Development of dual purpose,industrially important PLA–PEG based coated abrasives and packaging materials

Fabrication of industrially valuable PLA based coated abrasive and packaging products are made using bio-polymeric blends of PLA–PEG without involving the use of hazardous halogen based solvents, such as, chloroform and dichloromethane. Accordingly, an attempt has been made in our study to substitute a relatively less harmful ethyl acetate (EA) solvent in place of the toxic halogenated solvents to dissolve both PLA and PEG polymer blends to produce an environmentally safe PLA–PEG coating and film formulation in EA. This attempt in turn eliminates and replaces the use of non-degradable polymer coatings, (such as, acrylates, PVC, and synthetic latex) on Kraft paper thereby contributing to sustainability and environmental safety besides reduction in waste disposal to realize a cleaner environment. PLA is a hard and brittle polymer, which restricts its unexplored industrial user applications. On the other hand, PEG toughens the brittle PLA due to its plasticizing action. Hence, PLA–PEG polymer blends were prepared using increasing percentage of PEG content systematically from 5% to 25% and the % of PEG in PLA was optimized to 10% to get the maximum toughening effect in PLA–PEG formulation, which is ascertained by differential scanning calorimetry analysis. FTIR analysis confirmed the possible interaction that occurred between PLA and PEG, due to which a shift in vibration frequency of the PLA carbonyl group is observed. The other important test results from mechanical properties, contact angle, surface roughness, Cobb values, WVTR, and SEM analysis support to reveal that PLA–PEG (10%) blend is the best coating and film forming material on Kraft paper for the fabrication of industrially valuable both coated abrasive and packaging products to demonstrate its dual purpose applications.     

Targeting an Aromatic Hotspot in Plasmodium falciparum 1‐Deoxy‐d‐xylulose‐5‐phosphate Reductoisomerase with β‐Arylpropyl Analogues of Fosmidomycin

Blocking the 2‐C‐methyl‐d ‐erythrithol‐4‐phosphate pathway for isoprenoid biosynthesis offers new ways to inhibit the growth of Plasmodium spp. Fosmidomycin [(3‐(N‐hydroxyformamido)propyl)phosphonic acid, 1 ] and its acetyl homologue FR‐900098 [(3‐(N‐hydroxyacetamido)propyl)phosphonic acid, 2 ] potently inhibit 1‐deoxy‐d ‐xylulose‐5‐phosphate reductoisomerase (Dxr), a key enzyme in this biosynthetic pathway. Arylpropyl substituents were introduced at the β‐position of the hydroxamate analogue of 2 to study changes in lipophilicity, as well as electronic and steric properties. The potency of several new compounds on the P. falciparum enzyme approaches that of 1 and 2 . Activities against the enzyme and parasite correlate well, supporting the mode of action. Seven X‐ray structures show that all of the new arylpropyl substituents displace a key tryptophan residue of the active‐site flap, which had made favorable interactions with 1 and 2 . Plasticity of the flap allows substituents to be accommodated in many ways; in most cases, the flap is largely disordered. Compounds can be separated into two classes based on whether the substituent on the aromatic ring is at the meta or para position. Generally, meta‐substituted compounds are better inhibitors, and in both classes, smaller size is linked to better potency.     

Physics and Limitations of HgCdTe APDs: A Review

Avalanche photodiodes (APDs) made in HgCdTe have been developed for a large number of applications over the last 15 years. The developments have been motivated by exceptional gain characteristics that enables the detection of a low number of photons with close to negligible loss of information over observation times ranging from sub nanoseconds up to milliseconds. In this communication, we review the present understanding of the physics that governs the gain, noise, and response time characteristics of HgCdTe APDs. Recent data resulting from impulse response measurements are also reported that demonstrate a fast 4 GHz bandwidth response at 80 K and show the capacity to obtain bandwidths in excess of 10 GHz in such detectors.     

A Versatile and Convenient Synthesis of 34S‐Labeled Phosphorothioate Oligonucleotides

A synthetic protocol for ³⁴S‐labeled phosphorothioate oligonucleotides (PS ONs) was developed to facilitate MS‐based assay analysis. This was enabled by a highly efficient, two‐step, one‐pot synthesis of ³⁴S‐labeled phenylacetyl disulfide (³⁴S‐PADS), starting from ³⁴S‐enriched elemental sulfur (³⁴S₈). ³⁴S‐PADS was subsequently used for stable isotope labeling (SIL) of oligonucleotides containing a phosphorothioate backbone. The ³⁴S‐SIL PS ONs are shown to retain the same melting temperature, antisense activity, and secondary structure as those of the corresponding unlabeled ³²S PS ONs.     

High resolution gas volume change sensor

Changes of gas quantity in a system can be measured either by measuring pressure changes or by measuring volume changes. As sensitive pressure sensors are readily available, pressure change is the commonly used technique. In many physiologic systems, however, buildup of pressure influences the gas exchange mechanisms, thus changing the gas quantity change rate. If one wants to study the gas flow in or out of a biological gas pocket, measurements need to be done at constant pressure. In this article we present a highly sensitive sensor for quantitative measurements of gas volume change at constant pressure. The sensor is based on optical detection of the movement of a droplet of fluid enclosed in a capillary. The device is easy to use and delivers gas volume data at a rate of more than 15 measurements/s and a resolution better than 0.06 microl. At the onset of a gas quantity change the sensor shows a small pressure artifact of less than 15 Pa, and at constant change rates the pressure artifact is smaller than 10 Pa or 0.01% of ambient pressure.     

A new method for the fast determination of the data retention lifetime of UV EPROM’s

The newly developped method involves a controlled partial erasure of a charged ultraviolet erasable programmable read only memory device followed by a period of high temperature storage. The model is based on two assumptions: the amount of charge stored at the floating gate of a programmed cell is assumed to be equal throughout a component and the trip the minimum level of charge stored at the floating gate of a programmed cell, has a Gaussian distribution throughout a component. The experimental data are well described by the model. After implementation of the experimental results in the model we extrapolate the data retention lifetimes of the UVEPROM’S under operational conditions. Our measurements show that most of the tested UVEPROM devices (64 ko to 256 ko) have a similar operational lifetime, only the charge leakage activation energy differs (0.35 to 0.9 eV) depending on the type of component. In conclusion this method and model are suitable for a fast determination of UVEPROM’S data retention lifetimes under operational conditions.     

The dufour gland and the secretion placed on eggs of two species of social wasps,Liostenogaster flavolineata andParischnogaster jacobsoni (vespidae: Stenogastrinae)

The secretion placed on eggs and fed to larvae and the ant guard placed on the nest stalk ofParischnogaster jacobsoni contain the same hydrocarbons and in approximately the same proportions as is found in the Dufour gland. The secretion on eggs is a mixture of the contents of the Dufour gland and nectar. The emulsifying agent is a palmitic acid salt. Similarly, inLiostenogaster flavolineata, the egg secretion is an emulsion of nectar and Dufour gland secretion, which contains alkoxyethanol emulsifiers, found in nature for the first time.     

Aroma-volatile profile and its changes in Australian grown black Périgord truffle (Tuber melanosporum) during storage

Black Périgord truffle (Tuber melanosporum) is one of the most expensive fungi in the world that appreciated by gourmets. Studies have indicated the impact of growing location and soil microorganisms on the aroma profile of truffle. The aroma profile of West Australian black Périgord truffle (Tuber melanosporum) has not been previously reported, which was studied over a 14 day storage period. Sixty-four compounds were identified in all truffle samples. Significant changes (P > 0.05) were observed in 11 key volatiles (carbon dioxide, acetaldehyde, 2-butanone, 3-methyl-1-butanal, toluene, 2-butenal, formic acid 2-methyl butyl ester, 3-methyl-1-butanol, 6-methyl-2-heptanol, 3-octanol and dimethyl sulfoxide) over time. Comparison of these results against published aroma profile of European grown black Périgord truffle identified number of significant similarities and differences were also detected. Dimethyl sulfoxide, a compound previously identified in European grown white truffle (Tuber magnatum), was detected. Principle component analysis (PCA) showed that the major changes in the truffle aroma profile took place in the first 7 days of storage.     

Electrodeposition of BiVO4 with needle-like flower architecture for high performance photoelectrochemical splitting of water

Photoelectrochemical (PEC) water splitting is a green and sustainable approach capable of driving mass hydrogen production in the future. To realize this vision, development of a well-performing photoelectrode is highly demanded. In this comprehensive study, electrodeposition technique was applied for fabricating BiVO₄ films by regulating the deposition time from 1 min until 9 min. Interestingly, the morphology, crystallinity, chemical structure, and optical properties of BiVO₄ films depend strongly on the deposition time. It is found that BiVO₄ layer deposited for 7 min with a cross-section thickness of around 321.1–326.5 nm showed the optimum performance, whereby the photocurrent reached up to ~0.32 mA/cm^?2 at 1.23 V vs. RHE. The deposited BiVO₄ represents tiny and long petals, similar to “needle” nanostructures, which is embedded closely into compact agglomerates. Such morphology enables the BiVO₄ films to perform efficiently as photoanode in PEC cells. Besides, high crystallinity is detected from the sharp peaks of XRD and Raman analysis, as well as good light absorption capability that are the main contributors to the enhancement of PEC performance. In addition to the facile fabrication offered by electrodeposition method, the non-toxic attributes and the impressive PEC performance of the optimum BiVO₄ layer could serve as an interesting option for other applications such as gas sensors, solar cells, degradation of pollutants and photocatalytic water splitting.