National Academy Science Letters最新文献

In the past two decades, several studies have been reported on the 3D printing of acrylonitrile butadiene styrene (ABS) based functional prototypes (of amorphous nature) using the fused filament fabrication (FFF) process. It has been reported that the reinforcements (commercial metallic powders) result in the tuned crystalline behaviour of the ABS matrix, leading to compromised 3D printing capabilities. This study highlights the fabrication of secondary (2°) recycled ABS filament with reinforcement of burnt incense stick powder waste (ISPW) for acceptable thermo-mechanical properties and 3D printing capabilities. The reinforcement of ISPW (0.75% by wt.) in ABS was selected based on the rheological and mechanical properties. The X-ray diffraction (XRD) results show an improvement in crystallinity (from 28.5 to 34.9%) with a minor change in mechanical strength (from 29.8 MPa to 29.47 MPa) in the ABS-0.75%ISPW composite. The differential scanning calorimetry (DSC) analysis outlined that glass transition temperature (Tg) was improved (from 94.97 °C to 105.27 °C) for the prepared composite. The results were also validated through Fourier-transform infrared spectroscopy (FTIR) analysis.

With the increasing manufacture of plastics and its resultant plastic waste generation, disease outbreaks are likely to occur through the interactive effects of climatic hazards and (transformed) plastic-induced antibiotic resistance. However, no information is available regarding the climatic hazards linked to antibiotic-resistant pandemics in the plastisphere. This comment article offers a new forum for commenting on issues that have not been addressed. Several approaches with remedial and mitigation strategies are suggested in four primary areas (i.e., manufacture of plastics, education, risk assessment, research in public health and medicine).

This short communication presents a novel GaN LED design featuring multiple quantum wells (MQW). The MQW is designed using a specific arrangement of GaN/AlGaN layers in a 5-period superlattice (SL) configuration, positioned both above and below a 3-period stack of AlGaN/InGaN active layers (SAL). The incorporation of SL layers effectively curbs electron and hole leakage from the SAL towards the anode and cathode. This proposed structure optimizes radiative recombination within the quantum wells, resulting in remarkable LED performance: an impressive output power of 9.77 W/cm and internal quantum efficiency of 89%. Notably, efficiency droop is reduced to merely 3.33% at maximum current, rendering it highly promising for low-power lighting applications.

In the Himalayan region of India, conflicts between humans and big cats, particularly common leopards and snow leopards, are an age-old saga. In this study, we used forest department data on compensation to farmers who suffered livestock losses due to leopard attacks in the Great Himalayan National Park Conservation Area to unravel the patterns of livestock depredation, offering a deeper understanding of this enduring and complex human-wildlife dynamic. We found that the intensity of livestock depredation by common leopards varies with the seasons, surging during the pre-monsoon and winter months and spiking during natural calamities. Interestingly, they show a preference for smaller prey over medium and large-sized preys. Yet, amid these seasonal and situational peaks, the overall intensity of livestock depredation by common leopards has been on a decline in recent years. While conflicts in the region appear to be diminishing, it is crucial to reduce villagers' dependence on forests, and alternative livelihood options should be adopted. Both government and non-government organizations can play a pivotal role in mitigating these conflicts and promote harmonious coexistence.

Invasive alien plant species pose a serious threat to plant diversity worldwide, including in India. Many alien plant species have invaded various habitats in the past, making them difficult to control and manage. An interesting plant was collected during a recent floral exploration excursion to the Rajaji National Park, Uttarakhand. This plant was later identified as Hypoestes phyllostachya Baker, commonly known as the Polka Dot Plant. This invasive alien plant species was previously reported from the state of Kerala as a new record for India and later reported from West Bengal and Tamil Nadu. A critical review of the literature shows that this is a new record for North India. This paper deals with the taxonomic treatment of Hypoestes phyllostachya Baker and its potential threats to native plants in Rajaji National Park and in North India across different habitats.

Present study provides first live occurrence of a mantis shrimp Lysiosquilla tredecimdentata Holthuis, 1941 (Total length—238 mm and Total wet weight—110 g) from the intertidal sea grass bed of Haripur creek (19°15′ 45″ N and 84°54′ 52″ E) of Gopalpur-on-sea, Odisha coast being noticed on 21st June 2022. This study reports about the Lysiosquilla tredecimdentata range extension from Andhra Pradesh in south and West Bengal in north to Odisha coast of India. Although the creek ecosystem is not completely free from the impact of pollution stress and natural calamities such as tropical cyclone, the factors responsible for such occurrence have not been identified yet. Conversely, habitat suitability and availability of preferred food substance due to the newly formed sea grass meadow might have supported such type of stomatopod species for migrating towards the creek waters. Indeed, this record has increased the Odisha coast’s stomatopod species diversity to fifteen.

Many papers are being published in many different journals on modeling of Covid-19 data. The vast majority of these papers contributes much to how to handle the epidemic. On the other hand, there have been papers misusing Covid-19 data, for example, simply for mathematical/statistical innovation. In this note, we discuss one such paper where modeling of two data sets of Covid-19 were considered. We show that the data sets can be modeled better by simpler distributions, including the one-parameter exponential distribution. The better fits were shown by the Kolmogorov-Smirnov statistic, its p-value, probability plots and other goodness-of-fit criteria.

The signal peptide sequence of Salmonella OsmY and OmpA proteins as well as beta-lactamase (Bla) was synthesized and cloned into the Nco I/Nde I site of plasmid pET28a-EGFP, resulting in the construction of plasmid pET28a-OsmY-EGFP, pET28a-OmpA-EGFP, and pET28a-Bla-EGFP, respectively. Followed by transfermation into the wild-type Salmonella strain TT-1, the signal peptide fused EGFP were expressed in the presence of 0.5% isopropyl β-D-thiogalactopyranoside (IPTG). The localization of EGFP in Salmonella was determined by periplasmic protein quantification, fluorescence microscopy and the measurement of fluorescence intensity. The signal peptide of OsmY, OmpA or Bla not only direct EGFP to the periplasm of Salmonella but also kept its activity. Amongest the three peptides, the signal peptide of OsmY was the most efficient, resulting in the highest level of EGFP in the periplasmic space of Salmonella. In the present study, we assessed the efficacy of the signal peptide of OsmY, OmpA or Bla in directing the EGFP to the periplasm of Salmonella. We suggested that the Sec pathway of Salmonella is capable of exporting heterologous proteins in an active form, and the signal peptide of OsmY could deliver EGFP to the periplasm of Salmonella effectively.

A comparative performance analysis has been investigated on wire-cut electrical discharge machining (WEDM) responses while machining a hybrid titanium matrix composite (TMC) varying the key input parameters like power (P), peak current (IP) and time-off (Toff). Two novel multi-objective optimization algorithms are developed namely desirable multi-objective genetic algorithm (DMOGA) and desirable particle swarm optimization (DPSO). The principal advantage of DMOGA to other algorithm is accuracy and robustness. The novelty fits in the iterative progression of growth of efficient grandee set, uttered as population congregating to a fitness function. DPSO is an enthralling computational method depending on the social behavior of birds and fish where ‘swarm’ of potential solutions termed as particles explores the problem in space for obtaining the multi-objective optimization (MOO) solution where the desirable objective function is fetched in python using PSO. Experimental investigation is accepted on material removal rate (MRR), surface roughness (SR), kerf width (KW) and over cut (OC). Combined desirability in case of DMOGA is 0.716 which improved to 0.813 when DPSO is proposed. MOO is improved with DPSO of 13.547% when contrasted with DMOGA, with MRR of 3.81 mm³/min, SR of 0.79 µm, KW of 0.349 mm, OC of 0.099 mm and combined desirability of 0.813. Improved optimality set is obtained when DPSO is used. %improvement of MRR is 5.54%, SR is 75.95%, KW is 0.29% and OC is 4.21%.

The science of cytogenetics deals with the structure and behavior of chromosomes during the mitotic and meiotic division of cells. Chromosomal studies have received significant attention over the past few years, especially in the disciplines of Karyology and Cytogenetics. Animal species provide a vital contribution to the knowledge of chromosome evolution. The species studied during the present investigation possessed 2n = 74 chromosomes and the karyotypic formula of Himalayapotamon emphysetum was found to be 2n = 46 m + 10sm + 6st + 12t. Meiosis was observed to be normal and thirty-seven bivalents in the form of rings were observed during diakinesis. The individual chromosomes in the Karyotype were identified by using NOR-banding method. The data generated during the present study adds great knowledge to the karyosystematics of the crab species and will help understand interrelationships among the different crab species and also aids in undertaking hybridization programmes. Data related to the karyotypic features is considered a pre-requisite for genomic studies.