Performance testing of a cross-flow membrane-based liquid desiccant dehumidification system

A membrane-based liquid desiccant dehumidification system is one of high energy efficient dehumidification approaches, which allows heat and moisture transfers between air stream and desiccant solution without carryover problem. The system performance is investigated experimentally with calcium chloride, and the impacts of main operating parameters on dehumidification effectiveness (i.e. sensible, latent and total effectiveness) are evaluated, which include dimensionless parameters (i.e. solution to air mass flow rate ratio m∗ and number of heat transfer units NTU) and solution properties (i.e. concentration Csol and inlet temperature Tsol,in). The sensible, latent and total effectiveness reach the maximum values of 0.49, 0.55, and 0.53 respectively at m∗= 3.5 and NTU = 12, and these effectiveness are not limited by m∗ and NTU when m∗ > 2 and NTU > 10. Both the latent and total effectiveness increase with Csol , while almost no variation is observed in the sensible effectiveness. All effectiveness can be improved by decreasing Tsol,in. The experimental data provide a full map of main design parameters for the membrane-based liquid desiccant air conditioning technology

Purification, characterization and cDNA cloning of a trypsin inhibitor from Pentaclethra macroloba.

The larval growth of the European corn borer, Ostrinia nubilalis , was reduced when grown on artificial diet containing either purified PmTI or PmSTI fusion protein expressed in E. coli. Likewise, high mortalities were observed with the free-living nematode Caenohabditis elegans cultured on E. coli expressing PmSTITwo types of trypsin inhibitors, designated PmLTI and PmSTI, were isolated and purified from seeds of Pentaclethra macroloba. The two predominant forms of PmLTI have estimated molecular weights of 43 and 39 kDa, whereas the major forms of PmSTI have molecular weights around 7 to 8 kDa. SDS-PAGE analysis of samples indicated that PmLTI exists as a dimer, and PmSTI appears to be a monomer. Inhibitory activity of PmLTIs was about 2.78 and 3.93 IU/mgTI against bovine trypsin and Heliocoverpa zea midgut trypsin, respectively. Inhibitory activity of PmSTI was 50.94 and 14.23 IU/mgTI against bovine and H. zea midgut trypsin, respectively. PmSTI was still active after boiling for 30 minutes but lost activity immediately when boiled with reducing agent. PmSTI is the first low molecular weight TI isolated from seeds of the legume subfamily Mimosaceae.A PmSTI cDNA clone was successfully expressed in tobacco plants after Agrobacterium-mediated plant transformation. Transformation and expression of the PmSTI coding sequence were confirmed by Southern blot analysis, trypsin inhibitor assay and Western blot. When the effects of the expression of the PmSTI transgene in tobacco plants was evaluated, results indicated that the transgenic plants exhibited some degree of protection to the tobacco hornworm (Manduca sexta).Amino acid sequencing revealed that two PmSTI variants, one 60 and the other 61 amino acid residues in length, were present in seeds. Analysis of PmSTI sequence indicates that it belongs to the Bowman-Birk inhibitor family. Although PmSTI has an estimated pI of 8.15 based on experimental data, PmSTI did not bind to either an anion exchange column at pH 9.0 or a cation exchange column at pH 5.0. PmSTI is a tight binding inhibitor of trypsin with an inhibition constant of 0.1 nM against bovine trypsin, but did not inhibit chymotrypsin. A full-length 558-bp cDNA sequence encoding the precursor of PmSTI has been isolated and characterized. The cDNA sequence possesses typical sequence motifs observed in plants. These include a Kozak ribosome binding site (GAAG ATGG), a cis-acting signal for the 3' -end mRNA formation which consists of a TATGTA domain upstream of the transcription stop signal AATAAA and a GT or T rich downstream region. The deduced PmSTI precursor has 120 aa residues which comprises a 52 residue N-terminal peptide, a mature PmSTI sequence and an 8-residue carboxyl-terminal extension peptide

Hygroscopic porous polymer for sorption-based atmospheric water harvesting

Sorption-based atmospheric water harvesting (SAWH) holds huge potential due to its freshwater capabilities for alleviating water scarcity stress. The two essential parts, sorbent material and system structure, dominate the water sorption–desorption performance and the total water productivity for SAWH system together. Attributed to the superiorities in aspects of sorption–desorption performance, scalability, and compatibility in practical SAWH devices, hygroscopic porous polymers (HPPs) as next-generation sorbents are recently going through a vast surge. However, as HPPs’ sorption mechanism, performance, and applied potential lack comprehensive and accurate guidelines, SAWH\u27s subsequent development is restricted. To address the aforementioned problems, this review introduces HPPs’ recent development related to mechanism, performance, and application. Furthermore, corresponding optimized strategies for both HPP-based sorbent bed and coupling structural design are proposed. Finally, original research routes are directed to develop next-generation HPP-based SAWH systems. The presented guidelines and insights can influence and inspire the future development of SAWH technology, further achieving SAWH\u27s practical applications

Human umbilical cord-derived mesenchymal stem cells do not undergo malignant transformation during long-term culturing in serum-free medium.

BACKGROUND:Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are in the foreground as a preferable application for treating diseases. However, the safety of hUC-MSCs after long-term culturing in vitro in serum-free medium remains unclear. METHODS:hUC-MSCs were separated by adherent tissue culture. hUC-MSCs were cultured in serum-free MesenCult-XF medium and FBS-bases DMEM complete medium. At the 1st, 3rd, 5th, 8th, 10th, and 15th passage, the differentiation of MSCs into osteogenic, chondrogenic, and adipogenic cells was detected, and MTT, surface antigens were measured. Tumorigenicity was analyzed at the 15th passage. Conventional karyotyping was performed at passage 0, 8, and 15. The telomerase activity of hUC-MSCs at passage 1-15 was analyzed. RESULTS:Flow cytometry analysis showed that very high expression was detected for CD105, CD73, and CD90 and very low expression for CD45, CD34, CD14, CD79a, and HLA-DR. MSCs could differentiate into osteocytes, chondrocytes, and adipocytes in vitro. There was no obvious chromosome elimination, displacement, or chromosomal imbalance as determined from the guidelines of the International System for Human Cytogenetic Nomenclature. Telomerase activity was down-regulated significantly when the culture time was prolonged. Further, no tumors formed in rats injected with hUC-MSCs (P15) cultured in serum-free and in serum-containing conditions. CONCLUSION:Our data showed that hUC-MSCs met the International Society for Cellular Therapy standards for conditions of long-term in vitro culturing at P15. Since hUC-MSCs can be safely expanded in vitro and are not susceptible to malignant transformation in serum-free medium, these cells are suitable for cell therapy

Comparison of the Effects of Different Cryoprotectants on Stem Cells from Umbilical Cord Blood

Purpose. Cryoprotectants (CPA) for stem cells from umbilical cord blood (UCB) have been widely developed based on empirical evidence, but there is no consensus on a standard protocol of preservation of the UCB cells. Methods. In this study, UCB from 115 donors was collected. Each unit of UCB was divided into four equal parts and frozen in different kinds of cryoprotectant as follows: group A, 10% ethylene glycol and 2.0% dimethyl sulfoxide (DMSO) (v/v); group B, 10% DMSO and 2.0% dextran-40; group C, 2.5% DMSO (v/v) + 30 mmol/L trehalose; and group D, without CPA. Results. CD34+, cell viability, colony forming units (CFUs), and cell apoptosis of pre- and postcryopreservation using three cryoprotectants were analyzed. After thawing, significant differences in CD34+ count, CFUs, cell apoptosis, and cell viability were observed among the four groups (P<0.05).  Conclusion. The low concentration of DMSO with the addition of trehalose might improve the cryopreservation outcome

Xceptional water production yield enabled by batch-processed portable water harvester in semi-arid climate

Sorption-based atmospheric water harvesting has the potential to realize water production anytime, anywhere, but reaching a hundred-gram high water yield in semi-arid climates is still challenging, although state-of-the-art sorbents have been used. Here, we report a portable and modularized water harvester with scalable, low-cost, and lightweight LiCl-based hygroscopic composite (Li-SHC) sorbents. Li-SHC achieves water uptake capacity of 1.18, 1.79, and 2.93 g g−1 at 15%, 30%, and 60% RH, respectively. Importantly, considering the large mismatch between water capture and release rates, a rationally designed batch processing mode is proposed to pursue maximum water yield in a single diurnal cycle. Together with the advanced thermal design, the water harvester shows an exceptional water yield of 311.69 g day−1 and 1.09 g gsorbent−1 day−1 in the semi-arid climate with the extremely low RH of ~15%, demonstrating the adaptability and possibility of achieving large-scale and reliable water production in real scenarios

A conventional karyotype analysis performed at the 15^th passage (46,XY).

<p>The MSCs expanded <i>in vitro</i> did not show chromosome elimination, displacement, or imbalances.</p