Low-Temperature Oxidation of Methane on Rutile TiO2(110): Identifying the Role of Surface Oxygen Species.

Understanding the microkinetic mechanism underlying photocatalytic oxidative methane (CH4) conversion is of significant importance for the successful design of efficient catalysts. Herein, CH4 photooxidation has been systematically investigated on oxidized rutile(R)-TiO2(110) at 60 K. Under 355 nm irradiation, the C-H bond activation of CH4 is accomplished by the hole-trapped dangling OTi- center rather than the hole-trapped Ob- center via the Eley-Rideal reaction pathway, producing movable CH3• radicals. Subsequently, movable CH3• radicals encounter an O/OH species to form CH3O/CH3OH species, which could further dissociate into CH2O under irradiation. However, the majority of the CH3• radical intermediate is ejected into a vacuum, which may induce radical-mediated reactions under ambient conditions. The result not only advances our knowledge about inert C-H bond activation but also provides a deep insight into the mechanism of photocatalytic CH4 conversion, which will be helpful for the successful design of efficient catalysts.

Unlocking growth potential in Halomonas bluephagenesis for enhanced PHA production with sulfate ions.

The mutant strain Halomonas bluephagenesis (TDH4A1B5P) was found to produce PHA under low-salt, non-sterile conditions, but the yield was low. To improve the yield, different nitrogen sources were tested. It was discovered that urea was the most effective nitrogen source for promoting growth during the stable stage, while ammonium sulfate was used during the logarithmic stage. The growth time of H. bluephagenesis (TDH4A1B5P) and its PHA content were significantly prolonged by the presence of sulfate ions. After 64 hr in a 5-L bioreactor supplemented with sulfate ions, the dry cell weight (DCW) of H. bluephagenesis weighed 132 g/L and had a PHA content of 82%. To promote the growth and PHA accumulation of H. bluephagenesis (TDH4A1B5P), a feeding regimen supplemented with nitrogen sources and sulfate ions with ammonium sodium sulfate was established in this study. The DCW was 124 g/L, and the PHA content accounted for 82.3% (w/w) of the DCW, resulting in a PHA yield of 101 g/L in a 30-L bioreactor using the optimized culture strategy. In conclusion, stimulating H. bluephagenesis (TDH4A1B5P) to produce PHA is a feasible and suitable strategy for all H. bluephagenesis.

Photocatalytic ethane conversion on rutile TiO2(110): identifying the role of the ethyl radical.

Oxidative dehydrogenation of ethane (C2H6, ODHE) is a promising approach to producing ethene (C2H4) in the chemical industry. However, the ODHE needs to be operated at a high temperature, and realizing the ODHE under mild conditions is still a big challenge. Herein, using photocatalytic ODHE to obtain C2H4 has been achieved successfully on a model rutile(R)-TiO2(110) surface with high selectivity. Initially, the C2H6 reacts with hole trapped OTi- centers to produce ethyl radicals , which can be precisely detected by a sensitive TOF method, and then the majority of the radicals spontaneously dehydrogenate into C2H4 without another photo-generated hole. In addition, parts of the radicals rebound with diversified surface sites to produce C2 products via migration along the surface. The mechanistic model built in this work not only advances our knowledge of the C-H bond activation and low temperature C2H6 conversion, but also provides new opportunities for realizing the ODHE with high C2H4 efficiency under mild conditions.

Identification of crucial genes related to heart failure based on GEO database.

BACKGROUND: The molecular biological mechanisms underlying heart failure (HF) remain poorly understood. Therefore, it is imperative to use innovative approaches, such as high-throughput sequencing and artificial intelligence, to investigate the pathogenesis, diagnosis, and potential treatment of HF. METHODS: First, we initially screened Two data sets (GSE3586 and GSE5406) from the GEO database containing HF and control samples from the GEO database to establish the Train group, and selected another dataset (GSE57345) to construct the Test group for verification. Next, we identified the genes with significantly different expression levels in patients with or without HF and performed functional and pathway enrichment analyses. HF-specific genes were identified, and an artificial neural network was constructed by Random Forest. The ROC curve was used to evaluate the accuracy and reliability of the constructed model in the Train and Test groups. Finally, immune cell infiltration was analyzed to determine the role of the inflammatory response and the immunological microenvironment in the pathogenesis of HF. RESULTS: In the Train group, 153 significant differentially expressed genes (DEGs) associated with HF were found to be abnormal, including 81 down-regulated genes and 72 up-regulated genes. GO and KEGG enrichment analyses revealed that the down-regulated genes were primarily enriched in organic anion transport, neutrophil activation, and the PI3K-Akt signaling pathway. The upregulated genes were mainly enriched in neutrophil activation and the calcium signaling. DEGs were identified using Random Forest, and finally, 16 HF-specific genes were obtained. In the ROC validation and evaluation, the area under the curve (AUC) of the Train and Test groups were 0.996 and 0.863, respectively. CONCLUSIONS: Our research revealed the potential functions and pathways implicated in the progression of HF, and designed an RNA diagnostic model for HF tissues using machine learning and artificial neural networks. Sensitivity, specificity, and stability were confirmed by ROC curves in the two different cohorts.

Low-Temperature Ethylbenzene Conversion on Rutile TiO2(100) via Photocatalysis: The Strong Photon Energy Dependence.

Direct dehydrogenation of alkanes under mild conditions offers a green route to produce valuable olefins, but realizing C-H bond activation at a low temperature presents a significant challenge. Here, photocatalytic ethylbenzene conversion into styrene has been achieved by one hole on rutile (R)-TiO2(100) at 80 K under 257 and 343 nm irradiation. Although the rates of the initial α-C-H bond activation are nearly the same at the two wavelengths, the rate of the ß-C-H bond cleavage is strongly dependent upon hole energy, leading to the much higher yield of 290 K styrene formation at 257 nm, which raises doubt about the simplified TiO2 photocatalysis model in which excess energy of the charge carrier is useless and highlights the importance of intermolecular energy redistribution in photocatalytic reactions. The result not only advances our understandings in low-temperature C-H bond activation but also calls for the development of a more sophisticated photocatalysis model.

Deep Eutectic Solvents-Based Ultrasound-Assisted Extraction of Antioxidants from Kudingcha (llex kudingcha C.J. Tseng): Process Optimization and Comparison with Other Methods.

Kudingcha (KDC) is an important tea substitute containing abundant antioxidants. Herein, a ultrasonic-assisted extraction (UAE) technique based on deep eutectic solvents (DESs) was applied to optimize the total phenolic/total flavonoid content (TPC/TFC) from the KDC extracts. Results indicated that DES composed of L-proline and glycerol (Pro-Gly) had excellent extraction performance for TPC, TFC, ABTS•+ and FRAP, which were significantly better than other solvents. Response surface methodology (RSM) was used to obtain optimal extraction parameters for simultaneously maximizing the TPC, TFC and antioxidant activity. Results revealed that water content in Pro-Gly, liquid to solid ratio (L/S), ultrasonic temperature and extraction time were the major influence factors of the TPC, TFC, ABTS•+ and FRAP of the KDC extracts. The optimal conditions included water content in Pro-Gly of 46.4%, L/S of 25:1 (mL/g), ultrasonic temperature of 55 °C and extraction time of 50 min. Meanwhile, HPLC-MS/MS was adopted to identify the KDC extracts, which revealed the presence of major phytochemicals, including 5-chlorogenic acid, 4,5-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, 3,4-dicaffeoylquinic acid, kaempferol 3-rutinoside, myricetin and isorhamnetin. Moreover, UAE-Pro-Gly achieved further higher individual phenolics contents, TPC, TFC, ABTS•+ and FRAP than other methods. In conclusion, UAE-Pro-Gly is a highly efficient method for extraction of phenolic antioxidants from KDC.

Photocatalytic Oxidative Dehydrogenation of Propane for Selective Propene Production with TiO2.

Oxidative dehydrogenation of propane (ODHP) as an exothermic process is a promising method to produce propene (C3H6) with lower energy consumption in chemical industry. However, the selectivity of the C3H6 product is always poor because of overoxidation. Herein, the ODHP reaction into C3H6 on a model rutile(R)-TiO2(110) surface at low temperature via photocatalysis has been realized successfully. The results illustrate that photocatalytic oxidative dehydrogenation of propane (C3H8) into C3H6 can occur efficiently on R-TiO2(110) at 90 K via a stepwise manner, in which the initial C-H cleavage occurs via the hole coupled C-H bond cleavage pathway followed by a radical mediated C-H cleavage to the C3H6 product. An exceptional selectivity of ∼90% for C3H6 production is achieved at about 13% propane conversion. The mechanistic model constructed in this study not only advances our understanding of C-H bond activation but also provides a new pathway for highly selective ODHP into C3H6 under mild conditions.

Low-Temperature C-H Bond Activation via Photocatalysis: Highly Efficient Ethylbenzene Dehydrogenation into Styrene on Rutile TiO2(110).

The direct dehydrogenation of hydrocarbons to olefins under mild conditions is an atom-economical but challenging route. Here, we have investigated photocatalytic ethylbenzene dehydrogenation into styrene on rutile(R)-TiO2(110) using the temperature-programmed desorption (TPD) method. The results demonstrate that photocatalytic ethylbenzene dehydrogenation into styrene occurs on R-TiO2(110) in a stepwise manner, in which the initial α-C-H bond cleavage occurs facilely under UV irradiation via a possible homolytic hydrogen atom transfer process and then is followed by the second C-H bond cleavage induced by either photocatalysis at ∼120 K or thermocatalysis at >400 K. With preadsorbed oxygen atoms to eliminate hydrogen atoms from ethylbenzene dehydrogenation and excess electrons on the surface, the yield of styrene is largely enhanced by about 4 times. The results not only demonstrate a photocatalytic route for ethylbenzene dehydrogenation into styrene on R-TiO2(110) but also advance our understanding of the photocatalytic activation of the saturated C-H bond with TiO2.

Low-Temperature Aldol Condensation of Aldehydes on R-TiO2(100)-(1 × 1): Exceptional Selectivity for α,ß-Unsaturated Enal Production.

Selective C-C coupling of oxygenates via aldol condensation has the potential to produce useful chemicals from aldehydes and ketones. Here we report a combined experimental and theoretical study on the aldol condensation of unbranched aldehydes (CnH2n+1-CHO, n = 1-4) on rutile (R)-TiO2(100)-(1 × 1). Experimental results show that the R-TiO2(100)-(1 × 1) surface has a very high reactivity and selectivity for aldol product formation from tested aldehydes at room temperature. Theoretical calculations indicate that the CH3CHO enolization and the aldol dehydration occur with low energy barriers, and the 3-butanolal intermediate adsorbs on R-TiO2(100)-(1 × 1) stably, suggesting that the surface has a "modest" acid-base strength for efficient crotonaldehyde formation. The adsorption configuration of CH3CHO and surface structure of R-TiO2(100)-(1 × 1) may contribute to the exclusive selectivity of (E)-crotonaldehyde formation, which provides us a deep insight into the high selectivity of aldol condensation of aldehydes on the TiO2 catalyst.

Effects of different preservation methods on inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) molecular markers in botanic samples.

To evaluate the effects of different preservation methods (stored in a -20°C ice chest, preserved in liquid nitrogen and dried in silica gel) on inter simple sequence repeat (ISSR) or random amplified polymorphic DNA (RAPD) analyses in various botanical specimens (including broad-leaved plants, needle-leaved plants and succulent plants) for different times (three weeks and three years), we used a statistical analysis based on the number of bands, genetic index and cluster analysis. The results demonstrate that methods used to preserve samples can provide sufficient amounts of genomic DNA for ISSR and RAPD analyses; however, the effect of different preservation methods on these analyses vary significantly, and the preservation time has little effect on these analyses. Our results provide a reference for researchers to select the most suitable preservation method depending on their study subject for the analysis of molecular markers based on genomic DNA.

Serum levels of C1q/TNF-related protein-1 (CTRP-1) are closely associated with coronary artery disease.

BACKGROUND: Complement C1q tumor necrosis factor related proteins (CTRPs) have been proved to have diverse biological influences on cardiovascular system. CTRP 1 is a member of the CTRP superfamily, however, the relevance with coronary artery disease (CAD) are seldom explored. This study was designed to investigate the correlation between serum levels of CTRP 1 and CAD. METHODS: CTRP 1 levels of 150 CAD patients and 50 non-CAD subjects were determined by enzymelinked immunosorbent assay. Further analysis of CTRP 1 levels in different stages and lesion vessels of CAD were conducted. RESULTS: Serum levels of CTRP 1 in CAD patients were significantly elevated, and it was increased with the severity of CAD. CTRP 1 level in acute myocardial infarction group was much higher than that in stable/unstable angina and non-CAD groups. And significant differences of CTRP 1 were also found between single-vessel disease and triple-vessel disease. Multiple logistic regression analysis showed that CTRP 1 was an independent risk factor of the occurrence of myocardial infarction. CONCLUSIONS: Increased serum CTRP 1 levels were closely associated with the prevalence and severity of CAD, it might be regarded as a marker for myocardial infarction.

A method to label biological molecules with dsDNA coated gold nanoparticles.

We described a new method to label biological molecules using gold nanoparticles (GNPs) and double stranded DNA. Researchers can conveniently label their own samples with GNPs using this method. The label is based on dsDNA with a 93.5% coverage of GNPs (dsDNA:GNP = 303:1). Antigens, streptavidin and biotin were labeled on GNPs and the success of the method was investigated with agarose gel electrophoresis, laser particle size analysis and ultraviolet spectrophotometry. These analyses confirmed that biological molecules were successfully bound to the GNPs. These molecules retained their biological activity and were able to detect targets on PVDF and NC membranes with excellent selectivity and low levels of background. Modified GNPs were also able to detect targets on nylon membranes, but with some degree of false positives. The maximum limit of detection was 25 ng proteins.