997 resultados para HELIUM 6
Resumo:
The electrochemical formation of highly porous CuTCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane) and CuTCNQF4 (TCNQF4 = 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) materials was undertaken via the spontaneous redox reaction between a porous copper template, created using a hydrogen bubbling template technique, and an acetonitrile solution containing TCNQ or TCNQF4. It was found that activation of the surface via vigorous hydrogen evolution that occurs during porous copper deposition and TCNQ mass transport being hindered through the porous network of the copper template influenced the growth of CuTCNQ and CuTCNQF4. This approach resulted in the fabrication of a honeycomb layered type structure where the internal walls consist of very fine crystalline needles or spikes. This combination of microscopic and nanoscopic roughness was found to be extremely beneficial for anti-wetting properties where superhydrophobic materials with contact angles as high as 177° were created. Given that CuTCNQ and CuTCNQF4 have shown potential as molecular based electronic materials in the area of switching and field emission, the creation of a surface that is moisture resistant may be of applied interest.
Resumo:
Introduction: Mothers’ sleep during the postpartum period is commonly characterised by bouts of sleep across the night, resulting in low sleep efficiency and daytime sleepiness. Understanding of the nature of mothers’ sleep disruption needs to incorporate indices of both sleep quantity and sleep quality, but objective assessment of sleep disturbance experienced during the first postpartum months has not been investigated in great detail. This longitudinal study aimed to objectively measure mothers’ sleep during the first 18 weeks postpartum, to ascertain the level of sleep disturbance experienced. Method: Eleven mothers (Mean age = 29.82, SD = 4.45) from Australia wore Actiwatch-2 devices for up to 7 days and nights at 6, 12 and 18 weeks postpartum. For each night of recording, a number of sleep bouts were identified. Total sleep time (TST) was calculated as the total number of minutes across the night within these bouts. Sleep efficiency was calculated as the percentage of minutes across the night classified as being part of a sleep bout, with higher scores indicating higher efficiency. Sleep quality captured the efficiency of sleep within sleep bouts, and was calculated as the percentage of epochs classified as sleep within sleep bouts, with higher scores indicating higher sleep quality. Results: At 6 weeks postpartum, mean total sleep time was 420.22 minutes (SD = 50.61). Total sleep time did not significantly differ across the assessment; however there was a trend towards an increase over time. Sleep efficiency increased across the time periods (F(2,10) = 10.30, p = .001), with a significant increase between week 12 and week 18. At 6 weeks postpartum, mean sleep quality was 93.15% (SD = 2.68) and scores did not significantly change across the assessment periods. While there was no relationship between sleep efficiency and sleep quality during weeks 6 and 12, a significant positive relationship was observed at week 18, r2 = .52, p = .013. Conclusions: Within this sample, a low level of disruption was consistently shown within the mothers’ night time sleep bouts. However, overall sleep efficiency suggested a significant proportion of time spent awake between sleep bouts. While TST remained stable over time, overall sleep efficiency improved, suggesting the mothers’ sleep was becoming more consolidated. A single sleep bout a night was not often experienced.
Resumo:
OBJECTIVE To assess the prevalence of childhood sexual abuse (CSA) in college students and to explore the association of CSA with youth mental health problem. METHODS A retrospective survey was conducted among 2508 students (females 1360, males 1148) in Nov. 2003 to Mar. 2004. The students were from 6 colleges/universities in Beijing, Hebei, Shanxi, Jiangsu, Shaanxi and Anhui provinces of China. RESULTS Of the 2508 students, 24.8% of females and 17.6% of males reported one or more types of nonphysical contact CSA (females 20.0% vs. males 14.6%) or/and physical contact CSA (females 14.1% vs. males 7.8%) before the age of 16 years. Risk of any CSA was not associated with the existence of siblings (one-child vs. two-or more child families), rural/non-rural residence during childhood, or parental education. Compared with their peers who had no CSA, the students with CSA showed significantly higher mean scores of psychological symptoms of somatization, obsessiveness, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation and psychoticism. CONCLUSION The problem of CSA was not uncommon and there was a significant correlation between CSA experience and students mental health problems. More attention should be paid on CSA prevention and provision of health services for the victims.
Resumo:
Kallikrein-related peptidases, in particular KLK4, 5, 6 and 7 (4-7), often have elevated expression levels in ovarian cancer. In OV-MZ-6 ovarian cancer cells, combined expression of KLK4-7 reduces cell adhesion and increases cell invasion and resistance to paclitaxel. The present work investigates how KLK4-7 shape the secreted proteome ("secretome") and proteolytic profile ("degradome") of ovarian cancer cells. The secretome comparison consistently identified >900 proteins in three replicate analyses. Expression of KLK4-7 predominantly affected the abundance of proteins involved in cell-cell communication. Among others, this includes increased levels of transforming growth factor β-1 (TGFβ-1). KLK4-7 co-transfected OV-MZ-6 cells share prominent features of elevated TGFβ-1 signaling, including increased abundance of neural cell adhesion molecule L1 (L1CAM). Augmented levels of TGFβ-1 and L1CAM upon expression of KLK4-7 were corroborated in vivo by an ovarian cancer xenograft model. The degradomic analysis showed that KLK4-7 expression mostly affected cleavage sites C-terminal to arginine, corresponding to the preference of kallikreins 4, 5 and 6. Putative kallikrein substrates include chemokines, such as growth differentiation factor 15 (GDF 15) and macrophage migration inhibitory factor (MIF). Proteolytic maturation of TGFβ-1 was also elevated. KLK4-7 have a pronounced, yet non-degrading impact on the secreted proteome, with a strong association between these proteases and TGFβ-1 signaling in tumor biology. © 2013 Federation of European Biochemical Societies.
Resumo:
Background Chlamydia trachomatis infection results in reproductive damage in some women. The process and factors involved in this immunopathology are not well understood. This study aimed to investigate the role of primary human cellular responses to chlamydial stress response proteases and chlamydial infection to further identify the immune processes involved in serious disease sequelae. Results Laboratory cell cultures and primary human reproductive epithelial cultures produced IL-6 in response to chlamydial stress response proteases (CtHtrA and CtTsp), UV inactivated Chlamydia, and live Chlamydia. The magnitude of the IL-6 response varied considerably (up to 1000 pg ml-1) across different primary human reproductive cultures. Thus different levels of IL-6 production by reproductive epithelia may be a determinant in disease outcome. Interestingly, co-culture models with either THP-1 cells or autologous primary human PBMC generally resulted in increased levels of IL-6, except in the case of live Chlamydia where the level of IL-6 was decreased compared to the epithelial cell culture only, suggesting this pathway may be able to be modulated by live Chlamydia. PBMC responses to the stress response proteases (CtTsp and CtHtrA) did not significantly vary for the different participant cohorts. Therefore, these proteases may possess conserved innate PAMPs. MAP kinases appeared to be involved in this IL-6 induction from human cells. Finally, we also demonstrated that IL-6 was induced by these proteins and Chlamydia from mouse primary reproductive cell cultures (BALB/C mice) and mouse laboratory cell models. Conclusions We have demonstrated that IL-6 may be a key factor for the chlamydial disease outcome in humans, given that primary human reproductive epithelial cell culture showed considerable variation in IL-6 response to Chlamydia or chlamydial proteins, and that the presence of live Chlamydia (but not UV killed) during co-culture resulted in a reduced IL-6 response suggesting this response may be moderated by the presence of the organism.
Resumo:
Small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) measurements of the structure of two Australian bituminous coals (particle size of 1-0.5 mm) before, during, and after exposure to 155 bar of helium were made to identify any effects of pressure alone on the pore size distribution of coal and any irreversible effects upon exposure to high pressures of helium in the pore size range from 3 nm to 10 μm. No irreversible effects upon exposure were identified for any pore size. No effects of pressure on pore size distribution were observed, except for a small effect at a pore size of about 2 μm for one coal. This study provides a convenient baseline for SANS and USANS investigations on sorption of gases at elevated pressures on coals, by distinguishing between the effect of pressure alone on coal pore size distribution and against the effect of the gas to be investigated.
Resumo:
The anion radicals CnOn-. (n = 3-6) can be generated by ionization of cyclic carbonyl compounds in the negative ion mode. The ions as well as the corresponding neutral counterparts are probed by means of different mass spectrometric techniques. The results suggest that oxocarbons, i.e. cyclic polyketones, are formed under conservation of the skeletons of the precursor molecules. At least for n = 3, however, the experimental findings indicate partial rearrangement of the expected cyclopropanetrione structure to an oxycarboxylate for the anion, i.e. O-.-C=C-CO2-. For n = 4 and 6 almost complete dissociation of the neutral polyones into carbon monoxide is found, whereas for n = 5 a distinct recovery signal indicates the generation of genuine cyclopentanepentaone.
Resumo:
In the structure of the title complex [Cs(C8H4Cl3O2)(H2O)]n, the Cs salt of the commercial herbicide fenac [(2,3,6-trichlorophenyl)acetic acid], the irregular eight-coordination about Cs+ comprises a bidentate chelate (O:Cl) interaction involving a carboxyl O-atom and an ortho-related ring substituted Cl atom which is also bridging, a triple-bridging carboxyl O-atom and a bridging water molecule. A two-dimensional sheet polymer is generated, lying parallel to (100), within which there are water O---H...O(carboxyl) hydrogen-bonding interactions.
Resumo:
Methyl, methyl-d(3), and ethyl hydroperoxide anions (CH3OO-, CD3OO-, and CH3CH2OO-) have been prepared by deprotonation of their respective hydroperoxides in a stream of helium buffer, gas. Photodetachment with 364 nm (3.408 eV) radiation was used to measure the adiabatic electron affinities: EA[CH3OO, (X) over tilde (2)A"] = 1.161 +/- 0.005 eV, EA[CD3OO, (X) over tilde (2)A"] = 1.154 +/- 0.004 eV, and EA[CH3CH2OO, (X) over tilde (2)A"] = 1.186 +/- 0.004 eV. The photoelectron spectra yield values for the term energies: DeltaE((X) over tilde 2A"-(A) over tilde 2A')[CH3OO] = 0.914 +/- 0.005 eV, DeltaE((X) over tilde (2)A"-(A) over tilde 2A') [CD3OO] = 0.913 +/- 0.004 eV, and DeltaE((X) over tilde (2)A"-(A) over tilde (2)A')[CH3CH2OO] = 0.938 +/- 0.004 eV. A localized RO-O stretching mode was observed near 1100 cm(-1) for the ground state of all three radicals, and low-frequency R-O-O bending modes are also reported. Proton-transfer kinetics of the hydroperoxides have been measured in a tandem flowing afterglow-selected ion flow tube k(FA-SIFT) to determine the gas-phase acidity of the parent hydroperoxides: Delta (acid)G(298)(CH3OOH) = 367.6 +/- 0.7 kcal mol(-1), Delta (acid)G(298)(CD3OOH) = 367.9 +/- 0.9 kcal mol(-1), and Delta (acid)G(298)(CH3CH2OOH) = 363.9 +/- 2.0 kcal mol(-1). From these acidities we have derived the enthalpies of deprotonation: Delta H-acid(298)(CH3OOH) = 374.6 +/- 1.0 kcal mol(-1), Delta H-acid(298)(CD3OOH) = 374.9 +/- 1.1 kcal mol(-1), and Delta H-acid(298)(CH2CH3OOH) = 371.0 +/- 2.2 kcal mol(-1). Use of the negative-ion acidity/EA cycle provides the ROO-H bond enthalpies: DH298(CH3OO-H) 87.8 +/- 1.0 kcal mol(-1), DH298(CD3OO-H) = 87.9 +/- 1.1 kcal mol(-1), and DH298(CH3CH2OO-H) = 84.8 +/- 2.2 kcal mol(-1). We review the thermochemistry of the peroxyl radicals, CH3OO and CH3CH2OO. Using experimental bond enthalpies, DH298(ROO-H), and CBS/APNO ab initio electronic structure calculations for the energies of the corresponding hydroperoxides, we derive the heats of formation of the peroxyl radicals. The "electron affinity/acidity/CBS" cycle yields Delta H-f(298)[CH3OO] = 4.8 +/- 1.2 kcal mol(-1) and Delta H-f(298)[CH3CH2OO] = -6.8 +/- 2.3 kcal mol(-1).
Resumo:
Hyperactive inflammatory responses following cancer initiation have led to cancer being described as a 'wound that never heals'. These inflammatory responses elicit signals via NFκB leading to IL-6 production, and IL-6 in turn has been shown to induce epithelial to mesenchymal transition in breast cancer cells in vitro, implicating a role for this cytokine in cancer cell invasion. We previously have shown that conditioned medium derived from cancer-associated fibroblasts induced an Epithelial to Mesenchymal transition (EMT) in PMC42-LA breast cancer cells and we have now identify IL-6 as present in this medium. We further show that IL-6 is expressed approximately 100 fold higher in a cancer-associated fibroblast line compared to normal fibroblasts. Comparison of mouse-specific (stroma) and human-specific (tumor) IL-6 mRNA expression from MCF-7, MDA MB 468 and MDA MB 231 xenografts also indicated the stroma rather than tumor as a significantly higher source of IL-6 expression. Mast cells (MCs) feature in inflammatory cancer-associated stroma, and activated MCs secrete IL-6. We observed a higher MC index (average number of mast cells per xenograft section/average tumor size) in MDA MB 468 compared to MDA MB 231 xenografts, where all MC were observed to be active (degranulating). This higher MC index correlated with greater mouse-specific IL-6 expression in the MDA MB 468 xenografts, implicating MC as an important source of stromal IL-6. Furthermore, immunohistochemistry on these xenografts for pSTAT3, which lies downstream of the IL-6 receptor indicated frequent correlations between pSTAT3 and mast cell positive cells. Analysis of publically available databases for IL-6 expression in patient tissue revealed higher IL-6 in laser capture microdissected stroma compared to adjacent tissue epithelium from patients with inflammatory breast cancer (IBC) and invasive non-inflammatory breast cancer (non-IBC) and we show that IL-6 expression was significantly higher in Basal versus Luminal molecular/phenotypic groupings of breast cancer cell lines. Finally, we discuss how afferent and efferent IL-6 pathways may participate in a positive feedback cycle to dictate tumor progression.
Resumo:
Elevated circulating interleukin-6 (IL6) and up-regulated S100P in prostate cancer (PCa) specimens correlate independently with progression to androgen-independent and metastatic PCa. The cause of up-regulated S100P levels in advanced PCa remains to be determined. We investigated the possibility that IL6 is an inducer of S100P. Determination of mRNA and protein levels by real-time PCR and Western blotting revealed that IL6 is a more potent inducer of S100P than the synthetic androgen, R1881, in the LNCaP/C4-2B model of PCa progression. IL6 did not require androgen to induce S100P in these cells, which express a functional androgen receptor (AR). Like R1881, IL6 was unable to induce S100P in PC3 cells that lack a functional AR. IL6 did not strongly induce the AR-dependent genes PSA and KLK2 and, contrary to R1881, down-regulated Cyr61/CCN1, a potential marker that is down-regulated in PCa. Epidermal growth factor (EGF), which like IL6 is a non-androgen activator of the AR, did not induce S100P. The data identifies a unique gene-induction profile for IL6 and suggests that IL6 may require a functional AR for S100P induction. A link between elevated IL6 and up-regulated S100P in androgen-refractory and metastatic PCa is postulated.
Resumo:
Introduction Well-designed biodegradable scaffolds in combination with bone growth factors offer a valuable alternative to the current gold standard autograft in spinal fusion surgery Yong et al. (2013). Here we report on 6- vs 12- month data set evaluating the longitudinal performance of a CaP coated polycaprolactone (PCL) scaffold loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2) as a bone graft substitute within a large preclinical animal model. Methods Twelve sheep underwent a 3-level (T6/7, T8/9 and T10/11) discectomy with randomly allocated implantation of a different graft substitute at each of the three levels; (i) calcium phosphate (CaP) coated polycaprolactone based scaffold plus 0.54µg rhBMP-2, (ii) CaP coated PCL- based scaffold alone or (iii) autograft (mulched rib head). Fusion assessments were performed via high resolution clinical computed tomography and histological evaluation were undertaken at six (n=6) and twelve (n=6) months post-surgery using the Sucato grading system (Sucato et al. 2004). Results The computed tomography fusion grades of the 6- and 12- months in the rhBMP-2 plus PCL- based scaffold group were 1.9 and 2.1 respectively, in the autograft group 1.9 and 1.3 respectively, and in the scaffold alone group 0.9 and 1.17 respectively. There were no statistically significant differences in the fusion scores between 6- and 12- month for the rhBMP plus PCL- based scaffold or PCL – based scaffold alone group however there was a significant reduction in scores in the autograft group. These scores were seen to correlate with histological evaluations of the respective groups. Conclusions The results of this study demonstrate the efficacy of scaffold-based delivery of rhBMP-2 in promoting higher fusion grades at 6- and 12- months in comparison to the scaffold alone or autograft group within the same time frame. Fusion grades achieved at six months using PCL+rhBMP-2 are not significantly increased at twelve months post-surgery.
Resumo:
The mineral kidwellite, a hydrated hydroxy phosphate of ferric iron and sodium of approximate formula NaFe93+(PO4)6(OH)11⋅3H2O, has been studied using a combination of electron microscopy with EDX and vibrational spectroscopic techniques. Raman spectroscopy identifies an intense band at 978 cm−1 and 1014 cm−1. These bands are attributed to the PO43− ν1 symmetric stretching mode. The ν3 antisymmetric stretching modes are observed by a large number of Raman bands. The series of Raman bands at 1034, 1050, 1063, 1082, 1129, 1144 and 1188 cm−1 are attributed to the ν3 antisymmetric stretching bands of the PO43− and HOPO32− units. The observation of these multiple Raman bands in the symmetric and antisymmetric stretching region gives credence to the concept that both phosphate and hydrogen phosphate units exist in the structure of kidwellite. The series of Raman bands at 557, 570, 588, 602, 631, 644 and 653 cm−1are assigned to the PO43− ν2 bending modes. The series of Raman bands at 405, 444, 453, 467, 490 and 500 cm−1 are attributed to the PO43− and HOPO32− ν4 bending modes. The spectrum is quite broad but Raman bands may be resolved at 3122, 3231, 3356, 3466 and 3580 cm−1. These bands are assigned to water stretching vibrational modes. The number and position of these bands suggests that water is in different molecular environments with differing hydrogen bond distances. Infrared bands at 3511 and 3359 cm−1 are ascribed to the OH stretching vibration of the OH units. Very broad bands at 3022 and 3299 cm−1 are attributed to the OH stretching vibrations of water. Vibrational spectroscopy offers insights into the molecular structure of the phosphate mineral kidwellite.
Resumo:
Inhibition of cholesterol export from late endosomes causes cellular cholesterol imbalance, including cholesterol depletion in the trans-Golgi network (TGN). Here, using Chinese hamster ovary (CHO) Niemann-Pick type C1 (NPC1) mutant cell lines and human NPC1 mutant fibroblasts, we show that altered cholesterol levels at the TGN/endosome boundaries trigger Syntaxin 6 (Stx6) accumulation into VAMP3, transferrin, and Rab11-positive recycling endosomes (REs). This increases Stx6/VAMP3 interaction and interferes with the recycling of αVβ3 and α5β1 integrins and cell migration, possibly in a Stx6-dependent manner. In NPC1 mutant cells, restoration of cholesterol levels in the TGN, but not inhibition of VAMP3, restores the steady-state localization of Stx6 in the TGN. Furthermore, elevation of RE cholesterol is associated with increased amounts of Stx6 in RE. Hence, the fine-tuning of cholesterol levels at the TGN-RE boundaries together with a subset of cholesterol-sensitive SNARE proteins may play a regulatory role in cell migration and invasion.