Polarized Raman spectroscopy study of CVD-grown Cr2S3 flakes: unambiguous identification of phonon modes.

We report a systematic Raman spectroscopy investigation of chemical vapor deposited 2D nonlayered Cr2S3, with both linearly and circularly polarized light over a wide temperature range (5-300 K). Temperature-dependent Raman spectra exhibit a good linear relationship between the peak positions of the phonon modes and temperature. Angle-resolved polarized Raman spectra reveal the polarization-dependent optical response of in-plane and out-of-plane phonon modes. Helicity-dependent Raman investigations complete definite assignment of all the phonon modes observed in the Raman spectra of 2D nonlayered Cr2S3 by the optical selection rule based on a Raman tensor. Our work realizes clear phonon mode identification over a wide temperature range for the emerging material 2D Cr2S3, an important representative of nonlayered 2D system with unique properties for optoelectronic and spintronic applications.

Dynamics of the lipid body lipidome in the oleaginous yeast Yarrowia sp.

Time-dependent changes in the lipid body (LB) lipidome of two oleaginous yeasts, Yarrowia lipolytica NCIM 3589 and Yarrowia bubula NCIM 3590 differing in growth temperature was investigated. LB size and lipid content were higher in Y. lipolytica based on microscopy, Feret, and integrated density analysis with lipid accumulation and mobilization occurring at 48 h in both strains. Variations in LB lipidome were reflected in interfacial tension (59.67 and 68.59 mN m-1) and phase transition temperatures (30°C-100°C and 60°C-100°C) for Y. lipolytica and Y. bubula, respectively. Liquid Chromatography-Mass Spectroscopy (LC-MS) analysis revealed neutral lipids (NLs), phospholipids, sphingolipids, sterols, and fatty acids as the major classes present in both strains while fatty acid amides were seen only in Y. lipolytica. Amongst the lipid classes, a few species were present in abundance with a number of lipids being less dominant. Permutational multivariate analysis of variance (PERMANOVA) and Analysis of covariance (ANOCOVA) analysis suggest 22 lipids belonging to NLs, fatty acid amides, and free fatty acids were found to be statistically different between the two strains. Analysis of the ratios between different lipid components suggest changes in LB size and mobilization as a function of time. The results indicate influence of temperature and strain variation on the dynamics of LB lipidome in Yarrowia species.

Laron Syndrome: A Tale of Two Siblings.

Primary growth hormone (GH) resistance or growth hormone insensitivity syndrome, also called Laron syndrome, is a hereditary disease caused by mutations in the GH receptor or in the post-receptor signaling pathway. This disorder is characterized by postnatal growth failure resembling GH deficiency. Differentiating the two conditions is necessary. We present the cases of two siblings, a 16-year-old female and a 9-year-old male, born from a consanguineous union. Both had normal birth weights with subsequent severe short stature and delayed teeth eruption, with no features suggestive of any systemic illness. Serum insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein 3 (IGFBP3) were both low. Suspecting GH deficiency, provocative testing with clonidine was done revealing peak growth hormone >40 ng/mL in both patients. In view of low IGF1 and IGFBP3 and high GH on stimulation, IGF1 generation test was done for both siblings, with values supporting the diagnosis of GH insensitivity or Laron syndrome.

A Case of Elephantiasic Pretibial Myxedema Successfully Treated With Intralesional Triamcinolone Acetate.

Graves' dermopathy is one of the extra-thyroidal manifestations of Graves' disease (GD) and is characterized by the accumulation of glycosaminoglycans in the reticular dermis. In the majority of cases, pretibial myxedema is self-limiting but, in some cases, it can lead to structural and functional damage. Topical steroids with occlusive dressing remain the conventional treatment, but intralesional steroids have shown promising results. We hereby present a case of pretibial myxedema treated successfully with intralesional triamcinolone acetate.

Transformation of Peripheral Sexual Precocity to Central Sexual Precocity Following Treatment of Granulosa Cell Tumor of the Ovary.

Juvenile granulosa cell tumor leading to isosexual peripheral precocious puberty is a well-known association. Here, we report a rare case of central precocious puberty secondary to granulosa cell tumor of the ovary. A five-year and five-month-old girl presented with a history of progressive enlargement of bilateral breasts and intermittent vaginal spotting, associated with growth acceleration. Elevated estradiol and suppressed serum follicle-stimulating hormone were found on investigation. Additionally, abdominal and pelvic ultrasonography was suggestive of a right ovarian mass, which proved to be a juvenile granulosa cell tumor on histopathology and immunohistochemistry, leading to a diagnosis of peripheral precocious puberty secondary to granulosa cell tumor of the ovary. One and a half years after resection of the tumor, secondary sexual characteristics progressed with regression of tumor markers, and no mass was noted on ultrasonography, leading to the suspicion of central precocious puberty. Pubertal basal luteinizing hormone (LH) and elevated triptorelin-stimulated LH confirmed the diagnosis of central precocious puberty secondary to granulosa cell tumor of the ovary.

Cathepsin L inhibition prevents the cleavage of multiple nuclear proteins upon lysis of quiescent human cells.

Several studies have indicated a role for cathepsin L (CTSL) proteolytic activity in the nucleus under distinct cellular conditions, including during differentiation, senescence, and quiescence. Here we show that addition of CTSL inhibitors to a cell lysis buffer prevents the cleavage of several nuclear proteins during the lysis of quiescent human cells, including proteins previously thought to have functional relevance in other cell and tissue contexts. These findings suggest that care should be taken to use CTSL inhibitors when lysing cells and tissues containing high levels of CTSL protein to differentiate proteolysis that occurs in vivo versus artifactually in vitro.

Phylogenomic and biochemical analysis reassesses temperate marine yeast Yarrowia lipolytica NCIM 3590 to be Yarrowia bubula.

Yarrowia clade contains yeast species morphologically, ecologically, physiologically and genetically diverse in nature. Yarrowia lipolytica NCIM 3590 (NCIM 3590), a biotechnologically important strain, isolated from Scottish sea waters was reinvestigated for its phenotypic, biochemical, molecular and genomic properties as it exhibited characteristics unlike Y. lipolytica, namely, absence of extracellular lipolytic activity, growth at lower temperatures (less than 20 °C) and in high salt concentrations (10% NaCl). Molecular identification using ITS and D1/D2 sequences suggested NCIM 3590 to be 100% identical with reference strain Yarrowia bubula CBS 12934 rather than Y. lipolytica CBS 6124 (87% identity) while phylogenetic analysis revealed that it clustered with Y. bubula under a separate clade. Further, whole genome sequencing of NCIM 3590 was performed using Illumina NextSeq technology and the draft reported here. The overall genome relatedness values obtained by dDDH (94.1%), ANIb/ANIm (99.41/99.42%) and OrthoANI (99.47%) indicated proximity between NCIM 3590 and CBS 12934 as compared to the reference strain Y. lipolytica. No extracellular lipase activity could be detected in NCIM 3590 while LIP2 gene TBLASTN analysis suggests a low 42% identity with e value 2 e-77 and 62% coverage. Hence molecular, phylogenetic, genomics, biochemical and microbial analyses suggests it belongs to Yarrowia bubula.

Two-Dimensional Anisotropic C10 Carbon Allotrope with Mechanically Tunable Band Gap.

A high band gap, two-dimensional (2D) twisted octagonal (TO-)C10 allotrope of carbon is proposed. This dynamically and mechanically stable structure shows thermal stability up to 500 K and shows one of the largest Young's modulus of 306.4 GPa nm (close to graphene) among 2D carbon derivatives. TO-C10 also possesses one of the highest 2.94 eV (3.97 eV by HSE06) indirect band gap among reported 2D allotropes of carbon. Owing to structural anisotropy with respect to the basal plane and strong directional sp3 bonding, the band gap of the structure is tuned with high strain endurance along with variation in the band gap subject to applied direction of strain. The nature of the band gap also changes between indirect and direct on account of variation in the valence band states, dominantly governed by carbon atoms in the less symmetrically bonded ladder sites. Further, the band gap can be tuned with doping of Si and Ge and also by forming one-directional nanoribbons. Owing to structural inhomogeneity and inherent high band gap, the proposed 2D TO-C10 can be a potential candidate for future applications.

Electronic Structure of Visible Light-Driven Photocatalyst δ-Bi11VO19 Nanoparticles Synthesized by Thermal Plasma.

Size confinement for tailoring of electronic structures can in principle be explored for enhancement of photocatalytic properties. In the present work, vanadium-doped bismuth oxide nanoparticles, with an average particle size of 36 nm, are synthesized for the first time, using the thermal plasma method, in large scale with high yield to explore for photocatalytic applications. The electronic and crystallographic structures of the sample are studied experimentally and theoretically. Systematic investigations of the electronic structure of the fluorite type cubic phase of Bi11VO19 nanoparticles are reported for the first time. Enhancement is observed in the photocatalytic activity as compared to other delta phases of bismuth vanadate. The valence band is found to comprise mainly of O 2p states, whereas the conduction band arises from V 3d states giving rise to a band gap value of 2.26 eV. Absence of excess O in δ-Bi2O3 results in shrinking of the band gap because of O 2p, Bi 6s and 6p states from the surrounding atoms at doping sites. Bi11VO19 nanoparticles show an efficient visible light absorption and exhibit excellent photodegradation properties of methylene blue solution under visible light irradiation.

Effect of Passivation on Stability and Electronic Structure of Bulk-like ZnO Clusters.

Electronic structure of nearly stoichiometric and nonstoichiometric clusters of ZnO having bulk-like wurtzite geometry passivated with fictitious hydrogen atoms are comparatively analyzed for structural evolution using density functional theory-based electronic structure calculations. A parameter, average binding energy per atomic number (ABE-number), is introduced for better insight of structural evolution. The stability of a cluster is determined by binding energy per atom and ABE-number, whereas structural evolution on the basis of spin-polarized energy spectrum is studied via site projected partial density of states (l-DOS). The overall structural evolution is mapped for bare and passivated ZnO clusters to l-DOS. The study has established a correlation between the stability of clusters and their l-DOS. O-excess and O-surfaced clusters are found to be more stable. The HOMO-LUMO gap varies from 0 to 6.3 eV by tuning the size, composition, and surface termination of the clusters. Present results reported for clusters of sizes up to ∼1 nm can pave a path for formulating strategies for experimental synthesis of ZnO nanoparticles for tuning the HOMO-LUMO gap.

Cluster assembly route to a novel octagonal two-dimensional ZnO monolayer.

To explore the possibility of cluster assembly resulting in a two-dimensional (2D) stable monolayer of ZnO, a systematic study is performed on the structural evolution of bare and passivated stoichiometric clusters of [Formula: see text] [Formula: see text], [Formula: see text], using density-functional-theory-based first principles electronic structure calculations. The changes in hybridization are investigated with the aid of the site-projected partial density of states and partial charge density, while the effect of passivation and size on the ionicity of the cluster is studied using Bader charge analysis. The structural and chemical properties are found to be influenced by the coordination number of atoms in the clusters irrespective of the coordinating species. The physical parameters and hybridization of the states for the clusters on passivation resemble those of the bulk. Passivation thus provides an environment that leads to the stability of the clusters. Cluster assembly using the stable cluster geometries of passivated clusters (without the passivating atoms) has been shown to lead to stable 2D structures. This stability has been studied on the basis of binding energy, vibrational frequency, phonon dispersion and thermal properties. A new octagonal 2D monolayer planar geometry of ZnO is predicted.

Occurrence of parotoid glands in tadpoles of the tropical frog, Clinotarsus curtipes and their role in predator deterrence.

Tadpoles of the tropical bicolored frog, Clinotarsus curtipes are unique in having parotoid glands secreting a white viscous fluid and are structurally similar to granular glands from other amphibians. To ascertain the involvement of these glands and their secretion in predator deterrence, it was tested against a predatory fish, Clarias gariepinus, using a paired choice behavioral assay. The results showed that the fish avoid eating C. curtipes tadpoles when paired with tadpoles of a sympatric species, Sylvirana temporalis. While the fish fed on C. curtipes tadpoles whose parotoid glands were surgically removed, did not touch those with intact glands, suggesting a role for the parotoid gland secretion in predator deterrence. Histochemical and biochemical analyses of the gland secretion revealed the presence of high concentrations of proteins, lipids, and alkaloids. SDS-PAGE showed the presence of proteins with prominent bands at 17 and 50kDa. The presence of other small molecules (950-2000amu) as detected by LC-MS showed the presence of five major peaks. Peaks 1 and 2 are probably tetrodotoxin and/or its analogs. Peaks 3 and 5 are possibly bufalin and argininosuccinic acid, respectively while peak 4 remains unidentified. Thus, secretion of parotoid glands of larval C. curtipes contains chemicals which, either alone or in combination, might be responsible for deterring predators.