Enhanced hydrogen production from biomass via the sulfur redox cycle under hydrothermal conditions

A new method of hydrogen production from biomass via a sulfur redox cycle at moderate temperatures has been proposed. This method, which can utilize excess sulfur from hydrocarbon refining processes and waste or geothermal heat, consists of two half cycles: (1) hydrogen production from an aqueous alkaline solution at subcritical conditions of water, where sulfide, HS⁻ and S²⁻, acts as a reducing agent of water, and (2) sulfide regeneration under much milder conditions, with an organic compound derived from biomass acting as a reducing agent of polysulfide, S_n²⁻, and sulfur oxyanion, S_xO_y²⁻, formed in the first half cycle. During a 60-min reaction of an aqueous sodium sulfide solution, hydrogen production was observed at ≥280 °C and corresponding saturated vapor pressures. Addition of D-glucose, C₆H₁₂O₆, to the solution after hydrogen production at 300 °C resulted in sulfide regeneration at temperatures ≥60 °C in the present 10-min reaction. Moreover, hydrogen production from glucose via the sulfur redox cycle was demonstrated, where the hydrogen production and sulfide regeneration were conducted at 300 °C and 105 °C, respectively. Results indicated that hydrogen production from 1 mol glucose was greater than that by hydrothermal gasification of glucose at much higher temperatures up to 500 °C.     

肉制品绿色制造——低钠干腌肉制品研究进展

干腌肉制品因其具有独特的色泽、风味和口感等感官特性而深受广大消费者的喜爱。然而传统干腌肉制品的钠盐（氯化钠）含量过高,人体摄入过高的钠盐会对健康产生不良影响。本文讨论了食盐对干腌肉制品风味、质构和微生物安全的影响,概述了低钠干腌肉制品的相关研究动态,并对低钠干腌肉制品绿色制造的未来研究（如低钠复合盐）提出展望。     

Silicon Carbide Powder Synthesis from Silicon Monoxide and Methane

SiC was synthesized via the gas-phase reaction between SiO and CH₄ at 1500° and 1560°C in a tubular flow reactor. SiO vapor was generated from equimolar powder mixtures of Si and SiO₂ in the reactor while CH₄ was externally supplied. Products of different morphologies were collected at different longitudinal locations: whiskers, crystal aggregates, scale, and powder. The total yield of SiC, based on the amount of SiO generated, reached as high as 99%, of which 25–46% by mass was fine powder with sizes ranging from 60 to 300 nm.     

Macrophage Hitchhiking Nanoparticles for the Treatment of Myocardial Infarction: An In Vitro and In Vivo Study

Myocardial infarction (MI) is the leading cause of death worldwide. However, current therapies are unable to restore the function of the injured myocardium. Advanced approaches, such as stimulation of cardiomyocyte (CM) proliferation are promising, but suffer from poor pharmacokinetics and possible systemic adverse effects. Nanomedicines can be a solution to the above-mentioned drawbacks. However, targeting the cardiac tissue still represents a challenge. Herein, a MI-selective precision nanosystem is developed, that relies on the heart targeting properties of atrial natriuretic peptide (ANP) and lin-TT1 peptide-mediated hitchhiking on M2-like macrophages. The system based on pH-responsive putrescine-modified acetalated dextran (Putre-AcDEX) nanoparticles, shows biocompatibility with cultured cardiac cells, and ANP receptor-dependent interaction with CMs. Moreover, treatment with nanoparticles (NPs) loaded with two pleiotropic cellular self-renewal promoting compounds, CHIR99021 and SB203580, induces a 4-fold increase in bromodeoxyuridine (BrdU) incorporation in primary cardiomyocytes compared to control. In vivo studies confirm that M2-like macrophages targeting by lin-TT1 peptide enhances the heart targeting of ANP. In addition, NP administration does not alter the immunological profile of blood and spleen, showing the short-term safety of the developed system in vivo. Overall, the study results in the development of a peptide-guided precision nanosystem for delivery of therapeutic compounds to the infarcted heart.     

Integrating Oxygen and 3D Cell Culture System: A Simple Tool to Elucidate the Cell Fate Decision of hiPSCs

Oxygen, as an external environmental factor, plays a role in the early differentiation of human stem cells, such as induced pluripotent stem cells (hiPSCs). However, the effect of oxygen concentration on the early-stage differentiation of hiPSC is not fully understood, especially in 3D aggregate cultures. In this study, we cultivated the 3D aggregation of hiPSCs on oxygen-permeable microwells under different oxygen concentrations ranging from 2.5 to 20% and found that the aggregates became larger, corresponding to the increase in oxygen level. In a low oxygen environment, the glycolytic pathway was more profound, and the differentiation markers of the three germ layers were upregulated, suggesting that the oxygen concentration can function as a regulator of differentiation during the early stage of development. In conclusion, culturing stem cells on oxygen-permeable microwells may serve as a platform to investigate the effect of oxygen concentration on diverse cell fate decisions during development.     

Temperature- and pH-dependent mechanism of hydrogen production from hydrothermal reactions of sulfide

The effect of pH and temperature on hydrogen production from an aqueous alkaline solution with sulfide (HS⁻ and S²⁻) as a reducing agent of water has been studied at pH 9–13 and at temperatures between 230 and 320 °C, under corresponding saturated vapor pressure, in a Hastelloy C-22 reactor. A reaction time of 60 min at all pH values produced a significant amount of hydrogen at ≥280 °C and corresponding saturated vapor pressures. Hydrogen production increased with both pH and temperature, but was more significant with temperature. Sulfide consumption also increased with temperature, but its pH dependence was generally insignificant. The ratio of hydrogen produced to sulfide consumed (mol/mol) was 0.6–3.4, and the amount and/or oxidation state of sulfur product increased with pH and temperature. Results of this study confirm that hydrogen is produced from water reduction by sulfide under the experimental conditions, where the predominant reaction was pH- and temperature-dependent. Results of this study also suggest that optimum hydrogen production conditions via a sulfur redox cycle, based on the sulfide regeneration process, is optimized at 300 °C and pH 13, and at 320 °C and pH 11.     

Taste of Water-Soluble Extracts Obtained from Over-Fermented Tempe

Over-fermented tempe, known as tempe semangit, is popular in Indonesian culture, especially in Java, as an umami seasoning in traditional foods. The objective of this study was to characterize taste-active compounds in water soluble extracts of over-fermented tempe. Over-fermented tempe was prepared from fresh tempe in which the fermentation was prolonged (0 to 96 h). Free amino acids in the water soluble extract were analyzed and characterized for their taste activity values. Water soluble extracts contained umami and bitter tasting free amino acids at relatively high concentrations. Their umami and bitter taste activity values were higher than the taste threshold concentration. Water soluble extract from 72 h over-fermentation had a higher umami taste activity value than bitter taste activity, exhibiting the highest umami taste dilution factor. The high-performance liquid chromatography profile of water soluble extract fractions obtained using Sephadex G-25 gel filtration chromatography demonstrated that fractions having higher umami taste intensity had more hydrophilic components than hydrophobic components.