and(3)The lesion borders were marked using ESD techniques before treatment.Complete resection was performed without complications.CONCLUSION Anal canal lesions can be safely and reliably removed when ESD and TAR are used appropriately.展开更多
The main objectives of this study were to investigate the distribution features of the ^(210)Po in abiotic(water and bottom sediments)and biotic(zooplankton,mollusks,fish)components of the North Crimean Canal(NCC)aqua...The main objectives of this study were to investigate the distribution features of the ^(210)Po in abiotic(water and bottom sediments)and biotic(zooplankton,mollusks,fish)components of the North Crimean Canal(NCC)aquatic ecosystem and adjacent irrigated soils as well as assessment of the doses received by water organisms from α-radiation of absorbed ^(210)Po.The samples were processed using standard radiochemical methods accepted in international practice.The activity of ^(210)Po in the samples was measured using the alpha-spectrometric OCTETE Plus complex(ORTEC-AMETEK,USA).The measurement error did not exceed 20%.Activity concentration of ^(210)Po in the studied objects decreased in the following rank:suspended matter(73.6 Bq/kg d.w.)>soils(32.5 Bq/kg d.w.)≈bottom sediments(32.1 Bq/kg d.w.)>mollusks(23.4 Bq/kg w.w.)>fish(6.4 Bq/kg w.w.).The ^(210)Po distribution coefficient(K_(d))values in water between suspended matter and its dissolved parts varied within the 1.4×10^(4)-1.4×10^(5) L/kg range.The concentration factors(CF)of ^(210)Po for hydrobionts of the NCC were in the range 10^(3)-10^(4) L/kg.The calculated absorbed radiation doses from ^(210)Po alpha radiation for the hydrobionts of the North Crimean Canal were significantly below the recommended dose limits.展开更多
In order to analysis the distribution characteristics of in-bore magnetic field for C-shaped armature electromagnetic railgun, a computational model considering dynamic contact pressure is established. By solving the ...In order to analysis the distribution characteristics of in-bore magnetic field for C-shaped armature electromagnetic railgun, a computational model considering dynamic contact pressure is established. By solving the dynamic equation, the in-bore motion characteristics of the armature are obtained. The distribution of current in the rail and armature is analyzed based on the magnetic diffusion equation and Ampere’s law. On this basis, three simulation models are proposed, which correspond to static state,motion state and motion state considering the velocity skin effect. The magnetic field of the investigated points along the central axes of the armature front end are obtained. The results show that, in static state,the peak magnetic flux density of each investigated point is greater than the other two states. Velocity skin effect leads to a decrease in peak magnetic flux density. The change of motion state has little influence on the peak magnetic flux density of the investigated point that far away from the armature. The calculated results can be used in the electromagnetic shielding design of intelligent ammunition.展开更多
Ultra wide bands antennas with notched bands characteristics have recently been considered for efficient communication between devices. In this paper, a compact ultra-wideband antenna (UWB) for UWB applications with t...Ultra wide bands antennas with notched bands characteristics have recently been considered for efficient communication between devices. In this paper, a compact ultra-wideband antenna (UWB) for UWB applications with triple bandnotched characteristics is presented. The proposed antenna consists of a square patch with four truncated corners and a partial ground plane with a rectangular slit. The operation bandwidth of the designed antenna is from 2.66 GHz to more than 13.5 GHz. Band-notched characteristics of antenna to reject the frequency band of 3.18 - 3.59 GHz and 4.70 - 5.88 GHz, is realized by inserting two C-shaped slots in the patch, the third band of 9.54 - 12.22 GHz is achieved by slottype capacitively-loaded loop (CLL) inserted in the patch near the feed line. Details of the proposed antenna design and simulated results are presented and discussed.展开更多
Tropical peat comprises decomposed dead plant material and acts like a sponge to absorb water,making it fully saturated.However,drought periods dry it readily and increases its vulnerability to fire.Peat fires emit gr...Tropical peat comprises decomposed dead plant material and acts like a sponge to absorb water,making it fully saturated.However,drought periods dry it readily and increases its vulnerability to fire.Peat fires emit greenhouse gases and particles contributing to haze,and prevention by constructing fire-break canals to reduce fire spread into forest reserves is crucial.This paper aims to determine peat physical and chemical properties near a fire-break canal at different fire frequency areas.Peat sampling was conducted at two forest reserves in Malaysia which represent low fire frequency and high fire frequency areas.The results show that peat properties were not affected by the construction of a fire-break canal,however lignin and cellulose content increased significantly from the distance of the canal in both areas.The study concluded that fire frequency did not significantly influence peat properties except for porosity.The higher fibre content in the high frequency area did not influence moisture content nor the ability to regain moisture.Thus,fire frequency might contribute differently to changes in physical and chemical properties,hence management efforts to construct fire-break canals and restoration efforts should protect peatlands from further degradation.These findings will benefit future management and planning for forest reserves.展开更多
BACKGROUND We report a rare case of cervical spinal canal penetrating trauma and review the relevant literatures.CASE SUMMARY A 58-year-old male patient was admitted to the emergency department with a steel bar penetr...BACKGROUND We report a rare case of cervical spinal canal penetrating trauma and review the relevant literatures.CASE SUMMARY A 58-year-old male patient was admitted to the emergency department with a steel bar penetrating the neck,without signs of neurological deficit.Computed tomography(CT)demonstrated that the steel bar had penetrated the cervical spinal canal at the C6–7 level,causing C6 and C7 vertebral body fracture,C6 left lamina fracture,left facet joint fracture,and penetration of the cervical spinal cord.The steel bar was successfully removed through an open surgical procedure by a multidisciplinary team.During the surgery,we found that the cervical vertebra,cervical spinal canal and cervical spinal cord were all severely injured.Postoperative CT demonstrated severe penetration of the cervical spinal canal but the patient returned to a fully functional level without any neurological deficits.CONCLUSION Even with a serious cervical spinal canal penetrating trauma,the patient could resume normal work and life after appropriate treatment.展开更多
On the occasion of the 10th anniversary of the Grand Canal's application for the World Heritage status in 2024,with the strong support of the Department of International Cooperation of the National Radio and Telev...On the occasion of the 10th anniversary of the Grand Canal's application for the World Heritage status in 2024,with the strong support of the Department of International Cooperation of the National Radio and Television Administration and the International Tourism Alliance of Silk Road Cities.展开更多
Introduction: The choice of adopting unilateral pedicle screw fixation or using bilateral pedicle screw fixation in lumbar spinal stenosis remains controversial. In our context, very few studies have been performed co...Introduction: The choice of adopting unilateral pedicle screw fixation or using bilateral pedicle screw fixation in lumbar spinal stenosis remains controversial. In our context, very few studies have been performed comparing the clinical effectiveness of unilateral versus bilateral fixation in the surgical management of lumbar spinal canal stenosis. Objective: Evaluate the impact on quality of life and clinical efficacy of unilateral spondylodesis compared to bilateral spondylodesis in the surgical management of lumbar spinal canal stenosis at the Yaounde Central Hospital. Methods: This was a retrospective descriptive cross-sectional study for a period of 4 years, from June 2015 to June 2019. It involved all patients operated for lumbar canal stenosis and who underwent spondylodesis or spinal fusion at the neurosurgery department of the Yaounde Central Hospital. Results: A total of 68 participants were recruited during our study period. 32 (47%) of the study population were in the 50 - 60 age group, with a mean age of 56.98 years ranging from 41 to 75 years. Females, housewives and farmers were the most affected. In our study, 72% of patients had unilateral spondylodesis and 28% had bilateral fusion. Preoperatively, 71% of patients had insurmountable pain, refractory to medical treatment. At 3 months postoperatively, 73.7% of patients with bilateral setup had moderate pain compared to 69% of those with unilateral setup. At 6 months postoperatively, 79% of patients with bilateral fusion had mild pain compared to 82% of patients with unilateral setup. At 1 year postoperatively, all patients had mild pain. Preoperatively, 66.2% of patients were unable to walk and 19.1% of patients were bedridden according to the Oswestry score. At 3 months postoperatively, 10.2% of patients with unilateral setup were unable to walk compared to 10.5% of patients with bilateral fixation, while 67.3% of patients with unilateral fixation had moderate disability compared to 52.6% of patients with bilateral fixation. At 6 months postoperatively, 51% of patients with unilateral setup had moderate disability compared to 47.4% of patients with bilateral fixation, while 42.9% of patients with unilateral fixation had mild disability compared to 42.1% of patients with bilateral fixation. At 1 year postoperatively, 81.6% of patients who underwent unilateral fixation had only mild disability compared to 73.7% of patients with bilateral fixation. Conclusion: The assessment of quality of life according to the set-up used shows similar results at 3 months, 6 months and 1 year, with no statistically significant differences. Single-sided pedicle screw fixation combined with transforaminal lumbar interbody fusion or mounting has the advantage of being faster, with less bleeding and is less expensive compared to bilateral fixation.展开更多
This research aims to analyze the communication process between the different participating actors in the port of Balboa,in the Panamanian Pacific.The starting hypothesis begins with the normal operation of the port i...This research aims to analyze the communication process between the different participating actors in the port of Balboa,in the Panamanian Pacific.The starting hypothesis begins with the normal operation of the port itself.Considering which strategic actions have potential development and which specific strategic actions are proposed for their improvement,the article begins with a discussion of the nature of ports in Panama and their relationships with the Panama Canal,followed by a literary review of all the effects that climate change may have on navigation on the Panamanian Pacific coast.Next,the implication between the coordination and cooperation between the port,the Panama Canal pilots,and the other actors involved with the arrival and departure of vessels from the port will be analyzed.In a third part,the results of the perception of a significant sample of these actors who were surveyed,which are related to the process,are presented.The document concludes with recommendations on how the Panamanian Pacific port can improve its individual interests through the application of improvements derived from the results of the surveys,for more efficient inter-institutional coordination and cooperation.展开更多
On 22 September 2024,under the auspices of China NGO Network for International Exchanges(CNIE),the Chinese Association for International Understanding(CAFIU)and the World Heritage and Canal Cities Cooperation Organisa...On 22 September 2024,under the auspices of China NGO Network for International Exchanges(CNIE),the Chinese Association for International Understanding(CAFIU)and the World Heritage and Canal Cities Cooperation Organisation(WCCO)jointly hosted the Civilisation Lecture Series on"Canal Civilisation and International Exchanges"&Youth Dialogue on Canal Civilisation in Shaoxing.展开更多
I extend to all the authorities present and to those who participate in this important event,my respectful greeting,my thanks for the invitation and my congratulations for the inauguration of the Canal Walk within a l...I extend to all the authorities present and to those who participate in this important event,my respectful greeting,my thanks for the invitation and my congratulations for the inauguration of the Canal Walk within a larger project.展开更多
In seasonal frozen soil,freezing and thawing can change the physical and mechanical properties and affect slope stability.There are complex moisture conditions in the main water transfer canal.A study of the hydrother...In seasonal frozen soil,freezing and thawing can change the physical and mechanical properties and affect slope stability.There are complex moisture conditions in the main water transfer canal.A study of the hydrothermal evolution of canals with different initial water contents under the action of freezing and thawing is of great importance for the prevention and control of canal slope slides.Hydrothermal coupling models are the key to revealing the canal's hydrothermal evolution.As some of the modeling parameters in the current hydrothermal coupling model are based on empirical values,particularly those in the van Genuchten equation,which are not necessarily related to soil properties,they are not suitable for analyzing the hydrothermal evolution of canals.This paper determines the soil-water characteristic curve from the cumulative curve of particle gradation in the subsoil,and then determines the hydraulic parameters of the subsoil using the VG model,which then corrects the hydrothermal coupling model.The method of modifying the hydrothermal coupling model is original,which makes the model more realistically reflect drainage soil characteristics.During freezing and thawing of channel slopes with different initial water contents(21%,25%,29%,33%,37%,and 41%),temperature field,water field,and ice content distributions were investigated.Using the V-G model,the optimal parameters for canal subsoil were a=0.06,n=1.2,and m=0.17,and temperature distribution trends between canals with different water contents were basically similar.Water will accumulate at the bottom as the liquid water content increases at the canal boundary.展开更多
基金supported by the grant from the Independent Innovation Foundation of Shandong University of China (No. 2011JC019)the grant of Science and Technique Development Foundation of Shandong province(2010G0020230)
文摘The aims of the study were to investigate the incidence of C-shaped root canal systems in mandibular second molars in a native Chinese population using radiography and clinical examination under microscope and to compare the relative efficacies of these methods. For the recognition of C-shaped root canal system, 1 146 mandibular second molars were selected and examined. Teeth with C-shaped canal systems were categorized by using the radiographic classification criteria and the modified Melton＇s method. C-shaped canals were identified in 397 （34.64%） mandibular second molars by radiography （type I, 31.23%; type II, 38.29%; type III, 30.48%）. Clinical examination showed that 449 （39.18%） cases exhibited C-shaped canal systems （C1, 22.94%; C2, 48.11%; C3a, 15.59%; C3b, 13.36%）. As for the result of the radiographic and clinical combined examination, C-shaped root canals were found in 473 （41.27%） mandibular second molars （C1, 21.78%; C2, 45.67%; C3a, 16.70%; C3b, 15.86%）. The incidence of C-shaped root canal diagnosed by radiographic method was statistically different from that by clinical examination and the combined examination （P〈O.05）. The study indicated a high incidence of C-shaped canal system in a Chinese population. The combination of microscopic and radiographic examination is an effective method in identifying the C-shaped root canal system.
文摘BACKGROUND Odontogenic maxillary sinusitis,often triggered by dental issues like periapical periodontitis,significantly contributes to chronic sinusitis,mainly affecting adults around 50 years old,emphasizing the need for a multidisciplinary diagnostic and treatment approach.AIM To investigate the therapeutic effect and clinical value of root canal therapy combined with nasal endoscopic surgery compared with simple root canal the-rapy in the treatment of severe odontogenic maxillary sinusitis caused by peria-pical periodontitis.METHODS The clinical data,diagnosis,and treatment of 200 patients with severe odonto-genic maxillary sinusitis caused by periapical periodontitis from October 2020 to October 2021 were analyzed retrospectively.Among them,63 patients were treated with simple root canal therapy as the control group,and 137 patients were treated with root canal therapy combined with nasal endoscopic surgery as the observation group.The therapeutic effect,Lund-Kennedy endoscopic score,paranasal sinus Lund-Mackay score,complication rate,recurrence rate,and patient satisfaction were compared between the two groups.RESULTS First,we compared the effective rates:23 cases were cured,22 were improved,and 8 were ineffective in the control group,yielding a total effective rate of 84.90%.Meanwhile,97 cases were cured,34 improved,and 6 were ineffective in the observation group,resulting in a total effective rate of 95.62%.The observation group had a higher total effective rate compared with the control group(P<0.05).Second,we compared the Lund–Kennedy endoscopic score.Before treatment,no significant difference(P>0.05)was observed in this score between the two groups.After treatment,the Lund–Kennedy endoscopic score decreased in both groups.The Lund–Kennedy endoscopic score of the observation group at 3 and 6 mo after treatment was lower compared to that of the control group(P<0.05).Third,we compared the Lund–Mackay score of paranasal sinuses.Before treatment,there was no significant difference in this score between the two groups(P>0.05).After treatment,the Lund–Mackay scores of paranasal sinuses decreased in both groups.The Lund–Mackay scores of paranasal sinuses in the observation group at 3 and 6 mo after treatment were lower compared to those of the control group(P<0.05).Fourth,we compared the incidence and recurrence rate of complications.Three months after treatment,no significant difference was found in the incidence and recurrence rate of complications between the observation group(6.56%)and the control group(9.52%)(P>0.05).However,6 mo after treatment,the incidence and recurrence rate of complications in the observation group(2.91%)was significantly higher compared to that of the control group(12.69%)(P<0.05).Fifth,we compared patient satisfaction.Six months after treatment,the patient satisfaction of the observation group(93.43%)was significantly better than that of the control group(84.12%)(P<0.05).CONCLUSION Root canal therapy combined with nasal endoscopic surgery has a good therapeutic effect on severe odontogenic maxillary sinusitis caused by periapical periodontitis,and it can reduce the injury of maxillary sinus mucosa and bone,and significantly reduce the incidence of complications and recurrence rate.Meanwhile,it has high patient satisfaction and remarkable therapeutic effect,which is suggested to be popularized and applied in clinic.
文摘The Suez Canal is a unique sea-level waterway between northern Africa and southern Asia that connects the Mediterranean Sea to the Red Sea via the Isthmus of Suez. The canal’s artificial navigation route substantially reduced the sailing distance between countries in Europe and East Asia and offered a more direct route between the North Atlantic Ocean and the Indian Ocean through the Mediterranean Sea and the Red Sea. The primary objective of this study is to document the historical, economical, and environmental impacts of connecting the Mediterranean Sea and the Red Sea via a canal. After the completion of the Suez Canal in 1869 the canal became an economically lifeline for Egypt. However, the economic gains were partially offset by negative environmental impacts. The impact of port activities on the environment depends on their cargo volume and location, seaports can have an impact on the air quality and therefore on the health of the communities along the Suez Canal. The salinity barrier to migration was removed and animals and plants from the Red Sea began colonizing the eastern Mediterranean. Since the 1880s, species from the Indo-Pacific Ocean have been introduced, via the canal, into the Mediterranean ecosystem. They are endangering some local and endemic species and impacting the ecology. The results showed significant changes in the shoreline and land cover due to climate change and anthropogenic activities that necessitate the implementation of adequate protective measures. The findings of this study may assist policymakers in formulating adaptation plans to protect this crucial area, the communities along the Suez Canal and the Red Sea and Mediterranean ports, from climate change and human activities.
基金This work has been supported by the Russian Science FoundationProject No.23-26-00128,“The role of the North Crimean Canal irrigation system in the processes of transfer of long-lived radionuclides of the Chernobyl origin,heavy metals,as well as hydrocarbons with the Dnieper water to the irrigated farmlands of Crimea”。
文摘The North Crimean Canal is a watercourse originating from the Kakhovka Reservoir and flowing into the Crimean Peninsula.The canal is an important source of drinking water supply and is also used to irrigate agricultural lands and fillfish farms.Due to its location,in recent years its functioning has not been stable,and the processes occurring along the canal have been poorly studied.In this study,we determined the content(with a safety assessment),features of spatial and seasonal distribution,and potential sources of hydrocarbons in the water of the North Crimean Canal,Crimea.During the study period(from March to November 2023)in the primary canal,the content of aliphatic hydrocarbons did not exceed sanitary standards(0.05 mg·L~(-1)).Their increased concentrations in the secondary canals could be associated with the input of organic substances into the canal water as it moves across the Crimean Peninsula.The composition of n-alkanes had temporal and spatial variability.In the period from spring to autumn,the content of autochthonous compounds decreased sharply.The share of allochthonous compounds increased as a consequence of the natural processes.The analysis of biogeochemical markers showed that autochthonous compounds produced by phytoplankton predominated in the spring–summer period.Subsequently,they had less importance,and the main share was accounted for allochthonous n-alkanes.
文摘BACKGROUND The numbers of mandibular first premolar roots and root canals vary,and the incidence of three roots and three canals is 0.09%.CASE SUMMARY In this article,we review the root and root canal conditions for the mandibular first premolar and report the case of a mandibular left first premolar with three roots and three canals in a male patient,with suggestions for clinical diagnosis and treatment.The patient was referred by an orthodontist for the extraction of the tooth.Preoperative cone-beam computed tomography examination revealed that it had three roots.Under local anesthesia,the extraction socket was carefully expanded,and the tooth was successfully removed intact using forceps.The procedure was uneventful,with no root fractures,postoperative bleeding,or sensory abnormality observed.CONCLUSION The mandibular first premolar is characterized by multiple roots and canal variations that can increase the difficulty of treatment.
文摘BACKGROUND Early anal canal cancer is frequently treated with endoscopic submucosal dis-section(ESD)to preserve anal function.However,if the lesion is in the anal canal,then significant difficulties such as bleeding and challenges associated with scope manipulation can arise.CASE SUMMARY A 70-year-old woman undergoing follow-up after transverse colon cancer surgery was diagnosed with anal canal cancer extending to the dentate line.The patient underwent a combination of ESD and transanal resection(TAR).The specimen was excised in pieces,which resulted in difficulty performing the pathological evaluation of the margins,especially on the anal side where TAR was performed and severe crushing was observed.Careful follow-up was performed,and local recurrence was observed 3 years postoperatively.Because the patient had super-ficial cancer without lymph node metastasis,local resection was performed again.The second treatment attempt was improved as follows:(1)TAR and ESD were performed appropriately based on the situation by the same physician;(2)A needle scalpel was used during TAR to prevent tissue crushing;and(3)The lesion borders were marked using ESD techniques before treatment.Complete resection was performed without complications.CONCLUSION Anal canal lesions can be safely and reliably removed when ESD and TAR are used appropriately.
基金supported by the Russian Science Foundation,grant number 23-26-00128,“The role of the irrigation system of the North Crimean Canal in the transfer of long-lived radionuclides of Chernobyl origin,heavy metals,as well as hydrocarbons from the Dnieper water to irrigated farmlands of the Crimea.”。
文摘The main objectives of this study were to investigate the distribution features of the ^(210)Po in abiotic(water and bottom sediments)and biotic(zooplankton,mollusks,fish)components of the North Crimean Canal(NCC)aquatic ecosystem and adjacent irrigated soils as well as assessment of the doses received by water organisms from α-radiation of absorbed ^(210)Po.The samples were processed using standard radiochemical methods accepted in international practice.The activity of ^(210)Po in the samples was measured using the alpha-spectrometric OCTETE Plus complex(ORTEC-AMETEK,USA).The measurement error did not exceed 20%.Activity concentration of ^(210)Po in the studied objects decreased in the following rank:suspended matter(73.6 Bq/kg d.w.)>soils(32.5 Bq/kg d.w.)≈bottom sediments(32.1 Bq/kg d.w.)>mollusks(23.4 Bq/kg w.w.)>fish(6.4 Bq/kg w.w.).The ^(210)Po distribution coefficient(K_(d))values in water between suspended matter and its dissolved parts varied within the 1.4×10^(4)-1.4×10^(5) L/kg range.The concentration factors(CF)of ^(210)Po for hydrobionts of the NCC were in the range 10^(3)-10^(4) L/kg.The calculated absorbed radiation doses from ^(210)Po alpha radiation for the hydrobionts of the North Crimean Canal were significantly below the recommended dose limits.
基金supported by the Key Basic Research Projects of Basic Strengthening Plan under Grants 2017-JCJQ-ZD-004
文摘In order to analysis the distribution characteristics of in-bore magnetic field for C-shaped armature electromagnetic railgun, a computational model considering dynamic contact pressure is established. By solving the dynamic equation, the in-bore motion characteristics of the armature are obtained. The distribution of current in the rail and armature is analyzed based on the magnetic diffusion equation and Ampere’s law. On this basis, three simulation models are proposed, which correspond to static state,motion state and motion state considering the velocity skin effect. The magnetic field of the investigated points along the central axes of the armature front end are obtained. The results show that, in static state,the peak magnetic flux density of each investigated point is greater than the other two states. Velocity skin effect leads to a decrease in peak magnetic flux density. The change of motion state has little influence on the peak magnetic flux density of the investigated point that far away from the armature. The calculated results can be used in the electromagnetic shielding design of intelligent ammunition.
文摘Ultra wide bands antennas with notched bands characteristics have recently been considered for efficient communication between devices. In this paper, a compact ultra-wideband antenna (UWB) for UWB applications with triple bandnotched characteristics is presented. The proposed antenna consists of a square patch with four truncated corners and a partial ground plane with a rectangular slit. The operation bandwidth of the designed antenna is from 2.66 GHz to more than 13.5 GHz. Band-notched characteristics of antenna to reject the frequency band of 3.18 - 3.59 GHz and 4.70 - 5.88 GHz, is realized by inserting two C-shaped slots in the patch, the third band of 9.54 - 12.22 GHz is achieved by slottype capacitively-loaded loop (CLL) inserted in the patch near the feed line. Details of the proposed antenna design and simulated results are presented and discussed.
基金This research was funded by the Ministry of Higher Education Malaysia via the Fundamental Research Grant Scheme(FRGS/1/2020/WAB03/UPM/02/1)。
文摘Tropical peat comprises decomposed dead plant material and acts like a sponge to absorb water,making it fully saturated.However,drought periods dry it readily and increases its vulnerability to fire.Peat fires emit greenhouse gases and particles contributing to haze,and prevention by constructing fire-break canals to reduce fire spread into forest reserves is crucial.This paper aims to determine peat physical and chemical properties near a fire-break canal at different fire frequency areas.Peat sampling was conducted at two forest reserves in Malaysia which represent low fire frequency and high fire frequency areas.The results show that peat properties were not affected by the construction of a fire-break canal,however lignin and cellulose content increased significantly from the distance of the canal in both areas.The study concluded that fire frequency did not significantly influence peat properties except for porosity.The higher fibre content in the high frequency area did not influence moisture content nor the ability to regain moisture.Thus,fire frequency might contribute differently to changes in physical and chemical properties,hence management efforts to construct fire-break canals and restoration efforts should protect peatlands from further degradation.These findings will benefit future management and planning for forest reserves.
文摘BACKGROUND We report a rare case of cervical spinal canal penetrating trauma and review the relevant literatures.CASE SUMMARY A 58-year-old male patient was admitted to the emergency department with a steel bar penetrating the neck,without signs of neurological deficit.Computed tomography(CT)demonstrated that the steel bar had penetrated the cervical spinal canal at the C6–7 level,causing C6 and C7 vertebral body fracture,C6 left lamina fracture,left facet joint fracture,and penetration of the cervical spinal cord.The steel bar was successfully removed through an open surgical procedure by a multidisciplinary team.During the surgery,we found that the cervical vertebra,cervical spinal canal and cervical spinal cord were all severely injured.Postoperative CT demonstrated severe penetration of the cervical spinal canal but the patient returned to a fully functional level without any neurological deficits.CONCLUSION Even with a serious cervical spinal canal penetrating trauma,the patient could resume normal work and life after appropriate treatment.
文摘On the occasion of the 10th anniversary of the Grand Canal's application for the World Heritage status in 2024,with the strong support of the Department of International Cooperation of the National Radio and Television Administration and the International Tourism Alliance of Silk Road Cities.
文摘Introduction: The choice of adopting unilateral pedicle screw fixation or using bilateral pedicle screw fixation in lumbar spinal stenosis remains controversial. In our context, very few studies have been performed comparing the clinical effectiveness of unilateral versus bilateral fixation in the surgical management of lumbar spinal canal stenosis. Objective: Evaluate the impact on quality of life and clinical efficacy of unilateral spondylodesis compared to bilateral spondylodesis in the surgical management of lumbar spinal canal stenosis at the Yaounde Central Hospital. Methods: This was a retrospective descriptive cross-sectional study for a period of 4 years, from June 2015 to June 2019. It involved all patients operated for lumbar canal stenosis and who underwent spondylodesis or spinal fusion at the neurosurgery department of the Yaounde Central Hospital. Results: A total of 68 participants were recruited during our study period. 32 (47%) of the study population were in the 50 - 60 age group, with a mean age of 56.98 years ranging from 41 to 75 years. Females, housewives and farmers were the most affected. In our study, 72% of patients had unilateral spondylodesis and 28% had bilateral fusion. Preoperatively, 71% of patients had insurmountable pain, refractory to medical treatment. At 3 months postoperatively, 73.7% of patients with bilateral setup had moderate pain compared to 69% of those with unilateral setup. At 6 months postoperatively, 79% of patients with bilateral fusion had mild pain compared to 82% of patients with unilateral setup. At 1 year postoperatively, all patients had mild pain. Preoperatively, 66.2% of patients were unable to walk and 19.1% of patients were bedridden according to the Oswestry score. At 3 months postoperatively, 10.2% of patients with unilateral setup were unable to walk compared to 10.5% of patients with bilateral fixation, while 67.3% of patients with unilateral fixation had moderate disability compared to 52.6% of patients with bilateral fixation. At 6 months postoperatively, 51% of patients with unilateral setup had moderate disability compared to 47.4% of patients with bilateral fixation, while 42.9% of patients with unilateral fixation had mild disability compared to 42.1% of patients with bilateral fixation. At 1 year postoperatively, 81.6% of patients who underwent unilateral fixation had only mild disability compared to 73.7% of patients with bilateral fixation. Conclusion: The assessment of quality of life according to the set-up used shows similar results at 3 months, 6 months and 1 year, with no statistically significant differences. Single-sided pedicle screw fixation combined with transforaminal lumbar interbody fusion or mounting has the advantage of being faster, with less bleeding and is less expensive compared to bilateral fixation.
文摘This research aims to analyze the communication process between the different participating actors in the port of Balboa,in the Panamanian Pacific.The starting hypothesis begins with the normal operation of the port itself.Considering which strategic actions have potential development and which specific strategic actions are proposed for their improvement,the article begins with a discussion of the nature of ports in Panama and their relationships with the Panama Canal,followed by a literary review of all the effects that climate change may have on navigation on the Panamanian Pacific coast.Next,the implication between the coordination and cooperation between the port,the Panama Canal pilots,and the other actors involved with the arrival and departure of vessels from the port will be analyzed.In a third part,the results of the perception of a significant sample of these actors who were surveyed,which are related to the process,are presented.The document concludes with recommendations on how the Panamanian Pacific port can improve its individual interests through the application of improvements derived from the results of the surveys,for more efficient inter-institutional coordination and cooperation.
文摘On 22 September 2024,under the auspices of China NGO Network for International Exchanges(CNIE),the Chinese Association for International Understanding(CAFIU)and the World Heritage and Canal Cities Cooperation Organisation(WCCO)jointly hosted the Civilisation Lecture Series on"Canal Civilisation and International Exchanges"&Youth Dialogue on Canal Civilisation in Shaoxing.
文摘I extend to all the authorities present and to those who participate in this important event,my respectful greeting,my thanks for the invitation and my congratulations for the inauguration of the Canal Walk within a larger project.
基金Heilongjiang Provincial Key Research and Development Program Project,Grant/Award Number:JD2023SJ46National Natural Science Foundation of China,Grant/Award Number:U20A20318+3 种基金General program of China Post doctoral Fund,Grant/Award Number:2021M690946Major Science and Technology Project of Ministry of Water Resources,Grant/Award Number:SKS-2022095Heilongjiang Provincial Research Institutes Scientific Research Business Fund Project,Grant/Award Number:CZKYF2023-1-A009General program of China Postdoctoral Fund(2021M690946).
文摘In seasonal frozen soil,freezing and thawing can change the physical and mechanical properties and affect slope stability.There are complex moisture conditions in the main water transfer canal.A study of the hydrothermal evolution of canals with different initial water contents under the action of freezing and thawing is of great importance for the prevention and control of canal slope slides.Hydrothermal coupling models are the key to revealing the canal's hydrothermal evolution.As some of the modeling parameters in the current hydrothermal coupling model are based on empirical values,particularly those in the van Genuchten equation,which are not necessarily related to soil properties,they are not suitable for analyzing the hydrothermal evolution of canals.This paper determines the soil-water characteristic curve from the cumulative curve of particle gradation in the subsoil,and then determines the hydraulic parameters of the subsoil using the VG model,which then corrects the hydrothermal coupling model.The method of modifying the hydrothermal coupling model is original,which makes the model more realistically reflect drainage soil characteristics.During freezing and thawing of channel slopes with different initial water contents(21%,25%,29%,33%,37%,and 41%),temperature field,water field,and ice content distributions were investigated.Using the V-G model,the optimal parameters for canal subsoil were a=0.06,n=1.2,and m=0.17,and temperature distribution trends between canals with different water contents were basically similar.Water will accumulate at the bottom as the liquid water content increases at the canal boundary.
