Diffusive flux and pore anisotropy in sedimentary rocks

Diffusion of dissolved contaminants into or from bedrock matrices can have a substantial impact on both the extent and longevity of dissolved contaminant plumes. For layered rocks, bedding orientation can have a significant impact on diffusion. A series of laboratory experiments was performed on minimally disturbed bedrock cores to measure the diffusive flux both parallel and normal to mineral bedding of four different anisotropic sedimentary rocks. Measured effective diffusion coefficients ranged from 4.9×10(-8) to 6.5×10(-7)cm(2)/s. Effective diffusion coefficients differed by as great as 10-folds when comparing diffusion normal versus parallel to bedding. Differences in the effective diffusion coefficients corresponded to differences in the "apparent" porosity in the orientation of diffusion (determined by determining the fraction of pore cross-sectional area measured using scanning electron microscopy), with the difference in apparent porosity between normal and parallel bedding orientations differing by greater than 2-folds for two of the rocks studied. Existing empirical models failed to provide accurate predictions of the effective diffusion coefficient in either bedding orientation for all four rock types studied, indicating that substantial uncertainty exists when attempting to predict diffusive flux through sedimentary rocks containing mineral bedding. A modified model based on the apparent porosity of the rocks provided a reasonable prediction of the experimental diffusion data.

Multiparticle quantum Szilard engine with optimal cycles assisted by a Maxwell's demon

We present a complete-quantum description of a multiparticle Szilard engine that consists of a working substance and a Maxwell's demon. The demon is modeled as a multilevel quantum system with specific quantum control, and the working substance consists of identical particles obeying Bose-Einstein or Fermi-Dirac statistics. In this description, a reversible scheme to erase the demon's memory by a lower-temperature heat bath is used. We demonstrate that (1) the quantum control of the demon can be optimized for a single-particle Szilard engine so that the efficiency of the demon-assisted thermodynamic cycle could reach the Carnot cycle's efficiency and (2) the low-temperature behavior of the working substance is very sensitive to the quantum statistics of the particles and the insertion position of the partition.

Microbial reduction of structural iron in interstratified illite-smectite minerals by a sulfate-reducing bacterium

Clay minerals are ubiquitous in soils, sediments, and sedimentary rocks and could coexist with sulfate-reducing bacteria (SRB) in anoxic environments, however, the interactions of clay minerals and SRB are not well understood. The objective of this study was to understand the reduction rate and capacity of structural Fe(III) in dioctahedral clay minerals by a mesophilic SRB, Desulfovibrio vulgaris and the potential role in catalyzing smectite illitization. Bioreduction experiments were performed in batch systems, where four different clay minerals (nontronite NAu-2, mixed-layer illite-smectite RAr-1 and ISCz-1, and illite IMt-1) were exposed to D. vulgaris in a non-growth medium with and without anthraquinone-2,6-disulfonate (AQDS) and sulfate. Our results demonstrated that D. vulgaris was able to reduce structural Fe(III) in these clay minerals, and AQDS enhanced the reduction rate and extent. In the presence of AQDS, sulfate had little effect on Fe(III) bioreduction. In the absence of AQDS, sulfate increased the reduction rate and capacity, suggesting that sulfide produced during sulfate reduction reacted with the phyllosilicate Fe(III). The extent of bioreduction of structural Fe(III) in the clay minerals was positively correlated with the percentage of smectite and mineral surface area of these minerals. X-ray diffraction, and scanning and transmission electron microscopy results confirmed formation of illite after bioreduction. These data collectively showed that D. vulgaris could promote smectite illitization through reduction of structural Fe(III) in clay minerals.

Identification of the IFITM3 gene as an inhibitor of hepatitis C viral translation in a stable STAT1 cell line

To investigate the functions of signal transducers and activators of transcription 1 (STAT1)-induced anti-hepatitis C viral (HCV) effects, a stable Huh7.5 cell line (Huh7.5-STAT1ER) was established that constitutively expresses a fusion protein (STAT1ER) of STAT1 and the mouse oestrogen receptor (ER), which forms STAT1ER homodimers after 4-hydroxytamoxifen (4-HT) treatment. This inducible and cytokine/receptor-independent STAT1 activation system allowed us to investigate the anti-HCV effects of STAT1ER activation after inducing IFN-stimulated gene (ISG) expression. The anti-HCV effects of dimerized STAT1ER fusion protein were determined by real-time PCR in a time-dependent fashion post-HCV (JFH-1) infection. HCV (JFH-1) RNA decreased 48% at 72 h after 4-HT treatment. To distinguish the inhibitory effects of STAT1ER activation on HCV RNA replication or HCV internal ribosomal entry site (IRES)-mediated translation, a dicistronic pRL-HL construct was used in the studies. Both cellular (Cap-dependent) and HCV IRES-mediated (Cap-independent) translation were decreased by 63% and 57% at 72 h post-STAT1ER activation in the STAT1ER cell line. In our previous studies, interferon-induced transmembrane protein 3 [(IFITM3) (1-8U)] was found to inhibit HCV RNA replication. Subsequently, elevated expression of the 1-8U gene was confirmed by Western blotting in the Huh7.5-STAT1ER cell line. To further investigate the 1-8U function with both in vivo and in vitro studies, the 1-8U gene was found to suppress cellular and HCV IRES-mediated translation.

Notch signaling may negatively regulate neonatal rat cardiac fibroblast-myofibroblast transformation

Cardiac fibroblast-myofibroblast transformation (CMT) is a critical event in the initiation of myocardial fibrosis. Notch signaling has been shown to regulate myofibroblast transformation from other kinds of cells. However, whether Notch signaling is also involved in CMT remains unclear. In the present study, expressions of Notch receptors in cardiac fibroblasts (CFs) were examined, effects of Notch signaling inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT) and transforming growth factor-beta1 (TGF-beta1) on CMT were determined by increasing alpha-smooth muscle actin (alpha-SMA) expression and collagen synthesis, and Notch signaling was examined by analyzing expressions of Notch receptors. The results showed that: (1) Notch receptor 1, 2, 3 and 4 were all expressed in CFs; (2) DAPT promoted CMT in a time-dependent manner; (3) During the period of CMT induced by TGF-beta1, expressions of Notch receptor 1, 3 and 4 in CFs were down-regulated, whereas there was no change for Notch receptor 2. Moreover, the downtrends of Notch 1, 3 and 4 were corresponding to the trend growth of alpha-SMA expression and collagen synthesis. These results suggested that inhibiting of Notch signaling might promote CMT. The down-regulations of Notch receptor 1, 3 and 4 induced by TGF-beta1 may facilitate CMT. In conclusion, inhibition of Notch signaling might be a novel mechanism of CMT in myocardial fibrosis.

Dermoscopy of scalp tumours: a multi-centre study conducted by the international dermoscopy society

BACKGROUND

Little is known about the dermoscopic features of scalp tumours. Objective  To determine the dermoscopic features of scalp tumours.

METHODS

Retrospective analysis of dermoscopic images of histopathologically diagnosed scalp tumours from International Dermoscopy Society members.

RESULTS

A total of 323 tumours of the scalp from 315 patients (mean age: 52 years; range 3-88 years) were analysed. Scalp nevi were significantly associated with young age (<30 years) and exhibited a globular or network pattern with central or perifollicular hypopigmentation. Melanoma and non-melanoma skin cancer were associated with male gender, androgenetic alopecia, age >65 years and sun damage. Atypical network and regression were predictive for thin (≤1 mm) melanomas, whereas advanced melanomas (tumour thickness > 1 mm) revealed blue white veil, unspecific patterns and irregular black blotches or dots.

CONCLUSIONS

The data collected provide a new knowledge regarding the clinical and dermoscopy features of pigmented scalp tumours.

CAC2634-disrupted mutant of Clostridium acetobutylicum can be electrotransformed in air

AIMS

To simplify the electrotransformation process of Clostridium acetobutylicum, which currently needs to be performed in an anaerobic chamber, thus laborious and time-consuming.

METHODS AND RESULTS

The CAC2634 gene encoding PerR is a known peroxide regulon repressor in Cl. acetobutylicum. CAC2634 in a previously constructed Restriction-Modification system deficient Cl. acetobutylicum mutant SMB009 was disrupted using ClosTron method. The resulted mutant SMB012 can be electrotransformed in air with an efficiency of 1.2-3.1 × 10(3) transformants μg(-1) DNA.

CONCLUSIONS

We demonstrated that the disruption of CAC2634 in Cl. acetobutylicum enables its electrotransformation in air.

SIGNIFICANCE AND IMPACT OF THE STUDY

The electrotransformation process of Cl. acetobutylicum could be significantly simplified, especially when operating multiple electrotransformations.

Quantum Maxwell's demon in thermodynamic cycles

We study the physical mechanism of Maxwell's demon (MD), which helps do extra work in thermodynamic cycles with the heat engine. This is exemplified with one molecule confined in an infinitely deep square potential with a movable solid wall. The MD is modeled as a two-level system (TLS) for measuring and controlling the motion of the molecule. The processes in the cycle are described in a quantum fashion. It is discovered that a MD with quantum coherence or one at a temperature lower than the molecule's heat bath can enhance the ability of the whole working substance, formed by the heat engine plus the MD, to do work outside. This observation reveals that the essential role of the MD is to drive the whole working substance off equilibrium, or equivalently, to work between two heat baths with different effective temperatures. The elaborate studies with this model explicitly reveal the effect of finite size off the classical limit or thermodynamic limit, which contradicts common sense on a Szilard heat engine (SHE). The quantum SHE's efficiency is evaluated in detail to prove the validity of the second law of thermodynamics.

Neuroanatomic and behavioral traits for autistic disorders in age-specific restricted index selection mice

The pathogenesis of neurodevelopmental disorders such as autism is believed to be influenced by interactions between genetic and environmental factors, and appropriate animal models are needed to assess the influence of such factors on relevant neurodevelopmental phenotypes. A set of inbred mouse strains (Atchley strains) including A12 (E+L0) and A22 (E-L0) were generated by age-specific restricted index selection from a baseline random-bred ICR mouse population obtained from Harlan Sprague-Dawley [Atchley et al. (1997) Genetics 146(2):629-640; Indianapolis, IN, USA). As compared with the A22 strain, A12 mice had significantly increased early (P0-P10) body weight gain with minimal changes in late (P28-P56) body weight gain. We found that these strains also differed in brain weight, brain volume, cell proliferation, and FGF-2 levels in certain brain regions. Specifically, brain weight and volume were significantly greater in A12 mice than that in A22 mice at P10 and P28. Quantitative analysis of bromodeoxyuridine (BrdU) labeling of proliferating cells showed that the number of BrdU-positive cells in the A12 strain were significantly greater in the frontal cortex and lesser in the dentate gyrus than that in the A22 strain at P28. Western blot revealed that fibroblast growth factors-2 (FGF-2), but not brain-derived neurotrophic factor (BDNF), expression was significantly increased in the frontal cortex of A12 strain at P28. Also, A12 mice exhibited decreased intra-strain social interaction and increased repetitive stereotyped behaviors at P28. Our study suggests that A12 mice may partially mimic the anatomic and behavioral traits of patients with neurodevelopmental disorders such as autism spectrum disorders, and therefore may yield insights into the developmental mechanisms involved in their pathogenesis.

Expression of acid-sensing ion channels in intestinal epithelial cells and their role in the regulation of duodenal mucosal bicarbonate secretion

AIMS

As little is currently known about acid-sensing ion channels (ASICs) in intestinal epithelial cells, the aims of the present study were to investigate the expression and function of ASICs in intestinal epithelial cells, particularly their physiological role in the acid-stimulated duodenal mucosal bicarbonate secretion (DMBS).

METHODS

RT-PCR and digital Ca²(+) imaging were used to determine the expression and function of ASICs in HT29 cells and SCBN cells, intestinal epithelial crypt cell lines. The acid-stimulated DMBS was measured in C57 black mice in vivo to study the role of ASICs in this physiological process.

RESULTS

ASIC1a mRNA expression was detected in the duodenal mucosa stripped from mice and epithelial cell lines, in which cytoplasmic free Ca²(+) ([Ca²(+) ](cyt)) in response to extracellular acidosis was also increased. In Ca²(+) -containing solutions, acidosis (pH 6.0-5.0) raised [Ca²(+) ](cyt) in both HT29 cells and SCBN cells in a similar pH-dependent manner. Acidosis-induced increase in [Ca²(+) ](cyt) was markedly inhibited by amiloride (an ASICs blocker), SK&F96365 (a blocker for non-selective cation channels), or in Ca²(+) -free solutions; but was abolished by amiloride in Ca²(+) -free solutions. However, acidosis-induced increase in [Ca²(+) ](cyt) was slightly affected by U73122 (a PLC inhibitor), or nifedipine (a voltage-gated Ca²(+) channel blocker). After acidosis raised [Ca²(+) ](cyt) , stimulation of purinergic receptors with ATP further increased [Ca²(+) ](cyt) , but acidosis-induced increase in [Ca²(+) ](cyt) was not altered by suramin. Moreover, acid-stimulated murine DMBS was significantly attenuated by amiloride.

CONCLUSION

Therefore, ASICs are functionally expressed in intestinal epithelial cells, and may play a role in acid-stimulated DMBS through a Ca²(+) signalling pathway.

Effect of plasma surface modification on the biocompatibility of UHMWPE

In this paper active screen plasma nitriding (ASPN) is used to chemically modify the surface of UHMWPE. This is an unexplored and new area of research. ASPN allows the homogeneous treatment of any shape or surface at low temperature; therefore, it was thought that ASPN would be an effective technique to modify organic polymer surfaces. ASPN experiments were carried out at 120 °C using a dc plasma nitriding unit with a 25% N(2) and 75% H(2) atmosphere at 2.5 mbar of pressure. UHMWPE samples treated for different time periods were characterized by nanoindentation, FTIR, XPS, interferometry and SEM. A 3T3 fibroblast cell line was used for in vitro cell culture experiments. Nanoindentation of UHMWPE showed that hardness and elastic modulus increased with ASPN treatment compared to the untreated material. FTIR spectra did not show significant differences between the untreated and treated samples; however, some changes were observed at 30 min of treatment in the range of 1500-1700 cm(-1) associated mainly with the presence of N-H groups. XPS studies showed that nitrogen was present on the surface and its amount increased with treatment time. Interferometry showed that no significant changes were observed on the surfaces after the treatment. Finally, cell culture experiments and SEM showed that fibroblasts attached and proliferated to a greater extent on the plasma-treated surfaces leading to the conclusion that ASPN surface treatment can potentially significantly improve the biocompatibility behaviour of polymeric materials.

Using community wealth ranking to identify the poor for subsidies: a case study of community-based health insurance in Nouna, Burkina Faso

Access to health-care is low in developing countries. Poor people are less likely to seek care than those who are better off. Community-based health insurance (CBI) aims to improve healthcare utilisation by removing financial barriers, unfortunately CBI has been less effective in securing equity than expected. Poor people, who probably require greater protection from catastrophic health expenses, are less likely to enrol in such schemes. Therefore, it is important to implement targeted interventions so that the most in need are not left out. CBI has been offered to a district in Burkina Faso, comprising 7762 households in 41 villages and the district capital of Nouna since 2004. Community wealth ranking (CWR) was used in 2007 to identify the poorest quintile of households who were subsequently offered insurance at half the usual premium rate. The CWR is easy to implement and requires minimal resources such as interviews with local informants. As used in this study, the agreement between the key informants was more (37.5%) in the villages than in Nouna town (27.3%). CBI management unit only received nine complaints from villagers who considered that some households had been wrongly identified. Among the poorest, the annual enrolment increased from 18 households (1.1%) in 2006 to 186 (11.1%) in 2007 after subsidies. CWR is an alternative methodology to identify poor households and was found to be more cost and time efficient compared to other methods. It could be successfully replicated in low-income countries with similar contexts. Moreover, targeted subsidies had a positive impact on enrolment.

Selective effects of Lactobacillus casei Shirota on T cell activation, natural killer cell activity and cytokine production

Modulation of host immunity is an important potential mechanism by which probiotics confer health benefits. This study was designed to investigate the effects of a probiotic strain, Lactobacillus casei Shirota (LcS), on immune function using human peripheral blood mononuclear cells (PBMC) in vitro. In addition, the role of monocytes in LcS-induced immunity was also explored. LcS promoted natural killer (NK) cell activity and preferentially induced expression of CD69 and CD25 on CD8(+) and CD56(+) subsets in the absence of any other stimulus. LcS also induced production of interleukin (IL)-1beta, IL-6, tumour necrosis factor (TNF)-alpha, IL-12 and IL-10 in the absence of lipopolysaccharide (LPS). In the presence of LPS, LcS enhanced IL-1beta production but inhibited LPS-induced IL-10 and IL-6 production, and had no further effect on TNF-alpha and IL-12 production. Monocyte depletion reduced significantly the impact of LcS on lymphocyte activation, cytokine production and natural killer (NK) cell activity. In conclusion, LcS activated cytotoxic lymphocytes preferentially in both the innate and specific immune systems, which suggests that LcS could potentiate the destruction of infected cells in the body. LcS also induced both proinflammatory and anti-inflammatory cytokine production in the absence of LPS, but in some cases inhibited LPS-induced cytokine production. Monocytes play an important role in LcS-induced immunological responses.

Antioxidant treatment restores prejunctional regulation of purinergic transmission in mesenteric arteries of deoxycorticosterone acetate-salt hypertensive rats

Norepinephrine (NE) and ATP are co-released by periarterial sympathetic nerves. In mesenteric arteries (MA) from deoxycorticosterone-acetate (DOCA)-salt hypertensive rats, ATP, but not norepinephrine, release is impaired suggesting that their release may be regulated differently. We tested the hypothesis that different calcium channels contribute to ATP and norepinephrine release from sympathetic nerves in vitro in MA from normotensive and DOCA-salt hypertensive rats and that oxidative stress disrupts prejunctional regulation of co-transmission. Excitatory junction potentials (EJPs) were used to measure ATP release. Norepinephrine release was measured amperometrically with carbon-fiber microelectrodes. CdCl2 (30 microM) inhibited norepinephrine release in sham and DOCA-salt arteries by 78% and 85%, respectively. The N-type calcium channel antagonist, omega-conotoxin GVIA (CTX, 0.1 microM) inhibited norepinephrine release by 50% and 67% in normotensive and DOCA-salt arteries, respectively while CTX blocked EJPs. The P/Q-type calcium channel antagonist omega-agatoxin IVA (ATX; 0.03 microM) reduced norepinephrine release in sham but not DOCA-salt arteries and increased EJPs in sham but not DOCA-salt arteries. ATX did not increase EJPs in sham arteries in the presence of the alpha(2)-adrenergic receptor antagonist, yohimbine (1 microM). alpha(2)-Autoreceptor-sensitive EJP facilitation is impaired in DOCA-salt hypertension but this response is restored in DOCA-salt rats treated chronically with the antioxidant, apocynin. Apocynin restored alpha(2)-autoreceptor regulation of norepinephrine release. We conclude that ATP released from periarterial sympathetic nerves is controlled directly by N-type calcium channels. Norepinephrine release is controlled by N and P/Q type calcium channels. Norepinephrine release controlled by P/Q channels acts at alpha(2)-adrenergic receptors to inhibit norepinephrine release suggesting that there may be multiple pools of norepinephrine in periarterial sympathetic nerves. Regulation of norepinephrine release by alpha(2)-autoreceptors and P/Q-type channels is impaired in DOCA-salt hypertension and alpha(2)-autoreceptor function is disrupted by oxidative stress.

Optimum input states of polarization for Mueller matrix measurement in a system having finite polarization-dependent loss or gain

We present the theoretical and simulation results of the relationship between three input states of polarization (SOP) and the Mueller matrix measurement error in an optical system having birefringence and finite polarization-dependent loss or gain (PDL/G). By using the condition number as the criterion, it can be theoretically demonstrated that the three input SOPs should be equally-spaced on the Poincaré sphere and centered on the reversed PDL/G vector to achieve better measurement accuracy in a single test. Further, an upper bound of the mean of the Mueller matrix measurement error is derived when the measurement errors of output Stokes parameters independently and identically follow the ideal Gaussian distribution. This upper bound also shows that the statistically best Mueller matrix measurement accuracy can be obtained when the three input SOPs have the same relationship mentioned above. Simulation results confirm the validity of the theoretical findings.