Miniaturized double transit magnetic field measurement probe using the Faraday rotation principle.

This paper presents the design and experimental results of a double transit magnetic field measurement probe based on the Faraday rotation principle using terbium doped borosilicate glass as a sensor element. When the magnetic field is applied in the direction of propagation of light through the glass, the Faraday effect produces non-reciprocal circular birefringence. This property of the Faraday effect adds rotations when the light beam is reflected using a mirror placed at the other end of the glass and passed through the glass, making double transit of light through the sensor element. Experiments were carried out to verify the characteristics of the designed probe by inserting it inside the solenoid load coil. The Verdet constant of the glass is determined using the slope of the linear least-squares fitted curve between the Faraday rotation angle and the applied magnetic field, obtained as 89.22r a d/(T⋅m) with a relative uncertainty of 2.43%. The magnetic field was measured with 0.28% accuracy. In the optics experiments, alignment of components is the major task. To the authors' knowledge, this is the first of its kind double transit miniaturized magnetic field measurement probe configuration in which components are aligned inside the single probe structure. The probe is easily portable and can be used in inaccessible locations in various applications such as accelerators, Z/θ pinch devices, or fusion reactors such as tokamaks, in which the magnetic field is one of the main parameters.

Influence of tillage based crop establishment and residue management practices on soil quality indices and yield sustainability in rice-wheat cropping system of Eastern Indo-Gangetic Plains.

Rice-wheat cropping system (RWCS) is the most important system occupying around 26 M ha spread over the Indo Gangetic Plains in South Asia and China. Many long-term trials were led to assess the agronomic productivity and economic profitability of various combinations of conservation agricultural (CA) practices (zero tillage, residue management and crop establishment) in RWCS of Eastern Indo-Gangetic Plains (EIGP) of India. The purpose of this study was to investigate the best management practices involving different tillage-based crop establishment and residue retention techniques and their contribution to agricultural system sustainability through improvement in soil health by developing soil quality index (SQI). We have used SQI as an instrument based on physical [macro aggregate stability (MAS), available water capacity (AWC) and soil penetration resistance (SPR)], chemical [soil organic carbon (OC), available N, available P and available K] and biological [microbial biomass carbon (MBC), fluorescein diacetate (FDA) and dehydrogenase activity (DHA)] properties of soil, because these are very useful indicators of soil's functions for agronomic productivity and soil fertility. Soil properties like MAS, OC, MBC, FDA and DHA were higher by 47, 18, 56, 48 and 53%, respectively, under ZTDSR-ZTW (T7: Zero-till direct seeded rice - Zero-till wheat) than RPTR-CTW (T1: Random puddled transplanted rice - Conventional till broadcasted wheat), at 0-10 cm. CA based treatment T7 also recorded lower SPR (126 N cm-1). SQI for different treatments were calculated by performing principal component analysis based on the total data set method. The higher system rice equivalent yield of 12.41 t ha-1 was observed at SQI value of 0.90 at 0-10 cm and 0.86 at 10-20 cm in T7. It can be concluded that crop residue retention on the surface with zero tillage is beneficial for the sustainability and productivity of the RWCS in EIGP of India.

Gregarine infection accelerates larval development of the cat flea Ctenocephalides felis (Bouché).

A high degree of specialization between host and parasite is a well-known outcome of a long history of coevolution, and it is strikingly illustrated in a coordination of their life cycles. In some cases, the arms race ensued at the establishment of a symbiotic relationship results in the adoption of manipulative strategies by the parasite. We have already learned that Steinina ctenocephali, a gregarine living in the alimentary canal of cat flea, Ctenocephalides felis follows its phenology and metamorphosis. Despite these findings the outcome of their symbiotic partnership (mutualist, parasitic or commensal) remains unclear. To address this important question, we measured life history parameters of the flea in the presence of varying infection intensities of gregarine oocysts in laboratory conditions. We found that neither the emergence nor survival rate of fleas was affected by harbouring the gregarines. More surprisingly, our results show that flea larvae infected with gregarines developed faster and emerged earlier than the control group. This gregarine therefore joins the selected group of protists that can modify physiological host traits and provides not only new model taxa to be explored in an evolutionary scenario, but also potential development of control strategies of cat flea.

Vismodegib: the first drug approved for advanced and metastatic basal cell carcinoma.

Treatment of basal cell carcinoma (BCC) usually involves surgical interventions and laser ablation, but in locally advanced BCC, which arise either from earlier untreated lesions or from recurrence of aggressive BCC, surgery and radiotherapy are not helpful. Vismodegib, the first oral-targeted therapy for locally advanced and metastatic BCC, unsuitable for surgery or radiotherapy, was recently approved by US Food and Drug Administration (FDA). The drug was under the priority review program of FDA and was approved on the basis of promising results of phase II trial. Vismodegib acts by targeting the hedgehog pathway, which is activated abnormally in most BCCs. Approval of vismodegib is a big step ahead in the treatment of advanced BCC, where there was no other effective drug therapy till now.

Purification and characterization of pectin lyase secreted by Aspergillus flavus MTCC 10938.

An indigenously isolated fungal strain Aspergillus flavus MTCC 10938 was subjected to pectin lyase (PNL) production under submerged fermentation conditions. The enzyme was purified to homogeneity from the culture filtrate of the fungus involving concentration by ultrafiltration, anion exchange chromatography on DEAE cellulose and gel filtration chromatography on Sephadex G-100. The purified PNL gave a single protein band in SDS-PAGE analysis with a relative molecular mass corresponding to 50 kDa. Using citrus pectin as the substrate the K(m) and k(cat) values of the enzyme lyase were obtained as 1.7 mg/mL and 66 s(-1), respectively. The optimum pH of the purified PNL from A. flavus MTCC 10938 was 8.0 and up to 90% of its activity retained in the pH range from 3.0 to 11.0 after 24 h incubation. The optimum temperature of the purified enzyme was revealed at 55 degrees C and it was completely stable up to 40 degrees C when exposed for 30 min. The purified A. flavus MTCC 10938 PNL showed efficient retting of Crotalaria juncea fibres.

Paroxysmal neuralgia in pediatric population--a diagnostic dilemma for physicians and dental practioners.

Paroxysmal neuralgia is relatively uncommon in children. Neuropathic orofacial pain is a challenge for the clinician, as no obvious dental pathology exists either clinically or radiographically. Dentist and physician should be able to recognize the characteristics of neuropathic pain so as to correctly diagnose these conditions hence avoid unnecessary dental intervention. This article reviews the conditions with paroxysmal neuralgia in children and available treatment strategies.

Modular electromagnetic railgun accelerator for high velocity impact studies.

A modular electromagnetic railgun accelerator facility named "RAFTAR" (i.e., Railgun Accelerator Facility for Technology and Research) has been commissioned and its performance has been characterized for high velocity impact testing on materials in a single-shot mode. In the first tests, RAFTAR demonstrated an acceleration of more than 1000 m/s for an 8 g solid aluminum-7075 armature projectile. The current fed was 220 kA, having a muzzle time of about 1.75 ms. It is a single pulse breech-fed rectangular bore (14 × 13 mm2) railgun, and its 1.15 m long barrel assembly consists of two parallel copper bars with an inter-gap of 13 mm that are encased within 50 mm thick high strength reinforced fiberglass sheets (Garolite G10-FR4) and bolted from both the sides. RAFTAR is powered by two capacitor bank modules that have a maximum stored energy of 160 kJ each (containing eight 178 µF/15 kV capacitors), two high power ignitron switches, and a pulse shaping inductor. To obtain consistent acceleration of the armature inside the barrel, reversal of driving current is prevented, and its pulse duration is stretched by tactical integration of the crowbar switch and bitter coil inductor in the circuit. Armature projectile velocity measurement in-bore and outside in free space was performed by the time-of-flight technique using indigenously made miniature B-dot sensors and a novel shorting-foil arrangement, respectively. The time resolved measurement of the in-bore armature evidenced a velocity-skin-effect in the high acceleration phase. There is good agreement between the experimentally measured and theoretically predicted efficiency, confirming the optimal choice of operating parameters. The conclusion summarizes important experimental findings and analyzes the underlying causes that limit the performance of railguns.

Biological cell-electrical field interaction: stochastic approach.

The present work demonstrates how a stochastic model can be implemented to obtain a realistic description of the interaction of a biological cell with an external electric field. In our model formulation, the stochasticity is adopted by introducing various levels of forcing intensities in model parameters. The presence of noise in nuclear membrane capacitance has the most significant effect on the current flow through a biological cell. A plausible explanation based on underlying physics and biological structure of the nuclear membrane is proposed to explain such results.

Human occupation of northern India spans the Toba super-eruption ~74,000 years ago.

India is located at a critical geographic crossroads for understanding the dispersal of Homo sapiens out of Africa and into Asia and Oceania. Here we report evidence for long-term human occupation, spanning the last ~80 thousand years, at the site of Dhaba in the Middle Son River Valley of Central India. An unchanging stone tool industry is found at Dhaba spanning the Toba eruption of ~74 ka (i.e., the Youngest Toba Tuff, YTT) bracketed between ages of 79.6 ± 3.2 and 65.2 ± 3.1 ka, with the introduction of microlithic technology ~48 ka. The lithic industry from Dhaba strongly resembles stone tool assemblages from the African Middle Stone Age (MSA) and Arabia, and the earliest artefacts from Australia, suggesting that it is likely the product of Homo sapiens as they dispersed eastward out of Africa.

Synthesis and characterization of monodispersed water dispersible Fe3O4 nanoparticles and in vitro studies on human breast carcinoma cell line under hyperthermia condition.

Monodispersed Fe3O4 magnetic nanoparticles (MNPs) having size of 7 nm have been prepared from iron oleate and made water dispersible by functionalization for biomedical applications. Three different reactions employing thioglycolic acid, aspartic acid and aminophosphonate were performed on oleic acid coated Fe3O4. In order to achieve a control on particle size, the pristine nanoparticles were heated in presence of ferric oleate which led to increase in size from 7 to 11 nm. Reaction parameters such as rate of heating, reaction temperature and duration of heating have been studied. Shape of particles was found to change from spherical to cuboid. The cuboid shape in turn enhances magneto-crystalline anisotropy (Ku). Heating efficacy of these nanoparticles for hyperthermia was also evaluated for different shapes and sizes. We demonstrate heat generation from these MNPs for hyperthermia application under alternating current (AC) magnetic field and optimized heating efficiency by controlling morphology of particles. We have also studied intra-cellular uptake and localization of nanoparticles and cytotoxicity under AC magnetic field in human breast carcinoma cell line.

Molecular variants and derivatives of insulin for improved glycemic control in diabetes.

Insulin is a historic molecule. It presents many first instances, such as the first protein to be fully sequenced, one of the first proteins to be crystallized in pure form, one among the early proteins whose structure was investigated using X-ray crystallography, the first protein to be chemically synthesized and the first Biotech drug. Therefore, the development of insulin in the early years is intricately intertwined with the progress in molecular and structural biology. In recent years, development of a range of insulin analogs has led to better control of glucose levels, thus preventing secondary complications and improving the quality of life in diabetic patients. Such analogs were obtained by modification of the native insulin sequence. They vary with regard to their pharmacokinetic profile, stability, tissue specificity and mode of administration. In addition, alterations involving incorporation of various chemical moieties in insulin and its co-crystallization with insoluble derivatives are used to modulate the time-action profile of the drug. This article traces the development of molecular variants and derivatives of insulin. It discusses future directions for further improvement in their properties to produce still better insulin therapeutics for tight glycemic control.

Prescribing patterns in the orthopaedics outpatient department in a teaching hospital in Pokhara, western Nepal.

OBJECTIVES: Information on the utilization patterns of drugs in the orthopaedics outpatient department (OPD) are lacking in hospitals in western Nepal. The present study was carried out to obtain demographic information about the respondents selected for analysis, information on the average number of drugs prescribed and the average cost of drugs per prescription. The prescriptions were critically analyzed using predetermined criteria. MATERIALS AND METHODS: The study was carried out over a four-month period (01.09.2002 to 31.12.2002) at the Manipal Teaching hospital, Pokhara, Nepal. The percentage of encounters with an injection or an antibiotic prescribed was noted. The percentage of drugs prescribed from the Essential drug list of Nepal and the mean cost of drugs per prescription was calculated. RESULTS: 1238 patients attended the orthopaedics OPD during the study period. 186 prescriptions were randomly selected for analysis. The mean number of drugs per prescription was 1.9. Low backache was the most common reason for attending the OPD. Nonsteroidal anti-inflammatory drugs (NSAIDs) were the most commonly prescribed drug group. Diclofenac and meloxicam were the most commonly prescribed drugs. Mean cost of drugs was 166.2 Nepalese rupees. Injections and antibiotics were prescribed in 16 (8.6%) and 7 (3.8%) encounters respectively. 51 prescriptions (27.4%) had various problems. Absence of diagnosis on the prescriptions and the duration of treatment were most commonly observed. CONCLUSIONS: Percentage of prescribing by generic name was low. Educational sessions for the doctors at different levels to encourage prescribing by generic names and on correct writing of prescriptions may be considered. Studies covering a larger number of patients and for a longer time period are required. A greater number of patients can be studied, seasonal variations can be overcome and drug utilization can be measured quantitatively.

Knowledge about heart attack and hypertension among individuals attending a cardiac camp in Pokhara city.

OBJECTIVES: Previous studies in other countries had shown lacunae in patients' and general publics' understanding of cardiovascular diseases. Such studies are lacking in Nepal. Hence the present study was carried out to: a) note the respondent's knowledge regarding myocardial infarction and hypertension and b) note the association, if any, of the knowledge with demographic and personal characteristics. MATERIALS AND METHODS: Respondents attending a cardiac camp organized in the Manipal Teaching hospital during September 2002 were interviewed by previously briefed seventh semester students using a structured questionnaire. Basic demographic information and knowledge about myocardial infarction and hypertension was collected. The median score was calculated. Differences in scores among different subgroups of respondents were noted using appropriate statistical tests (p<0.05). RESULTS: Sixty-six respondents were interviewed; 44 were male. The knowledge scores for heart attack and hypertension were 6 (maximum score 8) and 11 (maximum score 14) respectively. The scores were significantly lower among respondents with a monthly family income below 2000 rupees and was higher among respondents/family members suffering from cardiovascular disease. CONCLUSION: The respondents were aware of the basic facts regarding myocardial infarction and hypertension. However, lacunae in knowledge were noted. Further studies are required.

Avalanches dynamics in reaction fronts in disordered flows.

We report on numerical studies of avalanches of an autocatalytic reaction front in a porous medium. The front propagation is controlled by an adverse flow resulting in upstream, static, or downstream regimes. In an earlier study focusing on front shape, we identified three different universality classes associated with this system by following the front dynamics experimentally and numerically. Here, using numerical simulations in the vicinity of the second-order transition, we identify an avalanche dynamics characterized by power-law distributions of avalanche sizes, durations, and lateral extensions. The related exponents agree well with the quenched-Kardar-Parisi-Zhang theory, which describes the front dynamics. However, the geometry of the propagating front differs slightly from that of the theoretical one. We show that this discrepancy can be understood in terms of the nonquasistatic correction induced by the finite front velocity.

Prescribing patterns among paediatric inpatients in a teaching hospital in western Nepal.

INTRODUCTION: Infants and children constitute a large proportion of the population in developing countries. In Nepal, studies on drug use patterns in the paediatric age group are lacking in hospitals in the western region. The present study was carried out to obtain demographical information and information on the prescribing patterns of drugs. The antibiotic sensitivity patterns of commonly-isolated micro-organisms and the mean cost of drugs were obtained. METHODS: The study was carried out over a four-month period (December 1, 2003 to March 31, 2004) at the Manipal Teaching Hospital, a tertiary care hospital in Pokhara, western Nepal. The case records of patients discharged from the paediatrics ward during the study period were analysed. Mean number of drugs prescribed was calculated. The percentage of admissions that were prescribed antibiotics was determined. RESULTS: 356 patients were admitted during the study period, of which 228 were male. The median duration of hospitalisation was four days. The mean number of drugs prescribed per admission was 4.5. 789 drugs (48.9 percent) were prescribed by the parenteral route. Antibiotics were prescribed in 249 admissions (69.9 percent). Staphylococcus aureus, Escherichia coli, and Acinetobacter species were the common organisms isolated, and were resistant in some cases to the commonly-used antibiotics. The mean (+/- standard deviation) cost of drugs per admission was 5.4 (+/-1.6) US dollars. CONCLUSION: Prescribing by generic name should be encouraged. Use of parenteral antibiotics was high and route conversion programmes should be instituted. Use of antibiotics for predominantly viral infections should be reduced. Treatment guidelines for common conditions should be formulated.

Learning styles of preclinical students in a medical college in western Nepal.

OBJECTIVES: Information on the learning styles of medical students are lacking in medical colleges in Nepal. Learning styles may be associated with student understanding and may predict success in examination. The present study was carried out to obtain information on learning styles and preferences for teaching of fourth semester medical students and note the association, if any, between respondents' personal characteristics and preferences for learning styles and types of teaching. The correlation between preferences for learning styles and types of teaching and performance in the second year university examination was also explored. METHODS: The study was carried out during October 2003 at the Manipal College of Medical Sciences, Pokhara, Nepal using the Approaches and Study Skills Inventory (ASSIST) instrument. Information on the respondents' personal characteristics was collected. Respondents had to indicate their degree of agreement with a set of statements using a modified Likert-type scale. The statements were grouped into three main learning styles and two types of teaching. The median scores among different subgroups of respondents were compared using appropriate non-parametric tests (p<0.05). RESULTS: Ninety-two students (92%) participated; fifty-six were male. Thirty-one respondents were Nepalese, 48 were Indians. Majority were educated in English medium schools. The median scores for deep and surface learning styles were 64 and 49 respectively (maximum score=80). The scores for strategic learning was 75.5 (maximum score=100). There was no clear preference for any particular type of teaching. Indian students used more surface apathetic learning strategies compared to others. There was a negative correlation between surface learning and marks obtained in the final examination. CONCLUSIONS: The students mainly used deep and strategic learning styles. Differences in preference for learning styles and types of teaching were noted according the respondents' personal characteristics. This was a preliminary study and further studies are required.

Reconstruction of Cranial Defects in Armed Forces Personnel - Our Experience.

BACKGROUND: The aim of this study was to evaluate the efficacy of heat cured 'poly methyl methacrylate resin prosthesis and to assess the acceptability of the indigenously manufactured titanium mini bone plate and screws in patients treated for repair of cranial defects. METHODS: 17 patients with cranial defect were treated for reconstruction of the skull defect with two types of implants i.e. Acrylic resin plate prosthesis and titanium minibone plates, either in combination or singularly. In these cases, the skull defects resulted from trauma (88.23%) or due to ablative tumour surgery (11.96%). Acrylic implant was used in 12 cases (70.85%), titanium plates and screws in 2 cases (11.76%) and a combination of both of the above in 3 cases (17.64). RESULTS: The primary reconstruction was carried out in 2 cases (11.96%) and secondary reconstruction was done in 15 cases (88.23%). Majority of the cases underwent secondary reconstruction because of the initial surgical emergency requiring quick debulking and closure. In 2 cases where primary reconstruction was done, the second surgery could be avoided with gratifying results. CONCLUSION: 70.85% underwent reconstruction with polymethyl methacrylate resin prosthesis and in the rest either titanium plates were used singly or in combination. Only in one patient, there was rejection of the implant due to infection. In 94% cases the graft was well taken up with excellent results.

Spontaneous nontraumatic subarachnoid hemorrhage without cerebrovascular malformations in a maintenance hemodialysis patient.

Nontraumatic subarachnoid hemorrhage (SAH) in a dialysis patient is an uncommon occurrence and is often associated with high mortality. We report for the first time in India, a case of spontaneous nontraumatic, nonaneurysmal SAH without any cerebrovascular malformation in a maintenance hemodialysis patient, following a session of hemodialysis. The dialysis prescription needs to be modified in these patients, in order to prevent worsening of cerebral edema and progression of hemorrhage. Where available, continuous forms of renal replacement therapies, with regional anticoagulation seem to be the best option for such patients, till neurologic stabilization is achieved.

Evidence from the rhesus monkey (Macaca mulatta) for the view that negative feedback control of luteinizing hormone secretion by the testis is mediated by a deceleration of hypothalamic gonadotropin-releasing hormone pulse frequency.

The site and mode of the feedback actions of testicular hormones on gonadotropin secretion in the adult rhesus monkey were investigated using the arcuate-lesioned preparation previously employed by others to study cognate problems in the female. The negative feedback loop that governs LH and FSH release in the male monkey was opened without changing either the frequency or amplitude of intermittent GnRH stimulation of the pituitary gonadotrophs, which was clamped by exogenous GnRH replacement at a level that approximated the intact or closed loop hypophysiotropic signal. In this manner, the relative importance of adenohypophysial vs. hypothalamic sites of feedback action of testicular hormones on LH and FSH secretion was assessed. To accomplish the foregoing, radiofrequency lesions were placed in the region of the arcuate nucleus to abolish endogenous hypothalamic GnRH secretion. Patterns of temporally coupled episodes of pituitary LH and testicular testosterone discharge that in nonlesioned animals characteristically occur, on the average, once every 3 h throughout the 24-h light-dark cycle were restored in lesioned animals by an intermittent iv infusion of GnRH (0.1 micrograms/min for 3 min every 3 h). Bilateral orchidectomy in this experimental paradigm elicited only small increments in LH pulse amplitude and mean plasma LH concentration, a response in striking contrast to the dramatic postcastration LH hypersecretion observed in animals with intact hypothalami that respond to the opening of the negative feedback loop with an apparent acceleration in the endogenous frequency of intermittent GnRH secretion. A marked rise in mean plasma LH concentration in arcuate-lesioned males, however, was forth-coming when the frequency of intermittent exogenous GnRH stimulation was increased 2-3 weeks after castration from one pulse every 3 h (intact frequency) to one pulse per h (castrate frequency). These findings fail to provide evidence for a major inhibitory feedback action of the testes on LH secretion at the level of the adenohypophysis. They are entirely consistent, however, with the hypothesis that the negative feedback control of LH release by the male gonad is mediated, principally, via the central nervous system by an action of testicular hormone, most probably testosterone, to retard the frequency of the neural timing mechanism that governs the intermittent pattern of GnRH release by the hypothalamus.(ABSTRACT TRUNCATED AT 400 WORDS)

In the rhesus monkey (Macaca mulatta), the negative feedback regulation of follicle-stimulating hormone secretion by an action of testicular hormone directly at the level of the anterior pituitary gland cannot be accounted for by either testosterone or estradiol.

In the male rhesus monkey, the negative feedback regulation of gonadotropin secretion by the gonad appears to involve a specific inhibitory action of testicular hormone on FSH release at the level of the anterior pituitary gland. The purpose of the present study, which used the hypophysiotropic clamp preparation, was to determine whether circulating testosterone (T) or estradiol (E) comprises a major component of the testicular FSH-inhibiting factor in this species. Endogenous hypothalamic GnRH secretion was abolished or severely compromised in five adult male rhesus monkeys by placement of radiofrequency lesions in the region of the arcuate nucleus. Subsequently, an episodic pattern of activity in the pituitary-Leydig cell axis of these animals was restored by a chronic and unchanging intermittent iv infusion of GnRH (0.1 microgram/min for 3 min ever 3 h), which appears to provide the gonadotropes of lesioned animals with a hypophysiotropic drive comparable to that produced by the hypothalamus of animals with an intact central nervous system. Treatment of three animals with a specific anti-E-gamma-globulin fraction resulted in a marked and sustained rise in E-binding activity in serum, but this neutralization of circulating E did not elicit hypersecretion of FSH. In all five animals, initiation of T replacement on the day of orchidectomy, which maintained circulating T concentrations in the high testis-intact control range, failed to prevent the postcastration hypersecretion of FSH that is evoked after removal of testis in the hypophysiotropic clamp preparation. As expected, the changes in circulating LH levels during immunoneutralization and after orchidectomy and T replacement were unremarkable. These findings indicate that neither circulating T nor E can account for the testicular inhibition of FSH secretion in the rhesus monkey and thus lead, by a process of exclusion, to the view that in this species the negative feedback regulation of FSH release by the testis is mediated directly at the level of the gonadotrope by an inhibitory action of a nonsteroidal hormone, most probably the recently identified gonadal peptide inhibin.