Entropy production and irreversibility of dissipative trajectories in electric circuits.

We experimentally examine the equivalence between the entropy production evaluated from irreversibility of trajectories and the physical dissipation in dissipative processes via electric resistor-capacitor (RC) circuits. The examinations are performed for two nonequilibrium steady states that are driven by an injected current and temperature difference, respectively. Such an equivalence demonstrates a parameter-free method to evaluate the entropy production of a system. The effects of configurational and temporal resolutions are also studied.

Electrical autonomous Brownian gyrator.

We study experimentally and theoretically the steady-state dynamics of a simple stochastic electronic system featuring two resistor-capacitor circuits coupled by a third capacitor. The resistors are subject to thermal noises at real temperatures. The voltage fluctuation across each resistor can be compared to a one-dimensional Brownian motion. However, the collective dynamical behavior, when the resistors are subject to distinct thermal baths, is identical to that of a Brownian gyrator, as first proposed by Filliger and Reimann [Phys. Rev. Lett. 99, 230602 (2007)PRLTAO0031-900710.1103/PhysRevLett.99.230602]. The average gyrating dynamics is originated from the absence of detailed balance due to unequal thermal baths. We look into the details of this stochastic gyrating dynamics, its dependences on the temperature difference and coupling strength, and the mechanism of heat transfer through this simple electronic circuit. Our work affirms the general principle and the possibility of a Brownian ratchet working near room temperature scale.

Personal beliefs, learned resourcefulness, and adaptive functioning in depressed adults.

Learned resourcefulness and personal beliefs are significant predictors of adaptive functioning. The mediating effect of personal beliefs on the relationship between learned resourcefulness and adaptive functioning was validated in adults with depression. The findings from this study may provide the basis for developing a useful nursing intervention constituting resourcefulness skills with positive personal beliefs to help patients with depression improve their ability to function well in their daily activities. ABSTRACT: Research has shown that patients with depression have difficulty with performing daily tasks and meeting their own personal care needs. According to Beck's cognitive theory of depression, such deficits in adaptive functioning are affected by disturbances in specific personal beliefs that reflect the process of regulating cognitions. Rosenbaum's learned resourcefulness theory proposed that adaptive functioning is influenced by learned resourcefulness, while learned resourcefulness is associated with the process regulating cognitions. This study aims to test the mediating effect of personal beliefs on the relationship between resourcefulness and adaptive functioning. The study involved a cross-sectional design. Participants consisted of 187 adults with depression in southern Taiwan. The data were collected through four instruments: Cognitive Triad Inventory, Self-Control Schedule, modified Community Living Skills Scale, and a demographic questionnaire. Both resourcefulness and personal beliefs were significant predictors of adaptive functioning, and personal beliefs mediated the effect of learned resourcefulness on the adaptive functioning of the adults with depression. The results validate the role played by personal beliefs in effecting learned resourcefulness and adaptive functioning among adults with depression and provide direction for designing nursing interventions that consider personal beliefs when teaching resourcefulness skills to adults with depression.

Tumoral presence of human cytomegalovirus is associated with shorter disease-free survival in elderly patients with colorectal cancer and higher levels of intratumoral interleukin-17.

Infectious diseases are closely related to cancer. Human cytomegalovirus (HCMV) has been implicated in the promotion of tumour growth, and is present in the tumour specimens of colorectal cancer (CRC). This study aimed to investigate whether tumoral presence of HCMV is associated with a different clinical outcome in elderly patients with CRC. We analysed archived tumour specimens from 95 CRC patients aged ≥65 years. HCMV was detected by PCR. Clinical, pathological, disease-free and overall survival data were compared between patients with HCMV-positive and HCMV-negative tumours. A quantitative RT-PCR array was used to evaluate the expression levels of cytokines genes of T-helper subpopulations in tumours. In the Kaplan-Meier analysis of the 81 patients who underwent curative surgery, 39 patients with HCMV-positive tumours had a lower disease-free survival rate (p 0.024). For patients with stage II or stage III tumours, tumoral HCMV status correlated with disease-free survival more closely than the traditional histopathological staging methods. In a multivariate Cox proportional hazard model, tumoral presence of HCMV independently predicted tumour recurrence in 5 years (hazard ratio 4.42; 95% CI 1.54-12.69, p 0.006). The qRT-PCR analysis of ten stage II tumours showed that the gene expression levels of interleukin-17-the signature cytokine of T-helper 17 cells-and its receptor, interleukin-17 receptor C, were higher in the five HCMV-positive tumours. Our results suggest that the presence of HCMV in CRC is associated with poorer outcome in elderly patients. How the virus interacts with the tumour microenvironment should be further investigated.

Steroidogenic Factor 1 (NR5A1) resides in centrosomes and maintains genomic stability by controlling centrosome homeostasis.

SF-1 (Steroidogenic Factor 1, NR5A1) is a tissue-specific transcription factor critical for the growth, development and differentiation of steroidogenic and a few other endocrine tissues. But how SF-1 regulates cell growth is not entirely clear. Here we found that SF-1 was localized to the centrosome in addition to the nucleus, and SF-1 depletion by shRNA caused centrosome over-duplication, aberrant mitosis and genomic instability, leading to a reduction of cell number. Centrosome amplification defect was rescued by both wild-type SF-1 and transcription-defective SF-1-G35E, suggesting a non-genomic activity of SF-1 involved in centrosome homeostasis. In addition, we identified in SF-1 a centrosome localization signal, whose overexpression led to reduced localization of both SF-1 and γ-tubulin to the centrosome. Our results uncover a novel role of SF-1 in the control of centrosome homeostasis and genomic stability.

Metabolism and pharmacokinetics of genipin and geniposide in rats.

Geniposide, an iridoid glucoside, is a major constituent in the fruits of Gardenia jasminoides (Gardenia fruits), a popular Chinese herb. Genipin, the aglycone of geniposide, is used to prepare blue colorants in food industry and also a crosslinking reagent for biological tissue fixation. In this study, we investigated the metabolism and pharmacokinetics of genipin and geniposide in rats. Blood samples were withdrawn via cardiopuncture and the plasma samples were assayed by HPLC method before and after hydrolysis with sulfatase and beta-glucuronidase. The results indicated that after oral administration of genipin or Gardenia fruit decoction, genipin sulfate was a major metabolite in the bloodstream, whereas the parent forms of genipin and geniposide were not detected. Importantly, oral administration of 200mg/kg of genipin resulted in a mortality of 78% (7/9) in rats.

Observation of two forms of conformations in the reentrant condensation of DNA.

Reentrant condensation of DNA in the presence of spermidine (SPD) is studied by gel electrophoresis (GEP). It is found that the reentrant condensation of DNA induced by SPD can produce a reentrant jamming of DNA molecules at the liquid-gel interface during GEP. However, not all the DNA are jammed at the interface indicating that there are different forms of condensed DNA. A model of condensed DNA consisting of two conformations can be used to explain the experimental observations. A phase diagram of the reentrant condensation based on the jamming states of DNA in terms of the length of DNA (L) and concentration of SPD is constructed. Furthermore, no charge inversion is observed during the reentrant transition.

Nonequilibrium relaxation times in polymer knot groups.

Flexible polymer knots with strict topological constraint of no segment crossing are studied by Monte Carlo simulations. The nonequilibrium relaxation time of an equilibrated polymer knot cut at one point to relax to a linear chain is measured. Prime knots up to 20 essential crossings from the groups (3(1),5(1),7(1),...), (4(1),6(1),8(1),...) and (5(2),7(2),9(2),...), (6(2),8(2),10(2),...) are studied. The nonequilibrium relaxation time for knots within a group are found to increase stepwise linearly with the number of essential crossings of the original knot. Our results suggest an equally spaced topological interaction energy spectrum for knots in the same group and thus provide a quantitative description of topological interactions.

Crossings and writhe of flexible and ideal knots.

The data of ideal knots [Nature, 384, 142 (1996)] are reanalyzed and the average crossing number of the ideal knots (ideal) shows a nonlinear behavior with the essential crossing number C. Supplemented with our Monte Carlo simulations using the bond fluctuation model on flexible knotted polymers, our analysis indicates that (ideal) varies nonlinearly with both C and the corresponding average crossing number of the flexible knot, which is contrary to previous claims. Our extensive simulation data on the average crossing number of flexible knots suggest that it varies linearly with the square root of C. Furthermore, our data on the average writhe number indicate that various knots are classified into holonomous groups, and has a quantized linear increment with C in all four knot groups in our study.

Bond strengths of orthodontic brackets to restorative resin composite surfaces.

In orthodontic practice, it is not uncommon to bond brackets to resin composite restorations. With this in mind, this study was designed to compare first the shear/peel strengths of metal, ceramic and polycarbonate brackets bonded to microfilled resin composite (RC), using either a light-cured resin-modified glass ionomer cement (Fuji Ortho LC), a chemical-cured composite (System 1+) or a light-cured composite adhesive (Transbond XT); and then to examine the effects of thermocycling on the shear/peel strengths of these systems. Four different brackets were used: two stainless steel (Victory and Optimesh), one ceramic (Transcend 6000) and one polycarbonate (Spirit MB). Seventy-two specimens of each bracket were divided into three groups for bonding with one of the three adhesives. Half the specimens from each group were also thermocycled. Mean shear/peel bond strengths were found to be significantly different for the four different brackets, although not influenced by the three adhesives used within each group. All groups were found to have clinically-acceptable mean bond strengths, except for Spirit MB-System 1+. After thermocycling, both Optimesh-Transbond XT and Victory-System 1+ groups showed superior mean bond strengths (26.8 and 24.4 MPa, respectively) when compared with all other groups (p < 0.05). Applying the Weibull survival analysis for groups utilising Victory, Transcend 6000 and Spirit MB brackets, those with 90 per cent or greater probabilities of survival included Victory-System 1+, Transcend 6000-Fuji Ortho LC, Victory-Fuji Ortho LC and Spirit MB-Transbond XT groups. In all groups, bond failure was mainly (64 per cent) cohesive within the RC restorative surface. The thermocycled Spirit MB-Transbond XT group had the highest frequency of undamaged RC failure interfaces. Despite the focus of this study being on bond strength and the potential for surface damage, it was noted that these properties should always be considered alongside other factors such as the strength of the bracket itself, friction within the bracket slot, patients' wishes, cost of the materials and the presenting malocclusion.

Prevalence and heterogeneity of Helicobacter pylori in gastric biopsies of patients with gastroduodenal diseases.

Helicobacter pylori is a risk factor for development of peptic ulcers and adenocarcinoma of distal stomach. There are several highly specialized virulence factors, such as the production of sialic acid-specific hemagglutinins, cytotoxins and enzymes. This study was designed to study the in vivo prevalence of H. pylori in patients with gastroduodenal diseases, the in vivo correlation between H. pylori infection and blood group O, and the heterogeneity of H. pylori isolates in central Taiwan. We enrolled 776 symptomatic patients residing in the central Taiwan area. The age-specific in vivo prevalence of H. pylori in patients with gastroduodenal diseases increased from 11.1% in those between the ages of 1 to 20, 73.1% in those between the ages of 21 and 30, and to 79.8% in those between the ages of 51 and 60. In conclusion, H. pylori was present in 70% of biopsied specimens of symptomatic patients with gastroduodenal diseases and had the highest incidence (86%) in patients with peptic ulcers. The prevalence of H. pylori cag A expression positive strains in central Taiwan was 92.5%. This study has also demonstrated the high correlation between H. pylori and the blood group O-positive patients with gastroduodenal diseases. The prevalence of H. pylori infection in blood O-positive patients in central Taiwan was 86.4%.

Enamel hypoplasia and dental caries in very-low birthweight children: a case-controlled, longitudinal study.

This longitudinal study investigated the sequelae of enamel defects in a group of 25 white, very-low birthweight (VLBW), preterm children (mean birthweight 969 +/- 218 g, mean gestational age 27 +/- 1.9 weeks). Twenty-five race-, age-, and sex-matched, full-term normal birthweight (NBW) control children born at the same hospital, were selected randomly from hospital records. The children were examined at approximate ages of 30, 44, and 52 months. At all examinations, VLBW children had significantly higher prevalence of enamel hypoplasia than did the NBW children. At the last recall examination, 96% of VLBW group, and 45% of the NBW group had at least one tooth with enamel defect, with a mean of 7.6 +/- 4.9 affected teeth per VLBW child, and only 1.0 +/- 1.3 affected teeth per control child (P < 0.001). A significant association of enamel defects with dental caries was observed only in the VLBW group on the second and third examinations (P < 0.001). The defect identified to be most significantly associated with dental caries was a variant showing both enamel hypoplasia and opacity. In spite of a high prevalence of enamel defects, the overall prevalence of dental caries in the VLBW children was not significantly different from that of NBW controls at all three examinations (P < 0.1). Other caries risk factors such as levels of Streptococcus mutans infection, fluoride supplementation, plaque scores, toothbrushing frequency, and daily sugar exposures were examined but none was found to be related significantly to development of dental caries.

Dental health of aboriginal pre-school children in Brisbane, Australia.

This investigation studied the dental health status of a group of 184 Australian Aboriginal children with a mean age of 4.4 +/- 0.8 years, who were attending pre-schools in metropolitan Brisbane, a non-fluoridated state capital city. The DDE (Developmental Defects of Enamel) Index was used to chart enamel hypoplasia and enamel opacities. WHO criteria was used to diagnose dental caries. The results showed that 98% of children had at least one tooth showing developmental enamel defects. Each child had a mean of 3.8 +/- 1.7 teeth affected by enamel hypoplasia and another 1.1 +/- 0.8 teeth affected by enamel opacity. Seventy-eight percent of the children had dental caries. The mean number of decayed, missing, filled teeth (dmft) per child was 3.8 +/- 3.7. The decayed component constituted 3.5 (95%) of the mean dmft, indicating a high unmet restorative need in this group. The mean dmfs (decayed, missing, filled, surfaces) was 5.9 +/- 7.3. Maxillary anterior labial decay of at least one tooth affected 43 (23%) of the children. In this sub-group, the dmft and dmfs was 9.1 +/- 2.8 and 15.4 +/- 7.7 respectively. Oral debris was found in 98% of the children. It is hypothesized that the high levels of underlying developmental enamel defects, compounded by low fluoride exposure, poor oral hygiene and a diet high in refined sugars pose an important caries risk factor in this group of children.

A survey of work undertaken in 1 year by a medical officer working in a maternal and child health clinic in Hong Kong: implications for training.

A survey of child health work undertaken in 1 year by a medical officer in a typical maternal and child health (MCH) clinic in Hong Kong is reported. The wide spectrum of physical and developmental problems encountered by the MCH doctor demands sound knowledge of basic paediatrics and normal human development. The need for a comprehensive training programme in child health is highlighted.

A controlled study of the association of various dental anomalies with hypodontia of permanent teeth.

Although hypodontia, or oligodontia, is one of the most common human dental anomalies observed, there have been few studies on the association of other anomalies occurring with it. The present investigation of 1032 patient records found that 65.7% of patients with hypodontia showed ankylosis of primary molars compared to only 1.5% of control children (P less than 0.001). In addition, taurodontism of the mandibular first permanent molar was observed in 34.3% of hypodontia cases compared to 7.1% in the controls (P less than 0.001). Other dental anomalies significantly associated with hypodontia include enamel hypoplasia (11.9%, P less than 0.01) and conical incisors (8.9%, P less than 0.01). In contrast, there were significantly more impacted teeth in control children compared to the hypodontia group. The results indicate that for patients with missing permanent teeth, clinicians should be alert to the possibility of these associated anomalies and their accompanying clinical implications.

Association of taurodontism with hypodontia: a controlled study.

Although taurodontism has been reported in many syndromes which also feature hypodontia, there have been no previous investigations on the prevalence of taurodontism in patients with hypodontia. Using a novel biometric method for the assessment of taurodontism, we found that 34.8% of 66 patients with hypodontia had at least one mandibular first permanent molar which showed taurodontism compared to only 7.5% of a control group without hypodontia. The trait may be seen both unilaterally and bilaterally and is most frequently seen in patients with multiple missing teeth. The results indicate that clinicians should be alerted to the possibility of taurodontism with its accompanying clinical difficulties in patients with hypodontia.

Diuretic actions in man of a selective kappa opioid agonist: U-62,066E.

The effect of a selective kappa opioid agonist, U-62,066E, on urine formation in human volunteers was assessed. Volunteers received single intramuscular injections of either placebo or 2, 3, 4, 5 or 6 micrograms/kg of U-62,066E in a randomized, double-blind study. U-62,066E caused dose-dependent maximal increases in urine volume of 2.6 times control in the first 4 hr after administration. A corresponding decrease in urine osmolality to 20% of base-line values occurred. No changes in total urinary Na, K or Cl excretion were identified. Kappa agonists produce a water-only diuresis at low doses in humans. The mechanism of this effect was not examined in this study but probably relates to alterations in antidiuretic hormone activity.