Needle-like structures discovered on positively charged lightning branches.

Lightning is a dangerous yet poorly understood natural phenomenon. Lightning forms a network of plasma channels propagating away from the initiation point with both positively and negatively charged ends-called positive and negative leaders1. Negative leaders propagate in discrete steps, emitting copious radio pulses in the 30-300-megahertz frequency band2-8 that can be remotely sensed and imaged with high spatial and temporal resolution9-11. Positive leaders propagate more continuously and thus emit very little high-frequency radiation12. Radio emission from positive leaders has nevertheless been mapped13-15, and exhibits a pattern that is different from that of negative leaders11-13,16,17. Furthermore, it has been inferred that positive leaders can become transiently disconnected from negative leaders9,12,16,18-20, which may lead to current pulses that both reconnect positive leaders to negative leaders11,16,17,20-22 and cause multiple cloud-to-ground lightning events1. The disconnection process is thought to be due to negative differential resistance18, but this does not explain why the disconnections form primarily on positive leaders22, or why the current in cloud-to-ground lightning never goes to zero23. Indeed, it is still not understood how positive leaders emit radio-frequency radiation or why they behave differently from negative leaders. Here we report three-dimensional radio interferometric observations of lightning over the Netherlands with unprecedented spatiotemporal resolution. We find small plasma structures-which we call 'needles'-that are the dominant source of radio emission from the positive leaders. These structures appear to drain charge from the leader, and are probably the reason why positive leaders disconnect from negative ones, and why cloud-to-ground lightning connects to the ground multiple times.

First Leptophobic Dark Matter Search from the Coherent-CAPTAIN-Mills Liquid Argon Detector.

We report the first results of a search for leptophobic dark matter (DM) from the Coherent-CAPTAIN-Mills (CCM) liquid argon (LAr) detector. An engineering run with 120 photomultiplier tubes (PMTs) and 17.9×10^{20} protons on target (POT) was performed in fall 2019 to study the characteristics of the CCM detector. The operation of this 10-ton detector was strictly light based with a threshold of 50 keV and used coherent elastic scattering off argon nuclei to detect DM. Despite only 1.5 months of accumulated luminosity, contaminated LAr, and nonoptimized shielding, CCM's first engineering run has already achieved sensitivity to previously unexplored parameter space of light dark matter models with a baryonic vector portal. With an expected background of 115 005 events, we observe 115 005+16.5 events which is compatible with background expectations. For a benchmark mediator-to-DM mass ratio of m_{V_{B}}/m_{χ}=2.1, DM masses within the range 9 MeV≲m_{χ}≲50 MeV are excluded at 90% C. L. in the leptophobic model after applying the Feldman-Cousins test statistic. CCM's upgraded run with 200 PMTs, filtered LAr, improved shielding, and 10 times more POT will be able to exclude the remaining thermal relic density parameter space of this model, as well as probe new parameter space of other leptophobic DM models.

Beam steered graphene-based Yagi-Uda array antenna with a transverse magnetic to hybrid mode conversion approach.

This work presents the existence of the mode conversion technique in a graphene-based Yagi-Uda array antenna. It comprises four arrays whose strands are placed on a silicon dioxide substrate, and are eventually connected with the graphene ring. All four driven elements of the Yagi-Uda array antenna are excited through the 50Ω silver nanostrip feedline. The proposed antenna offers mode conversion due to variation of the chemical potential of graphene. It controls conversion of the TM32δ to HEM21δ mode of the antenna. This is attributed to the change in the biasing voltage of graphene. This in turn shifts the radiation pattern from the end-fire to the broadside direction, which effectively confirms the beam reconfigurability. This antenna provides a high directivity of 12.21 dBi at 4.55 THz center frequency. The proposed antenna is designed and analyzed by using CST Microwave Studio, which is based on the finite difference time domain scheme. The beam steered graphene-based antenna has been utilized for several terahertz communication systems.

Electron versus Muon Neutrino Induced Cross Sections in Charged Current Quasielastic Processes.

Differences between ν_{e} and ν_{µ} quasielastic cross sections are essential in neutrino oscillation analyses and CP violation searches for experiments such as DUNE and T2HK. The ratio of these is however poorly known experimentally and for certain kinematic regions theoretical models give contradictory answers. We use two independent mean-field based models to investigate this ratio using ^{40}Ar and ^{12}C targets. We demonstrate that a proper treatment of the final nucleon's wave function confirms the dominance of ν_{µ} over ν_{e} induced cross sections at forward lepton scattering.

Characterizing the hypertolerance potential of two indigenous bacterial strains (Bacillus flexus and Acinetobacter junii) and their efficacy in arsenic bioremediation.

AIMS: The aims of the study were to (i) isolate and characterize arsenic-tolerant bacterial strains, (ii) study the plant growth-promoting traits and (iii) explore their bioremediation potential. METHODS AND RESULTS: Indigenous arsenic hypertolerant bacterial isolates NM02 and NM03 were screened as they were capable of growing at 150 mmol l-1 As (V) and 70 mmol l-1 As (III). They were identified on the basis of morphological, physiological and biochemical parameter and 16sDNA sequence as Bacillus flexus and Acinetobacter junii respectively. Genomic DNA analysis for the investigation of ars operon revealed the presence of metalloregulatory arsC gene, suggesting their ability to detoxify arsenic. The analysis for siderophore, phosphate solubilization, indole acetic acid (IAA) and ACC deaminase highlighted the intrinsic plant growth-promoting rhizobacteria traits of both the bacterial strains. The energy dispersive spectroscopy analysis proved the potential of cellular arsenic sequestration within the strains. Moreover, Fourier-transform infrared spectra revealed the repositioning of the spectral bands in As presence, indicating the presence of those functional groups on the bacterial surface that is involved in As adsorption. CONCLUSIONS: Our results indicate that bacterial strains NM02 and NM03 were identified as potent applicants for arsenic bioremediation and possess the ability to facilitate plant growth. SIGNIFICANCE AND IMPACT OF THE STUDY: The bacterial strains are proficient in As detoxification and can be employed for arsenic bioremediation; a cost-effective and in situ remediation technique for the polluted soil.

Postoperative coagulopathy after live related donor hepatectomy: Incidence, predictors and implications for safety of thoracic epidural catheter.

BACKGROUND: Coagulopathy after living donor hepatectomy (LDH) may endanger donor safety during removal of thoracic epidural catheter (TEC). The present study was conducted to evaluate the extent and duration of immediate postoperative coagulopathy after LDH. MATERIALS AND METHODS: A retrospective analysis of perioperative record of LDH over three years was conducted after IRB approval. Variables such as age, gender, BMI, ASA classification, liver volume on CT scan, preoperative and postoperative INR, platelet count (PC) and ALT of each donor for five days was noted. In addition, duration of surgery, remnant as percentage total liver volume (Remnant%), blood loss, day of peak in PC and INR were also noted. Coagulopathy was defined as being present if INR exceeded 1.5 or platelet count fell below 1 × 10 5 /mm 3 on any day. Data was analyzed using SPSS 20 for Windows. Between group comparison was made using the Student 't' test for continuous variables and chi square test for categorical variables. Univariate analysis was done. Multiple logistic regression analysis was used to find independent factor associated with coagulopathy. RESULTS: Eighty four (84) donors had coagulopathy on second day (mean INR 1.9 ± 0.42). Low BMI, % of remnant liver and duration of surgery were independent predictors of coagulopathy. Right lobe hepatectomy had more coagulopathy than left lobe and low BMI was the only independent predictor. There was no correlation of coagulopathy with age, gender, blood loss, presence of epidural catheter, postoperative ALT or duration of hospital stay. High INR was the main contributor for coagulopathy. CONCLUSIONS: Coagulopathy is seen after donor hepatectomy. We recommend removal of the epidural catheter after the fifth postoperative day when INR falls below 1.5.

Biodegradation of wheat straw by Pleurotus ostreatus.

Wheat straw pretreated with chemicals as well as hot water was subjected to degradation by edible mushroom Pleurotus ostreatus. Lignin, cellulose and hemicelluloses component of both chemically as well as hot water treated wheat straw was degraded by the fungus and in turn the edible and nutritious fruiting body of the mushroom was produced. Biodegradation of wheat straw in terms of loss of lignin, cellulose and hemicellulose showed positive correlation with cellulases, xylanase, laccase and polyphenol oxidase (PPO) activity of the fungus. During vegetative growth of the fungus, lignin degradation was faster and during fructification, lignin degradation was slower than cellulose and hemicellulose. The carbon content of the wheat straw decreased while, nitrogen content increased during degradation of the waste. Hot water treated wheat straw supported better production of enzymatic activity and degraded more efficiently than chemically sterilized substrate. The cumulative yield and biological efficiency (BE) of the mushroom was maximum on the hot water treated substrate. Degradation of the hot water treated wheat straw was better and faster than chemically treated substrate.

Direct red decolorization and ligninolytic enzymes production by improved strains of Pleurotus using basidiospore derived monokaryons.

In the present investigation the efficiency of three species of Pleurotus and their improved dikaryons (heterokaryons) was assessed for decolorization of direct red and production of lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase enzymes. All the species of Pleurotus i.e. P. flabellatus, P. ostreatus, and P. citrinopileatus decolorized the dye Direct Red well. However, Pfo 6X9 and Poc 9X6 decolorized the dye more effectively than three species of Pleurotus. The improved dikaryons also showed higher ligninolytic activity than the parental species. Poc 9X6 showed higher LiP (76.27U), MnP (623.24U) and laccase activity (594.80U). In the present work different pH, age and concentration of inoculum and effect of surfactant i.e. sodium dodecyl sulphate (SDS) and Tween—80 were analyzed in order to determine the optimum ones to decolorize maximum concentration of dye. 5 ml of 10 days old culture on pH 5.5 and 0.1% Tween—80 supported maximum decolorization of direct red dye.

Production of ligninolytic enzymes by white rot fungi on lignocellulosic wastes using novel pretreatments.

Production of extracellular ligninolytic enzymes (laccase and polyphenol oxidase) secreted by three species of white rot fungi (Pleurotus florida, P. flabellatus and P. sajor—caju) under in vivo condition was studied on two lignocellulosic substrates i.e., paddy straw and wheat straw. These lignocellulosic substrates were treated with neem (Azadirachta indica) oil and ashoka (Saraca indica) leaves extract. Between the two lignocellulosic substrates, paddy straw pretreated with neem oil supported maximum activity of laccase and polyphenol oxidase (PPO). The activities of both the enzymes were low on the 5th day of cultivation which increased on the 10th day and reached at peak on the 15th day. Thereafter, there was continuous decrease in the enzymatic activity. Among the three species, P. flabellatus (P3) showed maximum ligninolytic enzymatic activity followed by P. florida (P2)and P. sajor—caju (P1).

Production of cellulolytic enzymes by Pleurotus species on lignocellulosic wastes using novel pretreatments.

In the present investigation three species of Pleurotus i.e. P. sajor—caju (P1), P. florida (P2) and P. flabellatus (P3) along with two lignocellulosic substrates namely paddy straw and wheat straw were selected for evaluation of production of extracellular cellulolytic enzymes. During the cultivation of three species of Pleurotus under in vivo condition, the two lignocellulosic substrates were treated with plants extracts (aqueous extracts of ashoka leaves (A) and neem oil (B)), hot water (H) and chemicals (C).Among all treatments, neem oil treated substrates supported better enzyme production followed by aqueous extract of ashoka leaves, hot water and chemical treatment. Between the two substrates paddy straw supported better enzyme production than wheat straw. P. flabellatus showed maximum activity of exoglucanase, endoglucanase and β—glucosidase followed by P. florida and P. sajor—caju.

Brachial plexus injury in live related donor hepatectomy: a chart review.

Retrieval of the partial liver graft is a complicated and time-consuming procedure and reported to be associated with brachial plexus injury. We present a case series of brachial plexus injury in live related donor hepatectomy of 95 donors analyzed retrospectively. Seven donors suffered from brachial plexus injuries of varying severity and duration. Out of these, one donor had residual paresis. The reasons could be application of retractors, which may have led to traction and compression above the nerve roots.

Comparative evaluation of prophylactic use of pregabalin, gabapentin and diclofenac sodium for prevention of succinylcholine-induced myalgia: a randomized, double-blinded study.

CONTEXT: Succinylcholine a depolarizing muscle relaxant with rapid onset, predictable course and short duration of action is associated with myalgia. AIM: The aim of this study is to evaluate the efficacy of pregabalin, gabapentin and diclofenac on the incidence and severity of succinylcholine-induced myalgia. SETTINGS AND DESIGN: Tertiary Care Teaching Hospital. MATERIALS AND METHODS: A total of 120 patients undergoing laparoscopic cholecystectomy were randomly assigned into three groups: Pregabalin group received 150 mg of pregabalin, gabapentin group received 600 mg of gabapentin and diclofenac group received 100 mg of diclofenac sodium orally 2 h prior to surgery. Anesthesia was induced with fentanyl 3 µg/kg, propofol 2-2.5 mg/kg and succinylcholine 1.5 mg/kg and was maintained with oxygen with sevoflurane in the air and intermittent vecuronium bromide. A blinded observer recorded post-operative pain scores on visual analog scale at different time intervals and myalgia at 24 h. Post-operative pain relief was provided with fentanyl based patient-controlled analgesia. Fentanyl consumption in 24 h was recorded as a primary outcome. STATISTICAL ANALYSIS: Patients' characteristics and total fentanyl consumption were compared using one-way ANOVA followed by post-hoc test. Pain score was compared amongst the groups using Kruskal Wallis test. RESULTS: The myalgia occurred in 15, 14 and 13 patients in pregabalin, gabapentin and diclofenac sodium group respectively (P > 0.85). Patients in diclofenac group had significantly higher fentanyl consumption (674.85 ± 115.58 µg) compared with pregabalin group (601.87 ± 129.57 µg) (95% confidence interval [CI] = 34.8-120.7) and gabapentin group (612.29 ± 105.12 µg) (95% CI = 14.9-170.5). However, there was no significant difference in fentanyl consumption between pregabalin and gabapentin groups (95% CI = -34.8-120.7). There was a significant difference in visual analog score at time points 12, 18 and 24 h among the study groups. CONCLUSION: Pre-treatment with pregabalin, gabapentin and diclofenac had equal efficacy in reducing the incidence and severity of succinylcholine-induced myalgia. However, pre-treatment with pregabalin and gabapentin decreased post-operative pain scores and fentanyl consumption.

Seasonal variations in seminal plasma proteins of buffalo.

The study was designed to evaluate the influence of season on semen characteristics and seminal plasma protein profile of buffalo bull semen. Thirty-six ejaculates were collected in three seasons (winter, summer and rainy) from six adult Bhadawari bulls, and semen characteristics were evaluated immediately after collection. The seminal plasma was harvested by centrifugation and protein profiling, and percentage protein fractions were analysed by SDS-PAGE. The significant effect of season was observed on ejaculate volume, sperm concentration, progressive motility, percentage live spermatozoa, hypo-osmotic swelling test (HOST) and acrosomal integrity. The electrophoretogram of seminal plasma proteins revealed 20 protein bands in winter, 23 bands in rainy and 25 bands in summer seasons, illustrating the significant effect of seasons on seminal plasma proteins. Among these protein bands, 18 bands were observed common in semen samples of all three seasons while protein bands of 46, 55, 58, 144 and 160 kDa were found in rainy and summer seasons. The protein bands of 48 and 60 kDa were observed only in winter season, whereas 184 and 200 kDa were reported in summer season only. The protein fractions (protein%) of common protein bands observed in three seasons revealed a significant effect of season on protein bands of 24.5, 66, 70, 72, 84 and 86 kDa. From the study, it was pertinent that bull seminal plasma contains specific proteins in particular season, which may be associated with some of the semen characteristics, and these proteins could be used as markers of the semen quality of buffalo bulls.

Neonatal necrotising fasciitis managed conservatively: an experience from a tertiary centre.

OBJECTIVE: Conventional therapy for neonatal necrotising fasciitis (NF) involves resuscitation and aggressive surgical debridement of necrotic tissue. This approach adds surgical stress in septicaemic neonates with low reserves. The present study reports a more conservative approach to the management of neonatal NF. METHOD: A prospective study was conducted between July 2010 and June 2013 and included 11 cases of neonatal NF. Demographic characteristics of patients were noted. No debridement was performed. Dressings were applied after cleaning with normal saline every 24 hours. The necrotic slough was allowed to separate spontaneously. A record was made of type and duration of supportive modalities and complications. The primary outcome was recorded as final recovery, need of surgical intervention or need of grafting. RESULTS: Out of 11 neonates, 6 were males and 5 were females. Age ranged from 13 to 24 days (mean age 18.45±3.24 days), and weight varied from 1.8 to 2.6 kg (mean weight 2.12±0.24kg) at presentation. Duration of illness before admission to hospital ranged from 3 to 9 days (mean 4.84±2.13 days). The most common site of the initial involvement was the neck and upper thoracic region (n=4), scalp (n=3), lower back (n=2), face (n=1) and extremities (n=1). In all cases, the wound was cleaned with normal saline, dressed, necrotic slough was allowed to separate spontaneously and granulation tissue was allowed to develop; this took approximately 14 to 28 days (mean 20.45±5.78 days). CONCLUSION: As opposed to the conventional approach of aggressive debridement in neonatal NF, these cases can be managed conservatively without increase in morbidity or mortality. This approach also minimises the surgical risk and requirement of blood transfusion. Antifungal drugs have a definitive role in management of these immunologically deficient babies.