Search

The use of autonomous Unmanned Aerial Vehicles (UAVs) has been increasing, and the autonomy of these systems and their capabilities in dealing with uncertainties is crucial. Autonomous landing is pivotal for the success of an autonomous mission of UAVs. This paper presents an autonomous landing system for quadrotor UAVs with the ability to perform smooth landing even in undesirable conditions like obstruction by obstacles in and around the designated landing area and inability to identify or the absence of a visual marker establishing the designated landing area. We have integrated algorithms like version 5 of You Only Look Once (YOLOv5), DeepSORT, Euclidean distance transform, and Proportional-Integral-Derivative (PID) controller to strengthen the robustness of the overall system. While the YOLOv5 model is trained to identify the visual marker of the landing area and some common obstacles like people, cars, and trees, the DeepSORT algorithm keeps track of the identified objects. Similarly, using the detection of the identified objects and Euclidean distance transform, an open space without any obstacles to land could be identified if necessary. Finally, the PID controller generates appropriate movement values for the UAV using the visual cues of the target landing area and the obstacles. To warrant the validity of the overall system without risking the safety of the involved people, initial tests are performed, and a software-based simulation is performed before executing the tests in real life. A full-blown hardware system with an autonomous landing system is then built and tested in real life. The designed system is tested in various scenarios to verify the effectiveness of the system. The code is available at this repository: https://github.com/rnjbdya/Vision-based-UAV-autonomous-landing.

IntroductionPatients with chronic HBV infection (CHI) exhibit defective anti-viral immune-response whose underlying causes still remain unclear. Monocytes act as immune sentinels for pathogens and can regulate immunity via interaction with other immune-cells, apart from differentiating into macrophages. Immune-checkpoint molecules (ICMs) expressed by immune-cells, including monocytes are known to negatively regulate immune-responses. Here, we evaluated the expression of ICMs, namely, Gal-9, PD-L1, and CTLA-4 on monocytes in different phases of CHI, identified the viral and the host factors causing their aberrant expression and investigated their impact during interaction of monocytes with T-cells, B-cells and NK-cells and also on monocyte to macrophage differentiation. Influence of Tenofovir therapy on the expression of monocytic ICMs was also studied.MethodsCollection of blood and liver-tissue samples from HBV infected patients and controls, flow-cytometry, cell sorting, cell culture and immune-fluorescence were performed for this study.ResultsGal-9+ and PD-L1+-monocytes were significantly increased in HBeAg-positive as well as HBeAg-negative chronic hepatitis B (CHB) patients than healthy controls (HC). In immune-tolerant (IT) subjects, only Gal-9+-monocytes and in inactive carriers (IC), PD-L1+-monocytes were higher than HC while CTLA-4+-monocytes remained comparable among groups. High serum Hepatitis B surface antigen (HBsAg) concentration in CHB as well as IT and TNF-α in CHB triggered monocytic Gal-9-expression whereas, PD-L1 was induced by elevated TNF-α and IL-4 in CHB and IL-1β in CHB and IC. Purified monocytes from CHB and IT having high Gal-9 expression led to expansion of CD4+CD25+FOXP3+-Tregs, CD19+IL-10+-Bregs and CD19+CD27-CD21–atypical memory B-cells and these monocytes also preferentially differentiated into M2-macrophages. These phenomena were reversed by anti-Gal-9-antibody. Parallelly, PD-L1+-monocytes in CHB and IC reduced IL-2/IFN-γ and IL-6 production by HBV-specific T- and B-cells respectively, which were restored by anti-PD-L1-antibody. Both Gal-9+- and PD-L1+-monocytes caused decline in IFN-γ+-NK-cells but enhanced IL-10-expressing HBV-specific-T-cells and NK-cells. Increased intrahepatic CD14+Gal-9+ and CD14+PD-L1+-monocytes were noted in CHB patients than HC. One-year tenofovir therapy failed to reduce monocytic Gal-9 and PD-L1 along with the levels of HBsAg, TNF-α, IL-1β and IL-4.ConclusionsMonocytic Gal-9 and PD-L1, expressed heterogeneously in different phases of CHI, exert diverse inhibitory effects on immune-responses and their therapeutic targeting could boost anti-HBV immunity.

Abstract Successful nerve repair using bioadhesive hydrogels demands minimizing tissue–material interfacial mechanical mismatch to reduce immune responses and scar tissue formation. Furthermore, it is crucial to maintain the bioelectrical stimulation‐mediated cell‐signaling mechanism to overcome communication barriers within injured nerve tissues. Therefore, engineering bioadhesives for neural tissue regeneration necessitates the integration of electroconductive properties with tissue‐like biomechanics. In this study, we propose a stretchable bioadhesive based on a custom‐designed chemically modified elastin‐like polypeptides (ELPs) and a choline‐based bioionic liquid (Bio‐IL), providing an electroconductive microenvironment to reconnect damaged nerve tissue. The stretchability akin to native neural tissue was achieved by incorporating hydrophobic ELP pockets, and a robust tissue adhesion was obtained due to multi‐mode tissue–material interactions through covalent and noncovalent bonding at the tissue interface. Adhesion tests revealed adhesive strength ~10 times higher than commercially available tissue adhesive, Evicel®. Furthermore, the engineered hydrogel supported in vitro viability and proliferation of human glial cells. We also evaluated the biodegradability and biocompatibility of the engineered bioadhesive in vivo using a rat subcutaneous implantation model, which demonstrated facile tissue infiltration and minimal immune response. The outlined functionalities empower the engineered elastic and electroconductive adhesive hydrogel to effectively enable sutureless surgical sealing of neural injuries and promote tissue regeneration.

Hydrogels have been extensively used for tissue engineering applications due to their versatility in structure and physical properties, which can mimic native tissues. Although significant progress has been made toward designing hydrogels for soft tissue repair, engineering hydrogels that resemble load‐bearing tissues is still considered a great challenge due to their specific mechanophysical demands. Herein, microporous, tough, yet highly compressible poly(vinyl alcohol) (PVA)‐based hydrogels are reported for potential applications in repairing or replacing different load‐bearing tissues. The synergy of freeze‐thawing and the Hofmeister effect, which controlled the spatial arrangement and aggregation of polymer chains, facilitated the formation of microstructured frameworks with tunable porosity. While the maximum mechanical strength, toughness, and stretchability of the engineered hydrogel were ≈390 kPa, ≈388 kJ m−3, and ≈170%, respectively, Young's modulus based on compression testing wasfound to be in the range of ≈0.02–0.30 MPa, highlighting the all‐in‐one mechanically enriched nature of the hydrogel. Furthermore, the minimal swelling and degradation rate of the engineered hydrogel met the specific requirements for load‐bearing tissues. Finally, excellent antibacterial resistance as well as in vitro biocompatibility of the hydrogel demonstrates its potential for the replacement of load‐bearing tissues.

Real-time monitoring of human health can be significantly improved by designing novel electronic skin (E-skin) platforms that mimic the characteristics and sensitivity of human skin. A high-quality E-skin platform that can simultaneously monitor multiple physiological and metabolic biomarkers without introducing skin discomfort or irritation is an unmet medical need. Conventional E-skins are either monofunctional or made from elastomeric films that do not include key synergistic features of natural skin, such as multi-sensing, breathability, and thermal management capabilities in a single patch. Herein, a biocompatible and biodegradable E-skin patch based on flexible gelatin methacryloyl aerogel (FGA) for non-invasive and continuous monitoring of multiple biomarkers of interest is engineered and demonstrated. Taking advantage of cryogenic temperature treatment and slow polymerization, FGA is fabricated with a highly interconnected porous structure that displays good flexibility, passive-cooling capabilities, and ultra-lightweight properties that make it comfortable to wear for long periods of time. It also provides numerous permeable capillary channels for thermal-moisture transfer, ensuring its excellent breathability. Therefore, the engineered FGA-based E-skin can simultaneously monitor body temperature, hydration, and biopotentials via electrophysiological sensors and detect glucose, lactate, and alcohol levels via electrochemical sensors. This work offers a previously unexplored materials strategy for next-generation E-skin platforms with superior practicality.

Abstract Replacement of water-intensive winter rice with strawberry (Fragaria × ananassa Duch.) may restrict groundwater extraction and improve water productivity and sustainability of agricultural production in the arsenic-contaminated Bengal basin. The potential of strawberry cultivation in terms of yield obtained and water use efficiency need to be evaluated under predominant soil types with mulch applications. Water-driven model AquaCrop was used to predict the canopy cover, soil water storage and above-ground biomass of strawberry in an arsenic-contaminated area in the Bengal basin. After successful calibration and validation over three seasons, AquaCrop was used over a range of management scenarios (nine drip-irrigation × three soil types × four mulch materials) to identify the best irrigation options for a drip-irrigated strawberry crop. The most appropriate irrigation of 176 mm for clay loam soil in lowland and 189 mm for sandy clay loam in medium land rice areas and the use of organic mulch from locally available jute agrotextile improved 1.4 times higher yield and 1.7 times higher water productivity than that of without mulch. Strawberry can be introduced as an alternative crop replacing rice in non-traditional upland and medium land areas of the arsenic-contaminated Bengal basin with 88% lower groundwater extraction load and better economic return to farmers.

The global outbreak of COVID-19 infection is the first pandemic the world has experienced in this 21st century. The novel coronavirus 2019 (nCoV-19) also called the SARS-CoV-2 is the reason behind the severe acute respiratory syndrome (SARS) that led to this worldwide crisis. In this current post-pandemic situation, despite having effective vaccines, the paucity of orally administrable drug molecules for such infections is a major drawback in this current scenario. Among the different viral enzymes, the SARS-CoV-2 3CLpro is an encouraging target for effective drug discovery and development. In this context, the understanding of the requirements of the small molecules at the active site and their interactions is a crucial aspect of such drug candidate development. Here in this study, structure-based pharmacophore model development and molecular docking-dependent 2D-interaction-based and 3D-field-based QSAR studies have been carried out for a set of potential SARS-CoV-2 3CLpro inhibitors. This study exposed the importance of interactions with amino acids of the active site (such as Leu167 and Gln189 amino acid residues) as well as the importance of hydrogen bond acceptor groups at the S2 and S1′ pockets. The presence of hydrophobic aromatic features as well as hydrophobic contacts at the S1 and S4 pockets were also found to have a key contribution to the SARS-CoV-2 3CLpro inhibition. Moreover, the screened drug candidate Elobixibat from the structure-based virtual screening also explored promising results as evidenced in MD simulation study and thus, can be a promising drug candidate that can be repurposed to assist in the development of effective anti-SARS-CoV-2 therapy.

Abstract Wheat contributes one‐fifth of the global food supply with an estimated 29% of global production in low and lower‐middle income countries. As production expands across southern Asia, yields are often negatively impacted by outbreaks of fungal rust diseases. A wheat rust early warning and advisory system comprising surveillance, near real‐time disease risk forecasts and advisory dissemination has been established in two target countries in South Asia, including Nepal and Bangladesh. However, as wheat rust spores can be aerially transmitted over long distances, near real‐time estimates of disease incidence are required from sources of infection in neighbouring regions. To address this challenge, we developed and tested a novel algorithm to generate proxy observations of infection sources using online media reports in two neighbouring countries, India and Pakistan. Media sampling could provide an effective alternative where data from ground surveys are not readily available in near real‐time. Our results show that west Nepal was exposed to a substantial inoculum pressure from aerially dispersed stripe rust spores originating from India and Pakistan. There were no outbreaks of stripe rust disease in Bangladesh with only very low levels of cross‐border dispersion and generally unfavourable environmental conditions for infection. We further describe how proxy observations informed farmer decision‐making in near real‐time in Nepal and filled a knowledge gap in identifying early sources of infection for a major outbreak of stripe rust during 2020 in Nepal. Our results highlight the importance of international cooperation in mitigating transboundary plant pathogens.

Rice False Smut (RFS) caused by Ustilaginoidea virens is a major emerging disease of rice due to expanded area of hybrid rice cultivars, increasing use of nitrogenous fertilizers and change in climate. Due to the increasing incidences of this disease across the globe, there is a pressing need to develop techniques for false smut management. The application of fungicides with high efficiency, low toxicity, and low residue is currently the best option to control RFS. Therefore, current research was conducted to determine the effectiveness of fungicides to manage RFS. The experiments were conducted in a completely randomized block design with three replications of seven treatments at RFS-prone subtropical hills of Nepal in the main rice growing season, during 2020 and 2021. The fungicides include trifloxystrobin 25 % + tebuconazole 50 %, chlorothalonil 75 %, carbendazim 12 % + mancozeb 63 %, propiconazole 25 %, azoxystrobin 50 %, carbendazim 50 % and untreated control. Fungicides were applied as two foliar sprays, one at booting and the other at flowering. Fungicide spray significantly increased number of tillers per plant (P ≤ 0.01) and reduced the number of false smut-infected tillers per plant (P ≤ 0.05), false smut severity (P ≤ 0.05), and incidence (P ≤ 0.05). False smut incidence percentages were significantly reduced by all the fungicides except mancozeb + carbendazim compared to the non-treated control. The reduction in RFS incidence was 70 % in propiconazole, 71 % in trifloxystrobin + tebuconazole sprayed plots compared to the non-treated control plots. Thus, the application of suitable fungicide at the appropriate stage would give the satisfactory suppression of RFS in a farmers' field in Nepal.

This research was carried out to assess the effects of dietary chitosan on the immunity and reproductive performance of adult Barbonymus gonionotus. The fish (average weight 66.7 ± 0. 86 g) were randomly divided into four treatments: control (0.00 g/kg), CHT-1 (1.00 g/kg), CHT-2 (2.00 g/kg) and CHT-3 (3.00 g/kg) and were fed the appropriately formulated diets for 60 days. The results showed significant differences in the immunological parameters such as lymphocytes, neutrophils, monocytes, immunoglobulin (IgM), and lysozyme activity in the chitosan-fed fish compared to those in the control diet-fed fish. The reproductive hormones such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were significantly enhanced in chitosan fed fish compared to the control. Furthermore, the chitosan-treated diet significantly improved the reproductive performance of adult B. gonionotus compared to control fish. Qualitative histological studies showed that chitosan significantly improved egg morphology and showed mature and uniformly sized eggs compared to the control fish. Similarly, a quantitative histological investigation revealed that chitosan significantly increased oocyte area (µm2) and number of oocyte-3 compared to the control. In conclusion, our study found that dietary chitosan at optimal dose of 1.00 g chitosan/kg feed enhanced immunity, regulated reproductive hormone levels, and promoted reproductive performance and ovarian development in B. gonionotus.

Introduction Diabetic neuropathy is frequently underdiagnosed and undertreated. Logistic problems accompany the routine use of the biothesiometer. Hence, we attempted to find a more easily available alternative.Research design and methods 149 patients with diabetes visiting the outpatient endocrinology clinic were assessed for vibration sense using a 128-Hz tuning fork (absolute timing method) and a biothesiometer. A reading of >25 V on the biothesiometer (known as vibration perception threshold or VPT) was taken as the diagnostic criterion for severe neuropathy while >15 V was used as an indicator of the mild form. The sensitivity and specificity were calculated by constructing the receiver operating characteristic curve (ROC). A p value of

Osteogenesis imperfecta (OI) commonly involving defects in COL1A1 and COL1A2 is a rare hereditary disease of bone fragility affecting 6–7 per 100,000 population. On the other hand, hypopituitarism is a separate entity that manifests with reduced levels of pituitary hormones. The cooccurrence of these two is seldom reported previously in literature as a deviation from Occam's razor. Here, we reported a case of pathological fracture in a 31-year-old male who had blue sclera and secondary adrenal insufficiency, hypogonadotropic hypogonadism, and growth hormone deficiency along with primary autoimmune hypothyroidism. Diagnosis of OI was suggested by heterozygous missense variant in exon 40 of the COL1A2 gene (chr7: g.94423092G > A; Depth: 99×) that resulted in the amino acid substitution of Serine for Glycine at codon 847. Replacement of glucocorticoid, levothyroxine, and testosterone was started along with antiresorptive therapy for better bone health outcomes.