Layer-by-layer thinning of two-dimensional materials.

Etching technology - one of the representative modern semiconductor device makers - serves as a broad descriptor for the process of removing material from the surfaces of various materials, whether partially or entirely. Meanwhile, thinning technology represents a novel and highly specialized approach within the realm of etching technology. It indicates the importance of achieving an exceptionally sophisticated and precise removal of material, layer-by-layer, at the nanoscale. Notably, thinning technology has gained substantial momentum, particularly in top-down strategies aimed at pushing the frontiers of nano-worlds. This rapid development in thinning technology has generated substantial interest among researchers from diverse backgrounds, including those in the fields of chemistry, physics, and engineering. Precisely and expertly controlling the layer numbers of 2D materials through the thinning procedure has been considered as a crucial step. This is because the thinning processes lead to variations in the electrical and optical characteristics. In this comprehensive review, the strategies for top-down thinning of representative 2D materials (e.g., graphene, black phosphorus, MoS2, h-BN, WS2, MoSe2, and WSe2) based on conventional plasma-assisted thinning, integrated cyclic plasma-assisted thinning, laser-assisted thinning, metal-assisted splitting, and layer-resolved splitting are covered in detail, along with their mechanisms and benefits. Additionally, this review further explores the latest advancements in terms of the potential advantages of semiconductor devices achieved by top-down 2D material thinning procedures.

High activity in the dry reforming of methane using a thermally switchable double perovskite and in situ generated molecular level nanocomposite.

This work emphasizes the dry reforming of methane (DRM) reaction on citrate sol-gel-synthesized double perovskite oxides. Phase pure La2NiMnO6 shows very impressive DRM activity with H2/CO = 0.9, hence revealing a high prospect of next-generation catalysts. Although the starting double perovskite phase gets degraded into mostly binary oxide phases after a few hours of DRM activity, the activity continues up to 100 h. The regeneration of the original double perovskite out of decomposed phases by annealing at near synthesis temperature, followed by the spectacular retention of activity, is rather interesting and hitherto unreported. This result unravels unique reversible thermal switching between the original double perovskite phase and decomposed phases during DRM without compromising the activity and raises challenge to understand the role of decomposed phases evolved during DRM. We have addressed this unique feature of the catalyst via structure-property relationship using the in situ generated molecular level nanocomposite.

Anti-inflammatory potential of aconitine produced by endophytic fungus Acremonium alternatum.

Argemone mexicana belonging to family Papaveraceae is a traditional medicinal plant widely utilized by tribal people in India for treating various ailments like skin infections, wounds and inflammation. This plant is very rich in alkaloidal content, which has a great potential in the treatment of anti-inflammatory disorders. Therapeutically promising bioactive molecules are often produced by endophytic fungi associated with medicinal plants. In this investigation, endophytic fungi were isolated from various parts of A. mexicana and screened for alkaloidal content. Among these, one of the fungal isolate, Acremonium alternatum AMEF-5 producing maximum alkaloids showed significant anti-inflammatory activity. Fractionation of this crude fungal extract through column chromatography yielded eight fractions, which were further screened for anti-inflammatory activities. Fraction 3 exhibited significant anti-inflammatory activity by the inhibition of lipoxygenase enzyme (IC50 15.2 ± 0.09 µg/ml), scavenging of the nitric oxide radicals (IC50 11.38 ± 0.35 µg/ml), protein denaturation (IC50 14.93 ± 0.4 µg/ml), trypsin inhibition (IC50 12.06 ± 0.64 µg/ml) and HRBC stabilization (IC50 11.9 ± 0.22 µg/ml). The bioactive alkaloid in fraction 3 was identified as aconitine which was confirmed by UV, FTIR, HPLC, HRMS, 1H NMR, and 13C NMR analysis. This study demonstrates that endophytic fungi serve a potential source for sustainable production of therapeutically important alkaloids.

Withanolides production by the endophytic fungus Penicillium oxalicum associated with Withania somnifera (L.) Dunal.

Withanolides are steroidal lactones with diverse bioactive potential and their production from plant sources varies with genotype, age, culture conditions, and geographical region. Endophytic fungi serve as an alternative source to produce withanolides, like their host plant, Withania somnifera (L.) Dunal. The present study aimed to isolate endophytic fungi capable of producing withanolides, characterization and investigation of biological activities of these molecules. The methanolic fungal crude extract of one of the fungal isolates WSE16 showed maximum withanolide production (219 mg/L). The fungal isolate WSE16 was identified as Penicillium oxalicum based on its morphological and internal transcribed spacer (ITS) sequence analysis and submitted in NCBI (accession number OR888725). The methanolic crude extract of P. oxalicum was further purified by column chromatography, and collected fractions were assessed for the presence of withanolides. Fractions F3 and F4 showed a higher content of withanolides (51.8 and 59.1 mg/L, respectively) than other fractions. Fractions F3 and F4 exhibited antibacterial activity against Staphylococcus aureus with an IC50 of 23.52 and 17.39 µg/ml, respectively. These fractions also showed antioxidant activity (DPPH assay with IC50 of 39.42 and 38.71 µg/ml, superoxide anion scavenging assay with IC50 of 41.10 and 38.84 µg/ml, and reducing power assay with IC50 of 42.61 and 41.40 µg/ml, respectively) and acetylcholinesterase inhibitory activity (IC50 of 30.34 and 22.05 µg/ml, respectively). The withanolides present in fraction 3 and fraction 4 were identified as (20S, 22R)-1a-Acetoxy-27-hydroxywitha-5, 24-dienolide-3b-(O-b-D-glucopyranoside) and withanamide A, respectively, using UV, FTIR, HRMS, and NMR analysis. These results suggest that P. oxalicum, an endophytic fungus isolated from W. somnifera, is a potential source for producing bioactive withanolides.

Coexistence of ferromagnetic-antiferromagnetic ground state, exchange bias effect and bandgap narrowing in Cr-doped ZnO nanocrystals derived by simple chemical method.

A detailed investigation of the structural, optical and magnetic properties of Cr-doped ZnO nanostructures obtained via a simple chemical method has been carried out. The structural study using X-ray powder diffraction indicates the hexagonal wurtzite structure for undoped ZnO and ZnO doped with 1% Cr, whereas the appearance of a secondary cubic phase (ZnCr2O4) is witnessed with the incorporation of Cr content ≥3% in the ZnO compounds. Furthermore, the secondary phase is observed to increase systematically with the increase of the Cr concentration. Field emission scanning electron microscopy and high-resolution transmission electron microscopy studies indicate cuboid, hexagonal and rod-type structural morphology in all the nanocrystals. The presence of the cubic structure along with the hexagonal structure is further confirmed from the selected area electron diffraction pattern. Raman spectroscopy has been used to study the crystalline quality, defects and disorder present in the host lattice. UV-visible spectra were obtained to study the effect of Cr doping on the optical absorption and hence to determine the bandgap, and show a decrease in bandgap with increasing Cr concentration. PL spectra show near-band-edge emission along with visible emission, which decreases with a higher concentration of Cr-doped nanocrystals. X-ray photoelectron spectroscopy analysis indicates the incorporation of Cr3+ and Cr2+ ions in the ZnO lattice. Detailed magnetic studies reveal the co-existing ferromagnetic (FM) and antiferromagnetic (AFM) ground states, which result in the observation of an exchange bias (EB) effect in all the doped compounds. The observation of an EB effect arises from the coupling between the FM and AFM components in the Cr-containing ZnO nanocrystals, and provides a way to design new principles and materials platform that are useful for futuristic spintronic devices.

Structural, optical and magnetic behavior of sol-gel derived Ni-doped dilute magnetic semiconductor TiO2 nanocrystals for advanced functional applications.

Dilute magnetic semiconductors based on TiO2 nanocrystals are the most promising class of materials exhibiting unique optical and magnetic properties. In the present investigation, we have performed a systematic study on the structural, morphological, optical and magnetic behavior of Ni-doped TiO2, synthesized via a simple, cost-effective sol-gel route. X-ray diffraction patterns together with Raman spectra confirmed the tetragonal anatase phase of Ni-doped TiO2. High-resolution transmission electron microscopy images indicated the formation of highly crystalline nanocrystals, and the compositional homogeneity of all the samples was confirmed from energy dispersive X-ray fluorescence spectroscopic studies. The functional groups in the samples were identified by Fourier transform infrared spectroscopy. UV-visible and photoluminescence (PL) spectroscopy were performed to provide an insight into the band-gap narrowing in the Ni-doped TiO2 nanocrystals. X-ray photoelectron spectroscopy results signified the existence of Ti4+ and Ni2+ in all the prepared samples. A decrease in coercivity was observed with Ni substitution, and at lower Ni concentration, the magnetic behavior was attributed to the bound magnetic polarons associated with the oxygen vacancy defects arising during the synthesis procedure. PL analysis revealed the presence of defects in the system and Langevin fitting was employed to estimate the concentration of bound magnetic polarons arising as a result of these defects. The band-gap narrowing and the enhanced magnetic moment observed in Ni-doped TiO2 reveal the potential of this semiconductor for advanced functional applications such as magneto-optics and spintronics.

Visible range optical absorption, Urbach energy estimation and paramagnetic response in Cr-doped TiO2 nanocrystals derived by a sol-gel method.

We have carried out a detailed study of the morphological, structural, optical and magnetic properties of Cr doped TiO2 nanocrystals with doping concentrations varying from 3 to 12 atomic weight%. The results obtained from transmission electron microscopy analysis, size-strain plots of all the Cr-doped samples and crystallite size estimation reveal the particle size of the prepared nanocrystals to be well below 10 nm, which is observed to exhibit a decreasing trend with an increase in the Cr dopant concentration. All the samples crystallize in the anatase tetragonal phase of TiO2, which is confirmed from the Rietveld refinement of the X-ray diffraction patterns and the different modes present in the Raman spectra. The Eg(1) mode shows a clear red shift and broadening with increase in the Cr concentration, which indicates the replacement of Ti ions with Cr ions in the TiO2 lattice. The possibility of the presence of different functional groups present is verified by Fourier transform infra-red spectroscopy. The presence of Cr3+ and Ti4+ is confirmed from the X-ray photoelectron spectroscopy (XPS) results suggesting the formation of oxygen vacancies to compensate for the charge neutrality. The XPS results validate the Cr3+ existence in the Cr:TiO2 system and corroborate with a slight peak shift towards lower diffraction angle and further confirm the substitutional doping in the present case. Enhanced visible range optical absorption and a clear red shift associated with the absorption edge also suggest the incorporation of Cr3+ ions into the host system. The estimated band-gap of Cr-doped TiO2 nanocrystals reveals a decreasing trend with increasing Cr concentration. The Urbach energy associated with all the Cr-doped samples signifies the presence of oxygen vacancy related defects in the present system, which is further verified using photoluminescence (PL) spectra, and the deconvolution of the PL spectra provides an insight into the oxygen vacancy defects associated with the system. Paramagnetic (PM) behaviour is observed with an increase in the PM moment, suggesting the increase in isolated Cr ions with increase in the Cr concentration, which is further explained using a bound magnetic polaron (BMP) model. Isolated BMP formation could be the reason for the observed PM behavior of the present system, where the trapping of 3d electrons associated with Cr3+ in the vacancy sites could ultimately lead to fewer overlapped BMPs, yielding a net PM moment. The present Cr:TiO2 system could be modified with tailored optical and magnetic properties for functional applications such as magneto-optics and optoelectronic devices.

Impression of magnetic clusters, critical behavior and magnetocaloric effect in Fe3Al alloys.

Herein, we report unusual magnetic behavior in arc melted bulk stoichiometric Fe3Al alloy with a D03 structure. The temperature variation in the magnetization measurements revealed two transitions, i.e. one at ∼763 K and another at ∼830 K. Below 763 K, it exhibits ferromagnetic ordering and the nature of the transition is second order. However, the second transition is more complex and detailed analysis of the magnetic data suggested the coexistence of ferromagnetic and paramagnetic phases (two-phase: α + D03/α + B2) and structural transitions triggered by temperature. We observed dual peaks in the magnetic entropy change curve, in accordance with the magnetization results, which corroborate the occurrence of a two-phase system. We believe that the concurrent magnetic ordering and the complex two-phase are associated with the evolution of short-range ordered magnetic clusters having a magnetic moment of ∼103µB in the host matrix. A cluster hypothesis is proposed to explain the observed intricate magnetic behavior of this alloy at high temperature. The estimated critical exponents using a modified Arrott plot, Kouvel-Fisher plot and critical isotherm analysis lie in between the 3D-Heisenberg and 3D-Ising model, indicating a short-range interaction and magnetic inhomogeneity, which again are consistent with the magnetization results. The obtained critical exponents follow the universal scaling behavior, which indicates the renormalization of interactions around the magnetic ordering transition (TC). Despite the obvious larger thermal entropy at very high temperature, our synthesized Fe3Al alloy showed enhanced magnetic entropy changes. The obtained magnetic entropy change for binary Fe3Al alloy shows twice the value of that of other binary/ternary Fe-based alloys.

Isolation of taxol producing endophytic fungus Alternaria brassicicola from non-Taxus medicinal plant Terminalia arjuna.

In the present study, an endophytic fungal strain was isolated from its non-Taxus host plant Terminalia arjuna and identified as Alternaria brassicicola based on its morphological characteristics and internal transcribed spacer sequence analysis. This fungus was grown in potato dextrose broth and analyzed for the presence of taxol by using chromatographic and spectrometric techniques. The ethyl acetate extract of A.brassicicola was subjected to column chromatography. Among the different fractions, the fraction 7 showed positive to taxol, which was further confirmed by UV absorption, HPLC, FTIR spectra and LC-ESI-MS by comparing with the authentic taxol (Paclitaxel). The peaks of fraction 7 obtained by UV spectroscopy, FTIR and HPLC analysis were quite similar to that of standard taxol confirming the presence of taxol. A parent ion peak of m/z 854.95 was observed in the LC-ESI-MS spectrum which was similar to paclitaxel with reported m/z of 854 [M+H]+ ion. A. brassicicola produced about 140.8 µg/l taxol as quantified through HPLC. Present study results suggest that the endophytic fungus A.brassicicola serves as a potential source for the production of taxol isolated from non-Taxus plant.

Probing the Mec1ATR Checkpoint Activation Mechanism with Small Peptides.

Yeast Mec1, the ortholog of human ATR, is the apical protein kinase that initiates the cell cycle checkpoint in response to DNA damage and replication stress. The basal activity of Mec1 kinase is activated by cell cycle phase-specific activators. Three distinct activators stimulate Mec1 kinase using an intrinsically disordered domain of the protein. These are the Ddc1 subunit of the 9-1-1 checkpoint clamp (ortholog of human and Schizosaccharomyces pombe Rad9), the replication initiator Dpb11 (ortholog of human TopBP1 and S. pombe Cut5), and the multifunctional nuclease/helicase Dna2. Here, we use small peptides to determine the requirements for Mec1 activation. For Ddc1, we identify two essential aromatic amino acids in a hydrophobic environment that when fused together are proficient activators. Using this increased insight, we have been able to identify homologous motifs in S. pombe Rad9 that can activate Mec1. Furthermore, we show that a 9-amino acid Dna2-based peptide is sufficient for Mec1 activation. Studies with mutant activators suggest that binding of an activator to Mec1 is a two-step process, the first step involving the obligatory binding of essential aromatic amino acids to Mec1, followed by an enhancement in binding energy through interactions with neighboring sequences.

Tailoring Thermoelectric Properties through Structure and Morphology in Chemically Synthesized n-Type Bismuth Telluride Nanostructures.

Here, we report a simple, cost-effective, surfactant-assisted, and aqueous-based low-temperature reflux method for the synthesis of Bi2Te3 nanocrystals. Thermoelectric properties of n-type bismuth telluride (BT) nanostructures are reported by varying the morphology and crystal structure. Tuning the reaction time from 1 to 36 h enables the phase transformation from BiTe with a hexagonal crystal structure to Bi2Te3 with a rhombohedral crystal structure, which is evident from the refined X-ray diffraction results and high-resolution transmission electron microscopy analysis. A perfect stoichiometric balance is achieved for all the compositions, and temperature variation of the electrical resistivity of all BT nanostructures shows the typical metal to semiconducting transition near room temperature. Seebeck coefficient and Hall measurements confirm electrons as the majority carriers and show the typical characteristics of n-type BT nanostructures. The nanocrystals inherited from the optimized reaction conditions and high densification of nanoparticle interfaces contribute to the considerable reduction of thermal conductivity in BT nanostructures. Highly crystalline, uniformly distributed nanocrystals of Bi2Te3 formed for 24 h reaction time demonstrate a promising figure of merit of 0.81 at 350 K, which can be attributed to their low thermal conductivity while the high electrical conductivity is maintained. Our research could provide new possibilities in low-temperature synthesis where structural, compositional, and morphological tuning of BT nanostructures could promote practical thermoelectric applications near room temperature.

The unstructured C-terminal tail of the 9-1-1 clamp subunit Ddc1 activates Mec1/ATR via two distinct mechanisms.

DNA damage checkpoint pathways operate to prevent cell-cycle progression in response to DNA damage and replication stress. In S. cerevisiae, Mec1-Ddc2 (human ATR-ATRIP) is the principal checkpoint protein kinase. Biochemical studies have identified two factors, the 9-1-1 checkpoint clamp and the Dpb11/TopBP1 replication protein, as potential activators of Mec1/ATR. Here, we show that G1 phase checkpoint activation of Mec1 is achieved by the Ddc1 subunit of 9-1-1, while Dpb11 is dispensable. However, in G2, 9-1-1 activates Mec1 by two distinct mechanisms. One mechanism involves direct activation of Mec1 by Ddc1, while the second proceeds by Dpb11 recruitment mediated through Ddc1 T602 phosphorylation. Two aromatic residues, W352 and W544, localized to two widely separated, conserved motifs of Ddc1, are essential for Mec1 activation in vitro and checkpoint function in G1. Remarkably, small peptides that fuse the two tryptophan-containing motifs together are proficient in activating Mec1.

A Novel Extract of Fenugreek Husk (FenuSMART™) Alleviates Postmenopausal Symptoms and Helps to Establish the Hormonal Balance: A Randomized, Double-Blind, Placebo-Controlled Study.

Despite the widespread use of hormone replacement therapy, various reports on its side effects have generated an increasing interest in the development of safe natural agents for the management of postmenopausal discomforts. The present randomized, double-blinded, placebo-controlled study investigated the effect of 90-day supplementation of a standardized extract of fenugreek (Trigonella foenum-graecum) (FenuSMART™), at a dose of 1000 mg/day, on plasma estrogens and postmenopausal discomforts. Eighty-eight women having moderate to severe postmenopausal discomforts and poor quality of life (as evidenced from the scores of Greene Climacteric Scale, short form SF-36® and structured medical interview) were randomized either to extract-treated (n = 44) or placebo (n = 44) groups. There was a significant (p < 0.01) increase in plasma estradiol (120%) and improvements on various postmenopausal discomforts and quality of life of the participants in the extract-treated group, as compared with the baseline and placebo. While 32% of the subjects in the extract group reported no hot flashes after supplementation, the others had a reduction to one to two times per day from the baseline stages of three to five times a day. Further analysis of haematological and biochemical parameters revealed the safety of the extract and its plausible role in the management of lipid profile among menopausal women. Copyright © 2016 John Wiley & Sons, Ltd.

Fusarium tricinctum, An Endophytic Fungus Exhibits Cell Growth Inhibition and Antioxidant Activity.

An endophytic fungus (strain T6) isolated from Taxus baccata was studied for its effect on the growth of human breast cancer cell line (MCF-7), human cervical cancer cell line (HeLa) and peripheral blood mononuclear cells (PBMCs) as well as for its antioxidant activity. Based on morphological characters and internal transcribed spacer (ITS) sequence analysis, this fungus (strain T6) was identified as Fusarium tricinctum. This fungus has shown inhibition in the growth of the MCF-7 and HeLa cancer cell lines. IC50 values of the fungal extract were 225 ± 26 and 220 ± 18 µg ml-1 for MCF-7 and HeLa cell lines, respectively. Further, F. tricinctum showed inhibition in the proliferation of concanavalin A stimulated PBMCs indicating its immunosuppressive potential (IC50 value 110 ± 44 µg ml-1). Tumour necrosis factor (TNF)-α production in concanavalin A stimulated PBMCs and MCF-7 were found to be inhibited which indicates that the antiproliferative effect may be associated with TNF-α. Free radical scavenging results revealed that this fungus also exhibited antioxidant activity (IC50 value 482 ± 9 µg ml-1). Present study results suggested that F. tricinctum has the potential to be used for therapeutic purposes because of its antiproliferative and antioxidant potential.

The intestinal-level metabolic benefits of green tea catechins: Mechanistic insights from pre-clinical and clinical studies.

BACKGROUND: The intestinal-level host-microbiota interaction has been implicated in the pathogenesis of chronic diseases. The current review is intended to provide a comprehensive insight into deciphering whether intestinal-level bioactivities mediate the overall metabolic health benefits of green tea catechins. PURPOSE: We have comprehensively discussed pre-clinical and clinical evidences of intestinal-level changes in metabolism, microbiota, and metabolome due to catechin-rich green tea treatments, ultimately limiting metabolic diseases. Exclusive emphasis has been given to purified catechins and green tea, and discussions on extraintestinal mechanisms of metabolic health benefits were avoided. METHODS: A literature search for relevant pre-clinical and clinical studies was performed in various online databases (e.g., PubMed) using specific keywords (e.g., catechin, intestine, microbiota). Out of all the referred literature, ∼15% belonged to 2021-2023, ∼51% were from 2011-2020, and ∼32% from 2000-2010. RESULT: The metabolic health benefits of green tea catechins are indeed influenced by the intestinal-level bioactivities, including reduction of mucosal inflammation and oxidative stress, attenuation of gut barrier dysfunction, decrease in intestinal lipid absorption and metabolism, favorable modulation of mucosal nuclear receptor signaling, alterations of the luminal global metabolome, and mitigation of the gut dysbiosis. The results from the recent clinical studies support the pre-clinical evidences. The challenges and pitfalls of the currently available knowledge on catechin bioactivities have been discussed, and constructive directions to harness the translational benefits of green tea through future interventions have been provided. CONCLUSION: The metabolism, metabolome, and microbiota at the intestinal epithelia play critical roles in catechin metabolism, pharmacokinetics, bioavailability, and bioactivities. Especially the reciprocal interaction between the catechins and the gut microbiota dictates the metabolic benefits of catechins.

Endophytic fungi: a potential source for drugs against central nervous system disorders.

Neuroprotection is one of the important protection methods against neuronal cells and tissue damage caused by neurodegenerative diseases such as Alzheimer's, Parkinson's, Huntington's, and multiple sclerosis. Various bioactive compounds produced by medicinal plants can potentially treat central nervous system (CNS) disorders. Apart from these resources, endophytes also produce diverse secondary metabolites capable of protecting the CNS. The bioactive compounds produced by endophytes play essential roles in enhancing the growth factors, antioxidant defence functions, diminishing neuroinflammatory, and apoptotic pathways. The efficacy of compounds produced by endophytic fungi was also evaluated by enzymes, cell lines, and in vivo models. Acetylcholine esterase (AChE) inhibition is frequently used to assess in vitro neuroprotective activity along with cytotoxicity-induced neuronal cell lines. Some of drugs, such as tacrine, donepezil, rivastigmine, galantamine, and other compounds, are generally used as reference standards. Furthermore, clinical trials are required to confirm the role of these natural compounds in neuroprotection efficacy and evaluate their safety profile. This review illustrates the production of various bioactive compounds produced by endophytic fungi and their role in preventing neurodegeneration.

Enhanced photocatalytic activity in ZnO nanoparticles developed using novel Lepidagathis ananthapuramensis leaf extract.

The present study focuses on the green synthesis of zinc oxide nanoparticles (ZnO NPs) using a novel Lepidagathis ananthapuramensis (LA) leaf extract and a systematic study on the photocatalytic degradation of methylene blue (MB) dye. The structural, thermal, morphological, optical, and surface area analysis of prepared ZnO NPs were examined using X-ray diffraction (XRD), UV-visible spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis, thermogravimetric analysis (TGA), field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX) and high-resolution transmission electron microscopy (HR-TEM). The LA stabilised ZnO NPs produced NPs with diverse morphologies, low band gap and cost-effective high yield of production. A systematic study has been carried out to determine the crystallinity and crystallite size of ZnO NPs based on the concentration of Zn(NO3)2 precursor, concentration of LA leaf extract, calcination temperature and calcination time. The crystallinity and crystallite size of ZnO NPs were evaluated based on the XRD technique. The photocatalytic activity of ZnO NPs was thoroughly investigated for the degradation of MB dye based on various physicochemical parameters such as reaction time, concentration of catalyst, concentration of precursors, concentration of LA extract, concentration of MB, calcination temperature and calcination time. These systematic photocatalytic studies followed green protocols and provided an excellent photocatalytic efficiency result of 96-98.5% towards the decomposition of MB. Hence, this material can work as a potential candidate for waste water treatment by also degrading other toxic dyes.

Intriguing physicochemical properties and impact of co-dopants on N-doped graphene oxide based ZnS nanowires for photocatalytic application.

Superparamagnetic N-doped graphene oxide (GO)- with ZnS nanowires was synthesized by a one-step hydrothermal method by doping dilute amounts of Ga, Cr, In, and Al ions for water treatment and biomedical applications. In these experiments, to enhance their properties, 2% of Ga3+, In3+, and or Al3+ were codoped along with 2% Cr ions in these ZnS nanowires. The nanocomposite with the composition, In0.02Cr0.02Zn0.96S, has better photocatalytic efficiency than other co-doped nanocomposites. The In (metalloids) and Cr (transition metal ion) are the best combinations to increase the magnetic properties which are beneficial for photocatalytic activity. Synthesized nanocomposite materials were characterized by several techniques such as X-ray diffraction, Field emission-scanning electron microscope (FESEM) with EDAX, vibrating sample magnetometer (VSM), UV-Vis, X-ray photoelectron spectroscopy (XPS), and fluorescence spectroscopy. The correlation of intriguing magnetic properties with their photocatalytic properties is also discussed. XPS was employed for the detection of surface defects, phase transformation, and the nature of chemical components present in the nanocomposites. The Frankel and substitutional defects have a direct impact on photocatalytic activity that was determined from the fluorescence (FL) spectroscopy. FL and XPS reveal that the Cr and In codoped composite has a higher percentage of defects hence its photocatalytic efficiency reaches 94.21%.

The unstructured C-terminal tail of yeast Dpb11 (human TopBP1) protein is dispensable for DNA replication and the S phase checkpoint but required for the G2/M checkpoint.

Budding yeast Dpb11 (human TopBP1, fission yeast Cut5) is an essential protein required for replisome assembly and for the DNA damage checkpoint. Previous studies with the temperature-sensitive dpb11-1 allele, truncated at amino acid 583 of the 764-amino acid protein, have suggested the model that Dpb11 couples DNA replication to the replication checkpoint. However, the dpb11-1 allele shows distinct replication defects even at permissive temperatures. Here, we determine that the 1-600-amino acid domain of DPB11 is both required and sufficient for full replication function of Dpb11 but that this domain is defective for activation of the principal checkpoint kinase Mec1 (human ataxia telangiectasia and Rad3-related) in vitro and in vivo. Remarkably, mutants of DPB11 that leave its replication function intact but abrogate its ability to activate Mec1 are proficient for the replication checkpoint, but they are compromised for the G(2)/M DNA damage checkpoint. These data suggest that replication checkpoint defects may result indirectly from defects in replisome assembly. Two conserved aromatic amino acids in the C terminus of Dpb11 are critical for Mec1 activation in vitro and for the G(2)/M checkpoint in yeast. Together with aromatic motifs identified previously in the Ddc1 subunit of 9-1-1, another activator of Mec1 kinase, they define a consensus structure for Mec1 activation.

Endophytic fungi: a potential source of industrial enzyme producers.

Microbial enzymes have gained interest for their widespread use in various industries and medicine due to their stability, ease of production, and optimization. Endophytic fungi in plant tissues produce a wide range of secondary metabolites and enzymes, which exhibit a variety of biological activities. The present review illustrates promising applications of enzymes produced by endophytic fungi and discusses the characteristic features of the enzymes, application of the endophytic fungal enzymes in therapeutics, agriculture, food, and biofuel industries. Endophytic fungi producing ligninolytic enzymes have possible biotechnological applications in lignocellulosic biorefineries. The global market of industrially important enzymes, challenges, and future prospects are illustrated. However, the commercialization of endophytic fungal enzymes for industrial purposes is yet to be explored. The present review suggests that endophytic fungi can produce various enzymes and may become a novel source for upscaling the production of enzymes of industrial use.