Efficient Silicon Solar Cells through Organic Self-Assembled Monolayers as Electron Selective Contacts

Effective charge carrier-selective contacts are a crucial component of high-performance crystalline silicon (c-Si) solar cells. Organic materials deposited via self-assembly on the c-Si surface are promising candidates for simplified, scalable, and cost-effective processing of charge extraction layers. This study investigates the application of nPACz self-assembled monolayers (SAMs), based on carbazole and phosphonic acid groups, where n (= 2, 4, or 6) is the aliphatic chain length, to facilitate electron extraction in c-Si solar cells by tuning the work function of aluminum (Al) at the rear contact. So far, these SAM molecules are mainly applied as the hole-selective layer in state-of-the-art perovskite and organic solar cells, via anchoring on a metal oxide electrode. Here, by inserting 2PACz between amorphous silicon passivated c-Si and Al, an electron-selective contact with a contact resistivity of 65 mΩ cm² is achieved and a power conversion efficiency of 21.4% with an open-circuit voltage of 725 mV and a fill factor of 79.2% is demonstrated. Although the 2PACz displays some instability in this study, its initial performance is comparable to those achieved with conventionally used n-type amorphous silicon. This study highlights the potential of solution-processable organic SAMs in forming carrier-selective contacts for c-Si heterojunction solar cells.     

Cordycepin: A bioactive metabolite with therapeutic potential

Cytotoxic nucleoside analogues were the first chemotherapeutic agents for cancer treatment. Cordycepin, an active ingredient of the insect fungus Cordyceps militaris, is a category of compounds that exhibit significant therapeutic potential. Cordycepin has many intracellular targets, including nucleic acid (DNA/RNA), apoptosis and cell cycle, etc. Investigations of the mechanism of anti-cancer drugs have yielded important information for the design of novel drug targets in order to enhance anti-tumor activity with less toxicity to patients. This extensive review covers various molecular aspects of cordycepin interactions with its recognized cellular targets and proposes the development of novel therapeutic strategies for cancer treatment.     

Calcium fertilization increases the concentration of calcium in sapwood and calcium oxalate in foliage of red spruce

Calcium cycling plays a key role in the health and productivity of red spruce forests in the northeastern US. A portion of the flowpath of calcium within forests includes translocation as Ca²⁺ in sapwood and accumulation as crystals of calcium oxalate in foliage. Concentrations of Ca in these tree tissues have been used as markers of environmental change due to acidic deposition or forest management practices. We compared the effects of Ca fertilization treatment on Ca concentration in wood and Ca and oxalate (Ox) concentration in foliage at two locations with different initial concentrations of Ca in the soil. We found greater amounts of Ca in wood from the high-Ca location than from the low-Ca location. Ca concentration was greater in wood formed in the 1970s than for wood formed in the 1980s, the outermost decadal band in these samples. The Ca-treatment was detected as an increased concentration of Ca in the 1970s and 1980s decadal bands. We also found that variation in Ca and Ox in foliage was essentially stoichiometric. The appearance and response to chemical tests of crystals in foliage were consistent with identification as calcium oxalate. The increased Ca in wood after Ca-treatment of the soil supports the use of dendrochemistry of base cations to investigate environmental change. However, differences in Ca concentration between the two outermost decadal bands of wood illustrate that internal processes of translocation and storage also affect Ca concentration. Calcium oxalate production in foliage diverts carbon from ordinary biosynthesis and energy-yielding processes. This sequestration, shedding, and decomposition of foliage may represent a significant and under-recognized contribution to carbon and Ca cycling.     

Adsorption of chromium from aqueous solution on treated sawdust

The adsorption of Cr(VI) from aqueous solutions on formaldehyde treated sawdust (SD) and sulphuric acid treated sawdust carbon (SDC) of Indian Rosewood, a timber industry waste, was studied at varying Cr(VI) concentrations, adsorbent dose, pH and agitation time. Similar experiments were conducted with commercially available coconut based activated carbon to compare the results. The Cr(VI) adsorption efficiency on SDC was higher than SD. The adsorption followed first order rate expression and Lagergren equation. An initial pH of 3.0 was most favorable for Cr(VI) removal by both the adsorbents. Maximum Cr(VI) was sequestered from the solution within 60 min after the beginning for every experiment. It is proposed that SDC and SD can be potential adsorbents for Cr(VI) removal from dilute solutions.     

培养条件对Bacillus pumilus转化油酸生产羟基脂肪酸的影响

利用一株Bacillus pumilus 突变株(简写为BP M-F641),在摇瓶条件下考察了碳源葡萄糖、底物油酸(OA)、亚油酸(LA)、种龄、溶氧和Mn2+ 离子对转化脂肪酸生成ω-1,2,3-羟基脂肪酸( 简写为ω-1,2,3-HFA) 的影响.试验了OA 添加时间对ω-1,2,3-HFA 产量和转化率的影响.结果表明,细胞生长最佳的葡萄糖浓度为8g/L ;OA 和LA 对菌株细胞生长有明显的抑制作用;培养菌龄对脂肪酸羟基化有明显的影响;溶氧变化对细胞生长有轻微的影响,但对ω-1,2,3-HHFA 的生成影响较大.在表面活性剂十二烷基硫酸钠(SDS)或吐温-80 存在下,能增加油酸的消耗量,但ω-1,2,3-HFA 的生成并没有增加,表明阴离子和非离子表面活性剂不能改进羟基化反应的能力;Mn2+ 是细胞生长和HFA 形成的一个重要影响因素,Mn2+ 浓度为0.2g/L 时细胞生长和HFA 形成最佳.这些研究结果对进一步改进脂肪酸微生物转化生产HFA 策略的运用具有重要作用.     

Development of chloroplast transformation vectors, and a new target region in the tobacco plastid genome

Plastid transformation vectors are used for high-level expression of industrially important recombinant proteins in plants. In the present study, new vectors for plastid transformation were developed. One of these vectors targets transgenes at a new site in the chloroplast genome. Intergenic regions of trnfM-trnG, ndhB-trnL and rrn16-trnV were selected as sites for transgene insertion. Tobacco chloroplast was successfully transformed with designed vectors, and the transplastomic plants accumulated recombinant protein as high as 5–6% of total soluble protein which remained localized in the chloroplasts. Although the vectors were designed using the plastid genome of Nicotiana tabacum, flanking regions used in two vectors show a high level of homology with chloroplast genomes of other plant species, thus it might be possible to use them for the transformation of a wider range of plant species.     

Protection from the 2009 H1N1 Pandemic Influenza by an Antibody from Combinatorial Survivor-Based Libraries

Influenza viruses elude immune responses and antiviral chemotherapeutics through genetic drift and reassortment. As a result, the development of new strategies that attack a highly conserved viral function to prevent and/or treat influenza infection is being pursued. Such novel broadly acting antiviral therapies would be less susceptible to virus escape and provide a long lasting solution to the evolving virus challenge. Here we report the in vitro and in vivo activity of a human monoclonal antibody (A06) against two isolates of the 2009 H1N1 pandemic influenza virus. This antibody, which was obtained from a combinatorial library derived from a survivor of highly pathogenic H5N1 infection, neutralizes H5N1, seasonal H1N1 and 2009 “Swine” H1N1 pandemic influenza in vitro with similar potency and is capable of preventing and treating 2009 H1N1 influenza infection in murine models of disease. These results demonstrate broad activity of the A06 antibody and its utility as an anti-influenza treatment option, even against newly evolved influenza strains to which there is limited immunity in the general population.