Ensemble GaAsSb/GaAs axial configured nanowire-based separate absorption, charge, and multiplication avalanche near-infrared photodetectors

In this study, molecular beam epitaxially grown axially configured ensemble GaAsSb/GaAs separate absorption, charge, and multiplication (SACM) region-based nanowire avalanche photodetector device on non-patterned Si substrate is presented. Our device exhibits a low breakdown voltage (V _BR) of ∼ -10 ± 2.5 V under dark, photocurrent gain (M) varying from 20 in linear mode to avalanche gain of 700 at V _BR at a 1.064 μm wavelength. Positive temperature dependence of breakdown voltage ∼ 12.6 mV K^-1 further affirms avalanche breakdown as the gain mechanism in our SACM NW APDs. Capacitance-voltage (C-V) and temperature-dependent noise characteristics also validated punch-through voltage ascertained from I-V measurements, and avalanche being the dominant gain mechanism in the APDs. The ensemble SACM NW APD device demonstrated a broad spectral room temperature response with a cut-off wavelength of ∼1.2 μm with a responsivity of ∼0.17-0.38 A W^-1 at -3 V. This work offers a potential pathway toward realizing tunable nanowire-based avalanche photodetectors compatible with traditional Si technology.

Correlation of Pelvic Parameters with Isthmic Spondylolisthesis

Background Spondylolisthesis is one of the major causes of low back pain. The anterior shift of the vertebra is mostly at L4 and L5 levels. Several types have been described, most common being the isthmic type. Pelvic parameters are said to be associated with development and progression of listhesis, and should be evaluated while treating it. Objective To study the correlation of Pelvic parameters with isthmic spondylolisthesis. Method It was a cross sectional case control study. In 68 cases with Isthmic Spondylolisthesis and of 34 cases with low back pain without listhesis (control), the spinopelvic parameters like lumbar lordosis, pelvic incidence, pelvic tilt and sacral slopes were measured together with degree of slip with lateral radiographs. Findings were analyzed and compared with control group. Result In control group, the pelvic incidence was 50.44±4.78o , the sacral slope was 34.38±6.79o , the pelvic tilt was 15.97±5.31o , and the lumbar lordosis was 46.76±6.78o . In Isthmic Spondylolisthesis group, the pelvic incidence was 60.85±6.79o , the sacral slope was 40.40±6.91o , the pelvic tilt was 20.63±7.51o , and the lumbar lordosis was 57.31±7.11o . The difference in spinopelvic parameters amongst control and Isthmic Spondylolisthesis group was statistically significant (p < 0.001). The degree of slip was directly proportional to the pelvic incidence angle (grade I=52o , II =62o and III 72.5o ). Conclusion Spino-pelvic parameters are higher in isthmic spondylolisthesis group and is significantly associated with severity of the slip.

Incidence of Post Operative Wound Infection Following the Use of Antibiotics in Clean Contaminated Head and Neck Surgery in a Tertiary Care Centre in Eastern Nepal

Introduction Post operative wound infection continues to be the major concern even after the appropriate antibiotic coverage.Objective To find out the incidence of post operative wound infection following the use of antibiotics in clean contaminated head and neck surgery in a tertiary care centre in Eastern Nepal.Methodology It is a prospective study conducted at Department of Otorhinolaryngology and Head and Neck Surgery, Nobel Medical  College Teaching Hospital, Biratnagar from 14th April 2013 to 12th April 2015. Patient who underwent clean contaminated head and neck surgery were followed up on 1st, 3rd and 6th post–operative day (POD) and wounds were inspected for any signs of wound infection.Results A total of 144 patients undergoing various clean contaminated head and neck surgeries were included in this study. Tonsillectomy was the commonest surgery performed (40.27%). An overall wound infection rate was 11.80%. Serous discharge rd from the surgical site observed on 3rd post operative day was the most common presentation of wound infection (29.41%). Parotidectomy was the surgery presenting with highest rate of wound infection (31.25%).Conclusion This study concludes that even the best technique and appropriate antibiotic has not completely eliminated the problem of wound infection in clean contaminated head and neck surgery.Birat Journal of Health Sciences 2016 1(1): 51-55

Hopelessness and Suicidal Ideation among Patients with Depression and Neurotic Disorders Attending a Tertiary Care Centre at Eastern Nepal

BACKGROUND

Hopelessness is thought to result from a negative appraisal system and interacts with, and worsens, appraisals of defeat and trap which in turn interact with suicide schema and lead to suicidal behaviour. This study was intended to assess hopelessness and suicidal ideation among patients with depression and neurotic disorders at tertiary care centre of eastern Nepal.

METHODS

A cross sectional design included 70 respondents by purposive sampling technique. Beck Hopelessness Scale and Scale of Suicidal Ideation were used to measure hopelessness and suicidal ideation, respectively. Data were analyzed using SPSS statistical software. Pearson chi-square, binary logistic regression and Spearmans' rho, test were applied at 95% confidence interval.

RESULTS

Mean ± SD age was 32.8 ± 13.5 years. Most (62.8%) of the patients were female and with the diagnosis of depression. Majority (66%) of the patients had hopelessness. There was no significant difference in hopelessness among patients with depression and neurotic disorders. About 17% respondents had suicidal ideation, among them 82.4% were female. There was no significant difference of suicidal ideation among patients with depression and neurotic disorders (p=0.013). Significant positive correlation between hopelessness and suicidal ideation was found (p=0.001). Binary logistic regression revealed hopelessness was independently related to income and family history of mental illness. Similarly, suicidal ideation was independently related to depression and family history of mental illness.

CONCLUSIONS

Female respondents, people living under poverty and positive family history of mental illness had more hopelessness and suicidal ideation.

Three-dimensional plastic response in polycrystalline coppervianear-field high-energy X-ray diffraction microscopy

The evolution of the crystallographic orientation field in a polycrystalline sample of copper is mapped in three dimensions as tensile strain is applied. Using forward-modeling analysis of high-energy X-ray diffraction microscopy data collected at the Advanced Photon Source, the ability to track intragranular orientation variations is demonstrated on an ∼2 µm length scale with ∼0.1° orientation precision. Lattice rotations within grains are tracked between states with ∼1° precision. Detailed analysis is presented for a sample cross section before and after ∼6% strain. The voxel-based (0.625 µm triangular mesh) reconstructed structure is used to calculate kernel-averaged misorientation maps, which exhibit complex patterns. Simulated scattering from the reconstructed orientation field is shown to reproduce complex scattering patterns generated by the defected microstructure. Spatial variation of a goodness-of-fit or confidence metric associated with the optimized orientation field indicates regions of relatively high or low orientational disorder. An alignment procedure is used to match sample cross sections in the different strain states. The data and analysis methods point toward the ability to perform detailed comparisons between polycrystal plasticity computational model predictions and experimental observations of macroscopic volumes of material.

Intraoperative Blood Loss & operating time in Tonsillectomy: Is Electrodissection Better?

DOI: 10.3126/njenthns.v1i1.4728 Nepalese J ENT Head Neck Surg Vol.1 No.1 (2010) p.6-7

Relationship between blood group and epistaxis among Nepalese

The relationship between blood group and epistaxis among the patients coming to Tribhuvan University Teaching Hospital, Kathmandu with idiopathic epistaxis was studied. A total of 235 patients coming to the Emergency Department or Department of Otorhinolaryngology with active nose bleeding in were included. ABO blood group was performed. Nearly half (45.5%) of the patients belonged to O-group followed by A-group others. O-group people were also had longer bleeding time compared to other blood groups.

Oesophageal foreign bodies in children

Foreign body ingestion is a common occurrence and carries significant morbidity and mortality. Failure to treat foreign bodies immediately can lead to various serious complications. This study was done to identify the types as well as site of foreign body ingested and its complication in children. A retrospective study of 122 cases of suspected foreign body ingestion in patients admitted in ENT and Head and Neck Surgery of TU Teaching Hospital, Kathmandu were done in between April 2004 to July 2008. Ages less than 12 years were included. In all cases x-ray soft tissue neck lateral and chest x-ray posterio-anterior views were done along with other preoperative investigations. Rigid oesophagoscopy or hypopharyngoscopy were done under general anesthesia to remove foreign bodies. There were 64.7% male and 35.3% female children. Foreign bodies were common in 0-4 year age group. Most common foreign body were coin (64.0%) followed by meat bone (14.0%). No foreign bodies were found in 2.4% patients as they were passed in stomach. No complications were noted during the entire period of this study. Most common foreign bodies in children are coin. Though complications with these foreign bodies are rare, these do occur due to delay in presentation and removal. No complications were noted in our series. Eventhough children who swallow foreign bodies are asymptomatic; we must maintain a high index of suspicion and undergo diagnostic procedure, if there is a positive history.

Ligation of medically refracted patent ductus arteriosus (PDA) in an extremely low body weight premature infant

Medically refracted patent ductus arteriosus (PDA) in an extremely low birth weight (ELBW) preterm (gestation 24 weeks 2 days) infant was successfully ligated under general anesthesia in the neonatal intensive care unit (NICU). Pharmacological agents are more effective to close PDA in preterm infants than in full-term infants, although within 48 h three doses of indomethacin were not sufficient to close PDA in this case. At the age of 69 h the infant developed severe symptoms including bradycardia, systemic hypotension, pulmonary hypertension, diastolic steal (reverse distal aorta flow velocity), and anuria. A PDA ligation was thus performed surgically at 72 h of age. General anesthesia and surgical stress were tolerated by this 531 g infant. Postoperatively all symptoms improved dramatically and the general conditions were stable. On the 38th day the endotracheal tube was extubated and on the 50th day nasogastric milk feeding was started. The oxygen supply was weaned on the 78th day. Growth and development until 6 months were within the normal range of very low birth weight infants. A surgical ligation as early as possible in medically refracted PDA in an ELBW infant is thus considered to be a safe and effective treatment. It prevents the development of further complications of cardiopulmonary vascular problems. Color Doppler echocardiography can reliably measure the PDA size, flow velocity, and hemodynamic changes of persistent PDA, even in tiny infants.