Sputtered Inx(O,S)y Buffer Layers for Cu(In,Ga)Se2 Thin-Film Solar Cells: Engineering of Band Alignment and Interface Properties

We propose a simple approach to engineering the sputtered In_x(O,S)_y/Cu(In,Ga)Se₂ heterojunction, in terms of band alignment and interface properties. The band alignment was tailored by tuning the base pressure of the sputtering deposition to incorporate oxygen into deposited In₂S₃ layers (termed as In_x(O,S)_y). The interface properties were improved by optimizing the air-annealing temperature on In_x(O,S)_y/Cu(In,Ga)Se₂ stacked layers. Increasing the base pressure raises the O/(S + O) ratio contained in deposited In_x(O,S)_y films and thus widens the band gaps. This could effectively tailor the conduction band offset (ΔE_C) at the In_x(O,S)_y/Cu(In,Ga)Se₂ interface from a cliff (-0.25 eV) to a nearly flat band (0.07 eV) alignment. On the other hand, the extra air annealing at 235 °C did not significantly change the band alignment but did ameliorate the interface properties by reducing the Cu content at the Cu(In,Ga)Se₂ surface and diminish the interface defect density induced by sputtering damages. The former might enhance the type of inversion and increase the hole barrier at the interface, preventing the detrimental recombination behavior. The latter could effectively strengthen the junction quality. Consequently, our approach substantially enhances the cell efficiency from 2.30% to 11.04%.

Surface functionalized electrospun fibrous poly(3-hydroxybutyrate) membranes and sleeves: a novel approach for fixation in anterior cruciate ligament reconstruction

Effective osteointegration for fixation of the tendon to bone junction is the most important issue in anterior cruciate ligament (ACL) reconstruction. In this study, functionalized electrospun poly(3-hydroxybutyrate) (PHB) membranes and sleeves were prepared and evaluated for the fixation of the tendon to bone junction. The electrospun fibrous PHB membranes were modified with hydrogen peroxide, dopamine (DA), chitosan (CS), glutaraldehyde (GA), and then immobilized with growth factors (GFs) from platelet rich plasma (PRP). The water-contact angle measurement showed enhanced wettability in the membranes after the sequential surface functionalization. Successful graftings of DA, CS and GFs from PRP on the membrane surface were demonstrated using X-ray photoelectron spectroscopy (XPS). The ninhydrin assay revealed the amount of immobilized TGF-β1 and PDFG-AB. The modified membranes showed good biocompatibility in an in vitro rabbit tenocyte cultivation study, as the cells showed good attachment and proliferation activity. Significant increases in extracellular matrix and gene expression of type I collagen were observed when the membrane surface was treated with the GFs from PRP. In a rabbit model, the tendon to bone junction was filled with newly formed fibrocartilage and osteointegration behavior was observed. This suggests that the use of functionalized PHB sleeves can enhance tendon to bone healing and the tendon sleeves might provide a novel method for ACL reconstruction.

Influence of patient and provider factors on the workload of on-call physicians: A general internal medicine cohort observational study

Factors associated with the physician workload are scarcely reported. The study aims to investigate the associated factors of on-call physician workload based on a published conceptual framework.The study was conducted in a general internal medicine unit of National Taiwan University Hospital. On-call physician workloads were recorded on a shift basis from 1198 hospitalized patients between May 2010 and April 2011. The proxy of on-call workloads included night calls, bedside evaluation/management (E/M), and performing clinical procedures in a shift. Multivariable logistic and negative binomial regression models were used to determine the factors associated with the workloads of on-call physicians.During the study period, 378 (31.6%) of patients had night calls with related workloads. Multivariate analysis showed that the number of patients with unstable conditions in a shift (odds ratio [OR] 1.89 and 1.66, respectively) and the intensive care unit (ICU) training of the nurse leader (OR 2.87 and 3.08, respectively) resulted in higher likelihood of night calls to and bedside E/M visits by the on-call physician. However, ICU training of nurses (OR = 0.37, 95% confidence interval: 0.16-0.86) decreased the demand of performing clinical procedures by the on-call physician. Moreover, number of patients with unstable conditions (risk ratio [RR] 1.52 and 1.55, respectively) had significantly increased the number of night calls and bedside E/M by on-call physicians by around 50%. Nurses with N1 level (RR 2.16 and 2.71, respectively) were more likely to place night calls and facilitate bedside E/M by the on-call physician compared to nurses with N0 level. In addition, the nurse leaders with ICU training (RR 1.72 and 3.07, respectively) had significant increases in night calls and bedside E/M by the on-call physician compared to those without ICU training.On-call physician workload is associated with patient factors and the training of nurses. Number of unstable patients in a shift may be considered in predicting workload. The training of nurses may improve patient safety and decrease demand for clinical procedure.

Perceptions and Practices of Mass Bat Exposure Events in the Setting of Rabies Among U.S. Public Health Agencies

Current guidelines in the setting of exposures to potentially rabid bats established by the Advisory Committee on Immunization Practices (ACIP) address post-exposure prophylaxis (PEP) administration in situations where a person may not be aware that a bite or direct contact has occurred and the bat is not available for diagnostic testing. These include instances when a bat is discovered in a room where a person awakens from sleep, is a child without an adult witness, has a mental disability or is intoxicated. The current ACIP guidelines, however, do not address PEP in the setting of multiple persons exposed to a bat or a bat colony, otherwise known as mass bat exposure (MBE) events. Due to a dearth of recommendations for response to these events, the reported reactions by public health agencies have varied widely. To address this perceived limitation, a survey of 45 state public health agencies was conducted to characterize prior experiences with MBE and practices to mitigate the public health risks. In general, most states (69% of the respondents) felt current ACIP guidelines were unclear in MBE scenarios. Thirty-three of the 45 states reported prior experience with MBE, receiving an average of 16.9 MBE calls per year and an investment of 106.7 person-hours annually on MBE investigations. PEP criteria, investigation methods and the experts recruited in MBE investigations varied between states. These dissimilarities could reflect differences in experience, scenario and resources. The lack of consistency in state responses to potential mass exposures to a highly fatal disease along with the large contingent of states dissatisfied with current ACIP guidance warrants the development of national guidelines in MBE settings.

Ghrelin level negatively predicts quality of life in obese women

A cross-sectional cohort study was conducted to investigate whether ghrelin level in obese women predicts the quality of life (QOL). A total of 307 subjects fulfilled the criteria: (1) age between 20 and 65 years old, (2) body mass index ≥27 kg/m² (3) waist circumference ≥80 cm were enrolled in the study. All subjects were assigned to one of the plasma ghrelin level categories according to the quartiles. The median of age and BMI of the 307 obese women were 45 ± 18 years and 29.9 ± 4.1 kg/m², respectively. The main outcome evaluated is the associations of plasma ghrelin level and QOL, which were evaluated using multiple linear regression analysis. Results of linear trend test show significant statistical difference in plasma lipoproteins (triglyceride, cholesterol, HDL-cholestero and LDL-cholesterol = and levels of obesity-related hormone peptides, including leptin, adiponectin, insulin among quartiles of ghrelin. Multiple liner regression analysis of serum obesity-related hormone peptide level and QOL using stepwise method shows ghrelin concentration was the only predictor of QOL, including PCS-12 level (β = -0.18, p = 0.001), MCS-12 level (β = -0.14, p = 0.009), WHOQOL-BREF scores: physical (β = -0.13, p = 0.03), psychological (β = -0.16, p = 0.007), social (β = -0.21, p =  < 0.001), and environmental (β = -0.22, p =  <0.001), after adjusting other factors for obese female subjects. This study demonstrated that ghrelin concentration is strongly associated with QOL level among obese women. Hence, ghrelin concentration might be a valuable marker to be monitored in obese women.

EFFECT OF SELENIUM SUPPLEMENTATION ON PROTEOMIC SERUM BIOMARKERS IN ELDERLY MEN

OBJECTIVES

To determine the effect of selenium supplementation on the human proteomic profile.

DESIGN

Serum samples were collected in this pilot study from a randomized placebo controlled Phase 2 clinical trial (Watchful Waiting (WW)).

SETTING

Subjects were followed every three months for up to five years at the University of Arizona Prostate Cancer Prevention Program.

PARTICIPANTS

One hundred and forty men (age < 85 years) had biopsy-proven prostate cancer, a Gleason sum score less than eight, no metastatic cancer, and no prior treatment for prostate cancer.

INTERVENTION

As part of the WW trial, men were randomized to placebo, selenium 200 μg/day or selenium 800 μg/day. For the purpose of the current study, 40 subjects enrolled in the WW study (20 from the placebo group and 20 from Se 800 μg/day group) were selected.

MEASUREMENTS

Baseline serum samples were collected at each follow-up visit and stored at -80 degrees Celsius. A multiplexed proteomic panel investigated changes in 120 proteins markers simultaneously.

RESULTS

Thirteen proteins (Apolipoprotein J, IL-10, IL-1 alpha, MMP-3, IL-12p70, IL-2 receptor alpha, cathepsin B, eotaxin, EGFR, FGF-basic, myeloperoxidase, RANTES, TGF-beta) were determined to be either statistically (p-value < 0.05) or marginally significantly (0.05 < p-value <0.1) changed in the selenium supplemented group as compared to placebo.

CONCLUSION

Although independent validation of these results is needed, this study is the first of its kind to utilize high throughput fluorescence based protein multiplex panel in analyzing changes in the proteomic profile due to selenium supplementation. Results from this study provide insight into the ability of selenium to modulate numerous protein markers and thus impact various biological processes in humans.

Does supplementation with green tea extract improve acne in post-adolescent women? A randomized, double-blind, and placebo-controlled clinical trial

BACKGROUND

Green tea is believed to have beneficial effects in the prevention and treatment of acne.

OBJECTIVE

To examine the effects of a decaffeinated green tea extract (GTE), providing a daily dose of 856 mg of epigallocatechin gallate (EGCG) upon women with post-adolescent acne.

METHODS

A randomized, double-blind, placebo-controlled clinical trial was conducted from May 2012 through October 2013. A final group of 80 subjects were randomly assigned to receive either 1500 mg of decaffeinated GTE or placebo (cellulose) daily for 4 weeks. Inflammatory lesion counts were used as the major outcome measurement. At baseline and after 4 weeks of treatment, anthropometric measurements, fasting glucose levels and a lipid profile were measured from both groups.

RESULTS

Sixty-four of 80 women, from 25 to 45 years of age with moderate-to-severe acne completed the study. Statistically significant differences were noted in inflammatory lesion counts distributed on the nose, periorally and on the chin between the two groups. However, there were no significant differences between groups for total lesion counts. Within-group comparison revealed that the GTE group had significant reductions in inflammatory lesions distributed on the forehead and cheek, and significant reductions in total lesion counts. GTE resulted in significant reductions in total cholesterol levels within the GTE group.

CONCLUSIONS

GTE resulted in significant reductions in lesions located on the nose, perioral area and chin. More research is required to determine whether a decaffeinated GTE standardized for EGCG content will provide clinical benefits in women with post-adolescent acne.

Room-Temperature Chemical Solution Treatment for Flexible ZnS(O,OH)/Cu(In,Ga)Se2 Solar Cell: Improvements in Interface Properties and Metastability

We demonstrate an effective room-temperature chemical solution treatment, by using thioacetamide (S treatment) or thioacetamide-InCl3 (In-S treatment) solution, on Cu(In,Ga)Se2 (CIGSe) surface to engineer the ZnS(O,OH)/CIGSe interface and junction quality, leading to enhanced efficiency and minimized metastability of flexible solar cells. The control device without treatment reveals a relatively low efficiency of 8.15%, which is significantly improved to 9.74% by In-S treatment, and 10.39% by S treatment. Results of X-ray photoelectron spectroscopy suggest that S is incorporated into CIGSe surface forming CIGSSe by S treatment, whereas a thin In-S layer is formed on CIGSe surface by In-S treatment with reduced amount of S diffusing into CIGSe. PL spectra and TRPL lifetime further reveal that S incorporation into CIGS surface may substitute the OSe and/or directly occupy the vacant anion site (VSe), resulting in the effective passivation of the recombination centers at CIGSe surface. Moreover, reducing the concentrations of VSe may thereby decrease the density of (VCu-VSe) acceptors, which can minimize the metastability of ZnS(O,OH)/CIGSe solar cells. With S treatment, the light soaking (LS) time of ZnS(O,OH)/CIGSe device is reduced approximately to one-half of control one. Our approach can be potentially applied for alternative Cd-free buffer layers to achieve high efficiency and low metastability.

Activated carbon derived from hydrothermal treatment of sucrose and its air filtration application

Design of an all biodegradable filter paper was achieved with activated carbon derived from sucrose. Full characterization of sucrose hydrochar and activated carbon are described.

A new mib allele with a chromosomal deletion covering foxc1a exhibits anterior somite specification defect

mibⁿⁿ²⁰⁰², found from an allele screen, showed early segmentation defect and severe cell death phenotypes, which are different from previously known mib mutants. Despite distinct morphological phenotypes, the typical mib molecular phenotypes: her4 down-regulation, neurogenic phenotype and cold sensitive dlc expression pattern, still remained. The linkage analysis also indicated that mibⁿⁿ²⁰⁰² is a new mib allele. Failure of specification in anterior 7-10 somites is likely due to lack of foxc1a expression in mibⁿⁿ²⁰⁰² homozygotes. Somites and somite markers gradually appeared after 7-10 somite stage, suggesting that foxc1a is only essential for the formation of anterior 7-10 somites. Apoptosis began around 16-somite stage with p53 up-regulation. To find the possible links of mib, foxc1a and apoptosis, transcriptome analysis was employed. About 140 genes, including wnt3a, foxc1a and mib, were not detected in the homozygotes. Overexpression of foxc1a mRNA in mibⁿⁿ²⁰⁰² homozygotes partially rescued the anterior somite specification. In the process of characterizing mibⁿⁿ²⁰⁰² mutation, we integrated the scaffolds containing mib locus into chromosome 2 (or linkage group 2, LG2) based on synteny comparison and transcriptome results. Genomic PCR analysis further supported the conclusion and showed that mibⁿⁿ²⁰⁰² has a chromosomal deletion with the size of about 9.6 Mbp.

Influenza A plasma and serum virus antibody detection comparison in dogs using blocking enzyme-linked immunosorbent assay

Background and Aim:

The influenza A virus (IAV) is an important zoonotic pathogen with infections also reported in dogs. IAV infections can be detected through the presence of antibodies using the enzyme-linked immunosorbent assay (ELISA). Serum is the only standard sample source; however, there is no information on the availability of other sample sources for IAV antibody detection in dogs. Compared with serum, plasma is more widely employed in most animal hospitals. The object of this study is to investigate whether plasma collected in ethylenediaminetetraacetic acid (EDTA) tubes (EDTA plasma) or heparin tubes (heparin plasma) could be used in the ELISA protocol instead of serum for IAV antibody detection in dogs.

Materials and Methods:

Totally, 82 matched EDTA plasma and serum sample pairs and 79 matched heparin plasma and serum sample pairs were employed using blocking enzyme-linked immunosorbent assay (bELISA). The agreement and correlation between the plasma (EDTA or heparin plasma) and serum were assessed using the agreement index kappa (kD) calculation and Pearson correlation coefficient, respectively.

Results:

The agreement index kD of EDTA plasma and serum was 1.0, and that of heparin plasma and serum was 0.85. The Pearson correlation coefficient of EDTA plasma and serum was 0.87 (p<0.01), and that of heparin plasma and serum was 0.82 (p<0.01).

Conclusion:

The results proved that plasma, especially EDTA plasma, could be substituted for serum in the bELISA test. This might greatly expand the clinical applicability of IAV antibody detection in dogs.

"V-Plasty" technique using dual synthetic vascular grafts to reconstruct outflow channel in living donor liver transplantation

BACKGROUND

The reconstruction of outflow is a crucial step in living donor liver transplantation. This study describes a suitable technique that uses synthetic vascular conduits in presence of multiple draining veins of right lobe of liver and the outcome of the recipients to evaluate safety of using multiple synthetic grafts.

METHODS

From March 2011 to September 2014, 325 patients underwent right lobe living donor liver transplantation. Expanded polytetra-fluoroethylene (ePTFE) grafts were used in total 155 of the liver allografts. Among these, 16 liver grafts required dual ePTFE grafts to reconstruct the outflow due to presence of multiple hepatic veins.

RESULTS

The mean diameters for venous branches of segment 5 (V5) and 8 (V8) were 5 mm (range, 4-8 mm) and 7 mm (range, 5-9 mm). The mean diameter of inferior right hepatic veins was 8 mm (7-10 mm). All the recipients who received the right liver with dual ePTFE grafts showed satisfactory inflow and outflow immediately after reconstruction as measured by Doppler flowmetry. Postoperative ultrasonographic studies showed no disturbances in outflow. Protocol dynamic computed tomography performed in the second postoperative month showed 100% patency rates of the artificial grafts. At median follow-up of 24 months graft survival was achieved in 88%, whereas the patency rates of the ePTFE grafts were 100%.

CONCLUSION

The use of "V-Plasty" technique using dual artificial vascular grafts is a safe and feasible technique in the presence of various allograft venous anomalies & ensures a single venous channel for outflow reconstruction. Our study also suggests that ePTFE graft may be a useful interposition material without serious complications.

Successful use of hepatitis B surface antigen-positive liver grafts - an effective source for donor organs in endemic areas: a single-center experience

BACKGROUND

Due to high prevalence of hepatitis B virus (HBV) infection in Taiwan, liver grafts from donors positive for hepatitis B surface antigen (HBsAg) without progressive disease can be effective alternative source of donor organs. This study aims to prove the safety of living donor liver transplantation (LDLT) using HBsAg-positive liver grafts and its long-term outcome.

MATERIAL AND METHODS

We studied 14 consecutive LDLT recipients that received HBsAg-positive grafts from November 2009 to December 2013 for various indications. All donors were chronic HBsAg carriers with normal liver function tests. Median follow-up was 46 months (range, 35-59).

RESULTS

All the donors and recipients recovered well post-transplant with no reactivation of HBV to date. Two of the recipients died due to extra-hepatic recurrence of HCC. At median follow-up of 46 months, 4-year cumulative survival of recipients was 77.38%.

CONCLUSIONS

In endemic areas, HBsAg-positive donor organs can clearly be used effectively under viral immunoprophylaxis. HBV disease reactivation does not appear to be a threat even with hepatitis B immunoglobulin (HBIG)-free antiviral monoprophylaxis regimen. This study thus proves the safety and feasibility of the option of using HBsAg-positive grafts in high-prevalence areas.

Control of metamorphic buffer structure and device performance of In(x)Ga(1-x)As epitaxial layers fabricated by metal organic chemical vapor deposition

Using a step-graded (SG) buffer structure via metal-organic chemical vapor deposition, we demonstrate a high suitability of In0.5Ga0.5As epitaxial layers on a GaAs substrate for electronic device application. Taking advantage of the technique's precise control, we were able to increase the number of SG layers to achieve a fairly low dislocation density (∼10(6) cm(-2)), while keeping each individual SG layer slightly exceeding the critical thickness (∼80 nm) for strain relaxation. This met the demanded but contradictory requirements, and even offered excellent scalability by lowering the whole buffer structure down to 2.3 μm. This scalability overwhelmingly excels the forefront studies. The effects of the SG misfit strain on the crystal quality and surface morphology of In0.5Ga0.5As epitaxial layers were carefully investigated, and were correlated to threading dislocation (TD) blocking mechanisms. From microstructural analyses, TDs can be blocked effectively through self-annihilation reactions, or hindered randomly by misfit dislocation mechanisms. Growth conditions for avoiding phase separation were also explored and identified. The buffer-improved, high-quality In0.5Ga0.5As epitaxial layers enabled a high-performance, metal-oxide-semiconductor capacitor on a GaAs substrate. The devices displayed remarkable capacitance-voltage responses with small frequency dispersion. A promising interface trap density of 3 × 10(12) eV(-1) cm(-2) in a conductance test was also obtained. These electrical performances are competitive to those using lattice-coherent but pricey InGaAs/InP systems.

Body mass index is negatively associated with acne lesion counts in Taiwanese women with post-adolescent acne

BACKGROUND

Acne in adult women tends to be chronic, refractory to treatment and associated with psychosocial problems. Body mass index (BMI) has been reported to be a risk factor for acne in school children and adolescents, but not in adult women.

OBJECTIVES

The aim of this study was to demonstrate the relationship between BMI and acne lesion counts in women with post-adolescent acne.

METHODS

Hundred and four women between 25 and 45 years of age, with moderate or severe acne vulgaris were enrolled in this study. The main outcome evaluated was the number of acne lesions, which were then assessed using multiple linear regression analysis.

RESULTS

The coefficients of multiple regression analysis with stepwise model showed that BMI (β = -0.36; p = 0.001) and family history (β = 0.21; p = 0.04) were the main predictors of the number of acne lesions.

CONCLUSION

Initial findings indicate that BMI is negatively associated with the number of acne lesions in Taiwanese women with moderate to severe post-adolescent acne.

New classes of mind bomb-interacting proteins identified from yeast two-hybrid screens

Notch signaling pathway defines an evolutionarily conserved mechanism in cell-fate determination in a broad spectrum of developmental processes through local cell interactions. mind bomb (mib) encodes an E3 ubiquitin ligase that is involved in Notch activation through Delta ubiquitylation and internalization. To further dissect the function of Mib, two yeast two-hybrid screens for zebrafish Mib/Mib2-binding proteins with different strategies have been performed. 81 putative interesting proteins were discovered and classified into six groups: ubiquitin proteasome pathway, cytoskeleton, trafficking, replication/transcription/translation factors, cell signaling and others. Confirmed by coimmunoprecipitation (Co-IP), Mib interacted with four tested proteins: ubiquitin specific protease 1 (Usp1), ubiquitin specific protease 9 (Usp9), tumor-necrosis-factor-receptor-associated factor (TRAF)-binding domain (Trabid)/zinc finger, RAN-binding domain containing 1 (Zranb1) and hypoxia-inducible factor 1, alpha subunit inhibitor (Hif1an)/factor inhibiting HIF 1 (Fih-1). Usp1, Usp9, Trabid and Fih-1 also bound to zebrafish Mib2, a Mib homolog with similar structural domains and functions. Both Mib and Mib2 can ubiquitylate Trabid and Fih-1, indicating a potential regulating role of Mib and Mib2 on Trabid and Fih-1 and, furthermore, the possible involvement of Notch signaling in hypoxia-regulated differentiation, tumorigenesis and NF-κB pathway. Finally, functions of confirmed Mib/Mib2-interacting proteins are collated, summarized and hypothesized, which depicts a regulating network beyond Notch signaling.

Differences in characteristics of men with localised prostate cancer who demonstrate low, intermediate or high prostate-specific antigen velocity

BACKGROUND

Current diagnostic tools are inadequate for reliable prediction of prostate cancer (PCa) aggressiveness in patients with localised disease. This results in many patients being exposed to potentially unnecessary invasive treatment and its associated morbidities. In order to develop appropriate treatment strategies, it is essential to understand the differences between patients who will develop aggressive disease and those who will not.

METHODS

A longitudinal study was conducted in men with localised PCa on active surveillance for their disease in which 140 subjects were followed every 3 months for up to 5 years. Change in prostate-specific antigen (PSA) over time (PSA velocity) was used as a marker for PCa progression. Subjects were categorised as slow, intermediate and fast progressors based on tertiles of PSA velocity. Differences in baseline markers were investigated using logistic regressions. Two approaches were used, slow progressors were compared with fast progressors (model 1) and slow progressors were compared with combination of intermediate and fast progressors (model 2).

RESULTS

Aspirin was negatively associated with high PSA velocity in model 1 (odds ratio (95% confidence interval): 0.24 (0.06, 0.94), P-value = 0.04) and model 2 (odds ratio = 0.22 (0.08, 0.59), P-value = 0.003), whereas smoking was positively associated with high PSA velocity in model 1 (1.03 (0.92, 1.13), P-value = 0.01).

CONCLUSIONS

These findings highlight the role of aspirin and smoking in PCa progression. They have potential towards risk stratification as well as PCa prevention and hence need to be investigated further.

A protein concentration measurement system using a flexural plate-wave frequency-shift readout technique

A protein concentration measurement system with two-port flexural plate-wave (FPW) biosensors using a frequency-shift readout technique is presented in this paper. The proposed frequency-shift readout method employs a peak detecting scheme to measure the amount of resonant frequency shift. The proposed system is composed of a linear frequency generator, a pair of peak detectors, two registers, and a subtractor. The frequency sweep range of the linear frequency generator is limited to 2 MHz to 10 MHz according to the characteristics of the FPW biosensors. The proposed frequency-shift readout circuit is carried out on silicon using a standard 0.18 μm CMOS technology. The sensitivity of the peak detectors is measured to be 10 mV. The power consumption of the proposed protein concentration measurement system is 48 mW given a 0.1 MHz system clock.

Novel genes that mediate nuclear respiratory factor 1-regualted neurite outgrowth in neuroblastoma IMR-32 cells

Nuclear respiratory factor-1 (NRF-1) is a transcription factor that functions in neurite outgrowth; however, the genes downstream from NRF-1 that mediate this function remain largely unknown. This study employs a genome-wide analysis approach to identify NRF-1-targeted genes in human neuroblastoma IMR-32 cells. A total of 916 human genes containing the putative NRF-1 response element (NRE) in their promoter regions were identified using a cutoff score determined by results from electrophoretic mobility shift assays (EMSA). Seventy-four NRF-1 target genes were listed according to the typical locations and high conservation of NREs. Fifteen genes, MAPRE3, NPDC1, RAB3IP, TRAPPC3, SMAD5, PIP5K1A, USP10, SPRY4, GTF2F2, NR1D1, SUV39H2, SKA3, RHOA, RAPGEF6, and SMAP1 were selected for biological confirmation. EMSA and chromatin immunoprecipitation confirmed that all NREs of these fifteen genes are critical for NRF-1 binding. Quantitative RT-PCR demonstrated that mRNA levels of 12 of these genes are regulated by NRF-1. Overexpression or knockdown of candidate genes demonstrated that MAPRE3, NPDC1, SMAD5, USP10, SPRY4, GTF2F2, SKA3, SMAP1 positively regulated, and RHOA and RAPGEF6 negatively regulated neurite outgrowth. Overall, our data showed that the combination of genome-wide bioinformatic analysis and biological experiments helps to identify the novel NRF-1-regulated genes, which play roles in differentiation of neuroblastoma cells.