Novel Photothermal Materials and Thermally Engineered Membranes for Solar Desalination

Although 71% of earth surface is covered with water, more than 97% of it is saltwater, and freshwater is limited to only about 2.5%. The freshwater shortage has been exacerbated due to the environmental pollution, increased agriculture needs, socio-economic development, and population growth. Among various desalination technologies, membrane distillation has gained wide attention due to its ability to treat highly saline water utilizing waste heat from industrial processes. However, the implementation of conventional membrane distillation is hindered in the remote regions and disaster-struck communities where the low-grade thermal energy from industrial plants and electricity are not readily available. To address this problem, photothermal driven membrane distillation (PMD), where membrane distillation is integrated with photothermal materials that can effectively convert light to thermal energy, has been recognized as an attractive and sustainable technology for freshwater generation. The overall objective of this work is to overcome several fundamental scientific challenges in realizing efficient PMD by exploring two key components of photothermal membranes, namely, substrates and photothermal materials.In the first part of this work, we have designed and investigated environmentally benign substrates (hydroxyapatite (HA) nanowires) for efficient PMD. Their structure and properties of this novel substrate material have been systematically investigated to reveal their potential in replacing the widely used polymeric substrates for efficient PMD. In the second part, we have investigated high-performance photothermal materials (polydopamine (PDA), MXene and polypyrrole (PPy)) for efficient PMD. Their excellent photothermal property, abundant functional groups and facile processability make them highly appealing in achieving high-performance PMD membranes. Taken together, this work further our understanding of the structure, properties, stability and performance of these novel materials and open up novel avenues in designing and realizing highly efficient PMD systems

Genome-wide comparative analysis of digital gene expression tag profiles during maize ear development

Background: Development of the maize (Zea mays L.) female inflorescence (ear) has an important impact on corn yield. However, the molecular mechanisms underlying maize ear development are poorly understood. Results: We profiled and analyzed gene expression of the maize ear at four developmental stages: elongation phase (I), spikelet differentiation phase (II), floret primordium differentiation phase (III), and floret organ differentiation phase (IV). Based on genome-wide profile analysis, we detected differential mRNA of maize genes. Among the ~6,800 differentially expressed genes (DEGs), 3,325 genes were differentially expressed in stage II, 3,765 genes in III, and 1,698 genes in IV, compared to its previous adjacent stages, respectively. Furthermore, some of DEGs were predicted to be potential candidates in maize ear development, such as AGAMOUS (GRMZM2G052890) and ATFP3 (GRMZM2G155281). Meanwhile, some genes were well-known annotated to the mutants during maize inflorescence development such as compact plant2 (ct2), zea AGAMOUS homolog1 (zag1), bearded ear (bde), and silky1 (si1). Some DEGs were predicted targets of microRNAs such as microRNA156. K-means clustering revealed that the DEGs showed 18 major expression patterns. Thirteen transcriptional factors from 10 families were differentially expressed across three comparisons of adjacent stages (II vs. I, III vs. II, IV vs. III). Antisense transcripts were widespread during all four stages, and might play important roles in maize ear development. Finally, we randomly selected 32 DEGs to validate their expression patterns using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The results were consistent with those from Solexa sequencing. Conclusions: DEGs technique had shown an advantage in detecting candidates, and some transcription factors during maize ear development. RT-PCR data were consistent with our sequencing data and supplied additional information on ear developmental processes. These results provide a molecular foundation for future research on maize ear development

Oleanolic Acid and Ursolic Acid Improve Bone Properties and Calcium Balance and Modulate Vitamin D Metabolism in Aged Female Rats

Oleanolic acid (OA) and ursolic acid (UA) are the major chemical constituents in Fructus Ligustri Lucidi (FLL), a kidney-tonifying Chinese herb that is previously shown to improve bone properties and enhance calcium balance in aged female rats. The present study was designed to study if OA and UA act as the active ingredients in FLL to exert the positive effects on bone and mineral metabolism in aged rats. Aged (13-month-old) Sprague-Dawley female rats were randomly assigned to four groups with oral administration of drug or vehicle treatment for 12 weeks: medium calcium diet (MCD, 0.6% calcium), high calcium diet (HCD, 1.2% calcium), MCD + FLL (700 mg/kg/day), MCD + OA (23.6 mg/kg/day) + UA (8.6 mg/kg/day). A group of mature (3-month-old) female rats fed with MCD was included as positive control. The results demonstrated that FLL and OA+UA increased bone mineral density and improved microarchitectural properties of aged female rats. The osteoprotective effects of FLL and OA+UA might be, at least in part, associated with their actions on enhancing calcium balance and suppressing age-induced secondary hyperparathyroidism in aged female rats. FLL and OA+UA also significantly induced renal CYP27B1 protein expression and OA+UA treatment decreased CYP24A1 mRNA and protein expressions in aged female rats. In addition, FLL and OA+UA significantly increased the promoter activity, mRNA and protein expressions of renal CYP27B1 in vitro in human proximal tubule HKC-8 cells. The present findings suggest that OA+UA can be regarded as the active ingredients of FLL and might be a potential drug candidate for prevention and treatment of osteoporosis

Sedimentary ancient DNA reveals past ecosystem and biodiversity changes on the Tibetan Plateau: Overview and prospects

Alpine ecosystems on the Tibetan Plateau are being threatened by ongoing climate warming and intensified human activities. Ecological time-series obtained from sedimentary ancient DNA (sedaDNA) are essential for understanding past ecosystem and biodiversity dynamics on the Tibetan Plateau and their responses to climate change at a high taxonomic resolution. Hitherto only few but promising studies have been published on this topic. The potential and limitations of using sedaDNA on the Tibetan Plateau are not fully understood. Here, we (i) provide updated knowledge of and a brief introduction to the suitable archives, region-specific taphonomy, state-of-the-art methodologies, and research questions of sedaDNA on the Tibetan Plateau; (ii) review published and ongoing sedaDNA studies from the Tibetan Plateau; and (iii) give some recommendations for future sedaDNA study designs. Based on the current knowledge of taphonomy, we infer that deep glacial lakes with freshwater and high clay sediment input, such as those from the southern and southeastern Tibetan Plateau, may have a high potential for sedaDNA studies. Metabarcoding (for microorganisms and plants), metagenomics (for ecosystems), and hybridization capture (for prehistoric humans) are three primary sedaDNA approaches which have been successfully applied on the Tibetan Plateau, but their power is still limited by several technical issues, such as PCR bias and incompleteness of taxonomic reference databases. Setting up high-quality and open-access regional taxonomic reference databases for the Tibetan Plateau should be given priority in the future. To conclude, the archival, taphonomic, and methodological conditions of the Tibetan Plateau are favorable for performing sedaDNA studies. More research should be encouraged to address questions about long-term ecological dynamics at ecosystem scale and to bring the paleoecology of the Tibetan Plateau into a new era