Several organisms, specifically microorganisms survive in a wide range of harsh environments including extreme temperature, pH, and salt concentration. We analyzed systematically a large number of ...protein sequences with their structures to understand their stability and to discriminate extremophilic proteins from their non-extremophilic orthologs. Our results highlighted that the strategy for the packing of the protein core was influenced by the environmental stresses through substitutive structural events through better ionic interaction. Statistical analysis showed that a significant difference in number and composition of amino acid exist among them. The negative correlation of pairwise sequence alignments and structural alignments indicated that most of the extremophile and non-extremophile proteins didn't contain any association for maintaining their functional stability. A significant numbers of salt bridges were noticed on the surface of the extremostable proteins. The Ramachandran plot data represented more occurrences of amino acids being present in helix and sheet regions of extremostable proteins. We also found that a significant number of small nonpolar amino acids and moderate number of charged amino acids like Arginine and Aspartic acid represented more nonplanar Omega angles in their peptide bond. Thus, extreme conditions may predispose amino acid composition including geometric variability for molecular adaptation of extremostable proteins against atmospheric variations and associated changes under natural selection pressure. The variation of amino acid composition and structural diversifications in proteins play a major role in evolutionary adaptation to mitigate climate change.
Regardless of its location, our electronic equipment does not always escape the threats of electromagnetic interference (EMI). Unrestrained radio and microwave radiation from communication devices, ...broadcasting stations, power lines and other electric equipment constantly bombards us and our precise circuitry equipment. Although its effects on human beings have not yet been directly demonstrated, our electronic gadgets are not that fortunate. A plethora of research work has already been published in the search for a perfect shielding material. Studies in the last decade reveal that dielectric ceramics, magnetic oxides/ferrites/particles, semiconductors, metal particles/foams, intrinsically conducting polymers, conducting carbon black/fibers/nanotubes and other carbon derivatives such as graphene
etc.
have been widely researched. The particles are either embedded in a wax medium or in a thermoplastic matrix to design an effective shield. To this end, polymer-based nanocomposites have been much discussed owing to their technology-matching properties, light weight, ease of fabrication and adaption, lack of corrosion, and design flexibility. However, the high dosage of nanofillers needed to meet the requirements of an effective shield mars their utility in many respects. Although bi-phasic polymer blends have been researched from different perspectives, utilizing them as a template for microwave shielding is currently drawing enormous interest compared with single-polymer-based nanocomposites. This review highlights the stepwise advancement of bi-phasic polymer blends towards EMI shielding applications. We in this manner endeavor to provide a necessary overview and point out the direction in which future research will keep on thriving as this new class of material emerges as an effective EMI shield.
This review features the limitations of single-polymer-based nanocomposites and discusses the stepwise advancement of bi-phasic polymer blends to meet the challenges of effective electromagnetic interference shielding.
► Extraction of actinide ions viz. Am3+, Pu4+ and UO22+. ► TODGA in room temperature ionic liquids. ► Ion-exchange mechanism of extraction. ► Significantly enhanced separation factors.
Extraction ...behavior of several actinide ions viz. Am3+, Pu4+ and UO22+ was investigated using N,N,N′,N′-tetra-n-octyl diglycolamide (TODGA) as extractant in three different room temperature ionic liquids (RTIL), viz. C4mim+·NTf2- , C6mim+·NTf2- , and C8mim+·NTf2- as the diluents. The solvent systems containing TODGA in the RTILs were found to result in higher distribution ratios for all the actinides (trivalent, hexavalent, tetravalent) as compared to that containing n-dodecane as the diluent. Moreover, the distribution ratio values of the metal ions at lower acidities were found to decrease with increasing feed nitric acid concentration. Extraction was found to be independent of the anion of the aqueous phase. Mechanism of extraction of the actinides was found to be different compared to n-dodecane, molecular diluent. Cation-exchange was found to be the mechanism of extraction followed in RTILs. Effect of carbon chain length of alkyl groups of the RTILs conclusively proved the mechanism of extraction of the actinides by TODGA. Nature of extracted species was also found to differ from n-dodecane. Stripping studies were carried out using complexing agents such as EDTA, DTPA in guanidine carbonate or a buffer mixture.
We report an easy to construct imaging system that can resolve particles separated by Formula: see text 0.68 Formula: see textm with minimum aberrations. Its first photon collecting lens is placed at ...a distance of 31.6 mm giving wide optical access. The microscope has a Numerical Aperture (NA) of 0.33, which is able to collect signal over 0.36 sr. The diffraction limited objective and magnifier recollects 77% photons into the central disc of the image with a transverse spherical aberration of 0.05 mm and magnification upto 238. The system has a depth of field of 142 Formula: see textm and a field of view of 56 Formula: see textm which images a large ensemble of atoms. The imaging system gives a diffraction limited performance over visible to near-infrared wavelengths on optimization of the working distance and the distance between the objective and magnifier.
The design of nanomedicines from the tuned architecture polymer is a leading object of immense research in recent years. Here, smart thermoresponsive micelles were prepared from novel architecture ...four-arm star block copolymers, namely, pentaerythritol polycaprolactone-b-poly(N-isopropylacrylamide) and pentaerythritol polycaprolactone-b-poly(N-vinylcaprolactam). The polymers were synthesized and tagged with folic acid (FA) to render them as efficient cancer cell targeting cargos. FA-conjugated block copolymers were self-assembled to a nearly spherical (ranging from 15 to 170 nm) polymeric micelle (FA-PM) with a sufficiently lower range of critical micelle concentration (0.59 × 10–2 to 1.52 × 10–2 mg/mL) suitable for performing as an efficient drug carrier. The blocks show lower critical solution temperature (LCST) ranging from 30 to 39 °C with high DOX-loading content (24.3%, w/w) as compared to that reported for a linear polymer in the contemporary literature. The temperature-induced reduction in size (57%) of the FA-PM enables a high rate of DOX release (78.57% after 24 h) at a temperature above LCST. The DOX release rate has also been tuned by on-demand administration of temperature. The in vitro biocompatibilities of the blank and DOX-loaded FA-PMs have been studied by the MTT assay. The cellular uptake study proves selective internalization of the FA-PM into cancerous cells (C6 glioma) compared that into normal cells (HaCaT). In vivo administration of the DOX-loaded FA-PMs into the C6 glioma rat tumor model resulted in significant accumulation in tumor sites, which drastically inhibited the tumor volume by ∼83.9% with respect to control without any significant systemic toxicity.
Phase-stabilized distribution of radio frequency (RF) signal is an essential requirement for many modern technological applications and advanced scientific experiments including clock synchronization ...or synchronization of distributed sensors. Coaxial cables are commonly used for the distribution of RF signal, but the phase of the RF signal is very much sensitive to the variation of ambient conditions, especially temperature variation. In this letter, we introduced a technique and verified with 10-MHz signal for real-time measurement of phase-drift due to varying ambient condition along with phase-stabilized RF signal transmission through the coaxial cables by active phase compensation.
Advanced and accurate measurement is a prerequisite for scientific research and innovation leading towards the development of new technologies. SI traceable measurements in the industry are essential ...for global acceptance of the products and international trading to break the trade barrier. National metrology institutes (NMIs) around the globe have been working on digital metrology, quantum metrology, calibration-free science and technology, risk-based calibration, measurement capabilities, and the traceability of fundamental physical constants with universal SI unit. This editorial discusses the outline of the special issue “Metrological Innovations for Science, Technology and Global Trade”. The research articles discuss the relevance of metrological innovations and ongoing research in the relevant fields with metrological perspectives by different research groups around the world. The significance of Metrological Innovations for science and technology and its importance in global trade have been presented.
Precise transfer of time and frequency signals over long distances as well as clock synchronization to an ultra‐stable reference are very crucial for many of the technological applications as well as ...for advanced scientific research. These reinforces a wide range of applications such as navigation, power grid management, mobile communication, and so on. In order to compare the performances of two highly stable and accurate atomic clocks, it is desirable that the link between the two clocks, that is, the transmission link has higher level of stability than those clocks. This article describes establishment of an ultra‐stable optical fiber link employing White Rabbit network for transfer of time and frequency signals and also for comparing performance of atomic clocks. Utilizing this link, time signals have been transferred within an uncertainty of ±130 ps at ambient temperature (30°C–40°C) and the instability of the link in terms of modified Allan‐deviation reaches to ∼10−16 within one day of integration time.
Key Points
An ultra‐stable optical fiber link has been established utilizing White Rabbit network for precise transfer of time and frequency signals
Effect of ambient temperature variation on the performance of time and frequency transfer through the optical fiber link has been studied
Instability of the fiber link in terms of modified Allan deviation has been reached to 10–16 within one day of integration time
A series of branched and folic acid (FA) conjugated amphiphilic block copolymers were synthesized by sequential steps of ring opening and atom transfer radical polymerizations. The chemical structure ...of the FA conjugated block copolymer was established by spectroscopic method. The FA conjugated copolymers give rise to nearly spherical polymeric micelles (PMs) in water (40–60 nm). The polymers are showing low range of CMC (0.63 × 10−2 to 2.01 × 10−2 mg/mL) with a negative zeta potential (−44.4 mV). The branched structure supports a very high loading (∼25%) of DOX molecules compare to the literature reported nanocarriers prepared from analogous linear block copolymers. The cell viability and cell uptake study of PMs were conducted on both normal and cancerous cell lines. The pH sensitive decrease of miceller size affords sparkling in vitro release of DOX molecule (67–88%) at physiological pH (5.0) of the cancer cells.
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•We have synthesized a pH responsive four armed branched block copolymer.•The biodegradable micelle carries the DOX molecule.•The branched structure supports a very high loading (∼25%) of DOX.•The micelle shows cancer cell specific pH responsive DOX delivery.•Micelles selectively enter into the cancer cell.
Narrow bandwidth and high voltage radiofrequency (RF) are essential requirement for confining ions within a quadrupole ion trap, commonly known as Paul Trap. Delivery of high voltage RF to the trap ...electrodes is usually done through a helical resonator as it allows efficient power transfer with very high quality factor (
Q
) through impedance matching. Resonant frequency of a helical resonator at loaded condition, i.e., when connected to an ion trap, is very much sensitive to external perturbation and the power transfer efficiency of the resonator is affected by movement of any conducting or inductive element near to the resonator. The present article reports about a technique for efficient delivery of high voltage RF to the trap electrodes through continuous monitoring of the drift of the resonant frequency of a helical resonator due to ambient variation and accordingly tuning the RF source frequency that it operates at resonant frequency. The reflected RF signal from ion trap is monitored and used as the feedback control for tuning the source to the resonant frequency of the helical resonator and eventually optimizing efficiency of power transfer of the helical resonator.
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