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Pupal colour–pupation substrate correlation in butterflies
No full textThe pupal colour of many butterflies is plastic, being green or brown depending on the environment in which they develop. In most species with pupal colour plasticity (PCP), larvae that pupate on leaves tend to develop into green pupae whereas those that pupate off-leaf (e.g., on the stem or soil) tend to become brown. This correlation between background and pupal colour has been hypothesized to protect the butterflies against predation by allowing them to match their background, although experimental evidence is scarce. Furthermore, not all butterflies exhibit PCP, and the extent to which substrate choice influences PCP remains unclear. We use a comparative approach involving multiple, closely related species varying in the degree of PCP to test predictions related to the correlation between pupal colour and pupation substrate. We studied PCP in response to larval density in five common satyrine species (Nymphalidae), two dimorphic and three monomorphic. As predicted, species with monomorphic green pupae preferred to pupate on leaves whereas those with monomorphic brown pupae preferred off-leaf substrates. In species with dimorphic pupae, pupal colour correlated with pupation substrate. We also predicted that higher larval density induces a greater proportion of off-leaf pupation in the dimorphic species, but not in the monomorphic species. However, this prediction was not supported. Overall, we found a strong across-species correlation between pupation substrate choice and pupal colour plasticity, and our results support the idea that pupal colour plasticity can be an adaptation against predation
Room-Temperature Electron-Hole Condensation in Direct-Band-Gap Semiconductor Nanocrystals
No full textAn electron-hole liquid (EHL) is a collective nonequilibrium macroscopic quantum state of matter arising from the condensation of charge carriers in the form of a droplet. However, achieving the EHL state in a direct-band-gap material at room temperature is extremely difficult due to the excess thermal energy, short carrier lifetime, and low binding energy. Herein, we report the experimental observation of an EHL in a direct-band-gap coupled metal-halide perovskite-nanocrystal film by exploiting the electron-phonon interaction at room temperature. The helicity-resolved transient-absorption measurements above a critical carrier density of approximately 1018+ cm-3 reveal the EHL below the exciton and biexciton states. These results are consistent with our theoretical calculations of the ground-state energy and the thermodynamic phase diagram. The condensation and evaporation times of the EHL are approximately 0.80 ps and approximately 60 ps, respectively. Our study hopefully paves the way for many-body correlations in optical processes and may offer exceptional opportunities to develop futuristic quantum technologies
Combined ultrafiltration and ozone processing of sugarcane juice: Quantitative assessment of polyphenols, investigation of storage effects by multivariate techniques and shelf life prediction
No full textSugarcane juice (SJ) is prone to rapid spoilage post-extraction that limits its storage and marketing. To address this problem, two non-thermal techniques, viz., ultrafiltration (UF) and ozone treatment (OZ) combinedly are attempted. Cumulative enzyme and microbial inactivation effects were obtained by combining the processes (UF-OZ) providing about 85% polyphenoloxidase, 91% peroxidase, 7 log bacteria and 5.2 log yeast and mold inactivation. The effects of processing on major phenolic acids, flavonoids and sensory properties were evaluated. From HPLC characterization, it was found that, caffeic acid (13.22 ppm) which was the most abundant accounting for 50.5% of the total evaluated phenolic acids reduced by 26.7% in processed SJ. Among flavonoids, vitexin and its derivatives (22.19 ppm) constituted the highest proportion (63.3%) of total evaluated flavones which did not decrease significantly (p>0.05) after processing. Principal component analysis (PCA) and hierarchical cluster analysis efficiently distinguished the stored samples and showed the dissimilarities in quality characteristics after 12 weeks of storage. PCA very well outlined the interrelationship status of quality parameters and spoilage indicators associated with browning and microbial degradation. The microbiological stability analysis using microbial growth (Gompertz) model confirmed that the ultrafiltered ozonised sugarcane juice could be safely stored up to 90 days under refrigeration
Gear up for the action replay: Leveraging lensing for enhanced gravitational-wave early warning
No full textPremerger gravitational-wave (GW) sky localization of binary neutron star (BNS) and neutron star–black hole (NSBH) coalescence events would enable telescopes to capture precursors and electromagnetic (EM) emissions around the time of the merger. We propose an astrophysical scenario that could provide early-warning times of hours to days before coalescence with subarcsecond localization, provided that these events are gravitationally lensed. The key idea is that if the BNS/NSBH is lensed, then so is the host galaxy identified via the EM counterpart. From the angular separation of the lensed host galaxy images, as well as its redshift and the (foreground) lens redshift, we demonstrate that, for galaxy-scale lenses, we can predict the time delays/arrival time differences assuming a standard lens model. We further assess the feasibility and benefits of lensing as a tool for early warning in various GW observing runs of the LIGO–Virgo–Kagra network, including Voyager and the third-generation network. To that end, we study the effect of the limited angular resolution of the telescopes on our ability to predict the time delays. We find that with an angular resolution of 0.05'' we can predict time delays of >1 day with 1σ error bar of O (hours) at best. We also construct realistic time delay distributions of detectable lensed BNSs/NSBHs to forecast the early-warning times we might expect in the observing scenarios we consider
Bioinspired synthesis of bioactive glass nanocomposites for hyaluronic acid delivery to bone and skin
No full textIn this study, we present nanocomposites of bioactive glass (BG) and hyaluronic acid (HA) (nano-BGHA) for effective delivery of HA to skin and bone. The synthesis of the nanocomposites has been carried out through the bio-inspired method, which is a modification of the traditional Stober's synthesis as it avoids using ethanol, ammonia, synthetic surfactants, or high-temperature calcination. This environmentally friendly, bio-inspired route allowed the synthesis of mesoporous nanocomposites with an average hydrodynamic radius of ∼190 nm and an average net surface charge of ∼−21 mV. Most nanocomposites are amorphous and bioactive in nature with over 70 % cellular viability for skin and bone cell lines even at high concentrations, along with high cellular uptake (90–100 %). Furthermore, the nanocomposites could penetrate skin cells in a transwell set-up and artificial human skin membrane (StratM®), thus depicting an attractive strategy for the delivery of HA to the skin. The purpose of the study is to develop nanocomposites of HA and BG that can have potential applications in non-invasive treatments that require the delivery of high molecular weight HA such as in the case of osteoarthritis, sports injury treatments, eye drops, wound healing, and some anticancer treatments, if further investigated. The presence of BG further enhances the range to bone-related applications. Additionally, the nanocomposites can have potential cosmeceutical applications where HA is abundantly used, for instance in moisturizers, dermal fillers, shampoos, anti-wrinkle creams, etc
Role of Tim17 transmembrane regions in regulating the architecture of presequence translocase and mitochondrial DNA stability
No full textMitochondrial life cycle and protein import are intricate cellular processes, which require precise coordination between the transport machineries of outer and inner mitochondrial membranes. Presequence translocase performs the indispensable function of translocating preproteins having N-terminal targeting sequences across the inner membrane. Tim23 forms the core of the voltage-gated import channel, while Tim17 is presumed to maintain the stoichiometry of the translocase. However, mechanistic insights into how Tim17 coordinates these regulatory events within the complex remained elusive. We demonstrate that Tim17 harbors conserved G/AXXXG/A motifs within its transmembrane regions and plays an imperative role in the translocase assembly through interaction with Tim23. Tandem motifs are highly essential, as most of the amino acid substitutions lead to nonviability due to the complete destabilization of the TIM23 channel. Importantly, Tim17 transmembrane regions regulate the dynamic assembly of translocase to form either the TIM23 (PAM)-complex or TIM23 (SORT)-complex by recruiting the presequence translocase-associated motor (PAM) machinery or Tim21, respectively. To a greater significance, tim17 mutants displayed mitochondrial DNA (mtDNA) instability, membrane potential loss, and defective import, resulting in organellar dysfunction. We conclude that the integrity of Tim17 transmembrane regions is critical for mitochondrial function and protein turnover
Role of land‐surface vegetation in the march of Indian monsoon onset isochrones in a coupled model
No full textAlthough the Climate Forecast System version-2 model simulates an overall dry bias in boreal summer mean rainfall over Indian land, the deficiency is particularly prominent over northwest India. The prevailing dryness limits the interannual prediction skill of the Indian summer monsoon rainfall and its subseasonal variability because of poor representation of latent heating due to weak moist convection and the resulting circulation. Here, we show that land-surface vegetation plays a crucial role in determining the dry bias in the Climate Forecast System version-2 model. We replaced the land-surface model's existing vegetation type over India with that derived from recent satellite-based observations. The modifications helped improve the seasonal mean rainfall over northwest India by 6%. The improvements are especially noticeable during the monsoon season's onset (14%) and withdrawal (10%) phases. Simulations with modified vegetation advanced the onset dates over Kerala, central India, and northwest India closer to that observed. This improvement in the mean onset dates is most prominent over northwest India. Such an improvement was possible owing to a substantial reduction of long rainfall hiatus after onset over Kerala in the simulation with modified vegetation. The modification makes the spatial orientation of monsoon onset isochrones more realistic. We found that although the vertically integrated moisture flux is eastward over most of the Indian monsoon region during its onset phase, its intraseasonal components are westward. In other words, at the intraseasonal time-scale, moisture propagates against the prevailing low-level westerlies. This intraseasonal eddy moisture transport advances onset from the Bay of Bengal toward the far northwest parts of the Indian land. The representation of such intraseasonal moisture seepage in the model updated with satellite-derived vegetation types was improved. Our study indicates the necessity of greater attention to land-surface representations for improved predictions of onset dates
Small molecular adjuvants repurpose antibiotics towards Gram-negative bacterial infections and multispecies bacterial biofilms
No full textGram-negative bacterial infections pose a significant challenge due to two major resistance elements, including the impermeability of the outer membrane and the overexpression of efflux pumps, which contribute to antibiotic resistance. Additionally, the coexistence of multispecies superbugs in mixed species biofilms further complicates treatment, as these infections are refractory to most antibiotics. To address this issue, combining obsolete antibiotics with non-antibiotic adjuvants that target bacterial membranes has shown promise in combating antibacterial resistance. However, the clinical translation of this cocktail therapy has been hindered by the toxicity associated with these membrane active adjuvants, mainly due to a limited understanding of their structure and mechanism of action. Towards this goal, herein, we have designed a small molecular adjuvant by tuning different structural parameters, such as the balance between hydrophilic and hydrophobic groups, spatial positioning of hydrophobicity and hydrogen bonding interactions, causing moderate membrane perturbation in bacterial cells without any toxicity to mammalian cells. Moderate membrane perturbation not only enhances the internalization of antibiotics, but also increases the intracellular concentration of drugs by hampering the efflux machinery. This revitalises the efficacy of various classes of antibiotics by 32–512 fold, without inducing toxicity. The leading combination not only exhibits potent bactericidal activity against A. baumannii biofilms but also effectively disrupts mature multispecies biofilms composed of A. baumannii and methicillin-resistant Staphylococcus aureus (MRSA), which is typically resistant to most antibiotics. Importantly, the combination therapy demonstrates good biocompatibility and excellent in vivo antibacterial efficacy (>99% reduction) in a skin infection model of A. baumannii. Interestingly, A. baumannii shows reduced susceptibility to develop resistance against the leading combination, underscoring its potential for treating multi-drug resistant infections
Stability analysis of infinite unsaturated soil slope based on analytical probabilistic approach.
No full textMost infinite slopes in tropical climates are frequently unsaturated in the beginning, and along with many soil properties like cohesion and friction, stability of these slopes is largely dependent on matric suction. These parameters are highly variable in the evaluation of slope stability for unsaturated soil. Hence, deterministic analysis is not enough to draw conclusions regarding stability of unsaturated slopes. This paper presents an analytical probabilistic method based on the theory of multivariate probability distribution to determine the stability of infinite unsaturated slopes. The stochastic soil parameters used in the study are cohesion, friction angle, unit weight, and matric suction. All the stochastic parameters were treated as uncertain variables which were defined by the normal distribution. The geometry-related parameters such as slope angle, slope height, and few stress variables such as net normal stress were regarded as deterministic parameters. The stability of the slope was determined by calculating the reliability index. Furthermore, the calculation formula for the probability density of slope safety factors was established. To inspect the correctness of the present methodology, the probability density of safety factors was determined by considering a conceptual infinite slope with arbitrary parameter values. Results showed that for the assumed set of parameters, the slope fails to meet the reliability index criteria of stability. A comparison between the outputs determined by the proposed technique and the Monte Carlo method indicates that the proposed methodology is efficient in order to calculate the stability of unsaturated slopes while taking the variability of various soil characteristics into account
Displacement-based finite element approach on analysing flexible combined pile–raft foundation in layered soil.
No full textThe present study proposes a new finite element methodology to analyse the behaviour of flexible combined pile–raft foundation (CPRF) situated in layered soil, in a displacement-based framework. The soil medium is idealised as an advanced elastic Pasternak medium and the piles and raft are modelled as bar and plate element, respectively. The two components of CPRF are analysed simultaneously and displacement compatibility is satisfied at the pile–raft junctions. A number of soil–structure interaction factors, which govern the behaviour of CPRF, are suitably subsumed in the analysis scheme. The proposed method is validated with available analytical and experimental studies. Further parametric studies, investigating the effects of soil layering and raft flexibility on the behaviour of CPRF, are explored. It is observed that the load sharing proportion between the components and the raft deformation pattern depend upon the thickness and position of the soft soil layer in a multilayered soil system. The thickness of the flexible raft plays a pivotal role in determining the behaviour of CPRF, founded in a multilayered soil profile. Thus, this research manifests notable advancement in understanding the behaviour of flexible CPRF in layered soil