Efficacy and safety of sedation with dexmedetomidine in adults undergoing gastrointestinal endoscopic procedures: systematic review and meta-analysis of randomized controlled trials.

Background: The sedative role of dexmedetomidine (DEX) in gastrointestinal endoscopic procedures is unclear. We performed this systematic review and meta-analysis to assess the efficacy and safety of sedation with DEX during gastrointestinal endoscopic procedures with a view to providing evidence-based references for clinical decision-making. Methods: The PubMed, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov databases were searched for randomized controlled trials (RCTs) that compared DEX with different sedatives comparators (such as propofol, midazolam, and ketamine) for sedation in a variety of adult gastrointestinal endoscopic procedures from inception to 1 July 2022. Standardized mean difference (SMD) and weighted mean difference (WMD) with 95% confidence interval (CI) or pooled risk ratios (RR) with 95% CI were used for continuous outcomes or dichotomous outcomes, respectively, and a random-effect model was selected regardless of the significance of the heterogeneity. Results: Forty studies with 2,955 patients were assessed, of which 1,333 patients were in the DEX group and 1,622 patients were in the control (without DEX) group. The results suggested that the primary outcomes of sedation level of DEX are comparable to other sedatives, with similar RSS score and patient satisfaction level, and better in some clinical outcomes, with a reduced risk of body movements or gagging (RR: 0.60; 95% CI: 0.37 to 0.97; p = 0.04; I2 = 68%), and a reduced additional requirement for other sedatives, and increased endoscopist satisfaction level (SMD: 0.41; 95% CI: 0.05 to 0.77; p = 0.03; I2 = 86%). In terms of secondary outcomes of adverse events, DEX may benefit patients in some clinical outcomes, with a reduced risk of hypoxia (RR:0.34; 95% CI: 0.20 to 0.55; p < 0.0001; I2 = 52%) and cough (RR: 0.25; 95% CI: 0.12 to 0.54; p = 0.0004; I2 = 0%), no significant difference in the risk of hypotension, while an increased risk of bradycardia (RR: 3.08; 95% CI: 2.12 to 4.48; p < 0.00001; I2 = 6%). Conclusion: This meta-analysis indicates that DEX is a safe and effective sedative agent for gastrointestinal endoscopy because of its benefits for patients in some clinical outcomes. Remarkably, DEX is comparable to midazolam and propofol in terms of sedation level. In conclusion, DEX provides an additional option in sedation for gastrointestinal endoscopic procedures. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/#searchadvanced.

TLR7 promotes skin inflammation via activating NFκB-mTORC1 axis in rosacea.

Rosacea is a chronic inflammatory skin disease originated from damaged skin barrier and innate/adaptive immune dysregulation. Toll-like receptors (TLRs) sense injured skin and initiate downstream inflammatory and immune responses, whose role in rosacea is not fully understood. Here, via RNA-sequencing analysis, we found that the TLR signaling pathway is the top-ranked signaling pathway enriched in rosacea skin lesions, in which TLR7 is highlighted and positively correlated with the inflammation severity of disease. In LL37-induced rosacea-like mouse models, silencing TLR7 prevented the development of rosacea-like skin inflammation. Specifically, we demonstrated that overexpressing TLR7 in keratinocytes stimulates rapamycin-sensitive mTOR complex 1 (mTORC1) pathway via NFκB signaling. Ultimately, TLR7/NFκ B/mTORC1 axis promotes the production of cytokines and chemokines, leading to the migration of CD4+T cells, which are infiltrated in the lesional skin of rosacea. Our report reveals the crucial role of TLR7 in rosacea pathogenesis and indicatesa promising candidate for rosacea treatments.

Longevity-Associated Transcription Factor ATF7 Promotes Healthspan by Suppressing Cellular Senescence and Systematic Inflammation.

Aging is characterized by persistent low-grade systematic inflammation, which is largely responsible for the occurrence of various age-associated diseases. We and others have previously reported that long-lived people (such as centenarians) can delay the onset of or even escape certain major age-related diseases. Here, by screening blood transcriptome and inflammatory profiles, we found that long-lived individuals had a relatively lower inflammation level (IL6, TNFα), accompanied by up-regulation of activating transcription factor 7 (ATF7). Interestingly, ATF7 expression was gradually reduced during cellular senescence. Loss of ATF7 induced cellular senescence, while overexpression delayed senescence progress and senescence-associated secretory phenotype (SASP) secretion. We showed that the anti-senescence effects of ATF7 were achieved by inhibiting nuclear factor kappa B (NF-κB) signaling and increasing histone H3K9 dimethylation (H3K9me2). In Caenorhabditis elegans, ATF7 overexpression significantly suppressed aging biomarkers and extended lifespan. Our findings suggest that ATF7 is a longevity-promoting factor that lowers cellular senescence and inflammation in long-lived individuals.

Identification of quantitative trait loci for related traits of stalk lodging resistance using genome-wide association studies in maize (Zea mays L.).

BACKGROUND: Stalk lodging is one of the main factors affecting maize (Zea mays L.) yield and limiting mechanized harvesting. Developing maize varieties with high stalk lodging resistance requires exploring the genetic basis of lodging resistance-associated agronomic traits. Stalk strength is an important indicator to evaluate maize lodging and can be evaluated by measuring stalk rind penetrometer resistance (RPR) and stalk buckling strength (SBS). Along with morphological traits of the stalk for the third internodes length (TIL), fourth internode length (FIL), third internode diameter (TID), and the fourth internode diameter (FID) traits are associated with stalk lodging resistance. RESULTS: In this study, a natural population containing 248 diverse maize inbred lines genotyped with 83,057 single nucleotide polymorphism (SNP) markers was used for genome-wide association study (GWAS) for six stalk lodging resistance-related traits. The heritability of all traits ranged from 0.59 to 0.72 in the association mapping panel. A total of 85 significant SNPs were identified for the association mapping panel using best linear unbiased prediction (BLUP) values of all traits. Additionally, five candidate genes were associated with stalk strength traits, which were either directly or indirectly associated with cell wall components. CONCLUSIONS: These findings contribute to our understanding of the genetic basis of maize stalk lodging and provide valuable theoretical guidance for lodging resistance in maize breeding in the future.

Health Related Quality of Life of Rosacea Patients in China Assessed by Dermatology Life Quality Index and Willingness to Pay.

Purpose: Rosacea is a chronic inflammatory dermatosis mainly involving facial skin, leading to physical and emotional problems, which greatly affect the quality of life (QoL) of patients. Dermatology Life Quality Index (DLQI) and willingness to pay (WTP) are well-established instruments assessing the health-related quality of life (HRQoL), while very few studies have been focused on this topic about rosacea in China. The present study investigated HRQoL in Chinese rosacea patients. Patients and Methods: This cross-sectional study was conducted on 973 patients with rosacea. Sociodemographic data, clinical features and DLQI were collected, and WTP was assessed by three standardized items. Multivariable logistic analysis was performed to investigate independent factors influencing QoL. Results: A total of 921 questionnaires were accomplished by participants. The mean DLQI score was 11.6 (median 11). Patients were willing to pay an average of € 896.2 (median € 368.1) for complete cure. 33.3% would like to pay more than 20% of their monthly income to achieve sustainable control. There were positive correlations between WTP with DLQI (P < 0.05). DLQI could be independently impacted by age (21-30 and 31-40 relative to > 50, OR = 3.242 and 3.617, respectively), the occupational requirement of appearance (high, OR = 4.410), disease duration (< 2 years, OR = 1.582), edema (OR = 1.844) and severity of flushing, burning, stinging and pruritus (severe, OR = 2.003, 1.981, 2.491, 2.249, respectively). There were no significant associations between WTP and most of the clinical factors. Conclusion: The QoL was greatly impaired and should not be ignored among rosacea patients in China. Patients aged 21-40y, having occupational requirement of appearance, with the disease duration less than 2 years, and suffering severe flushing and related sensitive symptoms were more likely to have severe or very severe limitation of QoL.

Association mapping for general combining ability with yield, plant height and ear height using F1 population in maize.

General combining ability (GCA) is an important index for inbred lines breeding of maize. To identify the genetic loci of GCA and associated agronomic traits, an association analysis with 195 SSRs was made in phenotypic traits of 240 F1 derived from 120 elite inbred lines containing current breeding resources of maize crossed with 2 testers (Zheng58 and Chang7-2) in two places in 2018. All of the 20 association loci detected for grain yield (GY), plant height (PH), ear height (EH) and GCA for the three traits in two places could explain a phenotypic variation range of 7.31%-9.29%. Among the 20 association loci, 9 (7.31%-9.04%) were associated with GY, 4 (7.22%-8.91%) were related to GCA of GY, 1 (7.56%) was associated with PH, and 3 (7.53%-8.96%) were related to EH. In addition, 3 loci (9.14%-9.29%) were associated with GCA of PH whereas no locus was identified for GCA of EH. In the comparison of the association loci detected in Baoding and Handan, interestingly, one locus (7.69% and 8.11%) was identified in both environments and one locus (7.52% and 7.82%) was identified for yield and GCA of yield. Therefore, the identification of GY-, PH-, EH- and GCA-related association loci could not only provide references for high yield breeding of maize, but also help us comprehend the relationships among GY, agricultural traits and GCA.

The Protective Effect of Dexmedetomidine Against Ischemia-Reperfusion Injury after Hepatectomy: A Meta-Analysis of Randomized Controlled Trials.

Background: Hepatic inflow occlusion proceeded to reduce blood loss during hepatectomy induces ischemia-reperfusion (IR) injury in the remnant liver. Dexmedetomidine, a selective α2-adrenoceptor agonist used as an anesthetic adjuvant, has been shown to attenuate IR injury in preclinical and clinical studies. However, a meta-analysis is needed to systematically evaluate the protective effect of perioperative dexmedetomidine use on IR injury induced by hepatectomy. Methods: A prospectively registered meta-analysis following Cochrane and PRISMA guidelines concerning perioperative dexmedetomidine use on IR injury after hepatectomy was performed via searching Cochrane Library, PubMed, EMBASE, ClinicalTrials.gov, Web of Science, CNKI, WanFang, and Sinomed for eligible randomized controlled trials up to 2021.3.31. The main outcome is postoperative liver function. Risk of bias was assessed by the Cochrane Risk of Bias tool. Review Manager 5.3 and Stata12.0 were applied to perform data analyses. Results: Eight RCTs enrolling 468 participants were included. Compared with 0.9% sodium chloride, dexmedetomidine decreased serum concentration of ALT (WMD = -66.54, 95% CI: -92.10--40.98), AST (WMD= -82.96, 95% CI: -106.74--59.17), TBIL (WMD = -4.51, 95% CI: -7.32--1.71), MDA (WMD = -3.09, 95% CI: -5.17--1.01), TNF-α (WMD = -36.54, 95% CI: -61.33--11.95) and IL-6 (WMD = -165.05, 95% CI: -225.76--104.34), increased SOD activity (WMD = 24.70, 95% CI: 18.09-31.30) within postoperative one day. There was no significant difference in intraoperative or postoperative recovery parameters between groups. Conclusions: Perioperative administration of dexmedetomidine can exert a protective effect on liver IR injury after hepatectomy. Additional studies are needed to further evaluate postoperative recovery outcomes of dexmedetomidine with different dosing regimens.

Genome-Wide Association Study of Vascular Bundle-Related Traits in Maize Stalk.

The vascular bundle plays an important role in nutrient transportation in plants and exerts great influence on crop yield. Maize is widely used for food, feed, and fuel, producing the largest yield in the world. However, genes and molecular mechanism controlling vascular bundle-related traits in maize have largely remained undiscovered. In this study, a natural population containing 248 diverse maize inbred lines genotyped with high-throughput SNP markers was used for genome-wide association study. The results showed that broad variations existed for the vascular bundle-related traits which are subject to genetic structure and it was suitable for association analysis. In this study, we identified 15, 13, 2, 1, and 5 SNPs significantly associated with number of small vascular bundle, number of large vascular bundle, average area of single small vascular bundle, average area of single large vascular bundle, and cross-sectional area, respectively. The 210 candidate genes in the confidence interval can be classified into ten biological processes, three cellular components, and eight molecular functions. As for the Kyoto Encyclopedia of Genes and Genomes analysis of the candidate genes, a total of six pathways were identified. Finally, we found five genes related to vascular development, three genes related to cell wall, and two genes related to the mechanical strength of the stalk. Our results provide the further understanding of the genetic foundation of vascular bundle-related traits in maize stalk.

Genome-wide association studies of grain quality traits in maize.

High quality is the main goal of today's maize breeding and the investigation of grain quality traits would help to breed high-quality varieties in maize. In this study, genome-wide association studies in a set of 248 diverse inbred lines were performed with 83,057 single nucleotide polymorphisms (SNPs), and five grain quality traits were investigated in diverse environments for two years. The results showed that maize inbred lines showed substantial natural variations of grain quality and these traits showed high broad-sense heritability. A total of 49 SNPs were found to be significantly associated with grain quality traits. Among these SNPs, four co-localized sites were commonly detected by multiple traits. The candidate genes which were searched for can be classified into 11 biological processes, 13 cellular components, and 6 molecular functions. Finally, we found 29 grain quality-related genes. These genes and the SNPs identified in the study would offer essential information for high-quality varieties breeding programs in maize.

Meta-analysis of the effects of overexpression of WRKY transcription factors on plant responses to drought stress.

BACKGROUND: The tryptophan-arginine-lysine-tyrosine (WRKY) transcription factors play important roles in plants, allowing them to adapt to environmental conditions that are not normally conducive to plant growth; in particular, drought. There has been extensive research on WRKY transcription factors and the effects of their overexpression in plants on resistance to drought stress. However, due to the materials (the type and species of donor and receptor, promoters) and treatments (the type and time of stress) used, different and often confounding results have been obtained between studies. Meta-analysis is a powerful statistical tool that can be used to summarize results from numerous independent experiments on the same research topic while accounting for variability across experiments. RESULTS: We carried out a meta-analysis of 16 measured parameters that affect drought resistance in plants overexpressing WRKY transcription factors and wild-type plants. We found that only one of these parameters was significantly different between transgenic and wild-type plants under drought and control conditions at a 95% confidence interval (p = 0.000, p = 0.009, respectively). Eleven of the sixteen parameters were obviously different in WRKY transgenic plants under drought and control conditions (SV, p = 0.023, SSC, p = 0.000, SOD, p = 0.012, SFW, p = 0.000, RL, p = 0.016, Pro, p = 0.000, POD, p = 0.027, MDA, p = 0.000, H2O2, p = 0.003, EL, p = 0.000, CHC, p = 0.000, respectively), seven of the eleven obviously different parameters showed positive effect (SSC, SOD, Pro, POD, MDA, H2O2, EL), four of them revealed negative effect (SV, SFW, RL, CHC). CONCLUSION: We have found that only one of these parameters was significantly different between transgenic and wild-type plants under drought and control conditions respectively, at a 95% confidence interval. And eleven of sixteen parameters showed obviously different of WRKY-overexpressed plants under different conditions (water-stressed and normal), suggesting that WRKY transcription factors play an important role in plant responses to drought stress. These findings also provide a theoretical basis for further study of the role of WRKY transcription factors in the regulation of plant responses to environmental stress.

Constructing Three-Dimensional Honeycombed Graphene/Silicon Skeletons for High-Performance Li-Ion Batteries.

Silicon has been considered to be an attractive high-capacity anode material for next-generation lithium-ion batteries (LIBs). Currently, the commercial application of Si-based anodes is still restricted by its limited cycle life and rate capacity, which could be ascribed to the colossal volumetric change during the cycling process and poor electronic conductivity. We report the design of a unique Si-based nanocomposite of three-dimensional (3D) honeycombed graphene aerogel and the reduced graphene oxide sheets preprotected silicon secondary particles (SiNPs@rGO1). Through simple electrostatic self-assembly and hydrothermal processes, SiNPs are able to be wrapped with rGO1 to form reunited SiNPs@rGO1, and embedded into the backbone of 3D graphene honeycomb (rGO2). Such an intriguing design (namely, SiNPs@rGO1/rGO2) not only provides a conductive skeleton to improve the electrical conductivity, but also possesses abundant void spaces to accommodate the dramatic volume changes of SiNPs. Meanwhile, the outer rGO1 coats protect the inner SiNPs away from the electrolyte and prevent the destruction of the solid electrolyte interphase (SEI) film. As a result, the 3D honeycombed architecture achieves a high cyclability and excellent rate capability.

Constitutive expression of the ZmZIP7 in Arabidopsis alters metal homeostasis and increases Fe and Zn content.

Iron (Fe) and zinc (Zn) are important micronutrients for plant growth and development. Zinc-regulated transporters and the iron-regulated transporter-like protein (ZIP) are necessary for the homeostatic regulation of these metal micronutrients. In this study, the physiological function of ZmZIP7 which encodes a ZIP family transporter was characterized. We detected the expression profiles of ZmZIP7 in maize, and found that the accumulation of ZmZIP7 in root, stem, leaf, and seed was relatively higher than tassel and young ear. ZmZIP7 overexpression transgenic Arabidopsis lines were generated and the metal contents in transgenic and wild-type (WT) plants were examined using inductively coupled plasma atomic emission spectroscopy (ICP-OES) and Zinpyr-1 staining. Fe and Zn concentrations were elevated in the roots and shoots of ZmZIP7-overexpressing plants, while only Fe content was elevated in the seeds. We also analyzed the expression profiles of endogenous genes associated with metal homeostasis. Both endogenic Fe-deficiency inducible genes and the genes responsible for Zn and Fe transport and storage were stimulated in ZmZIP7 transgenic plants. In conclusion, ZmZIP7 encodes a functional Zn and Fe transporter, and ectopic overexpression of ZmZIP7 in Arabidopsis stimulate endogenous Fe and Zn uptake mechanisms, thereby facilitating both metal uptake and homeostasis. Our results contribute to improved understanding of ZIP family transporter functions and suggest that ZmZIP7 could be used to enhance Fe levels in grains.

Comparative mapping combined with homology-based cloning of the rice genome reveals candidate genes for grain zinc and iron concentration in maize.

BACKGROUND: Grain zinc and iron concentration is a complex trait that is controlled by quantitative trait loci (QTL) and is important for maintaining body health. Despite the substantial effort that has been put into identifying QTL for grain zinc and iron concentration, the integration of independent QTL is useful for understanding the genetic foundation of traits. The number of QTL for grain zinc and iron concentration is relatively low in a single species. Therefore, combined analysis of different genomes may help overcome this challenge. RESULTS: As a continuation of our work on maize, meta-analysis of QTL for grain zinc and iron concentration in rice was performed to identify meta-QTL (MQTL). Based on MQTL in rice and maize, comparative mapping combined with homology-based cloning was performed to identify candidate genes for grain zinc and iron concentration in maize. In total, 22 MQTL in rice, 4 syntenic MQTL-related regions, and 3 MQTL-containing candidate genes in maize (ortho-mMQTL) were detected. Two maize orthologs of rice, GRMZM2G366919 and GRMZM2G178190, were characterized as natural resistance-associated macrophage protein (NRAMP) genes and considered to be candidate genes. Phylogenetic analysis of NRAMP genes among maize, rice, and Arabidopsis thaliana further demonstrated that they are likely responsible for the natural variation of maize grain zinc and iron concentration. CONCLUSIONS: Syntenic MQTL-related regions and ortho-mMQTL are prime areas for future investigation as well as for marker-assisted selection breeding programs. Furthermore, the combined method using the rice genome that was used in this study can shed light on other species and help direct future quantitative trait research. In conclusion, these results help elucidate the molecular mechanism that underlies grain zinc and iron concentration in maize.

The genetic architecture of zinc and iron content in maize grains as revealed by QTL mapping and meta-analysis.

Micronutrient malnutrition, especially zinc (Zn) and iron (Fe) deficiency in diets, has aroused worldwide attention. Biofortification of food crops has been considered as a promising approach for alleviating this deficiency. Quantitative trait locus (QTL) analysis was performed to dissect the genetic mechanism of Zn and Fe content in maize grains using a total of 218 F2:3 families derived from a cross between inbred lines 178 and P53. Meta-analysis was used to integrate genetic maps and detect Meta-QTL (MQTL) across several independent QTL researches for traits related to Zn or Fe content. Five significant QTLs and 10 MQTLs were detected. Two informative genomic regions, bins 2.07 and 2.08, showed a great importance for Zn and Fe content QTLs. The correlation between Zn and Fe level in maize grains was proposed by MQTLs as 8 of the 10 involved both traits. The results of this study suggest that QTL mapping and meta-analysis is an effective approach to understand the genetic basis of Zn and Fe accumulation in maize grains.

General combining ability of most yield-related traits had a genetic basis different from their corresponding traits per se in a set of maize introgression lines.

Evaluation of combining ability is a crucial process in hybrid breeding, and dissection of the genetic basis of combining ability will facilitate hybrid breeding. In this study, molecular markers significantly associated with general combining ability (GCA) of seven yield-related traits and the traits per se were detected in a set of maize introgression lines (ILs) under three environments. Totally 25 and 31 significant loci for GCA and the traits per se were commonly detected under multiple environments, respectively. Correlation analysis and comparison among these significant loci revealed that the genetic basis of GCA of these yield-related traits was generally different from that of the traits per se except for the trait of ear row number. In addition, GCA of the ILs was positively and significantly correlated to the total relative effects of significant GCA loci in the ILs in general, implying that the GCA loci identified in this study would be useful in molecular breeding. Correlation analysis also showed that the GCA of yield per plant was strongly correlated to the GCA of kernel number per row, ear length and 100-kernel-weight, thus these traits were more important in genetic improvement for GCA. Results in this study would provide useful information for hybrid breeding in maize.

Identification and characterization of the zinc-regulated transporters, iron-regulated transporter-like protein (ZIP) gene family in maize.

BACKGROUND: Zinc (Zn) and iron (Fe) are essential micronutrients for plant growth and development, their deficiency or excess severely impaired physiological and biochemical reactions of plants. Therefore, a tightly controlled zinc and iron uptake and homeostasis network has been evolved in plants. The Zinc-regulated transporters, Iron-regulated transporter-like Proteins (ZIP) are capable of uptaking and transporting divalent metal ion and are suggested to play critical roles in balancing metal uptake and homeostasis, though a detailed analysis of ZIP gene family in maize is still lacking. RESULTS: Nine ZIP-coding genes were identified in maize genome. It was revealed that the ZmZIP proteins share a conserved transmembrane domain and a variable region between TM-3 and TM-4. Transiently expression in onion epidermal cells revealed that all ZmZIP proteins were localized to the endoplasmic reticulum and plasma membrane. The yeast complementation analysis was performed to test the Zn or Fe transporter activity of ZmZIP proteins. Expression analysis showed that the ZmIRT1 transcripts were dramatically induced in response to Zn- and Fe-deficiency, though the expression profiles of other ZmZIP changed variously. The expression patterns of ZmZIP genes were observed in different stages of embryo and endosperm development. The accumulations of ZmIRT1 and ZmZIP6 were increased in the late developmental stages of embryo, while ZmZIP4 was up-regulated during the early development of embryo. In addition, the expression of ZmZIP5 was dramatically induced associated with middle stage development of embryo and endosperm. CONCLUSIONS: These results suggest that ZmZIP genes encode functional Zn or Fe transporters that may be responsible for the uptake, translocation, detoxification and storage of divalent metal ion in plant cells. The various expression patterns of ZmZIP genes in embryo and endosperm indicates that they may be essential for ion translocation and storage during differential stages of embryo and endosperm development. The present study provides new insights into the evolutionary relationship and putative functional divergence of the ZmZIP gene family during the growth and development of maize.

Identification of combining ability loci for five yield-related traits in maize using a set of testcrosses with introgression lines.

Combining ability is essential for hybrid breeding in crops. However, the genetic basis of combining ability remains unclear and has been seldom investigated. Identifying molecular markers associated with this complex trait would help to understand its genetic basis and provide useful information for hybrid breeding in maize. In this study, we identified genetic loci of general combining ability (GCA) and specific combining ability (SCA) for five yield-related traits under three environments using a set of testcrosses with introgression lines (ILs). GCA or SCA of the five yield-related traits of the ILs was estimated by the performance of testcrosses with four testers from different heterotic groups. Genetic correlations between GCA of the traits and the corresponding traits per se were not significant or not strong, suggesting that the genetic basis between them is different. A total of 56 significant loci for GCA and 21 loci for SCA were commonly identified in at least two environments, and only 5 loci were simultaneously controlling GCA and SCA, indicating that the genetic basis of GCA and SCA is different. For all of the traits investigated, positive and significant correlations between the number of GCA loci in the ILs and the performance of the corresponding GCA of the ILs were detected, implying that pyramiding GCA loci would have positive effect on the performance of GCA. Results in this study would be useful for maize hybrid breeding.

Temperature and solvent-dependent morphological sol gel transformation: an in situ microscopic observation.

A thermoreversible self-assemble process from gel (fiber) to sol (vesicle) state in the system alkylamine-ethylene glycol is for the first time monitored by in situ polarized optical microscopy, XRD, (1)H NMR, SEM, SAXRD, FTIR and drop shape analysis. It is found that the solvent molecules are intercalated with alkylamine molecules to form the organogel and vesicle structures. A model based on structural transformation with respect to these alkylamine gelator-solvent assembles is therefore proposed.

Strategy to introduce a pendent micellar structure into poly(N-isopropylacrylamide) hydrogels.

A novel class of functional poly(N-isopropylacrylamide) (PNIPAAm) hydrogels with pendent micellar structure resulting from the pending amphiphilic polymers was designed and prepared. The influence of the pendent micellar structure on the properties of the resulted PNIPAAm hydrogels was examined in terms of morphology observed by scanning electron microscopy, thermal response through differential scanning calorimetry, and deswelling/reswelling kinetics upon external temperature changes. In comparison with the conventional ones, the novel PNIPAAm hydrogels with pendent micellar structure presented improved temperature-sensitive properties, i.e., enlarged water containing capability at room temperature, as well as improved deswelling rate upon heating.