Atomically dispersed hexavalent iridium oxide from MnO2 reduction for oxygen evolution catalysis.

Hexavalent iridium (IrVI) oxide is predicted to be more active and stable than any other iridium oxide for the oxygen evolution reaction in acid; however, its experimental realization remains challenging. In this work, we report the synthesis, characterization, and application of atomically dispersed IrVI oxide (IrVI-ado) for proton exchange membrane (PEM) water electrolysis. The IrVI-ado was synthesized by oxidatively substituting the ligands of potassium hexachloroiridate(IV) (K2IrCl6) with manganese oxide (MnO2). The mass-specific activity (1.7 × 105 amperes per gram of iridium) and turnover number (1.5 × 108) exceeded those of benchmark iridium oxides, and in situ x-ray analysis during PEM operations manifested the durability of IrVI at current densities up to 2.3 amperes per square centimeter. The high activity and stability of IrVI-ado showcase its promise as an anode material for PEM electrolysis.

Hydroxy-Safflower Yellow A Mitigates Vascular Remodeling in Rat Pulmonary Arterial Hypertension.

Purpose: The underlying causes of pulmonary arterial hypertension (PAH) often remain obscure. Addressing PAH with effective treatments presents a formidable challenge. Studies have shown that Hydroxysafflor yellow A (HSYA) has a potential role in PAH, While the mechanism underlies its protective role is still unclear. The study was conducted to investigate the potential mechanisms of the protective effects of HSYA. Methods: Using databases such as PharmMapper and GeneCards, we identified active components of HSYA and associated PAH targets, pinpointed intersecting genes, and constructed a protein-protein interaction (PPI) network. Core targets were singled out using Cytoscape for the development of a model illustrating drug-component-target-disease interactions. Intersection targets underwent analysis for Gene Ontology (GO) functions and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Selected components were then modeled for target interaction using Autodock and Pymol. In vivo validation in a monocrotaline-induced PAH (MCT-PAH) animal model was utilized to substantiate the predictions made by network pharmacology. Results: We associated HSYA with 113 targets, and PAH with 1737 targets, identifying 34 mutual targets for treatment by HSYA. HSYA predominantly affects 9 core targets. Molecular docking unveiled hydrogen bond interactions between HSYA and several PAH-related proteins such as ANXA5, EGFR, SRC, PPARG, PGR, and ESR1. Conclusion: Utilizing network pharmacology and molecular docking approaches, we investigated potential targets and relevant human disease pathways implicating HSYA in PAH therapy, such as the chemical carcinogenesis receptor activation pathway and the cancer pathway. Our findings were corroborated by the efficacious use of HSYA in an MCT-induced rat PAH model, confirming its therapeutic potential.

A ring N(CH3)2-based derivative of resveratrol inhibits pulmonary vascular remodeling in hypoxia pulmonary hypertension.

Pulmonary artery smooth muscle cells (PASMCs) phenotypic switching and pulmonary artery endothelial cells (PAECs) endothelial-mesenchymal transition (EndMT) are important in promoting pulmonary hypertension (PH)-pulmonary vascular remodeling (PVR). Resveratrol can efficiently inhibit the proliferation of PASMCs, but its application is limited due to its low bioavailability and solubility. In this study, we modified resveratrol to assess the role of A ring N(CH3)2-based derivatives of resveratrol (Res4) in PVR-PASMCs phenotypic switching and PVR-PAECs EndMT. Chemical methods were used for the preparation of Res4; NMRS and HPLC were used to authenticate Res4. Mice developed PVR after 4 weeks of hypoxia (10% O2). Res4 (50 mg/kg/d) attenuated right ventricular systolic pressure, right ventricular hypertrophy, and PVR. PASMCs developed phenotypic switching and PAECs developed EndMT after 2 days of hypoxia (3% O2). Res4 (10 µM) could inhibit PASMCs and PAECs viability. Res4 could decrease proliferating cell nuclear antigen (PCNA) and osteopontin (OPN) expression, and increase α-smooth muscle actin (α-SMA) and vimentin expression in PASMCs. It could also decrease PCNA, α-SMA, vimentin expression and increase platelet endothelial cell adhesion molecule (CD31) expression in PAECs. Notably, Res4 inhibited the phosphorylation levels of mitogen-activated protein kinase kinase (MEK), extracellular signal-regulated protein kinase (ERK), Jun-N-terminal kinase (JNK), and p38 kinase in hypoxia-treated PASMCs and PAECs, indicating MAPK pathway may be involved in Res4-induced inhibition of PASMCs phenotypic switching and PAECs EndMT. Our data demonstrated that Res4 exerts antiproliferative effects by regulating PASMCs phenotypic switching and PAECs EndMT. Res4 may be potentially used as a drug against PH-PVR.

Identification of Zip8-correlated hub genes in pulmonary hypertension by informatic analysis.

Background: Pulmonary hypertension (PH) is a syndrome characterized by marked remodeling of the pulmonary vasculature and increased pulmonary vascular resistance, ultimately leading to right heart failure and even death. The localization of Zrt/Irt-like Protein 8 (ZIP8, a metal ion transporter, encoded by SLC39A8) was abundantly in microvasculature endothelium and its pivotal role in the lung has been demonstrated. However, the role of Zip8 in PH remains unclear. Methods: Bioinformatics analysis was employed to identify SLC39A8 expression patterns and differentially expressed genes (DEGs) between PH patients and normal controls (NC), based on four datasets (GSE24988, GSE113439, GSE117261, and GSE15197) from the Biotechnology Gene Expression Omnibus (NCBI GEO) database. Gene set enrichment analysis (GSEA) was performed to analyze signaling pathways enriched for DEGs. Hub genes were identified by cytoHubba analysis in Cytoscape. Reverse transcriptase-polymerase chain reaction was used to validate SLC39A8 and its correlated metabolic DEGs expression in PH (SU5416/Hypoxia) mice. Results: SLC39A8 expression was downregulated in PH patients, and this expression pattern was validated in PH (SU5416/Hypoxia) mouse lung tissue. SLC39A8-correlated genes were mainly enriched in the metabolic pathways. Within these SLC39A8-correlated genes, 202 SLC39A8-correlated metabolic genes were screened out, and seven genes were identified as SLC39A8-correlated metabolic hub genes. The expression patterns of hub genes were analyzed between PH patients and controls and further validated in PH mice. Finally, four genes (Fasn, Nsdhl, Acat2, and Acly) were downregulated in PH mice. However, there were no significant differences in the expression of the other three hub genes between PH mice and controls. Of the four genes, Fasn and Acly are key enzymes in fatty acids synthesis, Nsdhl is involved in cholesterol synthesis, and Acat2 is implicated in cholesterol metabolic transformation. Taken together, these results provide novel insight into the role of Zip8 in PH.

A pangenome reference of 36 Chinese populations.

Human genomics is witnessing an ongoing paradigm shift from a single reference sequence to a pangenome form, but populations of Asian ancestry are underrepresented. Here we present data from the first phase of the Chinese Pangenome Consortium, including a collection of 116 high-quality and haplotype-phased de novo assemblies based on 58 core samples representing 36 minority Chinese ethnic groups. With an average 30.65× high-fidelity long-read sequence coverage, an average contiguity N50 of more than 35.63 megabases and an average total size of 3.01 gigabases, the CPC core assemblies add 189 million base pairs of euchromatic polymorphic sequences and 1,367 protein-coding gene duplications to GRCh38. We identified 15.9 million small variants and 78,072 structural variants, of which 5.9 million small variants and 34,223 structural variants were not reported in a recently released pangenome reference1. The Chinese Pangenome Consortium data demonstrate a remarkable increase in the discovery of novel and missing sequences when individuals are included from underrepresented minority ethnic groups. The missing reference sequences were enriched with archaic-derived alleles and genes that confer essential functions related to keratinization, response to ultraviolet radiation, DNA repair, immunological responses and lifespan, implying great potential for shedding new light on human evolution and recovering missing heritability in complex disease mapping.

Carnosol Inhibits the Proliferation, Migration, and Invasion of Hepatocellular Carcinoma Cells in vitro by Regulating the AMPK Signaling Pathway.

Background: Hepatocellular carcinoma (HCC) is one of the most malignant cancers in the world, and its 5- year survival rate is low. At present, for advanced primary liver cancer, the clinical treatment often adopts the systemic method, but there is no effective targeted treatment. The average survival time of patients with liver cancer after drug treatment is only 3-5 months. Therefore, it is of great clinical significance to find new and effective drugs for the treatment of HCC. Carnosol (CA) is a bioactive diterpene compound present in Lamiaceae spp., which has been demonstrated to have antioxidant, anti-inflammatory, and anticancer properties. Aim: In this study, we aimed to reveal the effect of carnosol on HCC and provide new possibilities for the drug therapy of HCC. Obejective: The objective of this study is to observe the effect of carnosol on the tumor phenotype and signaling pathway of HCC cells. Methods: We treated two different human HCC cells, HepG2 and Huh7, with carnosol. The cells were analyzed using the CCK-8 assay for viability and proliferation. The cell migration and invasion were detected by Transwell assay. The molecular markers of cell proliferation, apoptosis, migration, invasion, and signaling pathways were detected by RTPCR and WB. In addition, we performed rescue experiments with inhibitors to verify the affected signaling pathway. Results: The results showed that carnosol could significantly inhibit HCC cell viability, effort, colony formation, migration, and invasion. Moreover, Carnosol promoted the apoptosis of HCC cells. Mechanically, carnosol activated the AMPK-p53 pathway. Conclusion: To conclude, our study demonstrated that carnosol could inhibit proliferation, migration, invasion, and promote apoptosis via activating AMPK-p53 in HCC cells.

Toward evaluation of multiresolution cortical thickness estimation with FreeSurfer, MaCRUISE, and BrainSuite.

Advances in Magnetic Resonance Imaging hardware and methodologies allow for promoting the cortical morphometry with submillimeter spatial resolution. In this paper, we generated 3D self-enhanced high-resolution (HR) MRI imaging, by adapting 1 deep learning architecture, and 3 standard pipelines, FreeSurfer, MaCRUISE, and BrainSuite, have been collectively employed to evaluate the cortical thickness. We systematically investigated the differences in cortical thickness estimation for MRI sequences at multiresolution homologously originated from the native image. It has been revealed that there systematically exhibited the preferences in determining both inner and outer cortical surfaces at higher resolution, yielding most deeper cortical surface placements toward GM/WM or GM/CSF boundaries, which directs a consistent reduction tendency of mean cortical thickness estimation; on the contrary, the lower resolution data will most probably provide a more coarse and rough evaluation in cortical surface reconstruction, resulting in a relatively thicker estimation. Although the differences of cortical thickness estimation at the diverse spatial resolution varied with one another, almost all led to roughly one-sixth to one-fifth significant reduction across the entire brain at the HR, independent to the pipelines we applied, which emphasizes on generally coherent improved accuracy in a data-independent manner and endeavors to cost-efficiency with quantitative opportunities.

Effects of animal manure and nitrification inhibitor on N2O emissions and soil carbon stocks of a maize cropping system in Northeast China.

The incorporation of animal manure (AM) in soil plays an essential role in soil carbon sequestration but might induce higher soil nitrous oxide (N2O) emissions. The use of nitrification inhibitors (NI) is an effective strategy to abate N2O emission in agro-ecosystems. However, very few studies have evaluated the effectiveness of applying NI under the combined application of organic and inorganic fertilizers for increasing soil carbon sequestration and reducing N2O emissions simultaneously in Northeast China. Here, a four-year field experiment was conducted with three treatments [inorganic fertilizer (NPK), inorganic fertilizer + manure (NPKM), and inorganic fertilizer with NI + manure (NPKI + M)], in a rainfed maize cropping system in Northeast China. Plots of different treatments were kept in the same locations for 4 years. Gas samples were collected using the static closed chamber technique, and nitrous oxide (N2O) concentration in gas samples was quantified using a gas chromatograph. Soil organic carbon sequestration rate (SOCSR) was calculated based on the changes in SOC from April 2012 to October 2015. Averaged over the four years, AM incorporation significantly increased soil N2O emissions by 25.8% (p < 0.05), compared to NPK treatment. DMPP (3,4-dimethylpyrazole phosphate) significantly decreased N2O emissions by 32.5% (p < 0.05) relative to NPKM treatment. SOC content was significantly elevated by 24.1% in the NPKI + M treatment than the NPK treatment after four years of manure application (p < 0.05). The annual topsoil SOCSR for the NPKM and NPKI + M treatments was 0.57 Mg ha-1 yr-1 and 1.02 Mg ha-1 yr-1, respectively, which were significantly higher than that of NPK treatment (- 0.61 Mg ha-1 yr-1, p < 0.05). AM addition significantly increased the aboveground biomass and crop yields of maize in the fourth year. Overall, combined application of DMPP, inorganic fertilizer and AM is strongly recommended in this rainfed maize cropping system, which can increase maize yield and SOC sequestration rate, and mitigate N2O emission.

Nitrogen fertilization decrease soil CO2 emission in a rainfed maize field in Northeast China.

Nitrogen fertilizer has considerable effects on soil carbon fluxes. However, the responses of soil CO2 emission to N fertilizer remain controversial. A field experiment was conducted to examine the effect of application of N fertilizer on soil CO2 emission in a maize (Zea mays L.) field in Northeast China. Soil CO2 emission was measured from May 2010 to April 2016. Soil CO2 emission during the growing season and non-growing season contributed 79.7-83.6% and 16.4-20.3%, respectively, to the total annual CO2 emission. Cumulative annual soil CO2 emissions were significantly higher in no-N addition treatment (CK) than that in N addition treatment (SU) from 2012/2013 to 2015/2016 (p < 0.05). Mean annual soil CO2 emission decreased on averaged by 21.2% after N fertilization (p < 0.05). 49.6-82.2% of CO2 flux variation was explained by soil temperature at 5 cm depth. Q10 of soil CO2 emission in the annual scale was not significantly affected by N fertilizer. The results highlight the importance of N fertilizer on soil CO2 emission in agricultural ecosystem.

Psychological Stress and Functional Endometrial Disorders: Update of Mechanism Insights.

The human endometrium plays a vital role in providing the site for embryo implantation and maintaining the normal development and survival of the embryo. Recent studies have shown that stress is a common factor for the development of unexplained reproductive disorders. The nonreceptive endometrium and disturbed early maternal-fetal interaction might lead to infertility including the repeated embryo implantation failure and recurrent spontaneous abortion, or late pregnancy complications, thereby affecting the quality of life as well as the psychological status of the affected individuals. Additionally, psychological stress might also adversely affect female reproductive health. In recent years, several basic and clinical studies have tried to investigate the harm caused by psychological stress to reproductive health, however, the mechanism is still unclear. Here, we review the relationship between psychological stress and endometrial dysfunction, and its consequent effects on female infertility to provide new insights for clinical therapeutic interventions in the future.

Effects of Trichoderma asperellum and its siderophores on endogenous auxin in Arabidopsis thaliana under iron-deficiency stress.

Iron (Fe) deficiency is one of the major limiting factors affecting crop yields. Trichoderma asperellum Q1, a biocontrol and plant growth promoting fungus, can produce the siderophore which has a high affinity to Fe3+ in the absence of iron. In this study, Trichoderma asperellum Q1 was found to be able to promote growth of Arabidopsis thaliana in an iron-deficient or insoluble iron-containing (Fe2O3) medium. It also can produce more siderophore and indole-3-acetic acid (IAA) as the concentration of iron ions decreased. However, it is unclear that the relationship between siderophore and IAA in promoting plant growth. Both Trichoderma asperellum Q1 and siderophore promotes not only the DR5::GFP transgenic Arabidopsis thaliana seedlings, in which the root IAA is labeled by green fluorescent protein gene, but also increases the content of endogenous IAA in the roots, which was shown by the fluorescence study. The strongest fluorescence was observed in the treated group inoculated with Trichoderma asperellum Q1 under the condition of insoluble iron. In the case of iron-free medium, adding siderophore also increased the observed fluorescence intensity. These results suggest that the siderophores produced by Trichoderma asperellum Q1 increased the content of IAA in Arabidopsis roots by enhancing the conversion of poorly soluble iron or by the siderophore itself.

The role of tyrosine phosphatase Shp2 in spermatogonial differentiation and spermatocyte meiosis.

The transition from spermatogonia to spermatocytes and the initiation of meiosis are key steps in spermatogenesis and are precisely regulated by a plethora of proteins. However, the underlying molecular mechanism remains largely unknown. Here, we report that Src homology domain tyrosine phosphatase 2 (Shp2; encoded by the protein tyrosine phosphatase, nonreceptor type 11 [Ptpn11] gene) is abundant in spermatogonia but markedly decreases in meiotic spermatocytes. Conditional knockout of Shp2 in spermatogonia in mice using stimulated by retinoic acid gene 8 (Stra8)-cre enhanced spermatogonial differentiation and disturbed the meiotic process. Depletion of Shp2 in spermatogonia caused many meiotic spermatocytes to die; moreover, the surviving spermatocytes reached the leptotene stage early at postnatal day 9 (PN9) and the pachytene stage at PN11-13. In preleptotene spermatocytes, Shp2 deletion disrupted the expression of meiotic genes, such as disrupted meiotic cDNA 1 (Dmc1), DNA repair recombinase rad51 (Rad51), and structural maintenance of chromosome 3 (Smc3), and these deficiencies interrupted spermatocyte meiosis. In GC-1 cells cultured in vitro, Shp2 knockdown suppressed the retinoic acid (RA)-induced phosphorylation of extracellular-regulated protein kinase (Erk) and protein kinase B (Akt/PKB) and the expression of target genes such as synaptonemal complex protein 3 (Sycp3) and Dmc1. Together, these data suggest that Shp2 plays a crucial role in spermatogenesis by governing the transition from spermatogonia to spermatocytes and by mediating meiotic progression through regulating gene transcription, thus providing a potential treatment target for male infertility.

Biallelic mutations in PMFBP1 cause acephalic spermatozoa.

The majority of men with defects in spermatogenesis remain undiagnosed. Acephalic spermatozoa is one of the diseases causing primary infertility. However, the causes underlying over half of affected cases remain unclear. Here, we report by whole-exome sequencing the identification of homozygous and compound heterozygous truncating mutations in PMFBP1 of two unrelated individuals with acephalic spermatozoa. PMFBP1 was highly and specifically expressed in human and mouse testis. Furthermore, immunofluorescence staining in sperm from a normal control showed that PMFBP1 localizes to the head-flagella junction region, and the absence of PMFBP1 was confirmed in patients harboring PMFBP1 mutations. In addition, we generated Pmfbp1 knock-out (KO) mice, which we found recapitulate the acephalic sperm phenotype. Label-free quantitative proteomic analysis of testicular sperm from Pmfbp1 KO and control mice showed 124 and 35 proteins, respectively, increased or decreased in sperm from KO mice compared to that found in control mice. Gene ontology analysis indicates that the biological process of Golgi vesicle transport was the most highly enriched in differentially expressed proteins, indicating process defects related to Golgi complex function may disturb formation of the head-neck junction. Collectively, our data indicate that PMFBP1 is necessary for sperm morphology in both humans and mice, and that biallelic truncating mutations in PMFBP1 cause acephalic spermatozoa.

Realizing p-Type MoS2 with Enhanced Thermoelectric Performance by Embedding VMo2S4 Nanoinclusions.

Two-dimensional transition-metal dichalcogenide semiconductors (TMDCs) such as MoS2 are attracting increasing interest as thermoelectric materials owing to their abundance, nontoxicity, and promising performance. Recently, we have successfully developed n-type MoS2 thermoelectric material via oxygen doping. Nevertheless, an efficient thermoelectric module requires both n-type and p-type materials with similar compatibility factors. Here, we present a facile approach to obtain a p-type MoS2 thermoelectric material with a maximum figure of merit of 0.18 through the introduction of VMo2S4 as a second phase by vanadium doping. VMo2S4 nanoinclusions, confirmed by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) measurements, not only improve the electrical conductivity by simultaneously increasing the carrier concentration and the mobility but also result in the reduction of lattice thermal conductivity by enhancing the interface phonon scattering. Our studies not only shed new light toward improving thermoelectric performance of TMDCs by a facile elemental doping strategy but also pave the way toward thermoelectric devices based on TMDCs.

Homeobox genes for embryo implantation: From mouse to human.

The proper development of uterus to a state of receptivity and the attainment of implantation competency for blastocyst are 2 indispensable aspects for implantation, which is considered to be a critical event for successful pregnancy. Like many developmental processes, a large number of transcription factors, such as homeobox genes, have been shown to orchestrate this complicated but highly organized physiological process during implantation. In this review, we focus on progress in studies of the role of homeobox genes, especially the Hox and Msx gene families, during implantation, together with subsequent development of post-implantation uterus and related reproductive defects in both mouse models and humans, that have led to better understanding of how implantation is precisely regulated and provide new insights into infertility.

Relationship between the abnormal diastolic vortex structure and impaired left ventricle filling in patients with hyperthyroidism.

Intraventricular hydrodynamics plays an important role in evaluating cardiac function. Relationship between diastolic vortex and left ventricular (LV) filling is still rarely elucidated. The aim of this study was to evaluate the evolution of vortex during diastole in hyperthyroidism (HT) and explore the alteration of hydromechanics characteristics with sensitive indexes.Forty-three patients diagnosed with HT were classified into 2 groups according to whether myocardial damage existed: simple hyperthyroid group (HT1, n = 21) and thyrotoxic cardiomyopathy (HT2, n = 22). Twenty-seven age- and gender-matched healthy volunteers were enrolled as the control group. Offline vector flow mapping (VFM model) was used to analyze the LV diastolic blood flow patterns and fluid dynamics. Hemodynamic parameters, vortex area (A), circulation (C), and intraventricular pressure gradient (ΔP), in different diastolic phases (early, mid, and late) were calculated and analyzed.HT2, with a lower E/A ratio and left ventricular ejection fraction (LVEF), had a larger left atrium diameter (LAD) compared with those of the control group and HT1 (P < .05). Compared with the control group, the vortex size and strength, intraventricular pressure gradient during early and mid-diastole were higher in HT1 and lower in HT2 (P < .05). And in late diastole, the vortex size and strength, intraventricular pressure gradient of HT2 became higher than those of the control group (P < .05). Good correlation could be found between CE and E/A (P < .05), CM and ΔPM (P < .01), CL and FT3 (P < .05).VFM is proven practical for detecting the relationship between the changes of left ventricular diastolic vortex and the abnormal left ventricular filling.

Role of (pro)rennin receptor in cardiomyocytes of heart failure rat model.

The role of (pro)rennin receptor (PRR) in cardiomyocytes of a heart failure (HF) rat model was studied. Spontaneously hypertensive rats (SHR) with HF (SHR-HF) or not were identified by two-dimensional (2-D) ultrasound. Age-matched Wistar Kyoto normotensive (WKY) rats were used as controls. PRR short hair RNA (sh-RNA) was injected into the heart of SHR-HF. Simultaneously SHR and controls received the same shRNA injection into the heart. Scramble shRNA was injected into the heart as controls. The expression of PRR mRNA and protein in cardiomyocytes was detected by using real-time PCR and Western blotting respectively. The heart function was evaluated by 2-D ultrasound, including eject fraction (EF%), fractional shortening (FS%), left ventricle thickness (LV), and inter-ventricular septal thickness (IVS). The number of apoptotic cardiomyocytes was counted by using flow cytometry. The results showed that the mRNA and protein expression levels of PRR were significantly higher in cardiomyocytes of SHR-HF group than in those of SHR group or control group. The apoptosis of myocytes in SHR-HF group was increased as compared with SHR group or control group. After knock-down of PRR with shRNA in SHR-HF group, the apoptosis of myocytes was reduced, resulting in the improved heart function. It was suggested that down-regulation of PRR might protect the heart from development of HF in SHR-HF by inhibiting the apoptosis of cardiomyocytes.

Dielectric spectroscopy investigation on the interaction of poly(diallyldimethylammonium chloride) with sodium decyl sulfate in aqueous solution.

The interaction between poly(diallyldimethylammonium chloride) (PDADMAC) and ionic surfactant sodium decyl sulfate (C(10)SO(4)Na) in aqueous solution was investigated by means of dielectric relaxation spectroscopy. To better understand the interaction, the dielectric behaviors of PDADMAC solution and C(10)SO(4)Na solution were also separately studied. For PDADMAC solution, two relaxations were observed, which were attributed to the polarization of loosely bound counterions along the directions parallel and perpendicular to the PDADMAC chain. For C(10)SO(4)Na solution, dielectric relaxation was observed at submicellar concentrations, which is ascribed to the counterion diffusion around premicelles. For the aqueous solutions of a PDADMAC/C(10)SO(4)Na mixture with different C(10)SO(4)Na concentrations, three surfactant concentration regions characterized by different dielectric behaviors were observed. The dielectric behavior in different regions was discussed through comparing it with that of PDADMAC solution and C(10)SO(4)Na solution. The possible interaction pattern and microstructure of the PDADMAC/C(10)SO(4)Na complex were proposed on the basis of the dielectric behavior.

Dielectric analysis of poly(diallyldimethylammonium chloride) aqueous solution coupled with scaling approach.

Dielectric measurements were carried out on aqueous solution of poly(diallyldimethylammonium chloride) (PDADMAC) with different concentrations at room temperature. Additionally, for selected solutions the temperature dependence of dielectric relaxation spectroscopy (DRS) was examined in the range of 5-70 degrees C. The dielectric relaxation in the order of around MHz was observed, and the dielectric parameters were determined from the dielectric spectra by fitting data with the Cole-Cole equation. The dielectric parameters showed strong dependences on concentration and on temperature, respectively, and these dependences are analyzed by the scaling theory. From the analysis of concentration dependence of dielectric parameters, the dielectric relaxation is assigned to the localized fluctuation of uncondensed counter-ions over the distance between chains in dilute solution and correlation length in semi-dilute solution, respectively, and the solvent quality parameter for the uncharged polyelectrolyte chain is evaluated. By the analysis of temperature dependence of dielectric parameters, we find that: the physical meanings of the typical lengths of uncondensed counter-ions are not influenced by temperature; in semi-dilute solution, the highly extended length of the chain (correlation length) increases and the end-to-end distance of the chain decreases with increasing solution temperature; in the change process of dielectric relaxation of PDADMAC solution induced by the increase of temperature, the increment of ionic diffusion coefficient and decrement of permittivity of the solvent medium are the major factors. The enthalpy and entropy of activation of the dielectric relaxation are experimentally determined by the dependence of relaxation time on temperature, individually.