Comparative study on ignition delay time and burning rate of modified double-base propellant and fuel-rich propellant.

With the higher requirements of various tactical and technical indicators of the weapon systems, the current research on the ignition and combustion characteristics of different types of solid propellants is not comprehensive. In more complex and harsh environmental conditions, the pressure affects the ignition and combustion characteristics. Therefore, the paper studies the ignition and combustion characteristics of the modified double-base propellants (MDB propellants) and fuel-rich propellants (FR propellants) under low-pressure environment. Combining experiment and theory, the ignition delay time and burning rate of two kinds of solid propellants are compared and analyzed at low pressure by the laser ignition experimental device. The results displayed that the burning flames of the FR and MDB propellant presented evident V-shape and cylindrical, respectively. The flame brightness decreased with the decrease in pressure. With the increase of pressure and heat flux, the ignition delay time of the MDB propellant and the FR propellant decreased. By comparison, Model 2 of the ignition delay time was more effective for the estimation of the ignition delay time of the FR propellant. The experimental results are compared with the three burning rate models, which are the Vielle formula (Model 1), Summerfield formula (Model 2), and B-number burning rate formula (Model 3). The results showed the burning rate was more in accord with Model 3.

High expression of prolyl 4-hydroxylase subunit alpha-2 in lung adenocarcinoma indicates poor prognosis.

OBJECTIVE: To analyze the Prolyl 4-Hydroxylase subunit Alpha-2 (P4HA2) expression in Lung Adenocarcinoma (LAUD). METHODS: The authors assessed P4HA2 expression in the LUAD tumor ecosystem using single-cell analysis. The authors analyzed the relationship between P4HA2 expression and clinical features in LUAD and Brain Metastasis (BM) cases. The authors assessed the biological functions of P4HA2 using The Cancer Genome Atlas-LUAD dataset. RESULTS: P4HA2 was more highly expressed in fibroblasts than in epithelial cells in normal lung and lung adenocarcinoma tissues (p < 0.001). P4HA2 was more highly expressed in malignant epithelial cells than in fibroblasts in the BM tissue (p = 0.002). P4HA2 expression was significantly higher in female cases than in male cases (p = 0.049) and was related to lymph node metastasis (p = 0.019) and a higher TNM stage (p = 0.020). High P4HA2 expression indicated a poor prognosis and served as an independent prognostic risk factor in lung cancer. P4HA2 was mainly enriched in the extracellular matrix organization, NADH regeneration, and canonical glycolysis. P4HA2 expression was negatively correlated with naive B cells, T-cells, CD8, and activated natural killer cells, but positively correlated with CD4 memory-activated T cells, regulatory T-cells, resting dendritic cells, and dendritic cell activation. P4HA2 messenger RNA expression was correlated with programmed death-ligand 1 and cytotoxic T-lymphocyte-associated protein 4. CONCLUSION: P4HA2 is highly expressed in LUAD tumor cells, especially for the BM subtype, and is a valuable prognostic indicator of LUAD. It may be involved in a biological activity of distant metastasis of LUAD tumor cells and serve as a potential treatment target.

Carboplatin-loaded surface modified-PLGA nanoparticles confer sustained inhibitory effect against retinoblastoma cell in vitro / Nanopartículas de PLGA com superfície modificada carregada com carboplatina conferem efeito inibitório sustentado contra células de retinoblastoma in vitro

ABSTRACT Purpose: To investigate the antiproliferative effect of carboplatin-loaded surface-modified poly(lactide-co-glycolide) on retinoblastoma cells. Methods: Carboplatin-loaded poly(lactide-co-glycolide) with or without sodium alginate surface modification was prepared using sodium alginate-poly(lactide-co-glycolide) and poly(lactide-co-glycolide). The zeta potential and carboplatin release behavior were investigated. The cellular uptake of the released drug was observed in the retinoblastoma cell line Y79. The inhibitory effect of carboplatin-loaded nanoparticles against the Y79 cell line was evaluated using methyl thiazolyl tetrazolium assay and western blot. Native carboplatin and void nanoparticles without carboplatin loading were used as controls. Results: The zeta potential was -(26.1 ± 3.1) mV for carboplatin-loaded poly(lactide-co-glycolide) and-(43.1 ± 8.1) mV for carboplatin-loaded sodium alginate-poly(lactide-co-glycolide). The burst release percentages of carboplatin-loaded poly(lactide-co-glycolide) and sodium alginate-poly(lactide-co-glycolide) were (40.0% ± 8.2%) and (18.9% ± 4.3%) at 24 hours, respectively. A significant difference was identified regarding drug release between carboplatin-loaded sodium alginate-poly(lactide-co-glycolide) and carboplatin-loaded poly(lactide-co-glycolide). Fluorescence detection revealed that intense uptake of carboplatin into the cytoplasm of the Y79 cell line that was exposed to carboplatin-loaded sodium alginate-poly(lactide-co-glycolide). Carboplatin-loaded poly(lactide-co-glycolide) or sodium alginate-poly(lactide-co-glycolide) exposure inhibited proliferating cell nuclear antigen expression in Y79 cells on day 3. Extension of exposure to day 5 revealed that the sodium alginate-poly(lactide-co-glycolide) surface modification was superior to that of poly(lactide-co-glycolide) in terms of proliferating cell nuclear antigen inhibition. The cell viability test using methyl thiazolyl tetrazolium revealed a similar inhibitory effect. Furthermore, the carboplatin-loaded nanoparticles of lower concentration inhibited cell viability more strongly than native carboplatin of higher concentration in methyl thiazolyl tetrazolium assay. Conclusions: Carboplatin-loaded sodium alginate-poly(lactide-co-glycolide) inhibited retinoblastoma cell proliferation with superior effect as compared with poly(lactide-co-glycolide) and native carboplatin. Sodium alginate surface modification offers a potential strategy for the sustained carboplatin release system.

RESUMO Objetivo: Investigar o efeito antiproliferativo de poli (lactídeo-coglicolídeo) com superfície modificada carregada com carboplatina contra células de retinoblastoma. Métodos: Preparou-se poli (lactídeo-co-glicolídeo) carregado com carboplatina com ou sem alginato de sódio para modifição da superfície, poli com alginato de sódio (lactídeo-co-glicolídeo) e poli (lactídeo-co-glicolídeo). O potencial zeta e o comportamento de liberação de carboplatina foram investigados. A captação celular do fármaco liberado foi observada na linha celular de retinoblastoma Y79. O efeito inibitório das nanopartículas carregadas com carboplatina contra a linha celular Y79 foi avaliado através do ensaio de metiltiazol tetrazólio e Western-blot. Carboplatina nativa e nanopartículas vazias sem carga de carboplatina serviram como controles. Resultados: O potencial zeta de poli carregado com carboplatina (lactídeo-co-glicolídeo) foi - (26,1 ± 3,1) mV versus - (43,1 ± 8,1) mV em poli com alginato de sódio carregado com carboplatina (lactídeo-co-glicolídeo). A percentagem de libertação de explosão de poli carregado com carboplatina (lactídeo-co-glicolídeo) e poli com alginato de sódio (lactídeo-co-glicolídeo) foram (40,0 ± 8,2)% e (18,9 ± 4,3)% às 24 horas, respectivamente. Uma diferença significativa foi identificada em relação à liberação de fármaco entre poli com alginato de sódio carregado com carboplatina (lactídeo-co-glicolídeo) e poli carregado com carboplatina (lactídeo-co-glicolídeo). A detecção de fluorescência revelou que a carboplatina foi assimilada intensamente no citoplasma da linha celular Y79 que foi exposta ao poli com alginato de sódio carregado com carboplatina (lactídeo-co-glicolídeo). A exposição de poli carregada com carboplatina (lactídeo-co-glicolídeo) ou poli com alginato de sódio (lactídeo-co-glicolídeo) inibiu a expressão de antígeno nuclear de proliferação celular em células Y79 no 3º dia. A extensão da exposição no 5º dia revelou que poli com alginato de sódio (lactídeo-co-glicolídeo) para modificação da superfície foi superior a poli (lactídeo-co-glicolídeo) em termos de inibição do antígeno nuclear de proliferação celular. O teste de viabilidade celular via metiltiazol tetrazólio mostrou um efeito inibitório semelhante. Além disso, as nanopartículas carregadas com carboplatina de concentração mais baixa inibiram a viabilidade celular mais fortemente em comparação com a carboplatina nativa de concentração mais alta no ensaio de metiltiazol tetrazólio. Conclusões: Poli com alginato de sódio carregado com carboplatina (lactídeo-co-glicolídeo) inibiu a proliferação de células de retinoblastoma com efeito superior em contraste com poli (lactídeo-co-glicolídeo) e carboplatina nativa. O alginato de sódio para modificação da superfície oferece uma estratégia potencial para o sistema de liberação de carboplatina sustentada.

Carboplatin-loaded surface modified-PLGA nanoparticles confer sustained inhibitory effect against retinoblastoma cell in vitro.

PURPOSE: To investigate the antiproliferative effect of carboplatin-loaded surface-modified poly(lactide-co-glycolide) on retinoblastoma cells. METHODS: Carboplatin-loaded poly(lactide-co-glycolide) with or without sodium alginate surface modification was prepared using sodium alginate-poly(lactide-co-glycolide) and poly(lactide-co-glycolide). The zeta potential and carboplatin release behavior were investigated. The cellular uptake of the released drug was observed in the retinoblastoma cell line Y79. The inhibitory effect of carboplatin-loaded nanoparticles against the Y79 cell line was evaluated using methyl thiazolyl tetrazolium assay and western blot. Native carboplatin and void nanoparticles without carboplatin loading were used as controls. RESULTS: The zeta potential was -(26.1 ± 3.1) mV for carboplatin-loaded poly(lactide-co-glycolide) and-(43.1 ± 8.1) mV for carboplatin-loaded sodium alginate-poly(lactide-co-glycolide). The burst release percentages of carboplatin-loaded poly(lactide-co-glycolide) and sodium alginate-poly(lactide-co-glycolide) were (40.0% ± 8.2%) and (18.9% ± 4.3%) at 24 hours, respectively. A significant difference was identified regarding drug release between carboplatin-loaded sodium alginate-poly(lactide-co-glycolide) and carboplatin-loaded poly(lactide-co-glycolide). Fluorescence detection revealed that intense uptake of carboplatin into the cytoplasm of the Y79 cell line that was exposed to carboplatin-loaded sodium alginate-poly(lactide-co-glycolide). Carboplatin-loaded poly(lactide-co-glycolide) or sodium alginate-poly(lactide-co-glycolide) exposure inhibited proliferating cell nuclear antigen expression in Y79 cells on day 3. Extension of exposure to day 5 revealed that the sodium alginate-poly(lactide-co-glycolide) surface modification was superior to that of poly(lactide-co-glycolide) in terms of proliferating cell nuclear antigen inhibition. The cell viability test using methyl thiazolyl tetrazolium revealed a similar inhibitory effect. Furthermore, the carboplatin-loaded nanoparticles of lower concentration inhibited cell viability more strongly than native carboplatin of higher concentration in methyl thiazolyl tetrazolium assay. CONCLUSIONS: Carboplatin-loaded sodium alginate-poly(lactide-co-glycolide) inhibited retinoblastoma cell proliferation with superior effect as compared with poly(lactide-co-glycolide) and native carboplatin. Sodium alginate surface modification offers a potential strategy for the sustained carboplatin release system.

High expression of prolyl 4-hydroxylase subunit alpha-2 in lung adenocarcinoma indicates poor prognosis

Abstract Objective To analyze the Prolyl 4-Hydroxylase subunit Alpha-2 (P4HA2) expression in Lung Adenocarcinoma (LAUD). Methods The authors assessed P4HA2 expression in the LUAD tumor ecosystem using single-cell analysis. The authors analyzed the relationship between P4HA2 expression and clinical features in LUAD and Brain Metastasis (BM) cases. The authors assessed the biological functions of P4HA2 using The Cancer Genome Atlas-LUAD dataset. Results P4HA2 was more highly expressed in fibroblasts than in epithelial cells in normal lung and lung adenocarcinoma tissues (p < 0.001). P4HA2 was more highly expressed in malignant epithelial cells than in fibroblasts in the BM tissue (p = 0.002). P4HA2 expression was significantly higher in female cases than in male cases (p = 0.049) and was related to lymph node metastasis (p = 0.019) and a higher TNM stage (p = 0.020). High P4HA2 expression indicated a poor prognosis and served as an independent prognostic risk factor in lung cancer. P4HA2 was mainly enriched in the extracellular matrix organization, NADH regeneration, and canonical glycolysis. P4HA2 expression was negatively correlated with naive B cells, T-cells, CD8, and activated natural killer cells, but positively correlated with CD4 memory-activated T cells, regulatory T-cells, resting dendritic cells, and dendritic cell activation. P4HA2 messenger RNA expression was correlated with programmed death-ligand 1 and cytotoxic T-lymphocyte-associated protein 4. Conclusion P4HA2 is highly expressed in LUAD tumor cells, especially for the BM subtype, and is a valuable prognostic indicator of LUAD. It may be involved in a biological activity of distant metastasis of LUAD tumor cells and serve as a potential treatment target.

Proof of Concept for Prevention of Natural Colonization by Oral Needle-Free Administration of a Microparticle Vaccine.

There has been substantial interest in the development of needle-free vaccine administration that has led to a variety of approaches for delivery through the skin for induction of a systemic immune response. The mucosal administration of vaccines has inherently been needle-free, but the simple application of vaccines on the mucosal surface by itself does not lead to mucosal immunity. Since many important bacterial infections develop after initial colonization of the upper respiratory tract of the host, prevention of colonization could not only prevent infection but also eliminate the reservoir of pathogens that reside exclusively in that ecologic niche. This study was designed to provide proof of concept for a needle-free immunization approach that would reduce or eliminate colonization and prevent infection. In order to accomplish this a microparticle vaccine preparation was delivered just below the oral mucosal epithelial cell layer where it would lead to a robust immune response. A vaccine antigen (mutant transferrin binding protein B) shown to be capable of preventing infection in pigs was incorporated into a polyphosphazene microparticle preparation and delivered by a needle-free device to the oral sub-epithelial space of pigs. This vaccination regimen not only provided complete protection from infection after intranasal challenge by Glaesserella parasuis but also eliminated natural colonization by this bacterium. Notably, the complete prevention of natural colonization was dependent upon delivery of the microparticle preparation below the epithelial layer in the oral mucosa as intradermal or intramuscular delivery was not as effective at preventing natural colonization. This study also demonstrated that a primary immunization in the presence of maternal antibody limited the resulting antibody response but a robust antibody response after the second immunization indicated that maternal antibody did not prevent induction of B-cell memory.

The amino acid selected for generating mutant TbpB antigens defective in binding transferrin can compromise the in vivo protective capacity.

Haemophilus parasuis is the causative agent of the Glässer's disease (GD), one of the most important bacterial diseases that affect young pigs worldwide. GD prevention based on vaccination is a major concern due to the limited cross-protection conferred by the inactivated whole cell vaccines used currently. In this study, vaccines based on two mutant recombinant proteins derived from transferrin binding protein B of H. parasuis (Y167A-TbpB and W176A-TbpB) were formulated and evaluated in terms of protection against lethal challenge using a serovar 7 (SV7) H. parasuis in a high susceptibility pig model. Our results showed that H. parasuis strain 174 (SV7) is highly virulent in conventional and colostrum-deprived pigs. The Y167A-TbpB and W176A-TbpB antigens were immunogenic in pigs, however, differences in terms of antigenicity and functional immune response were observed. In regard to protection, animals immunized with Y167A-TbpB antigen displayed 80% survival whereas the W176A-TbpB protein was not protective. In conjunction with previous studies, our results demonstrate, (a) the importance of testing engineered antigens in an in vivo pig challenge model, and, (b) that the Y167A-TbpB antigen is a promising antigen for developing a broad-spectrum vaccine against H. parasuis infection.

Genetic diversity in Echinococcus shiquicus from the plateau pika (Ochotona curzoniae) in Darlag County, Qinghai, China.

The metacestode of Echinococcus shiquicus has been recorded previously in the lung and liver of its intermediate host, the plateau pika (Ochotona curzoniae), but there is limited information regarding other organ sites. There is also limited evidence of intra-specific genetic variation within E. shiquicus. A PCR-amplified mitochondrial (mt) nad1 gene fragment (approximately 1400bp in size), with unique EcoRI and SspI restriction sites, was used to distinguish cysts or cyst-like lesions of E. shiquicus from E. multilocularis. Then, the complete mt nad1 and cox1 genes for the E. shiquicus isolates were amplified and sequenced. Phylogenetic tree and haplotype network analyses for the isolates were then generated based on a concatenated dataset of the nad1 and cox1 genes using the neighbour-joining (NJ) method and TCS1.21 software. Nineteen of eighty trapped pikas were found to harbor cysts (71 in total) when dissected at the survey site. Seventeen animals had cysts (fertile) present only in the lungs, one animal had fertile cysts in the lungs and spleen, and one individual had an infertile kidney cyst. Restriction endonuclease analysis of a fragment of the nad1 gene indicated all the cysts were due to E. shiquicus. Genetic diversity analysis revealed that the nad1 and cox1 genes varied by 0.1-1.2% and 0.1-1.0%, respectively. Haplotype network analysis of the concatenated nad1 and cox1 sequences of the isolates showed they were classified into at least 6 haplotypes, and different haplotype percentages ranged from 4.2% to 29.6%. Although, high haplotype diversity was evident in the study area, the complete nad1 and cox1 gene sequences obtained indicated that all samples represented isolates of E. shiquicus. The study has also provided a new PCR-restriction endonuclease-based method to rapidly distinguish E. shiquicus from E. multilocularis which provides a useful tool for epidemiological investigations where the two species overlap.

Synthesis and Structural Characterization of an Unusual Oxygen-Linked Double Cubane-Like Cluster {[Mo(3)PbOS(3)](OAc)(2)(py)(3)(dtp)(2)O}(2).

The unusual oxygen-linked double cubane-like cluster compound {[Mo(3)PbOS(3)](OAc)(2)(py)(3)(dtp)(2)O}(2) (A) (dtp = S(2)P(OEt(2))(-), OAc = CH(3)COO(-), py = C(5)H(5)N) was obtained for the first time by the reaction of the mixed S/O-bridged cluster [Mo(3)(&mgr;(3)-O)(&mgr;-S)(3)(dtp)(4)H(2)O] (B) with Pb(OAc)(2).3H(2)O in the presence of excess CH(3)COOH and pyridine. It has been characterized by IR, Raman, UV-vis, and X-ray structure analysis. The molecule contains a crystallographic center of inversion and can be viewed as consisting of two [Mo(3)PbOS(3)](6+) cubane-like cores linked through a pair of oxygen bridges with Mo-(&mgr;-O) bond lengths of ca. 1.89 Å. The cell dimensions are a = 11.705(8) Å, b = 19.527(8) Å, c = 20.670(9) Å, beta = 98.14(4) degrees, V = 4677(8) Å(3), Z = 2 in the space group P2(1)/n. The final R = 0.056, R(w) = 0.068 for 5424 reflections with I >/= 3sigma(I). The average Mo-Mo bond distance is 2.613(1) Å and the nonbonding Mo-Pb distances lie in the range from 3.997(1) to 4.090(1) Å. The spectra of IR, Raman, and UV-vis spectra are also shown in this paper.