Peat properties of a tropical forest reserve adjacent to a fire-break canal

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.

Steel bar penetrating cervical spinal canal without neurological injury:A case report

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.

The Millennia-Old Canal Takes on a New Look Nihao!China——2024 China's Grand Canal Tourism Overseas Promotion Season

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.

Surgical Management of Lumbar Spinal Canal Stenosis with Instrumentation at the Yaounde Central Hospital: Comparison of Unilateral versus Bilateral Pedicle Screw Fixation Combined with Transforaminal Lumbar Interbody Fusion

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.

Results Analysis of Surveys Made to Stakeholders in the Pacific Ports in the Panama Canal:A Study Focused to Improve the Efficiency of Loading/Discharging Operations

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.

Study on Tissue Culture of Leucophyta brownii ‘Canal Rocks Form’

[Objective] This study aimed to establish a tissue culture technology for Leucophyta brownii ‘Canal Rocks Form’. [Method] Leucophyta brownii ‘Canal Rocks Form’ stems with axillary buds were selected as explants in vitro to investigate the effects of different concentrations of 6-BA and NAA on proliferation culture and the effects of IBA, NAA and subculture cycle on rooting culture. [Result] The results showed that Leucophyta brownii ‘Canal Rocks Form’ plantlets need low concentrations of phytohormones and the rooting culture was significantly affected by the subculture cycle; the optimal medium for proliferation culture was MS＋0.5 mg/L 6-BA＋0.05 mg/L NAA＋30 g/L sucrose＋5.5 g/L agar, with a proliferation coefficient of 4.25; the plantlets with a subculture cycle of 28 d were the most suitable for rooting culture, with a rooting rate of 95.9% in 1/2 MS＋0.1 mg/L IBA＋0.05 mg/L NAA＋20 g/L sucrose＋5.5 g/L agar, and the average number and length of roots were 4.69 and 1.68 cm, respectively. [Conclusion] This study laid the foundation for establishing sterile culture system of Leucophyta brownii ‘Canal Rocks Form’.

Comprehensive evaluation of water quality parameters in Tianjin Dagu Dainage Canal

In this paper, some indices of sulfide, organic carbon, oil and heavy metals （copper, lead, zinc, cadmium, mercury, arsenic and chromium） in the sediments from Dagu Dainage Canal at the Bohai Bay during four seasons in 2012 - 2013 are selected, and Water Quality Pollution Index （API） is applied to evaluate water quality indices, aiming for the systematic evaluation of the water quality of Dagu Dainage Canal. The results showed that four stations of D3, D6, D7and D9 for S2 had the type Ⅱand Ⅲ of water; others had the type Ⅰ ; the total level of TOC, TPH, Cu, Pb, Zn, Cd, Hg, As and Cr were type Ⅰ, Ⅳ, Ⅱ, Ⅴ, Ⅱ, Ⅴ, Ⅲ, Vand Ⅴ. Water Quality Pollution Index （API） was 3.28, which illustrated Dagu Dainage Canal was in the state of contamination and the degree of pollution exceeded the standard functional areas.

Ecological Design of Flood Discharging Canals in Shijiazhuang City

From the perspective of ecological conservation and satisfaction of people's visual and psychological demands,existing problems in the urban revetment were analyzed,and the connotation of ecological revetment as well as the selection of different ecological revetments according to different types of river ways was discussed.

Tooth anatomy risk factors influencing root canal working length accessibility

The aim of this study was to analyze the specific influence of root canal anatomy on the accessibility of working length during root canal therapy. Four hundred seventy-six root canal therapy cases （amounting to a total of 1 005 root canals） were examined. The anatomy risk factors assessed in each case included： tooth type （tooth location）, root canal curvature, and root canal calcification, as well as endodontic retreatment. The investigation examined the correlation between each of these anatomic factors and the working length, with statistical analysis consisting of Chi-square tests and multiple logistic regression analysis. In an independent factor analysis, tooth type （tooth iocation）, root canal curvature, canal calcification, and endodontic retreatment were determined to be the primary risk factors. In a multiple-factor regression model, root curvature and canal calcification were found to most significantly influence root canal working length accessibility （P〈0.05）. Root canal anatomy increases the difficulty of root canal preparation. Appropriate consideration of tooth anatomy will assist in accurate determination of preparation difficulty before instrumentation. This study alerts clinical therapists to anatomical factors influencing the working length accessibility, and allows for a direct estimate of success rate given in situ measurements of tooth factors during the root canal treatment procedure.

Effect of vasectomy via inguinal canal on spermatogenesis in rabbits

Aim： To determine whether vasectomy away from the epididymal tail （via the inguinal canal） in rabbits can reduce the early postoperative effects on spermatogenesis. Methods： Twenty-nine normal male Japanese white rabbits （aged 4- 6 months） were subjected to unilateral close-ended （conventional） or open-ended （the cut end of the juxta-epididymal vas deferens not ligated） vasectomy via the inguinal canal. Ten days and 3 months after operation, testes, epididymides and vasa deferentia were removed and methacrylate resin-embedded sections prepared. The histology of the testis, epididymis and vas deferens was examined under light microscope, and the volume and diameter of the seminiferous tubules were quantitatively studied using stereological methods. Results： Neither of the methods of vasectomy led to apparent damage to spermatogenesis on the vasectomized side in comparison with the contralateral shamoperated side, but the juxta-epididymal vas deferens on the vasectomized side was highly distended and contained numerous sperm 3 months after operation. Conclusion： Vasectomy away from the cauda epididymis has no significant early postoperative effects on spermatogenesis in rabbits.

An in vitro study on the efficacy of removing calcium hydroxide from curved root canal systems in root canal therapy

To compare the efficacy of various irrigants(citric acid, ethylenediaminetetraacetic acid(EDTA) and Na OCl) and techniques in removing Ca(OH)2in two types of curved root canal systems, simulated root canals with specific curvatures were used to investigate the effects of different irrigants and instruments on Ca(OH)2removal. The optimal methods were verified on extracted human teeth. Simulated root canals were assigned to one of two groups based on the irrigation solution: 10% citric acid or2.5% Na OCl. Each group was divided into four subgroups according to the technique used to remove Ca(OH)2. The percentage of Ca(OH)2removal in different sections of root canals was calculated. On the basis of the results obtained for the simulated canals, 10% citric acid and 17% EDTA were applied to remove Ca(OH)2from the extracted human teeth with curved root canal systems. The teeth were scanned by micro computed tomography to calculate the percentage of Ca(OH)2removal in the canals.In simulated root canals, we found that 10% citric acid removed more Ca(OH)2than 2.5% NaOCl in the 0–1 mm group from the apex level(Po0.05). Ultrasonic and Endo Activator activation significantly removed more Ca(OH)2than a size 30 K file in the apical third(Po0.05). However, there were no significant differences in any sections of the canals for 10% citric acid or 17%EDTA in removing Ca(OH)2in extracted human teeth. We concluded that it was effective to remove residual Ca(OH)2using the decalcifying solution with Endo Activator or Passive Ultrasonic Irrigation in a curved root canal system. A protocol for Ca(OH)2removal was provided based on the conclusions of this study and the methods recommended in previous studies.

Pathophysiology, diagnosis and treatment of intermittent claudication in patients with lumbar canal stenosis

Spinal nerve roots have a peculiar structure, different from the arrangements in the peripheral nerve. The nerve roots are devoid of lymphatic vessels but are immersed in the cerebrospinal fluid(CSF) within the subarachnoid space. The blood supply of nerve roots depends on the blood flow from both and peripheral direction(ascending) and the spinal cord direction(descending). There is no hypovascular region in the nerve root, although there exists a so-called water-shed of the bloodstream in the radicular artery itself. Increased mechanical compression promotes the disturbance of CSF flow, circulatory disturbance starting from the venous congestion and intraradicular edema formation resulting from the breakdown of the blood-nerve barrier. Although this edema may diffuse into CSF when the subarachnoid space is preserved, the endoneurial fluid pressure may increase when the area is closed by increased compression. On the other hand, the nerve root tissue has already degenerated under the compression and the numerous macrophages releasing various chemical mediators, aggravating radicular symptomsthat appear in the area of Wallerian degeneration. Prostaglandin E1(PGE1) is a potent vasodilator as well as an inhibitor of platelet aggregation and has therefore attracted interest as a therapeutic drug for lumbar canal stenosis. However, investigations in the clinical setting have shown that PGE1 is effective in some patients but not in others, although the reason for this is unclear.

Incidence of C-shaped root canal systems in mandibular second molars in the native Chinese population by analysis of clinical methods

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.

Root canal morphology and configuration of 123 maxillary second molars by means of micro-CT

The aim of this study was to investigate the root canal configuration, accessory canals and number of main foramina of 123 maxillary second molars by means of micro-computed tomography. The teeth were scanned and reproduced with 3D software imaging. The root canal configuration and number of main foramina were evaluated by means of a four-digit system. The morphological complexity of human maxillary second molars is depicted by the number of accessory and connecting canals. The most frequently observed root canal configurations in the mesiobuccal root were 2-2-2/2 （19.5%）, 2-2-1/1 （14.6%） and 2-1-1/1 （13.0%）. A 1-1-1/1 configuration was observed in 93.5% and in 96.7% in the distobuccal and palatal roots, respectively. The MB1 mot canal had one accessory canal （18.7%）, and 8.9% of the MB2 root canal had one or two accessory canals. The distobuccal （11.3%） and palatal （14.6%） root canals had at least one accessory canal, and connecting canals were observed in 16.3% of mesiobuccal roots. The MB1, MB2, distobuccal and palatal root canals had one main foramen in 99.2%, 43.1%, 98.4% and 99.2% of samples, respectively. In the mesiobuccal root, one accessory foramen was detected in 14.6%, two were detected in 7.3%, and three were detected in 5.7%. The distobuccal root showed one or two accessory foramina in 9.1% of samples. The root canal configuration of maxillary second molars is quite heterogeneous; the mesiobuccal root has predominantly two root canal entrances （58.4%, 1 in 41.1%） with one main foramen （54.4%）. Two main foramina were observed in 43.0%. Morphological variations, connecting and accessory canals were observed in all apical thirds.

Efficacy of Solution Form of Ethylenediaminetetraacetic Acid on Removing Smear Layer of Root Canal at Different Exposure Time In Vitro

Summary： This study was aimed to evaluate the effectiveness of solution form of 17% ethylenediaminetetraacetic acid （EDTA） on removing smear layer of root canals at different exposure time periods and to provide scientific basis for EDTA as a choice of root canal irrigation in clinical practice. Twenty-five single-rooted teeth were randomly divided into 5 groups： control group （group A） was given 2.5% NaOC1, and 4 experimental groups were given 2.5% NaOC1 and 17% EDTA, including groups B, C, D and E with exposure time of 1, 3, 5 and 7 min, respectively. After preparation of the root canals, the teeth were split along their longitudinal axis, and the root sections were examined under scanning elec- tron microscope for evaluation of smear layer removal and erosion on the surface of the root canal walls. The specimens in group B showed presence of smear layer on the walls of the root canal with no statistical difference from that in group A （P〉0.05）. In groups C and D, partial removal of smear layer was obtained, and there was no significant difference between the two groups （P〉0.05）, but there was significant difference in removal of smear layer between group C and group B （P〈0.05）. Root canal walls in group E specimens showed almost complete removal of smear layer, and the removal of smear layer was significantly different from that in group D （P〈0.01）. There was no significant change in the structure of the surface of root canal for each sample. It was concluded that combined irrigation with 17% EDTA and 2.5% NaOC1 could remove the smear layer with no significant alteration in dentinal structure when the chelating agent was applied for 7 min. At 3 and 5 min of application, partial removal of smear layer was observed and at 1 min negligible removal of smear layer was achieved.

Effect of restoration technique on resistance to fracture of endodontically treated anterior teeth with flared root canals

This study was designed to compare the impact of post and core systems on resistance to fracture of endodontically treated anterior teeth with flared root canals and to assess their fracture pattern. Sixty central incisors were cut horizontally 2 mm coronal to the cementoenamel junction(CEJ). After root canal therapy, teeth were assigned into 6 groups(n = 10 each) based on a post system and used as follows: Group C, non-flared root received size #1 glass fiber posts(Control); Group AP, flared root restored with anatomical post; Group RC, flared root restored with size #1 fiber post and cemented with thick layer of resin cement; Group CR, flared root restored with size #1 and reinforced with composite resin; Group CM, cast post-core; Group CP, CAD/CAM polymer-infiltrated ceramic post and core.Following post cementation, core build-up and crown insertion, the specimens were thermo-cycled up to 10,000 cycles(5 C/55 C; 30 seconds dwell time, 6 seconds transition time) and then statically loaded at 1 mm/minute crosshead speed using a universal testing machine. One-way ANOVA and Tukey HSD post hoc test(α= 0.05) were used for data analysis. Group C recorded significantly higher resistance to fracture values [(826.9±39.1) N] followed by group CP [(793.8±55.6) N] while group RC yielded the lowest fracture resistance values [(586.7±51.4) N]. The resistance to fracture of wide root canals can be enhanced by using one-piece CAM/CAM post and core as an alternative to the use of either glass fiber post, relined with composite resin increasing the thickness of luting cement or the use of cast post and core system. However, this was an in vitro investigation and further in vivo studies are necessary.

Quick repositioning maneuver for horizontal semicircular canal benign paroxysmal positional vertigo

Objective:To investigate the efficacy of quick repositioning maneuver for horizontal semicircular canal benign paroxysmal positional vertigo (H-BPPV). Methods:Clinical data of 67 patients with H-BPPV who underwent quick repositioning maneuver in our hospital from July 2009 to November 2014 were retrospectively analyzed. The maneuver involved rotating the patient in the axial plane for 180? from the involved side towards contralateral side as quickly as possible. Results:Complete symptom resolution was achieved in 61 patients (91.0%) at one week and in 64 patients (95.5%) at 3 months post-treatment. During the repositioning maneuver process, there were no obvious untoward responses except transient nausea with or without vomiting in a few patients. Conclusion:The results indicate that the quick repositioning maneuver is an easy and effective alternative treatment in the management of H-BPPV. Copyright ? 2015 The Authors. Production & hosting by Elsevier (Singapore) Pte Ltd On behalf of PLA General Hospital Department of Otolaryngology Head and Neck Surgery. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Cone-beam computed tomography analysis of curved root canals after mechanical preparation with three nickel-titanium rotary instruments

Cone beam computed tomography is a 3-dimensional high resolution imaging method. The purpose of this study was to compare the effects of 3 different NiTi rotary instruments used to prepare curved root canals on the final shape of the curved canals and total amount of root canal transportation by using cone-beam computed tomography. A total of 81 mesial root canals from 42 extracted human mandibular molars, with a curvature ranging from 15 to 45 degrees, were selected. Canals were randomly divided into 3 groups of 27 each. After preparation with Protaper, Revo-S and Hero Shaper, the amount of transportation and centering ability that occurred were assessed by using cone beam computed tomography. Utilizing preand post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Canals were metrically assessed for changes （surface area, changes in curvature and transportation） during canal preparation by using software SimPlant; instrument failures were also recorded. Mean total widths and outer and inner width measurements were determined on each central canal path and differences were statistically analyzed. The results showed that all instruments maintained the original canal curvature well with no significant differences between the different files （P=0.226）. During preparation there was failure of only one file （the protaper group）. In conclusion, under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. Areas of uninstrumented root canal wall were left in all regions using the various systems.

Prognostic factors of trans-ethmosphenoid optic canal decompression for indirect traumatic optic neuropathy

AIM： To investigate a possible correlation between visual acuity（VA） prognosis and the presence at baseline of various orbital and ocular signs in patients affected by indirect traumatic optic neuropathy（ITON）. METHODS： From July 1 st, 2012 to July 1 st, 2015, 224 adults diagnosed with ITON who underwent endoscopic transethmosphenoid optic canal decompression（ETOCD） were reviewed. Visual outcome before and after treatment were taken into comparison. RESULTS： Accompanied older in age, longer time to medical treatment and existence of optic canal fracture（OCF） were the independent predictors for poor postoperative VA and lower improvement degree of visual acuity（IDVA）, while worse preoperative VA was predictive factor for poor postoperative VA only. Mean value of IDVA in patients with OCF was 0.19±0.30. Mean value of IDVA in patients without OCF was 0.29±0.35. IDVA in cases without OCF was significant higher than those with OCF（t=2.272, P〈0.05）. CONCLUSION： Patients suffered from ITON without OCF before ETOCD have better surgical outcome than those with OCF. Older in age, longer time to medical treatment and existence of OCF are independent factors for poor VA prognosis and lower IDVA. Preoperative VA is independent factor for VA prognosis only.

Post-inflammatory acquired atresia of the external auditory canal

Acquired atresia of the external auditory canal(EAC)is a rare cause of conductive hearing loss.It has been traditionally classified into 4 categories:traumatic,post-operative,neoplastic and inflammatory.Post-inflammatory acquired auditory canal atresia is thought to be the result of chronic and repetitive infectious bouts affecting the auditory canal.Nevertheless,the underlying pathophysiology of this disorder is yet to be fully elucidated.Current data fail to clearly state the impact that certain underlying systemic disorders may have on the EAC.The possible association to metabolic disturbances such as iron deficiency is also emphasized.In the light of these findings,this analysis can be used to improve the classification of this entity thereby standardizing the assessment of therapeutic approaches.