Investigating the Solubility of CO2 in Polypropylene Using Various EOS Models

Generally, in order to obtain reliable gas solubility data in a polymer melt, one must determine the swollen volume of the polymer with dissolved gas. The swollen volume is typically estimated by an equation of state (EOS). This paper reports on the application of three different equations of state (the Sanchez-Lacombe (SL) EOS, the Simha-Somcynsky (SS) EOS, and the Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT) EOS) to a polymer/gas mixture system for the study of phase equilibria and gas solubility determination. The apparent solubility was obtained using a magnetic suspension balance (MSB). Approaches based on the SL, SS, and PC-SAFT EOS's are herein proposed for predicting the swelling behavior of polymer/gas mixtures and correlating the swollen volume to the apparent solubility.

The role of alpha-fetoprotein in maintaining the growth of human hepatoma cells

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Background: This study was to explored the functional mechanism of alpha-fetoprotein (AFP) in maintaining the proliferation of human hepatoma cells line Bel 7402 and the immunsuppression of lymphocyte Jurkat cells. Methods: Western blot was used to detecting the expression of some apoptosis-related gene, fluorescence labeled AFP and confocal microscopy scanning for receptor binding assay in the membrane in Jurkat cells. Results: It showed that AFP could enhance the expression of survivin and c-ras, but restrain caspase-3 express in Bel 7402 cells by Western blotting analysis. It also showed that AFP could bind to the membrane of Jurkat cells by confocal microscopy scanning, and when treated Jurkat with AFP, it indicated that AFP could repress the expression of survivin and Livin and elevated the activity of caspase-3 in the cells; Co-cultured Bel 7402 cells with Jurkat cells, the expression of tumor necrosis related-apoptosis induced ligand (TRAIL) in Jurkt cells was inhibited, when pretreatment with monoclonal antibody of AFP (Anti-AFP), the restrained effect of TRAIL express and the activity of caspase-3 was elevated in Jurkat cells was removed. It also indicated that Anti-AFP had an ability to block these functions of AFP. Conclusions: AFP has a capability to promote the growth and escape from immune surveillance of human hepatoma cells through enhancing the expression of ras and survivin gene in Bel 7402 cells, suppressing TRAIL, survivin and Livin expressed and upregulated activity of caspase-3 in Jurkat cells.

No significant financial relationships to disclose.

End-user survey for digital sensor characteristics: a pilot questionnaire study

OBJECTIVE

To survey end-user opinions on dental digital sensor characteristics for the design of a new X-ray imaging sensor.

MATERIALS AND METHODS

100 questionnaires were sent out to dentists and dental radiologists. The questionnaire consisted of six parts related to dental sensors. A: Details about the respondent; B: Prioritization of most important aspects of digital sensors; C: Rating advantages and D: disadvantages of digital sensors; F: Dental features that need to be enhanced by digital sensors; G: End-user comments.

RESULTS

Fifty-six questionnaires were returned. Contrast resolution and imaging time were assessed as the most and the least important aspects, respectively. Aspects considered as advantages by approximately 80% of respondents were: optimal contrast resolution, increased specificity, increased discrimination between diseased and healthy tissue, increased sensitivity, lower dose to the patient by more than 20%; as a disadvantage, increased patient dose was given. Dental features considered important by over 80% of the respondents were for intraoral radiographs: the visibility of caries, periapical, periodontal, and bone lesions; for panoramic radiographs: reduction of ghost images, image sharpness and bone. Bone and soft tissues on cephalograms and bone on temporomandibular joint (TMJ) tomograms were mentioned by over 70%.

CONCLUSION

The most desired characteristic for a new sensor is contrast resolution. Dose saving is not considered as important unless it is more than 20%. Examination time is not a major issue. Caries, periapical and periodontal, and bone lesions for intraoral radiographs, reduction of ghost images, image sharpness and bone for panoramic radiographs were the most frequently mentioned dental features that should be enhanced by digital sensors.

Nuclear ING2 expression is reduced in human cutaneous melanomas

Cutaneous malignant melanoma is a severe and sometimes life-threatening cancer. The molecular mechanism of melanomagenesis is incompletely understood. Deregulation of apoptosis is probably one of the key factors contributing to the progression of melanoma. The inhibitor of growth (ING) family proteins are candidate tumour suppressors which play important roles in apoptosis. Downregulated expression of ING proteins have been reported in several tumour types, including the loss of nuclear expression of p33ING1b in melanoma. As ING2 exhibits 58.9% homology with p33ING1b, we hypothesized that the aberrant expression of ING2 may be involved in melanomagenesis. Here, we used tissue microarray technology and immunohistochemistry to examine ING2 expression in human nevi and melanoma biopsies. Our data showed that nuclear ING2 expression was significantly reduced in radial growth phase (RGP), vertical growth phase (VGP), and metastatic melanomas compared with dysplastic nevi (P < 0.05). Our data also revealed that nuclear ING2 expression was not associated with patient's gender, age or tumour thickness, ulceration, American Joint Committee on Cancer (AJCC) stage, tumour subtype, location and 5-year survival (P > 0.05). Taken together, our results suggest that nuclear ING2 expression is significantly reduced in human melanomas and that reduced ING2 may be an important molecular event in the initiation of melanoma development.

Classifying G protein-coupled receptors and nuclear receptors on the basis of protein power spectrum from fast Fourier transform

As the potential drug targets, G-protein coupled receptors (GPCRs) and nuclear receptors (NRs) are the focuses in pharmaceutical research. It is of great practical significance to develop an automated and reliable method to facilitate the identification of novel receptors. In this study, a method of fast Fourier transform-based support vector machine was proposed to classify GPCRs and NRs from the hydrophobicity of proteins. The models for all the GPCR families and NR subfamilies were trained and validated using jackknife test and the results thus obtained are quite promising. Meanwhile, the performance of the method was evaluated on GPCR and NR independent datasets with good performance. The good results indicate the applicability of the method. Two web servers implementing the prediction are available at http://chem.scu.edu.cn/blast/Pred-GPCR and http://chem.scu.edu.cn/blast/Pred-NR.

A novel cellular survival factor--the B2 subunit of vacuolar H+-ATPase inhibits apoptosis

The ubiquitous vacuolar H(+)-ATPase, a multisubunit proton pump, is essential for intraorganellar acidification. Disruption of its function leads to disturbances of organelle function and cell death. Here, we report that overexpression of the B2 subunit of the H(+)-ATPase inhibits apoptosis. This antiapoptotic effect is not mediated by an increase in H(+)-ATPase activity but through activation of the Ras-mitogen-activated protein kinase (MAPK)-signaling pathway that results in the serine phosphorylation of Bad at residues 112 and 155. Increased Bad phosphorylation reduces its translocation to mitochondria, limits the release of mitochondrial cytochrome c and apoptosis-inducing factor and increases the resistance of the B2 overexpressing cells to apoptosis. Screening experiments of kinase inhibitors, including inhibitors of cAMP-activated protein kinase, protein kinase C, protein kinase B, (MAPK/extracellular signal-regulated (ERK) kinase) MEK and Ste-MEK1(13), a cell permeable ERK activation inhibitor peptide, revealed that the B2 subunit of H(+)-ATPase acts upstream of MEK activation in the MEK/ERK pathway to ameliorate apoptosis.

Photorefractive polymer device with video-rate response time operating at low voltages

The high-voltage bias required for video-rate compatible, efficient operation of a photorefractive polymer composite is reduced from 6-8 to 1.3 kV. At this low voltage, the device can hold erasable Bragg holograms with 80% efficiency in addition to having a video-rate response time. The transition of the hologram's state from thick to thin is analyzed in detail.

Combination of MIG (CXCL9) chemokine gene therapy with low-dose cisplatin improves therapeutic efficacy against murine carcinoma

MIG (monokine induced by interferon-gamma) is a CXC chemokine ligand (CXCL9) that can potently inhibit angiogenesis, and displays thymus-dependent antitumor effects. The effectiveness of a treatment combining gene therapy with plasmid-borne MIG (pORF-MIG) and low-dose cisplatin chemotherapy was determined using colon carcinoma (CT26) and Lewis lung carcinoma (LL/2c) murine models. The program was carried out via intramuscular delivery of pORF-MIG at 100 mug/mouse twice a week for 4 weeks, and/or intraperitoneal delivery of cisplatin at 0.6 mg/kg/mouse every 3 days for 48 days. Tumor volume and survival time were evaluated after treatment. CD31 immunohistochemical staining in tumor tissues and alginate capsule models in vivo was used to evaluate angiogenesis. Induction of apoptosis and cytotoxic T-lymphocyte (CTL) activity were also assessed. The combination of pORF-MIG and low-dose cisplatin produced significant antitumor activity, with complete tumor regression in 4/10 of CT26 colon carcinomas and 3/10 of LL/2c lung carcinomas, low vascularity, in alginate capsules, apparently degraded tumor microvessel density, and increased induction of apoptotic and CTL activities compared with either treatment alone. This study suggests that the combination of pORF-MIG plus cisplatin augments the inhibition of angiogenesis and the induction of apoptosis or CTL activity, all of which enhance antitumor activity. These findings may prove useful in further explorations of the application of combinatorial approaches to the treatment of solid tumors.

Effect of glycerol and cholesterol-loaded cyclodextrin on freezing-induced water loss in bovine spermatozoa

Recent experimental data show that incubating bovine sperm with cholesterol-loaded cyclodextrin (CLC) before cryopreservation increases the percentages of motile and viable cells recovered after freezing and thawing, compared with control sperm. In the present study, we report the effect of incubating bovine sperm with CLC on the subzero water transport response and the membrane permeability parameters (reference membrane permeability (Lpg) and activation energy (ELp)). Water transport data during freezing of bovine sperm cell suspensions were obtained at a cooling rate of 20 °C/min under three different conditions: 1. in the absence of cryoprotective agents (CPAs); 2. in the presence of 0.7 M glycerol; and 3. in the presence of 1.5 mg/ml CLC and 0.7 M glycerol. With previously published values, the bovine sperm cell was modeled as a cylinder of length 39.8 μm and radius 0.4 μm, with osmotically inactive cell volume (Vb) of 0.61Vo, whereVois the isotonic cell volume. By fitting a model of water transport to the experimentally obtained data, the best-fit water transport parameters (LpgandELp) were determined. The predicted best-fit permeability parameters ranged fromLpg= 0.02 to 0.036 μm/min-atm andELp= 26.4 to 42.1 kcal/mol. These subzero water transport parameters are significantly different from the suprazero membrane permeability values (obtained in the absence of extracellular ice) reported in the literature. Calculations made of the theoretical response of bovine spermatozoa at subzero temperatures suggest that the optimal cooling rate to cryopreserve bovine spermatozoa is 45–60 °C/min, agreeing quite closely with experimentally determined rates of freezing bovine spermatozoa.

Observation of a near-threshold enhancement in the omega(phi) mass spectrum from the doubly OZI-suppressed decay J/psi-->gamma(omega)phi

An enhancement near threshold is observed in the omega(phi) invariant mass spectrum from the doubly Okubo-Zweig-Iizuka-suppressed decays of J/psi-->gamma(omega)phi, based on a sample of 5.8 x 10(7) J/psi events collected with the BESII detector. A partial wave analysis shows that this enhancement favors JP=0+, and its mass and width are M=1812(+19)(-26)(stat)+/-18(syst) MeV/c2 and Gamma=105+/-20(stat)+/-28(syst) MeV/c2. The product branching fraction is determined to be B(J/psi-->gammaX)B(X-->omega(phi))=[2.61+/-0.27(stat)+/-0.65(syst)]x10(-4).

Potent regulation of microglia-derived oxidative stress and dopaminergic neuron survival: substance P vs. dynorphin

Unregulated microglial activation has been implicated as a pivotal factor contributing to Parkinson's disease. Using mesencephalic neuron-glia cultures, we address the novel possibility that peptides endogenous to the substantia nigra (SN), substance P and dynorphin (10(-13)-10(-14) M), are opposing mediators of microglial activation and consequent DA neurotoxicity. Here, we identify that substance P (10(-13)-10(-14) M) is selectively toxic to DA neurons in a microglia-dependent manner. Mechanistically, substance P (10(-13)-10(-14) M) activated microglial NADPH oxidase to produce extracellular superoxide and intracellular reactive oxygen species (ROS). Neuron-glia cultures from mice lacking a functional NADPH oxidase complex (PHOX-/-) were insensitive to substance P (10(-13)-10(-14) M) -induced loss of DA neuron function. Mixed glia cultures from (PHOX-/-) mice failed to show a significant increase in intracellular ROS in response to substance P compared with control cultures (PHOX+/+). Further, dynorphin (10(-14) M) inhibited substance P (10(-13) M) -induced loss of [3H] DA uptake. Here we demonstrate a tightly regulated mechanism governing microglia-derived oxidative stress, where the neuropeptide balance of dynorphin and substance P is critical to DA neuron survival.

Serum cholesterol and risk of Alzheimer disease: a community-based cohort study

OBJECTIVES

To examine the association of serum total cholesterol (TC) and high density lipoprotein (HDL) levels and subsequent incidence of dementia and Alzheimer disease (AD) in a population-based cohort study.

METHODS

A cohort of cognitively intact persons, aged 65 and older, was randomly selected from Group Health Cooperative (GHC), a large health maintenance organization, and was assessed biennially for dementia. Premorbid levels of TC and HDL were obtained from a computerized clinical laboratory database at GHC. Cox proportional hazards regression was used to calculate hazard ratios (HR, 95% CI) for dementia and AD associated with quartiles of TC and HDL levels.

RESULTS

Of the 2,356 eligible participants, 2,141 had at least one serum TC measure prior to the initial enrollment. Using the lowest TC quartiles as the reference group, the HR in the highest TC quartiles was not significantly elevated for dementia (1.16, 0.81 to 1.67) or for AD (1.00, 0.61 to 1.62) after adjusting for age, sex, education, baseline cognition, vascular comorbidities, body mass index, and lipid-lowering agent use. Serum HDL showed a similar lack of significant association with risk of dementia or AD. Models that included the presence of one or more APOE-epsilon4 alleles showed a typical association of epsilon4 with AD risk. This association was not materially modified by inclusion of TC level.

CONCLUSION

The data do not support an association between serum total cholesterol or high density lipoprotein in late life and subsequent risk of dementia or Alzheimer disease (AD). The increased risk of AD with APOE-epsilon4 is probably not mediated by serum total cholesterol levels.

Suprazero cooling conditions significantly influence subzero permeability parameters of mammalian ovarian tissue

To model the cryobiological responses of cells and tissues, permeability characteristics are often measured at suprazero temperatures and the measured values are used to predict the responses at subzero temperatures. The purpose of the present study was to determine whether the rate of cooling from +25 to +4 degrees C influenced the measured water transport response of ovarian tissue at subzero temperatures in the presence or absence of cryoprotective agents (CPAs). Sections of freshly collected equine ovarian tissue were first cooled either at 40 degrees C/min or at 0.5 degrees C/min from 25 to 4 degrees C, and then cooled to subzero temperatures. A shape-independent differential scanning calorimeter (DSC) technique was used to measure the volumetric shrinkage during freezing of equine ovarian tissue sections. After ice was induced to form in the extracellular fluid within the specimen, the sample was frozen from the phase change temperature to -50 degrees C at 5 degrees C/min. Replicate samples were frozen in isotonic medium alone or in medium containing 0.85 M glycerol or 0.85 M dimethylsulfoxide. The water transport response of ovarian tissue samples cooled at 40 degrees C/min from 25 to 4 degrees C was significantly different (confidence level >95%) from that of tissue samples cooled at 0.5 degrees C/min, whether in the presence or absence of CPAs. We fitted a model of water transport to the experimentally-derived volumetric shrinkage data and determined the best-fit membrane permeability parameters (L(pg) and E(Lp)) of equine ovarian tissue during freezing. Subzero water transport parameters of ovarian tissue samples cooled at 0.5 degrees C/min from 25 to 4 degrees C ranged from: L(pg) = 0.06 to 0.73 microm/min.atm and E(Lp) = 6.1 to 20.5 kcal/mol. The corresponding parameters of samples cooled at 40 degrees C/min from 25 to 4 degrees C ranged from: L(pg) = 0.04 to 0.61 microm/min.atm and E(Lp) = 8.2 to 54.2 kcal/mol. Calculations made of the theoretical response of tissue at subzero temperatures suggest that the optimal cooling rates to cryopreserve ovarian tissue are significantly dependent upon suprazero cooling conditions.