Free-ranging dogs are seriously threatening Himalayan environment: delineating the high-risk areas for curbing free-ranging dog infestation in the Trans-Himalayan region.

It is becoming more widely recognised that free-ranging dogs, which have a nearly global distribution, threatening native wildlife. Their increasing population and spread to new areas is of growing concern for the long-term viability of wildlife species. Hence, it is imperative to understand the factors responsible for their infestation and map areas where native species are most vulnerable. Using the random forests algorithm, we modelled the free-ranging dog infestation in the Trans-Himalayan region to pinpoint the high-risk areas where free-ranging dogs are threatening the native wildlife species. We found that the likelihood of free-ranging dog occurrence is most in valley regions and up to 4000 m, often in proximity to roads. Our results also indicated that free-ranging dog prefers areas with wildlife near to protected areas. The predictor variables, such as potential evapotranspiration of the coldest quarter, distance to protected areas, elevation, distance to roads, and potential evapotranspiration of the driest quarter, significantly influence the distribution of the free-ranging dogs. We found that within the Ladakh region of the Trans-Himalayan area, the high-risk zones for free-ranging dogs are located in and around Hemis National Park, Karakoram Wildlife Sanctuary, and Changthang Wildlife Sanctuary. While, in the Lahaul and Spiti region the high-risk areas encompass Pin Valley National Park, Inderkilla National Park, Khirganga National Park, Kugti Wildlife Sanctuary, and several other protected areas. We identified the potentially high-risk areas for implementing strategies to mitigate the possible impact of free-ranging dogs on native wildlife of the Himalayas. Hence, the identified high priority areas can be used for implementing actions for controlling the population growth and further preventing the infestation of the free-ranging dogs into the new areas.

Experimental investigation of degree of cross-polarization for an electromagnetic Gaussian-Schell model beam.

We investigate the properties of the degree of cross-polarization (DOCP) for an electromagnetic Gaussian-Schell model (EMGSM) beam in the radial direction of the cross section of the beam. The coherence and polarization features of a partially coherent light beam are engineered to construct the isotropic and non-isotropic EMGSM beams, and the resulting changes in the DOCP are examined. For experimental realization, a double-slit interferometer is utilized at the output to probe the coherence properties for different polarization components across the beam diameter of an electromagnetic source. Experimental observations infer that variation in DOCP does not become apparent for isotropic coherence widths in the orthogonal polarization directions, whereas the variation can be apparent only once both the coherence widths are distinct. Furthermore, experimentally, a special case is also investigated for which the value of DOCP goes beyond unity. The DOCP finds application in areas such as second-order intensity interference, imaging, and characterization of non-homogeneously polarized beams.

Statistical features of an electromagnetic Gaussian-Schell model beam propagating through a smoke aerosol environment.

In this paper, we investigate both theoretically and experimentally the statistical properties of an electromagnetic Gaussian-Schell model (EMGSM) beam propagating through polluted atmosphere specifically containing smoke aerosol medium. Experimentally, a glass chamber of 1 m length is constructed to mimic the smoky atmosphere inside the laboratory, in which incense sticks are used for smoke aerosol production inside the chamber in a time-controlled manner. An input EMGSM beam having a variable degree of coherence and degree of polarization (DOP) propagates through the aerosol medium, and its coherence and polarization features after propagation are probed. The results show that the coherence features of the vectorial beam are modified significantly by the smoke aerosol medium, while, for the given propagation length of 1 m, the polarization features remain unaffected. We also investigate the coherence features of the EMGSM beam through smoke aerosols in a particular condition when the DOP of the beam is kept zero. These results are expected to provide insights into atmospheric effects on free-space optical communication in real situations when the medium contains air pollution.

Organoids: A new approach in toxicity testing of nanotherapeutics.

Nanotechnology has revolutionized diverse fields, which include agriculture, the consumer market, medicine, and other fields. Widespread use of nanotechnology-based products has led to increased prevalence of these novel formulations in the environment, which has raised concerns regarding their deleterious effects. The application of nanotechnology-based formulations into clinical use is hampered by the lack of the availability of effective in vitro systems, which could accurately assess their in vivo toxic effects. A plethora of studies has shown the hazardous effects of nanoparticle-based formulations in two-dimensional in vitro cell cultures and animal models. These have some associated disadvantages when used for the evaluation of nano-toxicity. Organoid technology fills the space between existing two-dimensional cell line culture and in vivo models. The uniqueness of organoids over other systems for evaluating toxicity caused by nano-drug formulation includes them being a co-culture of diverse cell types, dynamic flow within them that simulates the actual flow of nanoparticles within biological systems, extensive cell-cell, cell-matrix interactions, and a tissue-like morphology. Thus, it mimics the actual tissue microenvironment and, subsequently, provides an opportunity to study drug metabolism and toxico-dynamics of nanotechnology-based novel formulations. The use of organoids in the evaluation of nano-drug toxicity is in its infancy. A limited number of studies conducted so far have shown good predictive value and efficiently significant data correlation with the clinical trials. In this review, we attempt to introduce organoids of the liver, lungs, brain, kidney intestine, and potential applications to evaluate toxicity caused by nanoparticles.

Superior Orbital Fissure Syndrome in a Case of Breast Cancer.

Metastasis from breast cancer to the head and neck region is a rare occurrence. However, of all the cancers that metastasise to the orbit, breast cancer is the leading cause in women. Usually, breast cancer metastasises to the fat and muscles in the orbit, and involvement of the bony orbital wall is rare. We report a case of a 52-year-old woman who presented with metastasis to the left greater wing of the sphenoid and adjacent squamous temporal bone. Ophthalmoplegia and proptosis were the initial manifestations in this patient, which lead to the diagnosis of the underlying breast cancer.

Minimally invasive surgery in India during the COVID-19 pandemic: A survey.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has posed an unprecedented challenge to the healthcare systems worldwide. This uncharted territory has changed the practices in modern healthcare delivery; this is particularly true in the case of minimally invasive surgery (MIS) where various changes are being adopted. This survey was conducted to determine the impact of the pandemic and the changes being adopted in the field of MIS, from a resource-limited developing country, India. MATERIALS AND METHODS: The survey was carried out from 27 July to 22 August 2020, amongst MIS surgeons in India using an online questionnaire generated on Google Forms. RESULTS: The survey was completed by 251 MIS surgeons nationwide. There was a proportional reduction of overall elective surgeries and MIS. Approximately 30% of the surgeons continued to use MIS, as during the pre-pandemic era. Pre-operative tests for COVID-19 (96.1%) and personal protective equipment (PPE, 66%-86%), including respirators (95.2%), are used uniformly across the nation. Almost half (43.1%) of the MIS surgeons are using ≥6 recommended intraoperative modifications in MIS to mitigate the COVID-19 transmission. CONCLUSION: MIS surgeons in India have adapted within a short time to the challenge of the pandemic by embracing pre-operative testing, PPE and new techniques/technologies to continue patient care. Innovations and low-cost indigenous customisations are the need of the hour for a developing country like India. Further studies are required to establish the true risk of viral transmission involved in MIS and the efficacies of the techniques/devices to reduce the spread of the virus.

Preparedness of the cancer hospitals and changes in oncosurgical practices during COVID-19 pandemic in India: A cross-sectional study.

BACKGROUND AND OBJECTIVES: Coronavirus disease-2019 (COVID-19) pandemic has impacted cancer care across India. This study aimed to assess (a) organizational preparedness of hospitals (establishment of screening clinics, COVID-19 wards/committees/intensive care units [ICUs]/operating rooms [ORs]), (b) type of major/minor surgeries performed, and (c) employee well-being (determined by salary deductions, paid leave provisions, and work in-rotation). METHODS: This online questionnaire-based cross-sectional study was distributed to 480 oncosurgeons across India. We used χ2 statistics to compare responses across geographical areas (COVID-19 lockdown zones and city tiers) and type of organization (government/private, academic/nonacademic, and dedicated/multispecialty hospitals). P < .05 was considered significant. RESULTS: Total of 256 (53.3%) oncologists completed the survey. About 206 hospitals in 85 cities had screening clinics (98.1%), COVID-19 dedicated committees (73.7%), ward (67.3%), ICU's (49%), and OR's (36%). Such preparedness was higher in tier-1 cities, government, academic, and multispecialty hospitals. Dedicated cancer institutes continued major surgeries in all oncological subspecialties particularly in head and neck (P = .006) and colorectal oncology (P = .04). Employee well-being was better in government hospitals. CONCLUSION: Hospitals have implemented strategies to continue cancer care. Despite limited resources, the significant risk associated and financial setbacks amidst nationwide lockdown, oncosurgeons are striving to prioritize and balance the oncologic needs and safety concerns of cancer patients across the country.

Evaluating five different loci (rbcL, rpoB, rpoC1, matK, and ITS) for DNA barcoding of Indian orchids.

Orchidaceae, one of the largest families of angiosperms, is represented in India by 1600 species distributed in diverse habitats. Orchids are in high demand owing to their beautiful flowers and therapeutic properties. Overexploitation and habitat destruction have made many orchid species endangered. In the absence of effective identification methods, illicit trade of orchids continues unabated. Considering DNA barcoding as a potential identification tool, species discrimination capability of five loci, ITS, matK, rbcL, rpoB, and rpoC1, was tested in 393 accessions of 94 Indian orchid species belonging to 47 genera, including one listed in Appendix I of CITES and 26 medicinal species. ITS provided the highest species discrimination rate of 94.9%. While, among the chloroplast loci, matK provided the highest species discrimination rate of 85.7%. None of the tested loci individually discriminated 100% of the species. Therefore, multi-locus combinations of up to five loci were tested for their species resolution capability. Among two-locus combinations, the maximum species resolution (86.7%) was provided by ITS+matK. ITS and matK sequences of the medicinal orchids were species specific, thus providing unique molecular identification tags for their identification and detection. These observations emphasize the need for the inclusion of ITS in the core barcode for plants, whenever required and available.

Is decompressive surgery the only treatment option? A case series of patients with spinal tuberculosis in advanced pregnancy.

PURPOSE: To present cases of spinal tuberculosis in advanced pregnancy treated on anti-tuberculous drug regimen with successful outcome and proposing alternative paradigm to surgical decompression. A case series of five patients in stages of advanced pregnancy with neurologic deterioration and spinal tuberculosis were reported and treated. METHODS: Five patients with backache in advanced stages of pregnancy were reported. Patients were diagnosed as cases of spinal tuberculosis on further imaging studies. Patients were treated and followed up till complete clinical and radiological recovery. RESULTS: Four out of five patients were treated conservatively on ATT and rest. One patient underwent decompression without instrumentation. All patients recovered neurologically. There were foetal complications in two cases with foetal demise. One patient who underwent surgical decompression had preterm labour with still birth, apparently due to adverse reactions with anaesthetic drugs. CONCLUSION: Spinal tuberculosis in pregnancy is a rare occurrence. Hesitation in performing radiographs complicates the outcome with delay in diagnosis and neurological compromise. There are no clear guidelines for treatment of such cases. Conservative treatment with ATT in pregnant patients may be a viable approach. Neurological compromise does not mandate surgical decompression, which in itself is not devoid of complications. Concern of foetal complications is high in surgical treatment.

An Enhanced Memetic Algorithm for Single-Objective Bilevel Optimization Problems.

Bilevel optimization, as the name reflects, deals with optimization at two interconnected hierarchical levels. The aim is to identify the optimum of an upper-level  leader problem, subject to the optimality of a lower-level follower problem. Several problems from the domain of engineering, logistics, economics, and transportation have an inherent nested structure which requires them to be modeled as bilevel optimization problems. Increasing size and complexity of such problems has prompted active theoretical and practical interest in the design of efficient algorithms for bilevel optimization. Given the nested nature of bilevel problems, the computational effort (number of function evaluations) required to solve them is often quite high. In this article, we explore the use of a Memetic Algorithm (MA) to solve bilevel optimization problems. While MAs have been quite successful in solving single-level optimization problems, there have been relatively few studies exploring their potential for solving bilevel optimization problems. MAs essentially attempt to combine advantages of global and local search strategies to identify optimum solutions with low computational cost (function evaluations). The approach introduced in this article is a nested Bilevel Memetic Algorithm (BLMA). At both upper and lower levels, either a global or a local search method is used during different phases of the search. The performance of BLMA is presented on twenty-five standard test problems and two real-life applications. The results are compared with other established algorithms to demonstrate the efficacy of the proposed approach.

Standardised extract of Bacopa monniera (CDRI-08) improves contextual fear memory by differentially regulating the activity of histone acetylation and protein phosphatases (PP1α, PP2A) in hippocampus.

Contextual fear conditioning is a paradigm for investigating cellular mechanisms involved in hippocampus-dependent memory. Earlier, we showed that standardised extract of Bacopa monniera (CDRI-08) improves hippocampus-dependent learning in postnatal rats by elevating the level of serotonin (5-hydroxytryptamine, 5-HT), activate 5-HT3A receptors, and cyclic adenosine monophosphate (cAMP) response element binding (CREB) protein. In this study, we have further examined the molecular mechanism of CDRI-08 in hippocampus-dependent memory and compared to the histone deacetylase (HDACs) inhibitor sodium butyrate (NaB). To assess the hippocampus-dependent memory, wistar rat pups were subjected to contextual fear conditioning (CFC) following daily (postnatal days 15-29) administration of vehicle solution (0.5 % gum acacia + 0.9 % saline)/CDRI-08 (80 mg/kg, p.o.)/NaB (1.2 g/kg in PBS, i.p.). CDRI-08/NaB treated group showed enhanced freezing behavior compared to control group when re-exposed to the same context. Administration of CDRI-08/NaB resulted in activation of extracellular signal-regulated kinase ERK/CREB signaling cascade and up-regulation of p300, Ac-H3 and Ac-H4 levels, and down-regulation of HDACs (1, 2) and protein phosphatases (PP1α, PP2A) in hippocampus following CFC. This would subsequently result in an increased brain-derived neurotrophic factor (Bdnf) (exon IV) mRNA in hippocampus. Altogether, our results indicate that CDRI-08 enhances hippocampus-dependent contextual memory by differentially regulating histone acetylation and protein phosphatases in hippocampus.

A framework for design optimization across multiple concepts.

In engineering design, there often exist multiple conceptual solutions to a given problem. Concept design and selection is the first phase of the design process that is estimated to affect up to 70% of the life cycle cost of a product. Currently, optimization methods are rarely used in this phase, since standard optimization methods inherently assume a fixed (given) concept; and undertaking a full-fledged optimization for each possible concept is untenable. In this paper, we aim to address this gap by developing a framework that searches for optimum solutions efficiently across multiple concepts, where each concept may be defined using a different number, or type, of variables (continuous, binary, discrete, categorical etc.). The proposed approach makes progressive data-driven decisions regarding which concept(s) and corresponding solution(s) should be evaluated over the course of search, so as to minimize the computational budget spent on less promising concepts, as well as ensuring that the search does not prematurely converge to a non-optimal concept. This is achieved through the use of a tree-structured Parzen estimator (TPE) based sampler in addition to Gaussian process (GP), and random forest (RF) regressors. Aside from extending the use of GP and RF to search across multiple concepts, this study highlights the previously unexplored benefits of TPE for design optimization. The performance of the approach is demonstrated using diverse case studies, including design of a cantilever beam, coronary stents, and lattice structures using a limited computational budget. We believe this contribution fills an important gap and capitalizes on the developments in the machine learning domain to support designers involved in concept-based design.

Leaching of organic matter from cigarette butt filters as a potential disinfection by-products precursor.

The study aimed to evaluate cigarette butt filters (CBFs) as a potential source of dissolved organic carbon (DOC) in water leading to the formation of disinfection by-products. Two different forms of CBFs - intact (I) and disintegrated (D), as they occur in the environment, were selected for leaching in chlorinated (CI, CD), non-chlorinated (NI, ND), and highly chlorinated (HCD) water samples. The UV absorbance profiles of the leachate samples showed that intact CBFs exhibited higher DOC leaching compared to the disintegrated ones, which was further accentuated in chlorinated samples (CI > CD > NI > ND). The Fourier Transform Infrared spectra of the leachates revealed the presence of characteristic functional groups of cellulose acetate and its chlorinated derivatives, indicating the potential degradation of the polymer. Moreover, trihalomethane (THM) formation in chlorinated samples was relatively higher in CI samples (2 - 11.5 times) compared to CD, consistent with the DOC leaching trends. Further, the speciation characteristics of different THMs in both CI and CD samples were similar. Although spectral and morphological analyzes of CI and CD samples revealed negligible variation, HCD samples depicted significant surface roughness characterized by the formation of pits and holes, along with the evolution of crystallinity. This suggested accelerated degradation of CBFs and disruption of acetyl groups as a factor of elevated chlorine concentrations.

ß-Carotene laden antibacterial and antioxidant gelatin/polyglyceryl stearate nano-hydrogel system for burn wound healing application.

Worldwide, burn wounds are severe health issues prone to bacterial infections and challenging to treat with traditional wound dressings. Therefore, a highly desirable biological macromolecules-based wound dressing with good antioxidant, antibacterial, biocompatible, and a large surface area is required. Herein, aim to develop a biological macromolecules-based physically cross-linked gelatin/polyglyceryl stearate/graphene oxide (GPGO) hydrogel to treat burn wounds. Four sets of hydrogels were prepared by varying GO concentrations. FT-IR, FE-SEM, viscosity analysis, mechanical and thermal stability confirmed the successful preparation of hydrogels with desired properties. Further, ß-carotene (0.5 mg/mL) was encapsulated in hydrogels to enhance the antioxidant activity, and a cumulative release as well as kinetics at pH 6.4 and 7.4 was performed. With an increase in GO concentration, hydrogels showed sustained release of ß-carotene. Among all, GPGO-3 ß hydrogel showed the highest antioxidant potency (57.75 %), hemocompatible (<5 %), cytocompatible (viable with NIH 3T3 cells), cell migration, proliferation, and in vitro wound healing. Also, GPGO-3 ß hydrogel showed efficient antibacterial activity (%inhibition of 85.5 % and 80.2 % and zone of 11 mm and 9.8 mm against S. aureus and E. coli). These results demonstrated the ability of GPGO-3 ß hydrogel as a promising candidate for burn wound healing applications.

Preserving plum perfection: Buckwheat starch edible coating with xanthan gum and lemongrass essential oil.

The research focused on the fabrication of composite coatings using buckwheat starch (BS) and xanthan gum (XG) with incorporation of lemongrass (Cymbopogon citratus) essential oil (LEO) with varying concentration (0.75 %, 1.0 % and 1.25 % (w/v). BS was extracted from buckwheat groats (Fagopyrum esculentum) and its physico-chemical characteristics were determined. BS showed spherical and polygonal morphology and its XRD pattern was similar to starch extracted from other cereal sources. The amount of reducing sugar, starch and amylose content in extracted BS were 0.99 ± 0.33 %, 86.32 ± 0.22 % and 21.02 ± 1.89 % respectively, which indicates that BS is a suitable base material for the formation of edible coatings. XG was mixed with BS in different ratios (1:1, 2:1, 3:1 and 4:1) to optimize the best ratio of combination for composite coatings. The coating with a ratio of 2:1 was very smooth and was chosen for incorporation of LEO and the coatings physical, functional, mechanical, thermal and micro-structural characteristics were examined. The coating S5 with 1.25 % (w/v) concentration of LEO showed the best results with least moisture content (MC), minimum water vapor permeability (WVP) and maximum contact angle value. Moreover, the S5 formulation had the highest antioxidant (73.3 %) ability and maximum antimicrobial efficiency with inhibition zones of 22.09 ± 0.06 mm and 28.65 ± 0.14 mm against S. aureus and E. coli respectively. The coatings were then coated on plum fruit, and various parameters like weight loss, pH, shrinkage and TSS were calculated every 4th day during the 20 days of refrigeration period. The coated plums' ripening pace was delayed by the S5 formulation which improved moisture retention, maintained the plums' TSS value and overall pH. Therefore, composite coatings made up of BS, XG and 1.25 % (w/v) can be used as a cost-effective bio-active coating material for plum preservation under refrigeration conditions.

Nanoengineered oxygen-releasing polymeric scaffold with sustained release of dexamethasone for bone regeneration.

Maintaining the continuous oxygen supply and proper cell growth before blood vessel ingrowth at the bone defect site are considerably significant issues in bone regeneration. Oxygen-producing scaffolds can supply oxygen and avoid hypoxia leading to expedited bone regeneration. Herein, first oxygen-producing calcium peroxide nanoparticles (CPO NPs) are synthesized, and subsequently, the various amounts of synthesized CPO NPs (0.1, 0.5, and 1 wt/v%) loaded in the scaffold composite, which is developed by simple physical blending of chitosan (CS) and polycaprolactone (PCL) polymers. To deliver the synergistic therapeutic effect, dexamethasone (DEX), known for its potential anti-inflammatory and osteogenic properties, is loaded into the nanocomposite scaffolds. The extensive physicochemical characterizations of nanocomposite scaffolds confirm the successful loading of CPO NPs, adequate porous morphology, pore size, hydrophilicity, and biodegradability.In vitro, biological studies support the antibacterial, hemocompatible, and cytocompatible (MG-63 and MC3T3-E1 cells) nature of the material when tested on respective cells. Field emission scanning electron microscopy and energy-dispersive x-ray spectroscopy confirm the successful biomineralization of the scaffolds. Scaffolds also exhibit the sustained release of DEX and efficient protein adsorption. This study revealed that a nanoengineered scaffold loaded with CPO NPs (PCL/CS/DEX/CPO 3) is a suitable candidate for bone tissue regeneration.

Technological Interventions Enhancing Curcumin Bioavailability in Wound-Healing Therapeutics.

Wound healing has been a challenge in the medical field. Tremendous research has been carried out to expedite wound healing by fabricating various formulations, some of which are now commercially available. However, owing to their natural source, people have been attracted to advanced formulations with herbal components. Among various herbs, curcumin has been the center of attraction from ancient times for its healing properties due to its multiple therapeutic effects, including antioxidant, antimicrobial, anti-inflammatory, anticarcinogenic, neuroprotective, and radioprotective properties. However, curcumin has a low water solubility and rapidly degrades into inactive metabolites, which limits its therapeutic efficacy. Henceforth, a carrier system is needed to carry curcumin, guard it against degradation, and keep its bioavailability and effectiveness. Different formulations with curcumin have been synthesized, and exist in the form of various synthetic and natural materials, including nanoparticles, hydrogels, scaffolds, films, fibers, and nanoemulgels, improving its bioavailability dramatically. This review discusses the advances in different types of curcumin-based formulations used in wound healing in recent times, concentrating on its mechanisms of action and discussing the updates on its application at several stages of the wound healing process. Impact statement Curcumin is a herbal compound extracted from turmeric root and has been used since time immemorial for its health benefits including wound healing. In clinical formulations, curcumin shows low bioavailability, which mainly stems from the way it is delivered in the body. Henceforth, a carrier system is needed to carry curcumin, guard it against degradation, while maintaining its bioavailability and therapeutic efficacy. This review offers an overview of the advanced technological interventions through tissue engineering approaches to efficiently utilize curcumin in different types of wound healing applications.

Easily injectable gelatin-nonanal hydrogel for endoscopic resectioning of gastrointestinal polyps.

The use of submucosal injection is crucial for satisfactory submucosal elevation in the early resection of flat polyps originating from the gastrointestinal tract (GIT). Injectable hydrogels derived from natural polypeptides are attractive candidates due to their excellent biocompatibility and easy gelation properties. However, most of the reported hydrogels are not the class of catheter delivery materials due to quick gelation, high inherent viscosity, and injection clogging. This study presents a novel injectable shear-thinning hydrogel platform of small molecules (nonanal) modified gelatin polymer, which offers a promising submucosal injection for effective removal of polyps from GIT. Physicochemical characterizations of hydrogel demonstrate the suitable features as an effective submucosal injection, including shear thinning property, self-assembly, methylene blue dye encapsulation, flow behavior, stability, syringeability (18 G, 21 G, and 24 G needles) and fibrous morphology. Ex vivo investigations of developed submucosal formulation on goat intestines demonstrate the enhanced visibility of cushions and the ability to produce stable, long-lasting cushions of about 8.07 mm up to ∼60 min of submucosal injection. The rapid blood clotting behavior of hydrogel was observed in about 120 s without compromising hemocompatibility with the hemolysis of about 3.77 % only. In vitro biocompatibility of the hydrogel was also verified using the HepG2 and nHDF cells. In vivo study depicts desirable biocompatibility, a non-toxic organ profile, and optimal cushion height in mice models. Studies established the foundation of novel submucosal fluid to improve the therapeutic outcomes of early resection for gastrointestinal polyps.

Recent Advances in Direct Regioselective C-H Chlorination at Aromatic and Aliphatic.

Direct installation of key functionalities in a molecule through C-H bond activation is one of the thrust areas as well as challenging task in organic synthesis. Particularly, introduction of chlorine in a molecule imparts additional benefits for further functionalizations as well as improves the electronic behaviour such as lipophilicity and polarity towards drug development process. The chlorinated molecules have also been established as efficient biologically relevant scaffolds. Current manuscript has been focused on the direct installation of the chlorine atom at various aromatic and aliphatic positions to produce functional molecules. The key highlight of the manuscript belongs to the site selectivity (regioselectivity) for the installation of chlorine functionality. Manuscript describes the advanced methods developed for the direct C-H chlorination reactions and further simplified for the chlorination reactions at various positions including aromatic (o-, m-, and p-), benzylic, heteroaromatic, and aliphatic positions. Directing groups (DGs) and the coordination with the catalyst is the key for the enhancement of regioselectivities during direct C-H chlorination reactions.

Chitosan-based electrospun fibers for bone-tissue engineering: Recent research advancements.

Chitosan, a sustainable and highly abundant animal-derived biopolymer, possesses versatile properties, such as solubility, film-forming ability, viscosity, ion binding, and antimicrobial qualities, which are suitable for biomedical applications. Due to its charged nature, chitosan is a lucrative biopolymer for scaffold fabrication, especially for bone-tissue engineering applications, using the electrospinning method, which is an industrially suitable, scalable, and swift method for fabricating porous nanocomposite structures. Despite a lot of research being conducted on chitosan-based electrospun materials for bone tissue engineering, the research on this topic has not been thoroughly reviewed. This review article aims to fill this knowledge gap and provides an in-depth discussion of the research on this topic. To start with, a brief overview of bone tissue engineering has been provided, followed by the properties of chitosan, which make it an important biopolymer for this application. Also, the important factors that must be considered while electrospinning chitosan, especially considering its application in bone tissue engineering, have been debated. Further, the type of chitosan-based electrospun material has been discussed along with the recent advancements in this research area. Finally, a brief perspective on the future of this technology has been provided.