Near-field radiative heat transfer in multilayered graphene system considering equilibrium temperature distribution.

In the present work, the near-field radiative heat transfer of a multilayered graphene system is investigated within the framework of the many-body theory. For the first time, the temperature distribution corresponding to the steady state of the system is investigated. Unique temperature steps are observed near both boundaries of the system, especially in the strong near-field regime. By utilizing the effective radiative thermal conductance, the thermal freedom of heat flux in different regions of the system is analyzed quantitatively, and the cause of various temperature distributions is explained accordingly. To characterize the heat transfer ability of the whole system, we evaluate the system with two heat transfer coefficients (HTC), transient heat transfer coefficient (THTC), and steady heat transfer coefficient (SHTC). A unique many-body enhancement is observed, which causes a red-shift of resonance peak corresponding to graphene surface plasmon polaritons. Furthermore, a three-body enhancement of SHTC emerges thanks to the relay effect and the complexity of the system. The regime of heat transport can be tuned by changing the chemical potentials of graphene and undergoes a transition from diffusive to quasi-ballistic transport in the strong near-field regime.

Retrieval of fractal dimension and size distribution of non-compact soot aggregates from relative intensities of multi-wavelength angular-resolved light scattering.

A new technique is developed to retrieve the fractal dimension and size distribution of soot aggregates simultaneously from the relative intensities of multi-wavelength angular-resolved light scattering. Compared with other techniques, the main advantage of this method is its independence of knowing complex refractive index, number density of aggregate, fractal prefactor and primary particle diameter. The forward light scattering procedure of soot aggregate is described by Rayleigh-Debye-Gans polydisperse fractal aggregate (RDG-PFA) scattering theory, and the retrieval process is performed by using the covariance matrix adaption-evolution strategy algorithm (CMA-ES). Three different measurement models, i.e. absolute scattering and transmittance, absolute scattering, relative scattering (RS), are investigated in present research. Numerical experiments have been performed to test the feasibility of the CMA-ES algorithm. Combined with the multi-wavelength RDG-PFA strategy, the retrieval accuracy of soot aggregate size distribution is proved to be more effectively by using the RS model. Satisfactory results under 10% Gaussian measurement noise have demonstrated the feasibility of the proposed method.

Optimal temperature control of tissue embedded with gold nanoparticles for enhanced thermal therapy based on two-energy equation model.

Thermal therapy is a very promising method for cancer treatment, which can be combined with chemotherapy, radiotherapy and other programs for enhanced cancer treatment. In order to get a better effect of thermal therapy in clinical applications, optimal internal temperature distribution of the tissue embedded with gold nanoparticles (GNPs) for enhanced thermal therapy was investigated in present research. The Monte Carlo method was applied to calculate the heat generation of the tissue embedded with GNPs irradiated by continuous laser. To have a better insight into the physical problem of heat transfer in tissues, the two-energy equation was employed to calculate the temperature distribution of the tissue in the process of GNPs enhanced therapy. The Arrhenius equation was applied to evaluate the degree of permanent thermal damage. A parametric study was performed to investigate the influence factors on the tissue internal temperature distribution, such as incident light intensity, the GNPs volume fraction, the periodic heating and cooling time, and the incident light position. It was found that period heating and cooling strategy can effectively avoid overheating of skin surface and heat damage of healthy tissue. Lower GNPs volume fraction will be better for the heat source distribution. Furthermore, the ring heating strategy is superior to the central heating strategy in the treatment effect. All the analysis provides theoretical guidance for optimal temperature control of tissue embedded with GNP for enhanced thermal therapy.

Application of the sequential quadratic programming algorithm for reconstructing the distribution of optical parameters based on the time-domain radiative transfer equation.

Sequential quadratic programming (SQP) is used as an optimization algorithm to reconstruct the optical parameters based on the time-domain radiative transfer equation (TD-RTE). Numerous time-resolved measurement signals are obtained using the TD-RTE as forward model. For a high computational efficiency, the gradient of objective function is calculated using an adjoint equation technique. SQP algorithm is employed to solve the inverse problem and the regularization term based on the generalized Gaussian Markov random field (GGMRF) model is used to overcome the ill-posed problem. Simulated results show that the proposed reconstruction scheme performs efficiently and accurately.

Fast method of retrieving the asymmetry factor and scattering albedo from the maximum time-resolved reflectance of participating media.

This research presents a parametric study of the time-resolved hemispherical reflectance of a semi-infinite plane-parallel slab of homogeneous, nonemitting, absorbing, and anisotropic scattering medium exposed to a collimated Gaussian pulse. The one-dimensional transient radiative transfer equation was solved by using the finite volume method. The internal reflection at the medium-air interface caused by the mismatch of the refractive indices was considered. In particular, this work focused on the maximum diffuse hemispherical reflectance. Three different optical regions were identified according to the dimensionless pulsewidth ßctp. The correlation between the normalized maximum hemispherical reflectance and ßctp was conformed to the Boltzmann function. The coefficients in the correlating functions of the match and mismatch refractive index cases were fitted as polynomial fitting functions of the single scattering albedo ω and Henyey-Greenstein asymmetric factor g. Thus, ω and g can be simultaneously reconstructed by the semi-empirical correlations without solving the forward model. In conclusion, the proposed method can potentially retrieve the asymmetry factor and single scattering albedo of participating media accurately and efficiently.

Preparation of RGD-modified long circulating liposome loading matrine, and its in vitro anti-cancer effects.

AIM: To prepare RGD-modified long circulating liposome (LCL) loading matrine (RGD-M-LCL) to improve the tumor-targeting and efficacy of matrine. METHODS: LCL which was prepared with HSPC, cholesterol, DSPE-PEG2000 and DSPE-PEG-MAL was modified with an RGD motif confirmed by high performance liquid chromatography (HPLC). The encapsulation efficiency of RGD-M-LCL was also detected by HPLC. MTT assay was used to examine the effects of RGD-M-LCL on the proliferation of Bcap-37, HT-29 and A375 cells. The percentage of apoptotic cells and morphological changes in Bcap-37 cells treated with RGD-M-LCL were detected by Annexin-V-FITC/PI affinity assay and observed under light microscope, respectively. RESULTS: Spherical or oval single-chamber particles of uniform sizes with little agglutination or adhesion were observed under transmission electronic microscope. The RGD motif was successfully coupled to the DSPE-PEG-MAL on liposomes, as confirmed by HPLC. An encapsulation efficiency of 83.13% was obtained when the drug-lipid molar ratio was 0.1, and the encapsulation efficiency was negatively related to the drug-lipid ratio in the range of 0.1-0.4, and to the duration of storage. We found that, compared with free matrine, RGD-M-LCL had much stronger in vitro activity, leading to anti-proliferative and pro-apoptotic effects against cancer cells (P<0.01). CONCLUSION: RGD-M-LCL, a novel delivery system for anti-cancer drugs, was successfully prepared, and we demonstrated that the use of this material could augment the effects of matrine on cancer cells in vitro.

Effects of Losartan on expression of connexins at the early stage of atherosclerosis in rabbits.

AIM: to investigate effects of Losartan on expression of connexin 40 and 43 (Cx40 and Cx43), in arteries at the early stage of atherosclerosis in a rabbit model. METHODS: A total of 28 male New Zealand white rabbits were divided into following groups: control group, high fat diet group, and Losartan group (10 mg/kg/day). Losartan was administrated in food for two weeks. Iliac arteries were obtained for immunohistochemistry, transmission electron microscopy, Western blot, and reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: Transmission electron microscopy revealed abundant gap junctions between neointimal smooth muscle cells (SMCs), which were markedly reduced by treatment. RT-PCR and Western blot assay showed that the mRNA and protein expression of Cx40 and Cx43 were elevated in the neointimal area at the early stage of atherosclerosis. The mRNA and protein expression of Cx43 were significantly down-regulated by losartan treatment but those of Cx40 were not markedly changed. CONCLUSION: Cx40 and Cx43 in the neointimal SMCs were up-regulated at the early stage of atherosclerosis. Losartan (an angiotensin-converting enzyme inhibitor) could reduce neointima proliferation and down-regulate the elevated protein expression of Cx43, suggesting the rennin-angiotensin system (RAS) plays an important role in the remodeling of gap junction between ventricular myocytes under pathological conditions.

Matrine inhibits invasiveness and metastasis of human malignant melanoma cell line A375 in vitro.

BACKGROUND: Matrine is a traditional Chinese medicine with significant inhibitory activity against malignant tumors. Its effects on the invasiveness and metastasis of malignant tumors have rarely been reported. AIM: To investigate whether matrine can inhibit the metastasis-related activities of the human malignant melanoma cell line A375 in vitro. METHODS: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and Annexin-V-fluorescein isothiocyanate/propidium iodide (Annexin-V-FITC/PI) affinity assay were used to examine the effects of matrine on the proliferation and apoptosis induction of A375 cells. The morphologic changes of A375 cells were observed by light and electron microscopy. Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were performed to evaluate the expression of heparanase mRNA and protein. The effect of matrine on the adhesion ability and invasiveness of treated A375 cells was tested by cell-Matrigel adhesion assay and Matrigel invasion assay, respectively. RESULTS: Matrine showed significant inhibition of the proliferation of A375 cells in a dose- and time-dependent manner. It also induced apoptosis in a dose-dependent manner. Compared with the control group, the levels of heparanase mRNA and protein expression of A375 cells treated with different concentrations of matrine were decreased significantly, as were their adhesion ability and invasiveness. CONCLUSIONS: These findings indicate that matrine inhibits the invasiveness and metastasis of A375 cells in vitro. The mechanisms may be linked to the inhibition of cellular proliferation, induction of apoptosis, and downregulation of heparanase mRNA and protein expression.

[Adhesional inhibiton of polyclonal anti-porin I antibody].

OBJECTIVE: To investigate the blockness effects of purified polyclonal anti-porin I antibody on N. gonorrhoeae adherence to genitourinary tract epithelia of BALB/c mouse. METHODS: Polyclonal anti GST-PI antibody was generated by immunizing rabbit with GST-PI fusion protein which was constructed and expressed by ourselves. The purified immunoglobulin G was obtained by ammonium sulphate deposition and DEAE cellulose chromatography. Mice model of gonorrhea was established. In order to evaluate the effects of PI-IgG on gonococcus adhesion to vagina mucus, the macroscopic and pathological assessing as well as gonococcus culture was employed after gonococcus challenge on PI-IgG immunized mice. RESULT: No pus and pathological inflammation were observed on mice vagina mucus treated with 1 mg/ml PI-IgG 3 hours before gonococcus challenge. Gonococcus could not be detected in the smears and washing solutions from vagina. Pathological inflammation was found in mice treated with anti PI-IgG, in which the concentrations were lower than 1 mg/ml or the treated time was longer than 3 hours prior to gonococcus challenge. CONCLUSION: The purified anti PI-IgG can effectively inhibit the adherence and infection of gonococci to genitourinary tract epithelia of BALB/c mice. In addition, the blocking duration of anti PI-IgG is associated with antibody concentration.

Effects of angiotensin II on connexin 43 of VSMCs in arteriosclerosis.

OBJECTIVE: To observe the effect of angiotensin II (Ang II) on expression of gap junction channel protein connexin 43 (Cx43) in the proliferation process of vascular smooth muscle cells (VSMCs) during the early stage of arteriosclerosis. METHODS: Thirty-two adult male rabbits were randomly divided into 4 groups. Rabbits in Group A were fed common diet while others in Groups B, C, and D were fed high-cholesterol diet. Losartan (10 mg/(kg.d)) and ramipril (0.5 mg/(kg.d)) were added in the diet of Groups C and D, respectively. The animals were sacrificed after 8 weeks and abdominal aortas were removed and dissected. The expression of Cx43 was assayed using RT-PCR and Western Blotting analysis. RESULTS: Cx43 was increased markedly in both protein and mRNA level in Groups B, C, and D fed high-cholesterol diet compared with that in control group (P<0.01). Cx43 level in losartan or ramipril treated groups was higher than that in control group (P<0.01, P<0.05), but lower than that in high-cholesterol diet groups (P<0.05, P<0.01). CONCLUSION: Cx43 level was upregulated in VSMCs during early atherosclerosis. Losartan and ramipril can inhibit the expression of Cx43.

[Inhibition of invasiveness and expression of heparanase-mRNA in human malignant melanoma cell line A375 by matrine].

OBJECTIVE: To investigate the effect of matrine on the invasiveness and expression of heparanase-mRNA in human malignant melanoma cell line A375. METHODS: The A375 cells were treated by matrine in different concentration. The total RNAs were extracted from the cells 48 hours after treatment and then semi-quantitative RT-PCR were performed to evaluate the heparanase-mRNA expression levels. Effect of matrine on adhesion of treated A375 cells was tested by cell-Matrigel adhesion assay. The invasiveness of treated A375 cells was measured by Matrigel invasion assay. RESULTS: The hepanase-mRNA expression, adhesion and invasiveness of A375 cells treated with matrine of different final concentrations significantly decreased compared with that of the controls (p < 0.01). Besides, the inhibitory effects were signifcantly different when the cells treated with matrine of different concentrations (P < 0.01). CONCLUSION: By down-regulating the expression of heparanase-mRNA, matrine has a significant inhibitory effect on the adhesion and invasiveness of human malignant melanoma cell line in a dose-dependent manner.

[Study on the screening program of thalassemia and the genotype and hematologic parameter among people of productive age in a village, Nanning Guangxi].

OBJECTIVE: To investigate the carrier ratio and the genotype of thalassemia in the rural people of reproductive age in Nanning, and to analyze the characteristics of hematologic parameter in thalassemia carriers. METHODS: 2044 cases of productive age youths were detected with hemoglobin autoanalyse-Variant (HPLC) and Cell Dyn 1700 automatic hemocyte analysator. Among them,430 cases (75 couples randomly selected in thalassemia screening, 140 couples who were told that one or both of them were positive for thalassemia phenotype through hemocyte analysis) carried out thalassemia gene detection in synchronism. RESULTS: 163 cases were detected beta-thalassemia and the thus beta-thalassemia carrier ratio was 7.97%. 13 cases were detected HbH disease, and 2 cases Hb Manitoba, 2 cases HbJ, and 1 case HbQ. As for genotypes,-alpha (3.7)/alpha,-alpha(CS)/alphaalpha and -alpha(WS)/alphaalpha were common ones with in alpha-thalassemia-2, --(SEA)/alphaalpha the most common one in alpha-thalassemia-1, and 41-42 were the most common ones in beta-thalassemia heterozygotes. The detection ratio of alpha,beta combination thalassemia was also relatively high. Mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were low in all cases of HbH disease and beta-thalassemia, also low in 86 cases of alpha-thalassemia-1 with the exception of normal MCH in 1 case, yet normal in 17 cases out of 66 cases of alpha-thalassemia-2. HbF raised in 32 cases out of 69 cases of beta-thalassemia heterozygote, no case showed raised HbF without the raise of HbA2. Hematologic characteristic of alpha, beta combination thalassemia was mainly caused by beta-thalassemia. CONCLUSION: Carrier ratio of thalassemia in rural productive age youths in Nanning was high while alpha-thalassemia-2 with the genotype -alpha(WS)/alphaalpha and -alpha(CS)/ alphaalpha were common. To those with low MCV and MCH in high-risk region, thalassemia should be suspected.

Effects of fructose-1,6-diphosphate on concentration of calcium and activities of sarcoplosnic Ca2+-ATPase in cardiomyocytes of Adriamycin-treated rats.

OBJECTIVE: To observe the effects of fructose-1,6-diphosphate (FDP) on serum levels of cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB), as well as the concentration of calcium in cardiomyocytes (Myo[Ca(2+)]) and activity of sarcoplosnic Ca(2+)-ATPase (SRCa(2+)-ATPase) in Adriamycin (ADR)-treated rats. METHODS: Rats were intraperitoneally injected with ADR (2.5 mg/kg every other day for 6 times) and then with different dosages of FDP (every other day for twenty-one times). Bi-antibodies sandwich Enzyme linked immune absorption assay (ELISA) was performed to detect serum level of cTnI. CK-MB was detected by monoclonal antibody, Myo[Ca(2+)] was detected by fluorescent spectrophotometry and the activity of SRCa(2+)-ATPase was detected by inorganic phosphate method. RESULTS: FDP (300, 600, 1200 mg/kg) significantly reduced the serum levels of cTnI and CK-MB, while at the same time decreased calcium concentration and increased SRCa(2+)-ATPase activity in cardiomyocytes of ADR-treated rats (P<0.01). CONCLUSIONS: FDP might alleviate the cardiotoxic effects induced by ADR through decreasing calcium level as well as increasing SRCa(2+)-ATPase activity in cardiomyocytes.