Quality control of the sheep bacterial artificial chromosome library, CHORI-243

<p>Abstract</p> <p>Background</p> <p>The sheep CHORI-243 bacterial artificial chromosome (BAC) library is being used in the construction of the virtual sheep genome, the sequencing and construction of the actual sheep genome assembly and as a source of DNA for regions of the genome of biological interest. The objective of our study is to assess the integrity of the clones and plates which make up the CHORI-243 library using the virtual sheep genome.</p> <p>Findings</p> <p>A series of analyses were undertaken based on the mapping the sheep BAC-end sequences (BESs) to the virtual sheep genome. Overall, very few plate specific biases were identified, with only three of the 528 plates in the library significantly affected. The analysis of the number of tail-to-tail (concordant) BACs on the plates identified a number of plates with lower than average numbers of such BACs. For plates 198 and 213 a partial swap of the BESs determined with one of the two primers appear to have occurred. A third plate, 341, also with a significant deficit in tail-to-tail BACs, appeared to contain a substantial number of sequences determined from contaminating eubacterial 16 S rRNA DNA. Additionally a small number of eubacterial 16 S rRNA DNA sequences were present on two other plates, 111 and 338, in the library.</p> <p>Conclusions</p> <p>The comparative genomic approach can be used to assess BAC library integrity in the absence of fingerprinting. The sequences of the sheep CHORI-243 library BACs have high integrity, especially with the corrections detailed above. The library represents a high quality resource for use by the sheep genomics community.</p

Electrochemical Evaluation of LaNi_(5–x)Ge_x Metal Hydride Alloys

We report a detailed evaluation of Ge-substituted LaNi_5 for electrochemical application as a negative electrode in alkaline rechargeable cells. Alloys with small substitutions of Ge for Ni show operating pressures, chargeability, cyclic lifetime, and kinetics for hydrogen absorption and desorption all superior to those found in many other substituted LaNi_5 alloys. These improved properties were achieved with a minimal reduction in hydrogen storage capacity

Electrochemical Studies on LaNi5–xSnx Metal Hydride Alloys

Electrochemical studies were performed on LaNi5–xSnx with 0 <= x <= 0.5. We measured the effect of the Sn substituent on the kinetics of charge-transfer and diffusion during hydrogen absorption and desorption, and the cyclic lifetimes of LaNi5–-xSnx electrodes in 250 mAh laboratory test cells. We report beneficial effects of making small substitutions of Sn for Ni in LaNi5 on the performance of the metal hydride alloy anode in terms of cyclic lifetime, capacity, and kinetics. The optimal concentration of Sn in LaNi5–xSnx alloys for negative electrodes in alkaline rechargeable secondary cells was found to lie in the range 0.25 <= x <= 0.3

Electrochemical Properties of LaNi5–xGex Alloys in Ni-MH Batteries

Electrochemical studies were performed on LaNi5–xGex metal hydride alloys with 0 <= x <= 0.5. We carried out single-electrode studies to understand the effects of the Ge substituent on the hydrogen absorption characteristics, the electrochemical capacity, and the electrochemical kinetics of hydrogen absorption and desorption. The electrochemical characteristics of the Ge-substituted alloys are compared to those of the Sn-substituted alloys reported earlier. LaNi5–xGex alloys show compositional trends similar to LaNi5–xSnx alloys, but unlike the Sn-substituted alloys, Ge-substituted alloys continue to exhibit facile kinetics for hydrogen absorption/desorption at high solute concentrations. Cycle lives of LaNi5–xGex electrodes were measured in 300 mAh laboratory test cells and were found to be superior to the Sn-substituted LaNi5 and comparable to a Mm(Ni,Co,Mn,Al)5 alloy. The optimum Ge content for LaNi5–xGex metal hydride alloys in alkaline rechargeable cells is in the range 0.4 <= x <= 0.5

Thermal Analysis of Cellulose Fibres Extracted from Locally Available Rice Straw

Agriculture sector plays a vital role in Sri Lankan economy. Although the country is moving towards industrialisation, the agricultural sector still contributes substantially to both foreign exchange earnings and GDP. Paddy is cultivated in almost all parts of the country, except at very high altitudes. In 2018, around 3.9 million metric tonnes of paddy was harvested across the country from both Yala and Maha seasons. Rice straw is a by-product from the paddy cultivation and identified as agricultural production residue that is generated in equal or greater quantities than the rice itself with no commercial interest. Therefore, it is of ecological and economical point of view to discover an advantageous utilization of this material. Agricultural crop residues are rich in lignocellulosic materials with cellulose as the principle constituent. Study on the thermal properties of rice straw fibers are important in order to estimate their industrial applications. In this study, cellulose fibers were extracted from rice straw (BG352) via a series of chemical treatments. The structure and chemical composition of cellulose fibers were investigated using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thermal stability of each sample was determined using TGA SDT Q600 simultaneous thermal analyser (TA instruments, Delaware, USA). Analysis of individual samples was carried out at a constant heating rate of 10 °C/min between ambient temperature to 700o C in a nitrogen atmosphere. FTIR analysis of fibers demonstrate that the chemical purification treatment results in sequential and complete removal of hemicellulose (1729 cm-1, carbonyl stretching), lignin (1516 cm-1, aromatic skeletal vibrations) and silica (796 cm-1 and 466 cm-1, Si–O–Si stretching). XRD results also reveal the removal of lignin (shoulder peak at 16.4o) and hemicellulose (weak peak at 34.76o) from rice straw thus, confirms the final product as cellulose. Three endothermic peaks were observed in thermogravimetric analysis. Initially a small weight loss was observed around 100o C due to the low molecular weight components in the fibers and the evaporation of remained moisture. Hemicellulose pyrolysis was occurred around 260o C. A resistant increase in cellulose was observed due to the removal of almost all hemicelluloses from the rice straw. Pyrolysis of lignin in rice straw started at 200o C and persisted till 700o C. Further, a significant difference between the contents of the residues were remained which indicated that the thermal stability of cellulose was visibly improved. Based on the results obtained, the extracted cellulose fibers from locally available rice straw could be used to produce textiles, composites, all kinds of paper and paper boards, photographic films, moisture proof coatings for food packaging and other fibrous products similar to those produced from the synthetic fibers. Using rice straw as a source of high-quality fibrous applications will add value to the rice crops, mitigate concerns regarding burning or disposing of rice straw, and provide an environmentally friendly alternative to replace the synthetic fibers currently in use.Keywords: Sri Lankan rice straw, Cellulose fibers, Chemical treatment, Thermal decomposition, Thermal propertie

Sodium-metal chloride batteries

It was concluded that rapid development in the technology of sodium metal chloride batteries has been achieved in the last decade mainly due to the: expertise available with sodium sulfur system; safety; and flexibility in design and fabrication. Long cycle lives of over 1000 and high energy densities of approx. 100 Wh/kg have been demonstrated in both Na/FeCl2 and Na/NiCl2 cells. Optimization of porous cathode and solid electrolyte geometries are essential for further enhancing the battery performance. Fundamental studies confirm the capabilities of these systems. Nickel dichloride emerges as the candidate cathode material for high power density applications such as electric vehicle and space

U.S. Aerospace Trade [2016-2021]: Analyzing the relationship between resilience and competitiveness in the global supply chain.

According to the International Trade Administration, the U.S. aerospace civil and military aircraft sectors comprise the largest trading volume among all U.S. manufacturing industries, recording $80.2 billion in 2019. However, the total U.S. aerospace trade dropped by 25% during the pandemic and continued falling by an additional 6% in 2021, indicating the risks and vulnerability the industry had experienced. This poster investigates the pandemic impacts on the U.S. aerospace trade and assesses the resilience and competitiveness of the aerospace sector across its various products. Using the U.S. merchandise trade data from the 2016-2021 period, we empirically estimate the relationship between the resilience and competitiveness of the U.S. aerospace trade in its global supply chain network. We expect to find a positive relationship between the competitiveness and resilience of the U.S. aerospace sector and this finding will assist policymakers, manufacturers, and suppliers in developing strategies to respond to future catastrophes

Lithium-Ion Electrolytes Containing Phosphorous-Based, Flame-Retardant Additives

Future NASA missions aimed at exploring Mars, the Moon, and the outer planets require rechargeable batteries that can operate over a wide temperature range (-60 to +60 C) to satisfy the requirements of various applications. In addition, many of these applications will require improved safety, due to their use by humans. Currently, the state-of-the-art lithium-ion (Li-ion) system has been demonstrated to operate over a wide range of temperatures (-40 to +40 C); however, abuse conditions can often lead to cell rupture and fire. The nature of the electrolyte can greatly affect the propensity of the cell/battery to catch fire, given the flammability of the organic solvents used within. Li-ion electrolytes have been developed that contain a flame-retardant additive in conjunction with fluorinated co-solvents to provide a safe system with a wide operating temperature range. Previous work incorporated fluorinated esters into multi-component electrolyte formulations, which were demonstrated to cover a temperature range from 60 to +60 C. This work was described in Fluoroester Co-Solvents for Low-Temperature Li+ Cells (NPO-44626), NASA Tech Briefs, Vol. 33, No. 9 (September 2009), p. 37; and Optimized Li-Ion Electrolytes Con tain ing Fluorinated Ester Co-Solvents (NPO-45824), NASA Tech Briefs, Vol. 34, No. 3 (March 2010), p. 48. Other previous work improved the safety characteristics of the electrolytes by adding flame-retardant additives such as triphenyl phosphate (TPhPh), tri-butyl phosphate (TBuPh), triethyl phosphate (TEtPh), and bis(2,2,2-trifluoroethyl) methyl phosphonate (TFMPo). The current work involves further investigation of other types of flame-retardant additives, including tris(2,2,2-trifluoroethyl) phosphate, tris(2,2,2-trifluoroethyl) phosphite, triphenylphosphite, diethyl ethylphosphonate, and diethyl phenylphosphonate added to an electrolyte composition intended for wide operating temperatures. In general, many of the formulations investigated in this study displayed good performance over a wide temperature range, good cycle life characteristics, and are expected to have improved safety characteristics, such as low flammability. Of the electrolytes studied, 1.0 M LiPF6 in EC+EMC+DEP (20:75:5 v/v %) and 1.0 M LiPF6 in EC+EMC+DPP (20:75:5 v/v %) displayed the best operation at low temperatures, whereas the electrolyte containing triphenylphosphite displayed the best cycle life performance compared to the baseline solution. It is anticipated that further improvements can be made to the life characteristics with the incorporation of a SET promoters (such as VC, vinylene carbonate), which will likely inhibit the decomposition of the flame-retardant additives

Investigation of the Presence of Heavy Metals in Plastic Toys Available in Sri Lankan Market

Many toys for children are partly or totally made of plastic. In these plastics, additives such as lead (Pb), cadmium (Cd), arsenic (As), chromium (Cr) and mercury (Hg) are added as pigments, fillers, UV stabilisers and plasticisers which are used to alter the properties of the material or to improve the production process. These additives, unreacted starting substances and impurities, can migrate from the plastic. As young children chew, lick and suck frequently on their toys, they can ingest certain amount of these compounds. The aim of this study was to identify the presence of heavy metals in plastic toy samples collected from market. Total of 145 plastic toys were screened on-site using handheld X-ray Fluorescence spectrometer (Skyray instrument-Genius 3000XRF) in Colombo Fort and Pettah area. The XRF device equipped with beryllium-window Silicon Drift Detector and 139 eV resolution was held on to the surface of the product and measurement was triggered for 45s in Plastics Mode. To eliminate the possibility of contamination, dust was removed prior to the XRF measurement. The built-in intensity correction method of the device corrects all deviations from samples of irregular geometric shape and uneven structure and density. The imported plastic toys were randomly selected from wholesale shops, retail shops and road side stalls considering accessibility to middle and low-income families. Results of the study revealed that the plastic toys contain heavy metals; Pb from 30.34 to 4,469.09 mg/kg, Cd from 15.09 to 1,140.73 mg/kg, As from 15.53 to 46.02 mg/kg, Cr from 15.21 to 247.78 mg/kg and Hg from 28.12 to 94.92 mg/kg respectively. Out of these 8.97% show high level of Cd and 1.38% show high level of Pb. However, the concentrations of Cr, As and Hg are under the permissible limits as per the testing standards by Restriction of Hazardous Substances (RoHS) directive. The permissible limits as per the testing standards by RoHS directive are 100 mg/kg for Cd and 1,000 mg/kg for Pb, Hg, and Cr and As. These results of the present study revealed that some toys are potential sources of heavy metals.Keywords: Plastic toys, Heavy metals, XRF, Chemical screenin

Lithium-Ion Electrolytes Containing Flame Retardant Additives for Increased Safety Characteristics

The invention discloses various embodiments of Li-ion electrolytes containing flame retardant additives that have delivered good performance over a wide temperature range, good cycle life characteristics, and improved safety characteristics, namely, reduced flammability. In one embodiment of the invention there is provided an electrolyte for use in a lithium-ion electrochemical cell, the electrolyte comprising a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), a fluorinated co-solvent, a flame retardant additive, and a lithium salt. In another embodiment of the invention there is provided an electrolyte for use in a lithium-ion electrochemical cell, the electrolyte comprising a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), a flame retardant additive, a solid electrolyte interface (SEI) film forming agent, and a lithium salt