Gas Permeation of Sulfur Thin-Films and Potential as a Barrier Material.

Elemental sulfur was formed into poly(ether sulfone)-supported thin-films (ca. 10 µm) via a melt-casting process. Observed permeabilities of C2H4, CO2, H2, He, and N2 through the sulphur thin-films were <1 barrer. The sulfur thin-films were observed to age over a period of ca. 15 days, related to the reversion of polymerized sulfur to the S8 allotrope. This structural conversion was observed to correlate with an increase in the permeability of all gases

Functionalized zeolites with hierarchical and core-shell architectures.

Zeolites are well known for their ordered microporous networks, good hydrothermal stability, large surface area, high acidity and selectivity. These excellent properties make zeolites extremely useful for petrochemical processes and refining. However, the sole presence of microporous channels also restricts the diffusion of reactants and products into and out of the microporous networks, especially limiting zeolite applications involving bulky molecules. The importance of developing hierarchical zeolites has attracted great attention in recent years due to the prospect of increased accessibility for bulky molecules. Introducing additional mesoporosity, and even macroporosity, into conventional zeolites produces a combination of three different size scales of porosity. It expands the original zeolite hierarchical structure and greatly enhances the mass transport of molecules while maintaining the intrinsic size, shape and transition state selectivity of zeolite. The promising applications of this new zeolite architecture have prompted a multitude of efforts to develop a variety of different synthesis strategies. Apart from hierarchical modification, core-shell structure also gives zeolites great advantages from both core and shell zeolites, such as ion exchange property for deposition of metal particles on inner zeolite, meanwhile a hydrophobic zeolite shell can protect the core complex from inhibition by water. The thesis herein focused on the development of zeolites with hierarchical and core-shell structures. We designed a zeolite stacking structure by using hydraulic pressing and programmed temperature calcination synthesis procedures. ZSM-5 type zeolites with particle sizes of approximately 100 nm, 1 μm and 2 μm were used to synthesize stacking ZSM-5 with a size ranging from 45 to 63 μm. The prepared ZSM-5 zeolite stacking structure was used as a support to deposit palladium. The performance of the palladium/stacking ZSM-5 was investigated on Sonogashira coupling reactions. Stacking samples with micro-sized units (1 μm and 2 μm) showed a 200-300% higher turnover number (TON) than their unit counterparts. However, stacking samples with nano-sized units (100 nm) showed decreased TON conversion compared with that of their unit counterparts, probably due to partial destruction of the nano-sized ZSM-5 structure during the stacking synthesis process at high temperature. The palladium/stacking ZSM-5 (micro-sized units) also showed better conversion on different bromides and alkynes than that of traditional homogenous catalysts. Moreover, the stacking composites showed good durability by recycling 4 runs without losing significant catalytic activity. The design of the stacking MFI structure exhibited improved catalytic activity, sustainability and hierarchical-resemblance properties. We also investigated the structure-performance relationships in different zeolite-solvent systems that are suitable for microwave-assisted dehydration of fructose to 5-hydroxymethylfurfural (HMF). Different types of zeolites (MFI, BEA, and Y) were examined as acid catalysts. The results showed that the HMF yield is independent of particle size for MFI zeolite in water. The secondary porosities improved the HMF yield, while byproducts formation (via rehydration or polymerization) was also increased due to the enlarged channels in zeolites. All tested zeolites showed higher fructose conversion, HMF yield, and HMF selectivity in organic-water solvent systems than in water. The synergistic effect of the substrates, catalysts, and solvent-product interactions in the hydrophobic Y zeolite/DMSO system yielded the highest fructose conversion (72.4%) and HMF yield (49.2%). This study supports the understanding of the requirement for microwave-assisted biomass conversion in biorefinery. Next, we developed a core-shell zeolite structure comprised of palladium-deposited ZSM-5 core and silicalite-1 (S-1) shell which favors selectivity towards light olefin in hydrogenation via increased diffusion length. A well designed S-1/Pd/ZSM-5 core-shell structure was prepared via secondary crystallization of S-1 layer on the Pd/ZSM-5 core. The catalytic and selectivity performance of the S-1/Pd/ZSM-5 composite was evaluated in catalytic hydrogenation of alkenes in liquid phase. The synthesized S-1/Pd/ZSM-5 gives a much higher selectivity towards 1-hexene (87%) over cyclohexene (13%) even though both reactants are able to enter the 10-membered ring channels of the core-shell structure. The zeolitic core-shell composite also showed an increased selectivity towards 1-hexene over 1-heptene as the S-1 layers built up, even though both are linear alkenes with similar kinetic diameters that are accessible to the MFI framework. In this work, we demonstrated a strong correlation between the thickness of the S-1 shell layer and the selectivity towards light olefins due to faster mass transfer rate. The design of the core-shell MFI structure is a new example of how selectivity in a zeolite-catalyzed reaction can be changed and enhanced without relying on typical molecular size exclusion process. Lastly, we synthesized a core-shell zeolite structure comprised of palladium-deposited nano-sized ZSM-5 core and silicalite-1 (S-1) shell, which favors ethylene adsorption and shows improved humidity tolerance. A well designed S-1/Pd/ZSM-5 core-shell structure was prepared via secondary crystallization of S-1 layer on the nano-sized Pd/ZSM-5 core. The ethylene removing ability of the S-1/Pd/ZSM-5 in both dry and humid conditions was evaluated by pressure drop method. The synthesized S-1/Pd/ZSM-5 gives a much higher ethylene uptake up to 290% than plain ZSM-5. The S-1 coated samples also shows strong humidity tolerance by only losing 7.6% of the ethylene uptake under 5 h of humidity pre-treatment, while the Pd/ZSM-5 lost 20% of ethylene uptake under the same condition. The design of the core-shell structure may offer the advantages of long-term economic benefit and sustainability for the fresh products market

Incorporating Hierarchy into Conventional Zeolites for Catalytic Biomass Conversions: A Review

Zeolites are promising catalysts that are widely used in petrochemical, oil, and gas industries due to their unique characteristics, such as ordered microporous networks, good hydrothermal stability, large surface area, tunable acidity, and shape-selectivity. Nevertheless, the sole presence of microporous channels in zeolites inevitably restricts the diffusion of bulky reactants and products into and out of the microporous networks, leading to retarded reaction rates or catalyst deactivation. This problem can be overcome by developing hierarchical zeolites which involve mesoporous and macroporous networks. The meso- and macro-porosities can enhance the mass transport of molecules and simultaneously maintain the intrinsic shape selectivity of zeolite microporosity. Hierarchical zeolites are mainly developed through post-synthesis and pre-synthesis or in situ modification of zeolites. In this review, we evaluated both pre-synthesis and post-synthesis modification strategies with more focus on post-synthesis modification strategies. The role of various synthesis strategies on the intrinsic properties of hierarchical zeolites is discussed. The catalytic performance of hierarchical zeolites in important biomass reactions, such as catalytic pyrolysis of biomass feedstock and upgradation of bio-oil, has been summarized. The utilization of hierarchical zeolites tends to give a higher aromatic yield than conventional zeolites with microporosity solely

Deep evolutionary fusion neural network: a new prediction standard for infectious disease incidence rates

Abstract Background Previously, many methods have been used to predict the incidence trends of infectious diseases. There are numerous methods for predicting the incidence trends of infectious diseases, and they have exhibited varying degrees of success. However, there are a lack of prediction benchmarks that integrate linear and nonlinear methods and effectively use internet data. The aim of this paper is to develop a prediction model of the incidence rate of infectious diseases that integrates multiple methods and multisource data, realizing ground-breaking research. Results The infectious disease dataset is from an official release and includes four national and three regional datasets. The Baidu index platform provides internet data. We choose a single model (seasonal autoregressive integrated moving average (SARIMA), nonlinear autoregressive neural network (NAR), and long short-term memory (LSTM)) and a deep evolutionary fusion neural network (DEFNN). The DEFNN is built using the idea of neural evolution and fusion, and the DEFNN + is built using multisource data. We compare the model accuracy on reference group data and validate the model generalizability on external data. (1) The loss of SA-LSTM in the reference group dataset is 0.4919, which is significantly better than that of other single models. (2) The loss values of SA-LSTM on the national and regional external datasets are 0.9666, 1.2437, 0.2472, 0.7239, 1.4026, and 0.6868. (3) When multisource indices are added to the national dataset, the loss of the DEFNN + increases to 0.4212, 0.8218, 1.0331, and 0.8575. Conclusions We propose an SA-LSTM optimization model with good accuracy and generalizability based on the concept of multiple methods and multiple data fusion. DEFNN enriches and supplements infectious disease prediction methodologies, can serve as a new benchmark for future infectious disease predictions and provides a reference for the prediction of the incidence rates of various infectious diseases

<i>In Situ</i> Regulation of Microphase Separation-Recognized Circularly Polarized Luminescence via Photoexcitation-Induced Molecular Aggregation

Circularly polarized luminescence (CPL) has attracted great interest owing to its extensive optical information and chiral structural dependence. However, rationally regulating solid-phase CPL signals remains difficult because of the close packing of molecules in solid-state materials and the lack of structural visualization. In this work, we proposed a microphase-separation-recognized CPL regulation strategy via coassembly of a hexathiobenzene-based luminophore and chiral block copolymer (cBCP) with in situ photocontrollability. As a consequence to the continuous increase in the luminophore-to-cBCP ratio, the CPL signal of the supramolecular system exhibited an increasing trend until a critical point. Then, further increasing the ratio stretched the helical pitch of cBCP, which led to CPL reduction. With the photoexcitation-induced molecular aggregation of the luminophore, which was implemented using in situ photoirradiation, the helical pitch was retracted along with the restoration of the CPL signal. These processes were fully recognized and monitored by the microphase-separated nanomorphological change of the coassembled system, which indicated that such a structural contrast could be an effective method for rationally regulating the supramolecular chiropticity of solid-state materials

Transcriptomic Analysis of Grapevine (cv. Summer Black) Leaf, Using the Illumina Platform

<div><p>Proceeding to illumina sequencing, determining RNA integrity numbers for poly RNA were separated from each of the four developmental stages of cv. Summer Black leaves by using Illumina HiSeq^™ 2000. The sums of 272,941,656 reads were generated from <i>vitis vinifera</i> leaf at four different developmental stages, with more than 27 billion nucleotides of the sequence data. At each growth stage, RNA samples were indexed through unique nucleic acid identifiers and sequenced. KEGG annotation results depicted that the highest number of transcripts in 2,963 (2Avs4A) followed by 1Avs4A (2,920), and 3Avs4A (2,294) out of 15,614 (71%) transcripts were recorded. In comparison, a total of 1,532 transcripts were annotated in GOs, including Cellular component, with the highest number in “Cell part” 251 out of 353 transcripts (71.1%), followed by intracellular organelle 163 out of 353 transcripts (46.2%), while in molecular function and metabolic process 375 out of 525 (71.4%) transcripts, multicellular organism process 40 out of 525 (7.6%) transcripts in biological process were most common in 1Avs2A. While in case of 1Avs3A, cell part 476 out of 662 transcripts (71.9%), and membrane-bounded organelle 263 out of 662 transcripts (39.7%) were recorded in Cellular component. In the grapevine transcriptome, during the initial stages of leaf development 1Avs2A showed single transcript was down-regulated and none of them were up-regulated. While in comparison of 1A to 3A showed one up-regulated (photosystem II reaction center protein C) and one down regulated (conserved gene of unknown function) transcripts, during the hormone regulating pathway namely SAUR-like auxin-responsive protein family having 2 up-regulated and 7 down-regulated transcripts, phytochrome-associated protein showed 1 up-regulated and 9 down-regulated transcripts, whereas genes associated with the Leucine-rich repeat protein kinase family protein showed 7 up-regulated and 1 down-regulated transcript, meanwhile Auxin Resistant 2 has single up-regulated transcript in second developmental stage, although 3 were down-regulated at lateral growth stages (3A and 4A). In the present study, 489 secondary metabolic pathways related genes were identified during leaf growth, which mainly includes alkaloid (40), anthocyanins (21), Diterpenoid (144), Monoterpenoid (90) and Flavonoids (93). Quantitative real-time PCR was applied to validate 10 differentially expressed transcripts patterns from flower, leaf and fruit metabolic pathways at different growth stages.</p></div

Helicobacter pylori and immunotherapy for gastrointestinal cancer

Helicobacter pylori infection is associated with the risk of gastrointestinal (GI) cancers; however, its impact on immunotherapy for GI cancers remains uncertain. In this study, we included 10,122 patients who underwent 13C-urea breath tests. Among 636 patients with Epstein-Barr virus–negative microsatellite-stable gastric cancer (GC) who were treated with anti-PD-1/PD-L1 therapy, H. pylori–positive patients exhibited significantly longer immune-related progression-free survival (irPFS) compared with H. pylori–negative patients (6.97 months versus 5.03 months, p < 0.001, hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.62–0.95, p = 0.015). Moreover, the H. pylori–positive group demonstrated a trend of 4 months longer median immune-related overall survival (irOS) than the H. pylori–negative group. H. pylori–positive GC displayed higher densities of PD-L1+ cells and nonexhausted CD8+ T cells, indicative of a “hot” tumor microenvironment. Transcriptomic analysis revealed that H. pylori–positive GC shared molecular characteristics similar to those of immunotherapy-sensitive GC. However, H. pylori–positive patients with DNA mismatch repair–deficient (dMMR)/microsatellite instability–high (MSI-H) colorectal adenocarcinoma and esophageal squamous cell carcinoma (ESCC) had shorter irPFS compared with H. pylori–negative patients (16.13 months versus not reached, p = 0.042, HR 2.26, 95% CI 1.13–4.50, p = 0.021 and 5.57 months versus 6.97 months, p = 0.029, HR 1.59, 95% CI 1.14–2.23, p = 0.006, respectively). The difference in irOS between H. pylori–positive and –negative patients had the same trend as that between dMMR/MSI-H colorectal adenocarcinoma and ESCC patients. We also identified a trend of shorter irPFS and irOS in H. pylori–positive liver cancer and pancreatic cancer patients. In summary, our findings supported that H. pylori infection is a beneficial factor for GC immunotherapy by shaping hot tumor microenvironments. However, in dMMR/MSI-H colorectal adenocarcinoma and ESCC patients, H. pylori adversely affects the efficacy of immunotherapy