An Investigation of the Effect of Chitosan on Isothermal Crystallization, Thermal Decomposition, and Melt Index of Biodegradable Poly(L-lactic acid)

Biodegradable chitosan (CS) was introduced into another biodegradable poly(L-lactic acid) (PLLA) to prepare the PLLA/CS composites, and the effect of CS on thermal behavior and melt index of PLLA was investigated using modern testing technologies including optical depolarizer, thermogravimetric analysis instrument, and melt index instrument. The relevant testing results showed that both crystallization temperature and CS concentration affected the isothermal crystallization behavior of PLLA. Compared to neat PLLA, the t1/2 of PLLA/5% CS decreased from 2991.54 s to the minimum value 208.76 s at 105°C. However, the t1/2 of PLLA/CS composites in high crystallization temperature zone was different from that in low crystallization temperature zone. The increase of CS concentration and heating rate made the thermal decomposition temperature of PLLA/CS composites shift to higher temperature. The melt index results indicated that 3% CS made the fluidity of PLLA become better

The Crystallization, Melting Behavior, and Thermal Stability of Poly(L-lactic acid) Induced by N,N,N′

N,N,N′-Tris(benzoyl) trimesic acid hydrazide (TTAD), as a novel nucleating agent of poly(L-lactic acid) (PLLA), was synthesized and characterized by FT-IR and 1H NMR. The crystallization, melting behavior, and thermal stability of PLLA induced by TTAD were investigated through DSC, TGA, depolarized-light intensity measurement, and so forth. The crystallization behavior indicated that the presence of TTAD accelerated the overall PLLA crystallization. Compared to neat PLLA, the crystallization onset temperature of PLLA/1%TTAD increased from 101.36°C to 125.26°C, the melt-crystallization peak temperature increased from 94.49°C to 117.56°C, crystallization enthalpy increased from 0.1023 J·g−1 to 33.44 J·g−1 at a cooling rate of 1°C/min from melt, and the crystallization half-time of PLLA/TTAD decreased from 2997.2 s to 108.9 s at 110°C. Moreover, the nonisothermal crystallization measurements also indicated that the crystallization peak became wider and shifted to a lower temperature with increasing cooling rate. With the presence of TTAD, the melting behavior of PLLA was affected significantly, and a double-melting peak occurred due to melting-recrystallization. Thermal stability research showed that there existed one degradation stage of PLLA and PLLA/TTAD samples, and the thermal degradation temperature of PLLA/TTAD decreased compared to neat PLLA

Comparative Study of TCM Syndrome Scale for Liver Disease and Chronic Liver Disease Questionnaire Based on Assessment of Posthepatitic Cirrhosis

Objective. To compare and analyze the relevance and applied value of chronic liver disease questionnaire (CLDQ) and Traditional Chinese Medicine liver disease questionnaire (TCMLDQ) in patients with posthepatitic cirrhosis. Methods. The data of 146 patients' scales of CLDQ and TCMLDQ which based on the characteristics of chinese medical symptoms were collected. We made comparative analysis of the relationship between these two scales by the linear regression model and canonical correlation method and evaluated the advantages and disadvantages of two scales about its items setting and dimension definition. Result. There is a negative correlation in total scores between the two scales and the linear regression equation: CLDQ = 239.38 − 1.232TCMLDQ. The further canonical correlation analysis was used to analyze the two extracted canonical correlative variables with significances (P < 0.05), and the results showed that the overall negative correlation between the two scales mainly came from contributions of both the four dimensions of TCMLDQ (CS, GSYX, GYPX, and OS) and the five dimensions of CLDQ (AS, FA, SS, AC, and EF). Conclusion. These two scales have good consistency in the evaluation of severity and life quality of liver cirrhosis patients, so we suggested that TCMLDQ can be used to evaluate the severity and life quality of patients with posthepatitic cirrhosis

Correlated two-photon imaging with true thermal light

We report the first experimental demonstration of two-photon correlated imaging with true thermal light from a hollow cathode lamp. The coherence time of the source is much shorter than that of previous experiments using random scattered light from a laser. A two-pinhole mask was used as object, and the corresponding thin lens equation was well satisfied. Since thermal light sources are easier to obtain and measure than entangled light it is conceivable that they may be used in special imaging applications.Comment: 3 pages, 5 figures, accepted by Optics Letter

Novel superconducting structures of BH2 under high pressure

The crystal structures of boron hydrides in a pressure range of 50–400 GPa were studied using the genetic algorithm (GA) method combined with first-principles density functional theory calculations. BH4 and BH5 are predicted to be thermodynamically unstable. Two new BH2 structures with Cmcm and C2/c space group symmetries, respectively, were predicted, in which the B atoms tend to form two-dimensional sheets. The calculated band structures showed that in the pressure range of 50–150 GPa, the Cmcm-BH2 phase has very small gaps, while the C2/c-BH2 phase at 200–400 GPa is metallic. The superconductivity of the C2/c-BH2 structure was also investigated, and electron–phonon coupling calculations revealed that the estimated Tc values of C2/c-BH2 are about 28.18–37.31 K at 250 GPa

Chemometry use in the evaluation of the sanya bay water quality

No presente estudo foi realizada a identificação dos efeitos antropogênicos e das características naturais marinhas das águas da Baía de Sanya, situada ao sul do Mar da China, através de método quimiométrico. A análise de componentes principais (PCA) aplicada aos dados extraiu quatro eixos que explicaram 85,52% da variância total dos dados. Através das análises de Agrupamento e PCA foram identificados três padrões diferentes de qualidade das águas, baseados nos efeitos antropogênicos e nas características marinhas: Grupo I, localizado nas partes externa e mediana da baía; Grupo II, próximo do centro urbano de Sanya; Grupo III, localizado no estuário do Rio Sanya. Quanto ao padrão temporal, as referidas análises distinguiram uma estação seca, de novembro a abril, e uma estação chuvosa, de maio a outubro, relacionadas ao clima e características naturais. Foi visto que tanto a fonte poluidora externa, representada pelo Rio Sanya, quanto as águas do Mar do Sul da China influenciam a qualidade das águas da Baía de Sanya. Esses resultados podem ser relevantes quando considerados sob o ponto de vista do desenvolvimento socioeconômico e de saúde humana dessa região.In this study, chemometric method is employed to identify anthropogenic effects on the water quality in Sanya Bay, South China Sea, and its marine and natural characteristics. Principal component analysis has extracted the four latent factors, thus explaining 85.52% of the total variance. Cluster analysis and principal component analysis have identified three different patterns of water quality based on anthropogenic effects and marine characteristics: Cluster I located in the outer and middle parts of the bay, Cluster II close to downtown Sanya, Cluster III located in the Sanya River estuary. In terms of the temporal pattern, principal component analysis and cluster analysis have distinguished the dry season from November to the following April, and the rainy season from May to October. The temporal pattern is related to climate and natural characteristics. The similarity index between variables and scores of samples can further distinguish the contribution of the variables to the samples. Both the polluting sources external to the Sanya River and the water from the South China Sea exercise an important influence on the water quality in Sanya Bay. These results may be valuable for socioeconomic development and human health in the Sanya Bay area

2-[(1,3-Benzothia­zol-2-yl)imino­meth­yl]phenol

The title compound, C14H10N2OS, is nearly planar, with a maximum deviation of 0.0698 (13) Å from the mean plane, and exists in an E configuration with respect to the C=N bond. The dihedral angle between the two benzene rings is 2.81 (9)°. There is an intra­molecular O—H⋯N hydrogen bond and inter­molecular C—H⋯O and C—H⋯N hydrogen bonds

Production and Radioprotective Effects of Pyrroloquinoline Quinone

Pyrroloquinoline quinone (PQQ) was produced by fermentation of the Methylovorus sp. MP688 strain and purified by ion-exchange chromatography, crystallization and recrystallization. The yield of PQQ reached approximately 125 mg/L and highly pure PQQ was obtained. To determine the optimum dose of PQQ for radioprotection, three doses (2 mg/kg, 4 mg/kg, 8 mg/kg) of PQQ were orally administrated to the experimental animals subjected to a lethal dose of 8.0 Gy in survival test. Survival of mice in the irradiation + PQQ (4 mg/kg) group was found to be significantly higher in comparison with the irradiation and irradiation + nilestriol (10 mg/kg) groups. The numbers of hematocytes and bone marrow cells were measured for 21 days after sublethal 4 Gy gamma-ray irradiation with per os of 4 mg/kg of PQQ. The recovery of white blood cells, reticulocytes and bone marrow cells in the irradiation + PQQ group was faster than that in the irradiation group. Furthermore, the recovery of bone marrow cell in the irradiation + PQQ group was superior to that in irradiation + nilestriol group. Our results clearly indicate favourable effects on survival under higher lethal radiation doses and the ability of pyrroloquinoline quinine to enhance haemopoietic recovery after sublethal radiation exposure