Five coordinated Mn in Ba4Mn2Si2Te9: synthesis, crystal structure, physical properties, and electronic structure.

We report the synthesis of single-crystals of a new transition metal-containing quaternary chalcogenide, Ba4Mn2Si2Te9, synthesized by the solid-state method at 1273 K. A single-crystal X-ray diffraction study shows that it crystallizes in the orthorhombic crystal system (space group: Pbam) with cell constants of a = 13.4690(6) Å, b = 8.7223(4) Å, and c = 10.0032(4) Å. The asymmetric unit of the structure consists of eight unique crystallographic sites: one Ba, two Mn, one Si, and four Te sites. In this structure, the two Mn sites, Mn(1) and Mn(2), are disordered, each with fractional occupancy of 50%. The short distance of 2.170(3) Å between Mn(1) and Mn(2) implies that both Mn sites are not occupied simultaneously. The Mn atoms show two types of polyhedra: unique Mn(1)Te5 units along with traditional Mn(2)Te4 tetrahedra. The main motifs of the Ba4Mn2Si2Te9 structure are dimeric Si2Te6 units (with Si-Si single bond), Mn(1)Te5, and Mn(2)Te4 polyhedra. The structure can be described as pseudo-two-dimensional if only Mn(1) atoms are present and one-dimensional when only Mn(2) atoms are filled in the structure. The extended 2∞[Mn(1)Si2Te9]10- layers and 1∞[Mn(2)Si2Te8]8- chains are separated by Ba2+ cations. The direct bandgap for the polycrystalline Ba4Mn2Si2Te9 sample is 0.6(1) eV, as determined from an optical absorption study consistent with the sample's black color. The resistivity study of the polycrystalline Ba4Mn2Si2Te9 also confirms the semiconducting behavior. The thermal conductivity (κ) values are extremely low and decrease with increasing temperature up to 0.46 W m-1 K-1 at 773 K. The DFT studies suggest that the computed bandgap depends on the magnetic ordering of Mn magnetic moments, and the value varies from ∼0.3-1.0 eV. Relative inter-atomic bond strengths of pertinent atom pairs have been analyzed using the crystal orbital Hamilton populations (COHP).

Heterostructures of tin and tungsten selenides for robust overall water splitting.

Layered transition metal selenides have garnered increased attention in recent times as non-noble metal bifunctional electrocatalysts for electrochemical water splitting. Tungsten diselenide @ tin diselenide heterostructures in the present study significantly increase the electrochemical performance of oxygen evolution reaction with a low overpotential of 250 mV at 10 mA cm-2 and high stability for 16 h (8.9 % loss), hydrogen evolution reaction with a low overpotential of 180 mV at 10 mA cm-2 with a 21.9% loss in 16 h. The overall water splitting using a lab-size electrolyzer shows a low cell voltage (1.52 V @ 10 mA cm-2) and high durability for 50 h (15.2% loss @ 10 mA cm-2 and 4.4% loss @ 50 mA cm-2). As a result, the heterostructures have demonstrated their ability to handle multiple challenges in energy conversion systems due to their unique properties.

Evaluation of enzyme and microwave-assisted conditions on extraction of anthocyanins and total phenolics from black soybean (Glycine max L.) seed coat.

The present study compares three methods viz. microwave-assisted extraction (MAE), enzyme-assisted extraction (EAE) and conventional solvent extraction (CSE) for extraction of polyphenolic compounds from Black Soybean Seed coat (BSSC). Box-Behnken design using response surface methodology (RSM) was employed to investigate and optimize the MAE and EAE for maximum bioactive content, antioxidant activity, colour density and minimum degradation parameters from BSSC. Optimized MAE conditions for BSSC were: microwave power of 569.46 W, extraction time of 262.54 s, solvent to solid ratio of 40:1 and ethanol concentration (59.99). The predicted anthocyanin content was 5021.47 mg/l, close to experimental optimized value of 5094.9 mg/l with minimum values of degradation parameters viz., Polymeric Colour (PC) (0.131 ±â€¯0.01), Browning Index (BI) (0.202 ±â€¯0.02) and Degradation Index (DI) (0.140 ±â€¯0.02). Overall results clearly indicate that MAE is the best suited method for extraction in comparison to EAE and CSE. The phenolic rich extract can be used as an effective functional ingredient in foods.

Single Electron Precision in the Measurement of Charge Distributions on Electrically Biased Graphene Nanotips Using Electron Holography.

We use off-axis electron holography to measure the electrostatic charge density distributions on graphene-based nanogap devices that have thicknesses of between 1 and 10 monolayers and separations of between 8 and 58 nm with a precision of better than a single unit charge. Our experimental measurements, which are compared with finite element simulations, show that wider graphene tips, which have thicknesses of a single monolayer at their ends, exhibit charge accumulation along their edges. The results are relevant for both fundamental research on graphene electrostatics and applications of graphene nanogaps to single nucleotide detection in DNA sequencing, single molecule electronics, plasmonic antennae, and cold field emission sources.

Valorisation of black carrot pomace: microwave assisted extraction of bioactive phytoceuticals and antioxidant activity using Box-Behnken design.

The present study compares three methods viz. microwave assisted extraction (MAE), ultrasonic-assisted extraction (UAE) and conventional solvent extraction (CSE) for extraction of phenolic compounds from black carrot pomace (BCP). BCP is the major by-product generated during processing and poses big disposal problem. Box-Behnken design using response surface methodology was employed to investigate and optimize the MAE of phenolics, antioxidant activity and colour density from BCP. The conditions for maximum recovery of polyphenolics were: microwave power (348.07 W), extraction time (9.8 min), solvent-solid ratio (19.3 mL/g) and ethanol concentration (19.8%). Under these conditions, the extract contained total phenolic content of 264.9 ± 10.02 mg gallic acid equivalents (GAE)/100 mL, antioxidant capacity (AOC) of 13.14 ± 1.05 µmol Trolox equivalents (TE)/mL and colour density of 68.63 ± 5.40 units. The total anthocyanin content at optimized condition was 753.40 ± 31.6 mg/L with low % polymeric colour of 7.40 ± 0.42. At optimized conditions, MAE yielded higher colour density (68.63 ± 5.40), polyphenolic content (264.9 ± 10.025 mg GAE/100 mL) and AOC (13.14 ± 1.05 µmol TE/mL) in a short time as compared to UAE and CSE. Overall results clearly indicate that MAE is the best suited method for extraction in comparison to UAE and CSE. The phenolic rich extract can be used as an effective functional ingredient in foods.

Nanostructured Silicon-Carbon 3D Electrode Architectures for High-Performance Lithium-Ion Batteries.

Silicon is an attractive anode material for lithium-ion batteries. However, silicon anodes have the issue of volume change, which causes pulverization and subsequently rapid capacity fade. Herein, we report organic binder and conducting diluent-free silicon-carbon 3D electrodes as anodes for lithium-ion batteries, where we replace the conventional copper (Cu) foil current collector with highly conductive carbon fibers (CFs) of 5-10 µm in diameter. We demonstrate here the petroleum pitch (P-pitch) which adequately coat between the CFs and Si-nanoparticles (NPs) between 700 and 1000 °C under argon atmosphere and forms uniform continuous layer of 6-14 nm thick coating along the exterior surfaces of Si-NPs and 3D CFs. The electrodes fabricate at 1000 °C deliver capacities in excess of 2000 mA h g-1 at C/10 and about 1000 mA h g-1 at 5 C rate for 250 cycles in half-cell configuration. Synergistic effect of carbon coating and 3D CF electrode architecture at 1000 °C improve the efficiency of the Si-C composite during long cycling. Full cells using Si-carbon composite electrode and Li1.2Ni0.15Mn0.55Co0.1O2-based cathode show high open-circuit voltage of >4 V and energy density of >500 W h kg-1. Replacement of organic binder and copper current collector by high-temperature binder P-pitch and CFs further enhances energy density per unit area of the electrode. It is believed that the study will open a new realm of possibility for the development of Li-ion cell having almost double the energy density of currently available Li-ion batteries that is suitable for electric vehicles.

In-situ STEM imaging of growth and phase change of individual CuAlX precipitates in Al alloy.

Age-hardening in Al alloys has been used for over a century to improve its mechanical properties. However, the lack of direct observation limits our understanding of the dynamic nature of the evolution of nanoprecipitates during age-hardening. Using in-situ (scanning) transmission electron microscopy (S/TEM) while heating an Al-Cu alloy, we were able to follow the growth of individual nanoprecipitates at atomic scale. The heat treatments carried out at 140, 160, 180 and 200 °C reveal a temperature dependence on the kinetics of precipitation and three kinds of interactions of nano-precipitates. These are precipitate-matrix, precipitate-dislocation, and precipitate-precipitate interactions. The diffusion of Cu and Al during these interactions, results in diffusion-controlled individual precipitate growth, an accelerated growth when interactions with dislocations occur and a size dependent precipitate-precipitate interaction: growth and shrinkage. Precipitates can grow and shrink at opposite ends at the same time resulting in an effective displacement. Furthermore, the evolution of the crystal structure within an individual nanoprecipiate, specifically the mechanism of formation of the strengthening phase, θ', during heat-treatment is elucidated by following the same precipitate through its intermediate stages for the first time using in-situ S/TEM studies.

Physiological, Anatomical and Metabolic Implications of Salt Tolerance in the Halophyte Salvadora persica under Hydroponic Culture Condition.

Salt tolerance mechanism of an extreme halophyte Salvadora persica was assessed by analyzing growth, nutrient uptake, anatomical modifications and alterations in levels of some organic metabolites in seedlings imposed to various levels of salinity (0, 250, 500, and 750 mM NaCl) under hydroponic culture condition. After 21 days of salt treatment, plant height, leaf area, and shoot biomass decreased with increase in salinity whereas the leaf succulence increased significantly with increasing salinity in S. persica. The RWC% of leaf increased progressively in salt-treated seedlings as compared to control. Na(+) contents of leaf, stem and root increased in dose-dependent manner whereas there was no significant changes in K(+) content. There was significant alterations in leaf, stem, and root anatomy by salinity. The thickness of epidermis and spongy parenchyma of leaf increased in salt treated seedlings as compared to control, whereas palisade parenchyma decreased dramatically in extreme salinity (750 mM NaCl). There was a significant reduction in stomatal density and stomatal pore area of leaf with increasing salinity. Anatomical observations of stem showed that the epidermal cells diameter and thickness of cortex decreased by salinity whereas thickness of hypodermal layer, diameter of hypodermal cell, pith area and pith cell diameter increased by high salinity. The root anatomy showed an increase in epidermal thickness by salinity whereas diameters of epidermal cells and xylem vessels decreased. Total soluble sugar content remained unchanged at all levels of salinity whereas reducing sugar content increased by twofold at high salinity (750 mM NaCl). The starch content of leaf decreased progressively in NaCl treated seedlings as compared to control. Total free amino acid content did not change at low salinity (250 mM), whereas it increased significantly at higher salinity (500 and 750 mM NaCl). The proline content increased in NaCl treated seedlings as compared to control. There was no significant changes in polyphenols level of leaf at all levels of salinity. The results from the present study reveal that seedlings imposed with various levels of salinity experience physiological, biochemical and anatomical modifications in order to circumvent under extreme saline environment. The vital mechanisms of salt tolerance in S. persica are higher accumulation of organic metabolites, increase in leaf succulency, efficient Na(+) sequestration in the vacuole, K(+) retention in the photosynthetic tissue and increase in WUE by reducing stomatal density. Therefore, S. persica is a potential halophytic species to be cultivated in saline lands to eliminate excess salt and make it favorable for agriculture.

A Review on Chemical Profile of Coumarins and their Therapeutic Role in the Treatment of Cancer.

Coumarin class of organic compounds consists of 1,2-benzopyrone ring system as a basic parent scaffold. These benzopyrones are subdivided into alpha-benzopyrones and gammabenzopyrones; with coumarin class of compounds belonging to alpha-benzopyrones. Since the last few years, coumarins were synthesized in many of their derivative forms. Their pharmacological, therapeutic and biochemical properties depend upon their pattern of substitution. Coumarins exhibit a wide range of pharmacological activities, which includes anti-diabetic, anti-viral, anti-microbial, anticancer, anti-oxidant, anti-parasitic, anti-helminthic, anti-proliferative, anti-convulsant, anti-inflammatory and antihypertensive activities. Among these properties, the present review article compiles the detailed research findings of coumarins as anti-cancer agents. Research reports reveal that coumarins inhibit human malignant tumor cell lines in vitro and also show anti-proliferative activity against many mammalian tumors in vivo. Clinical trials conducted on these coumarin class of compounds showed promising activity against several types of cancer such as breast cancer, lung cancer, malignant melanoma, prostate cancer and metastatic renal cell carcinoma etc. This review presents a comprehensive and up to date literature survey on coumarins as anti-cancer agents. Furthermore, a detailed overview of various clinical trials conducted on coumarin class of compounds tested for various types of malignancies has been described.

Plasma nitriding induced growth of Pt-nanowire arrays as high performance electrocatalysts for fuel cells.

In this work, we demonstrate an innovative approach, combing a novel active screen plasma (ASP) technique with green chemical synthesis, for a direct fabrication of uniform Pt nanowire arrays on large-area supports. The ASP treatment enables in-situ N-doping and surface modification to the support surface, significantly promoting the uniform growth of tiny Pt nuclei which directs the growth of ultrathin single-crystal Pt nanowire (2.5-3 nm in diameter) arrays, forming a three-dimensional (3D) nano-architecture. Pt nanowire arrays in-situ grown on the large-area gas diffusion layer (GDL) (5 cm(2)) can be directly used as the catalyst electrode in fuel cells. The unique design brings in an extremely thin electrocatalyst layer, facilitating the charge transfer and mass transfer properties, leading to over two times higher power density than the conventional Pt nanoparticle catalyst electrode in real fuel cell environment. Due to the similar challenges faced with other nanostructures and the high availability of ASP for other material surfaces, this work will provide valuable insights and guidance towards the development of other new nano-architectures for various practical applications.

Real-time atomic scale imaging of nanostructural evolution in aluminum alloys.

We present a new approach to study the three-dimensional compositional and structural evolution of metal alloys during heat treatments such as commonly used for improving overall material properties. It relies on in situ heating in a high-resolution scanning transmission electron microscope (STEM). The approach is demonstrated using a commercial Al alloy AA2024 at 100-240 °C, showing in unparalleled detail where and how precipitates nucleate, grow, or dissolve. The observed size evolution of individual precipitates enables a separation between nucleation and growth phenomena, necessary for the development of refined growth models. We conclude that the in situ heating STEM approach opens a route to a much faster determination of the interplay between local compositions, heat treatments, microstructure, and mechanical properties of new alloys.

Hybanthus enneaspermus (L.) F. Muell: a concise report on its phytopharmacological aspects.

Hybanthus enneaspermus (L.) F. Muell belonging to the family Violaceae, popularly known as Ratanpurus (Hindi) is a herb or a shrub distributed in the tropical and subtropical regions of the world. In the Ayurvedic literature, the plant is reported to cure conditions of "Kapha" and "Pitta", urinary calculi, strangury, painful dysentery, vomiting, burning sensation, wandering of the mind, urethral discharge, blood trouble, asthma, epilepsy, cough, and to give tone to the breasts. Phytochemically, the plant contains a considerable amount of dipeptide alkaloids, aurantiamide acetate, isoarborinol, and ß-sitosterol, sugars, flavonoids, steroids, triterpenes, phenols, flavones, catachins, tannins, anthraquinones and amino acids. Pharmacologically, the plant is reported to possess antidiabetic, antiplasmodial, antimicrobial, anticonvulsant, nephroprotective, aphrodisiac, hepatoprotective, antiinflammatory, aldose reductase inhibitory and free radical scavenging activities. The information provided in this review will be worthwhile to know the applicability of H. enneaspermus for the treatment of various acute or chronic diseases with a diverse nature of phytoconstituents. The overall data in this review article were collected from various scientific sources on the research of H. enneaspermus.

Controllable atomic scale patterning of freestanding monolayer graphene at elevated temperature.

We show that by operating a scanning transmission electron microscope (STEM) with a 0.1 nm 300 kV electron beam, one can sculpt free-standing monolayer graphene with close-to-atomic precision at 600 °C. The same electron beam that is used for destructive sculpting can be used to image the sculpted monolayer graphene nondestructively. For imaging, a scanning dwell time is used that is about 1000 times shorter than for the sculpting. This approach allows for instantaneous switching between sculpting and imaging and thus fine-tuning the shape of the sculpted lattice. Furthermore, the sculpting process can be automated using a script. In this way, free-standing monolayer graphene can be controllably sculpted into patterns that are predefined in position, size, and orientation while maintaining defect-free crystallinity of the adjacent lattice. The sculpting and imaging processes can be fully computer-controlled to fabricate complex assemblies of ribbons or other shapes.

Evaluation of in vitro aldose reductase inhibitory potential of different fraction of Hybanthus enneaspermus Linn F. Muell.

OBJECTIVE: To evaluate the aldose reductase inhibitory (ARI) activity of different fractions of Hybanthus enneaspermus for potential use in diabetic cataract. METHODS: Total phenol and flavonoid content of different fractions was determined. ARI activity of different fractions in rat lens was investigated in vitro. RESULTS: The results showed significant level of phenolic and flavonoid content in ethyl acetate fraction [total phenol (212.15±0.79 mg/g), total flavonoid (39.11±2.27 mg/g)] and aqueous fraction [total phenol (140.62±0.57 mg/g), total flavonoid (26.07±1.49 mg/g)] as compared with the chloroform fraction [total phenol (68.56±0.51 mg/g), total flavonoid (13.41±0.82 mg/g)] and petrolium ether fraction [total phenol (36.68±0.43 mg/g), total flavonoid (11.55±1.06 mg/g)]. There was a significant difference in the ARI activity of each fraction, and it was found to be the highest in ethyl acetate fraction [IC50 (49.26±1.76 µg/mL)] followed by aqueous extract [IC50 (70.83±2.82 µg/mL)] and it was least in the petroleum ether fraction [IC50 (118.89±0.71 µg/mL)]. Chloroform fraction showed moderate activity [IC50 (98.52±1.80 µg/mL)]. CONCLUSIONS: Different fractions showed significanct amount of ARI activity, where in ethyl acetate fraction it was found to be maximum which may be due to its high phenolic and flavonoid content. The extract after further evaluation may be used in the treatment of diabetic cataract.

Antidiabetic and in vitro antioxidant potential of Hybanthus enneaspermus (Linn) F. Muell in streptozotocin-induced diabetic rats.

OBJECTIVE: To evaluate antidiabetic and antioxidant potential of Hybanthus enneaspermus in different models. METHODS: The oral glucose tolerance test (OGTT) and normoglycemic effect of alcoholic extract of Hybanthus enneaspermus (AHE) were evaluated at a dose of 125, 250 and 500 mg/kg p.o. while hypoglycemic activity and effect on body weight were tested at 250 and 500 mg/kg p.o. per day for 21 days in Streptozotocin (STZ) induced diabetic rats. Further, glucose uptake by hemidiaphram was also evaluated. The total polyphenolic and flavonoid were determined and their correlation with various antioxidant assays was also determined. RESULTS: The results showed high level of phenolic content in AHE. AHE also exhibited higher total antioxidant capacity, good reducing power and a significant scavenger of reactive oxygen species like DPPH radical, nitric oxide, hydrogen peroxide and deoxyribose. Furthermore there was a significant increase in the body weight and decrease in the blood glucose level on treatment with the AHE. AHE increased glucose uptake on isolated rat hemi-diaphragm compared to control group. CONCLUSIONS: AHE reduce blood glucose level in STZ-induced diabetic model. It does not show significant effect in normoglycemic study but showes significant effect in OGT. AHE has significant antioxidant activity, which may be attributed to high phenolic content.

Robot assisted radical prostatectomy: current concepts.

Laparoscopic cholecystectomy has evolved from being a reluctantly accepted novelty to the most widely adopted procedure. It reached a high popularity even before randomized trials could be carried out. Open cholecystectomy was at one time considered the ''gold standard'', only to be replaced by laparoscopic cholecystectomy. Today the same is happening with radical prostatectomy. Open radical prostatectomy (ORP) was the reference standard. Afterwards, came laparoscopic radical prostatectomy (LRP), which matched ORP in terms of the trifecta of oncological, continence and sexual function outcomes. Robot-assisted radical prostatectomy (RARP) was the next step in the evolution. Since 2000, it has become very widespread because of private practice promotion among surgeons and marketing hype by the manufacturers. Furthermore, patients ask for this operation. In the last eight years, there has been a rise in conceptual changes, especially in operative techniques, to improve outcomes following RARP. This review will focus on some of the key concepts emerged in the field of robotic surgery, to improve outcomes following RARP. The lack of randomized controlled trials makes it difficult to make true comparisons with ORP, LRP and other methods of treating localized prostate cancer.

Acute urinary retention secondary to a urethral calculus in a bladder-drained kidney pancreas transplant patient - a metallic clip nidus.

Urological expertise is usually required for the management of any urological complications of bladder-drained pancreatic allografts whether they are the result of simultaneous pancreas-kidney transplants, pancreas after kidney transplants, or pancreas transplants alone. This study presents a case of urinary retention secondary to prostatic urethra calculus impaction, the nidus of which was found to be metallic staples from the donor duodenal segment of a pancreatic allograft. Knowledge of the pre-transplant benchwork gave a high index of suspicion to the urological sequelae of this case and, in particular, the presence of calculi should suggest a metal clip nidus. We examine the methods of exocrine pancreatic drainage, donor duodenum preparation and case management.

Robotic renal surgery.

Robotic surgery is being increasingly used for prostatectomy. Its use in renal surgery has been limited by a perception that it does not offer any extra benefit. This article explores the use of robot assistance in renal surgery. Extensive literature search undertaken using Medline and PubMed. The following keywords were used during the search: robot, robotic, kidney, renal, nephrectomy, partial nephrectomy, pyeloplasty. Relevant articles were extracted and data from these articles presented in the review. Comments on relevant aspects of either technique or results are provided. Apart from initial feasibility studies, little has been published on robot assisted laparoscopic nephrectomy (RALN) for diseased kidneys. Most of the cases of RALN has been carried out in live donors for renal transplantation in a few enthusiastic centres. Experience with robot assisted laparoscopic pyeloplasty (RALP) is more mature. Robot assisted laparoscopic partial nephrectomy (RALPN) is continuing to evolve. Robotic NOTES is currently experimental. Robot assistance seems to have a role in reconstructive renal procedures such as pyeloplasty and partial nephrectomy, due mainly to the precise suturing ability.

Antidiarrhoeal activity of the standardised extract of Cinnamomum tamala in experimental rats.

The present study was designed to investigate the antidiarrhoeal potential of 50% ethanolic extract of Cinnamomum tamala on experimentally induced castor oil diarrhoea, gastric emptying of phenol red meal, gastrointestinal transit of charcoal meal and in vitro mast cell degranulation activity. C. tamala extract (25, 50 and 100 mg/kg, orally) produced a dose-dependent reduction in the total amount of faecal matter in castor oil-induced diarrhoea. The mean distance travelled by charcoal meal at 50 and 100 mg/kg of extract showed a significant reduction in the secretion of gastrointestinal fluid accumulation by 32.5-65.0%. The Na(+) and K(+) concentrations on castor oil-induced fluid accumulation showed a greater inhibitory effect on Na(+) levels than on K(+) concentrations. C. tamala significantly reduced the lipid peroxidation (P < 0.001) and increased the catalase (P < 0.01) activity in comparison to the castor oil-induced groups. C. tamala leaf extract did not show any significant effect at a higher dose (15 mg/ml) on mast cell degranulation. However, the extract in the dose of 5 and 10 mg/ml conferred significant mast cell protective action (P < 0.001). The percentage of eugenol in extract is 3.8% w/w, and total tannin is 247.5 mg/g. The result indicates the Indian spice C. tamala is useful for diarrhoea.

Effect of standardized extract of Ocimum sanctum Linn. on gastric mucosal offensive and defensive factors.

The standardized methanolic extract of leaves of O. sanctum (OSE; eugenol content 5%) given in doses of 50-200 mg/kg, orally, twice daily for five days showed dose-dependent ulcer protective effect against cold restraint stress induced gastric ulcers. Optimal effective dose (100 mg/kg) of OSE showed significant ulcer protection against ethanol and pyloric ligation-induced gastric ulcers, but was ineffective against aspirin-induced ulcers. OSE significantly healed ulcers induced by 50% acetic acid after 5 and 10 days treatment OSE (100 mg/kg) significantly inhibited the offensive acid-pepsin secretion and lipid peroxidation and increased the gastric defensive factors like mucin secretion, cellular mucus, and life span of mucosal cells and had antioxidant effect, but did not induce mucosal cell proliferation. The results indicate that the ulcer protective and healing effects of OSE may be due to its effects both on offensive and defensive mucosal factors.