bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature dependence of the photoluminescence emission from InxGa1−xAs quantum wells on GaAs(311) substrates
Authors: Rojas-Ramírez J. S. , Goldhahn R. , Moser P. , Huerta-Ruelas J. , Hernández-Rosas J. , López-López M.
Published: December 2008

We studied the photoluminescence (PL) properties of In0.2Ga0.8As/GaAs quantum well structures grown by molecular beam epitaxy on (311)-oriented substrates. The structure consists of three quantum wells (QWs) of 100, 50, and 25 Å nominal thickness. The temperature dependence of the PL emission from the QWs in the range of 5–250 K is reported. Three models by Varshni, Viña, and Pässler, respectively, were employed to analyze the variation in the excitonic energy transitions as a function of temperature. We compared the excitonic behavior with the band gap temperature dependence of bulk In0.2Ga0.8As and found a difference, as opposed to the unstrained AlGaAs/GaAs system. We attributed this difference to the modification of the QW energy levels by the quantum confinement Stark effect, which is temperature and well width dependent.
Biexcitonic cavity quantum electrodynamics effect on nonlinear spectra of a quantum dot
Authors: Ajiki Hiroshi , Ishihara Hajime
Published: December 2008

We theoretically study cross-polarized pump-probe spectra of a quantum dot (QD) embedded in a microcavity in the cavity quantum electrodynamics treatment. Recently, observations of a vacuum Rabi splitting for a QD in microcavity have been reported. The vacuum Rabi splitting is the level separation of one-excitation dressed states (1e states). However, two-excitation dressed states (2e states) have not been observed in this system. We discuss the possibility to observe pump-probe signal coming from the cross-polarized 2e states, in which the energy levels of a QD are modeled by a four-level system consisting of the ground state, right- and left-polarized excitons, and a biexciton. The signal peaks due to the cross-polarized 2e states are found when the quality factor of the cavity is extremely large. The spectral intensity is dramatically enhanced due to the cavity effect. The enhancement rate is independent of the coupling constants between the exciton (biexciton) and a cavity photon when a well-defined vacuum Rabi splitting is formed. However, a strong suppression of the signal occurs at a condition where the energy of the 1e state coincides with the energy difference between 1e and cross-polarized 2e states.
Biomimetic optical directional microphone with structurally coupled diaphragms
Authors: Liu H. J. , Yu M. , Zhang X. M.
Published: December 2008

A biomimetic directional microphone based on structurally coupled diaphragms and a fiber-optic detection system is presented. The microphone design aims to mimic the fly Ormia Ochracea’s ear structure and capture its performance. Experiments show that the designed microphone amplifies the interaural time difference (ITD) by 4.4 times and has a directional sensitivity of 6.5 μs/deg. An important finding is that one needs to utilize both the rocking and translational vibration modes to obtain the appropriate ITD amplification without sacrifice of directional sensitivity. This work can serve as a foundation for realizing fly-ear inspired miniature directional microphones.
Ohmic contact probed by dark injection space-charge-limited current measurements
Authors: Koo Young-Mo , Choi Sung-Jin , Chu Ta-Ya , Song Ok-Keun , Shin Won-Ju , Lee Je-Yun , Kim Jae Chang , Yoon Tae-Hoon
Published: December 2008

The authors demonstrate through dark injection space-charge-limited current (DI-SCLC) and trap-free SCLC measurements that an indium tin oxide (ITO)/buckminsterfullerene (C60) electrode can form a quasi-Ohmic contact with N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl) benzidine (NPB). The DI-SCLC results show a clear peak current along with a shift of the peak position as the field intensity varies, implying an Ohmic (or quasi-Ohmic) contact. A theoretical simulation of the SCLC also shows that ITO/C60 forms an Ohmic contact with NPB when the electric field intensity is higher than 30 kV/cm. The Ohmic contact makes it possible to estimate the NPB hole mobility through the use of both DI-SCLC and trap-free SCLC analysis.
Near UV-near IR Fourier transform spectrometer using the beam-folding position-tracking method based on retroreflectors
Authors: Wang Xuzhu , Chan Robert K. Y. , Cheng Amelia S. K.
Published: December 2008

A near UV-near IR Fourier transform spectrometer based on a beam-folding position-tracking method realized by using retroreflectors is reported. The use of retroreflectors maintains all beams in the beam-fold arrangement in parallel with the incident beams. The beam-folding interferometer used for position tracking is arranged to have optical path symmetry with the measurement interferometer in the zero path difference position of the measurement interferometer, and the vertex of the movable retroreflector in the measurement interferometer is arranged very close to the midpoint of the vertices of two movable retroreflectors in the position-tracking interferometer. These measures keep the equivalent optical axis of the position-tracking interferometer well in line with that of the measurement interferometer even with translational misalignments. Therefore, the change in the optical path difference of the position-tracking interferometer is always synchronous to that of the measurement interferometer during the scanning process. That is, the position-tracking error can be suppressed to very small values during a scan. We have demonstrated a UV-near IR Fourier transform spectrometer with a standard quality ball-bearing translation stage achieving a resolution close to the theoretical resolution of ∼0.28 cm−1 at the He–Ne laser wavelength when the scan distance reaches the travel distance of over 2 cm. This was achieved without the need for elaborate optics, sophisticated detecting electronics, and high-precision servomotion control.
Temperature dependence of enhanced hole mobility in uniaxial strained p-channel metal-oxide-semiconductor field-effect transistors and insight into the physical mechanisms
Authors: Yang Xiaodong , Parthasarathy Srivatsan , Sun Yongke , Koehler Andrew , Nishida Toshikazu , Thompson Scott E.
Published: December 2008

Uniaxial stress enhanced hole mobility is measured for (100)/⟨110⟩ silicon (Si) p-channel metal-oxide-semiconductor field-effect transistor from 300 to 87 K. For the technologically important longitudinal compressive stress along ⟨110⟩, the percent change in the uniaxial stress enhanced hole mobility is observed to increase at lower temperatures, which is opposite to the trend for biaxially stressed devices. The stress enhanced mobility is compared with six band k⋅p with finite difference formalism, which shows that the larger mobility gain at lower temperatures results from greater uniaxial stress induced hole conductivity mass reduction. The larger mass reduction results from more holes occupying states at the band edge, which have a light hole conductivity mass in the channel direction. For the uniaxial stress range in this work (<500 MPa), negligible strain altered phonon and surface roughness scattering rates are observed.
Depth-resolved band gap in Cu(In,Ga)(S,Se)2 thin films
Authors: Bär M. , Nishiwaki S. , Weinhardt L. , Pookpanratana S. , Fuchs O. , Blum M. , Yang W. , Denlinger J. D. , Shafarman W. N. , Heske C.
Published: December 2008

The surface composition of Cu(In,Ga)(S,Se)2 (“CIGSSe”) thin films intrinsically deviates from the corresponding bulk composition, which also modifies the electronic structure and thus the optical properties. We used a combination of photon and electron spectroscopies with different information depths to gain depth-resolved information on the band gap energy (Eg) in CIG(S)Se thin films. We find an increasing Eg with decreasing information depth, indicating the formation of a surface region with significantly higher Eg. This Eg-widened surface region extends further into the bulk of the sulfur-free CIGSe thin film compared to the CIGSSe thin film.
Resistivity and thermopower measurement setups in the temperature range of 5–325 K
Authors: Soni Ajay , Okram G. S.
Published: December 2008

Automated precision measurement setups for electrical resistivity of eight metallic samples simultaneously and thermoelectric power of different types of samples in the temperature range of 5–325 K have been developed. The details of the setups and their capabilities have been described. Usually each run takes nearly 5 h and typical error is within 3% and 4%, respectively. The results of high purity Nb and Pt samples are used as examples to demonstrate this.
In
Ga
N
∕
Ga
N
multiple quantum wells grown on microfacets for white-light generation
Authors: Cho Chu-Young , Park Il-Kyu , Kwon Min-Ki , Kim Ja-Yeon , Park Seong-Ju , Jung Dong-Ryul , Kwon Kwang-Woo
Published: December 2008

We report the white color electroluminescence (EL) emission from InGaN∕GaN multiple quantum wells (MQWs) grown on GaN microfacets. The white color was realized by combining EL emission from InGaN∕GaN MQWs on c-plane (0001), semipolar {11−22}, and {1−101} microfacets of trapezoidal n-GaN arrays. The color of EL emission was changed from reddish to bluish color with injection current and showed a white color in the current range of 180–230mA. The variation in the color of EL emission was attributed to differences in current injection and quantum efficiency of MQWs grown on c-plane (0001) and semipolar GaN microfacets.
Transformation from an atomically stepped NiO thin film to a nanotape structure: A kinetic study using x-ray diffraction
Authors: Sakata Osami , Soon Jia Mei , Matsuda Akifumi , Akita Yasuyuki , Yoshimoto Mamoru
Published: December 2008

Transformation from an atomically stepped epitaxial thin film of NiO to a self-assemble nanotape structure at the step edge was observed in situ using synchrotron x-ray diffraction. The pristine NiO thin film was epitaxially grown on an ultrasmooth sapphire (0001) substrate with a regular step of 0.2nm in height using laser molecular beam epitaxy. Transformation from the thin film to the nanotape structure was facilitated by postannealing in air from room temperature to 620K. From the Arrhenius plot of ln(in-plane domain sizes) versus 1∕T, an atomic-scale transformation energy of ∼0.0135eV/atom was derived.
Evidence of dangling bond electrical activity at the Ge/oxide interface
Authors: Baldovino Silvia , Molle Alessandro , Fanciulli Marco
Published: December 2008

The nature of the defects present at the Ge/oxide interface has been investigated by electrically detected magnetic resonance spectroscopy. In vacuo atomic oxygen exposure has been exploited to generate germanium oxide with variable composition according to the oxidation temperature. Two different kinds of interfacial defects have been identified, which correspond to the Ge dangling bonds and to an oxygen-related defect.
Interpreting the change in shear band inclination angle in metallic glasses
Authors: Zhao Ming , Li Mo
Published: December 2008

Shear bands in metallic glasses subject to uniaxial loading such as tension and compression exhibit the inclination angle different from 45° on the maximum resolved shear stress plane with respect to the loading axis. The cause is often attributed to the effective normal stress acting on the shear plane, which also suggests Coulomb–Mohr yield criterion for metallic glasses. We show here that this argument is conceptually ill justified. Instead, shear band inclination angle can be described by a simple model taking into consideration the volume dilatation and the pressure effects.
SOCl
2
enhanced photovoltaic conversion of single wall carbon nanotube/n-silicon heterojunctions
Authors: Li Zhongrui , Kunets Vasyl P. , Saini Viney , Xu Yang , Dervishi Enkeleda , Salamo Gregory J. , Biris Alexandru R. , Biris Alexandru S.
Published: December 2008

We report solar cells based on high-density p-n heterojunctions between single wall carbon nanotubes (SWCNTs) and a n-type silicon wafer. Chemical modification by thionyl chloride of the SWCNT coating films was found to significantly increase the conversion efficiency by more than 45% through adjusting the Fermi level and increasing the carrier concentration and mobility. Electron-hole pairs are optically excited in the numerous heterojunctions formed between SOCl2-treated SWCNTs thin coating and n-type silicon substrate, and then split and transported through SWCNTs (holes) and n-Si (electrons), respectively.
Formation of X-waves at fundamental and harmonics by infrared femtosecond pulse filamentation in air
Authors: Xu Han , Xiong Hui , Fu Yuxi , Yao Jinping , Zhou Zenghui , Cheng Ya , Xu Zhizhan , Chin See Leang
Published: December 2008

We experimentally observe the formation of X-waves at fundamental, third harmonic, and fifth harmonic wavelengths by infrared (central wavelength at ∼1500 nm) femtosecond laser pulse filamentation in air. By fitting the angularly resolved spectra of the fundamental and harmonic waves using X-wave relations, we confirm that all the X-waves have nearly the same group velocity, indicating that they are locked in space and time during their propagation in filament.
A selective nanosensing probe for nitric oxide
Authors: Gouma P. I. , Kalyanasundaram K.
Published: December 2008

Measurement of NO gas in exhaled human breath may be used to monitor oxidative stress and pulmonary diseases. Until now, only bulk, expensive, chemiluminescence-based NO monitors have been available to medicine. A nanosensing probe based on WO3 selectively detecting minute nitric oxide gas concentrations in the presence of interfering volatile compounds is presented. This is possible due to the chemical affinity of rhenium trioxide based phases to oxidizing gases. The NO nanoprobe is expected to lead to portable and affordable, noninvasive, single breath sampling, NO diagnostics.
Interface roughness in short-period InGaAs∕InP superlattices
Authors: Pusep Yu. A. , Gozzo G. C. , LaPierre R. R.
Published: December 2008

Electron mobility was studied in lattice-matched short-period InGaAs∕InP superlattices as a function of the width of the wells. The decreasing mobility with decreasing well width was shown to occur due to the interface roughness. The roughnesses of InGaAs∕InP and GaAs∕AlGaAs interfaces were compared. Much smoother InGaAs∕InP interfaces resulted in higher electron mobility limited by interface roughness.
Stable nitride complex and molecular nitrogen in N doped amorphous Ge2Sb2Te5
Authors: Sun Zhimei , Zhou Jian , Shin Hyun-Joon , Blomqvist Andreas , Ahuja Rajeev
Published: December 2008

Nitrogen doping is identified to be a sufficient way to reduce the power consumption of Ge2Sb2Te5, a phase-change material for data storage. On the basis of ab initio molecular dynamics simulations, we show that the doped N in amorphous Ge2Sb2Te5 coexist as Ge(Sb, Te)N complex and N2, and high density of the film produces more N2. Furthermore, both Ge(Sb, Te)N complex and N2 are stable upon annealing at 600 K.
Tolerance of two perennial grasses to toxic levels of Ni2+
Authors: Kopittke Peter. M. , Asher Colin. J. , Blamey F. Pax. C. , Menzies Neal. W.
Published: December 2008

Environmental context. Nickel (Ni) may be present in soil at phytotoxic levels as a result of weathering of ultramafic (serpentine) minerals or activities such as mining and metal ore processing. We assessed the tolerance of two grasses to excess Ni and used electron microscopy to examine the distribution of the Ni within the root tissue. This study provides information on the influence of excess Ni on the growth of these two grasses with consideration to their suitability for the revegetation of areas contaminated with Ni.
Abstract. Toxic effects of Nickel (Ni) in solution were evaluated in signal grass and Rhodes grass, two species commonly used for the revegetation of contaminated sites in the tropics and sub-tropics. Both grasses had a similar response to Ni, a Ni2+ activity ({Ni2+}) of 14 × 10–6 M, which reduced the fresh mass by 50%. The sub-cellular distribution of Ni in the roots was similar for both species, with Ni accumulating primarily as particles <5 nm in the vacuoles of rhizodermal and outer cortical cells. The reduction in growth at elevated {Ni2+} caused a loss of apical dominance in the roots and a Ni-induced Fe deficiency in the shoots. Root hair growth was not reduced by Ni2+ toxicity and was prolific even at the highest {Ni2+} (35 × 10–6 M). The translocation of Ni to the plant tops of both grasses resulted in concentrations that exceeded the guidelines for Ni toxicity to grazing animals (100 μg g–1) when grown with ≥11 × 10–6 M {Ni2+} in solution.
Visualization of IFNβ production by plasmacytoid versus conventional dendritic cells under specific stimulation conditions in vivo
Authors: Scheu Stefanie , Dresing Philipp , Locksley Richard M.
Published: December 2008

Type I interferons, a protein family of multiple IFNαs and a single IFNβ, initially identified on the basis of their antiviral activities have recently been attributed important roles in bacterial and parasitic infections. To assess the cellular sources of IFNβ, the IFN produced first in most situations, we created an IFNβ reporter-knockin mouse, in which yellow fluorescent protein (YFP) is expressed from a bicistronic mRNA linked by an internal ribosomal entry site to the endogenous IFNβ mRNA. This YFP expression allows spatiotemporal tracking of the initiation of the type I IFN response on a single-cell level. In vitro bone marrow-derived macrophages (BMMΦs) and bone marrow-derived dendritic cells (BMDCs) show IFNβ production from distinct cell subpopulations in response to defined pathogen compounds. A subpopulation of GMCSF-derived BMDCs produced IFNβ after poly(I:C), 3′5′-cytidylylguanosine (CpG), or LPS treatment, whereas Flt3-L-cultured plasmacytoid DCs (pDCs) responded mainly to CpG. After poly(I:C) injection in vivo, IFNβ-producing cells localize to the splenic marginal zone and the lymph node subcapsular sinus. Infection with murine cytomegalovirus (MCMV) induces IFNβ/YFP expression exclusively in few activated pDCs at the T cell/B cell interface of the splenic white pulp. This IFNβ/YFP reporter mouse represents a reliable tool for the visualization and characterization of IFNβ-producing cells in vitro and in vivo.
Oncogenic kinase NPM/ALK induces through STAT3 expression of immunosuppressive protein CD274 (PD-L1, B7-H1)
Authors: Marzec Michal , Zhang Qian , Goradia Ami , Raghunath Puthiyaveettil N. , Liu Xiaobin , Paessler Michele , Wang Hong Yi , Wysocka Maria , Cheng Mangeng , Ruggeri Bruce A. , Wasik Mariusz A.
Published: December 2008

The mechanisms of malignant cell transformation caused by the oncogenic, chimeric nucleophosmin (NPM)/anaplastic lymphoma kinase (ALK) remain only partially understood, with most of the previous studies focusing mainly on the impact of NPM/ALK on cell survival and proliferation. Here we report that the NPM/ALK-carrying T cell lymphoma (ALK+TCL) cells strongly express the immunosuppressive cell-surface protein CD274 (PD-L1, B7-H1), as determined on the mRNA and protein level. The CD274 expression is strictly dependent on the expression and enzymatic activity of NPM/ALK, as demonstrated by inhibition of the NPM/ALK function in ALK+TCL cells by the small molecule ALK inhibitor CEP-14083 and by documenting CD274 expression in IL-3-depleted BaF3 cells transfected with the wild-type NPM/ALK, but not the kinase-inactive NPM/ALK K210R mutant or empty vector alone. NPM/ALK induces CD274 expression by activating its key signal transmitter, transcription factor STAT3. STAT3 binds to the CD274
gene
promoter
in vitro
and
in vivo
, as shown in the gel electromobility shift and chromatin immunoprecipitation assays, and is required for the PD-L1 gene expression, as demonstrated by siRNA-mediated STAT3 depletion. These findings identify an additional cell-transforming property of NPM/ALK and describe a direct link between an oncoprotein and an immunosuppressive cell-surface protein. These results also provide an additional rationale to therapeutically target NPM/ALK and STAT3 in ALK+TCL. Finally, they suggest that future immunotherapeutic protocols for this type of lymphoma may need to include the inhibition of NPM/ALK and STAT3 to achieve optimal clinical efficacy.
Trop2 identifies a subpopulation of murine and human prostate basal cells with stem cell characteristics
Authors: Goldstein Andrew S. , Lawson Devon A. , Cheng Donghui , Sun Wenyi , Garraway Isla P. , Witte Owen N.
Published: December 2008

The epithelium of the adult prostate contains 3 distinct cell types: basal, luminal, and neuroendocrine. Tissue-regenerative activity has been identified predominantly from the basal cells, isolated by expression of CD49f and stem cell antigen-1 (Sca-1). An important question for the field is whether all basal cells have stem cell characteristics. Prostate-specific microarray databases were interrogated to find candidate surface antigens that could subfractionate the basal cell population. Tumor-associated calcium signal transducer 2 (TACSTD2/Trop2/M1S1/GA733-1) was identified because it was enriched after castration, in prostate sphere cells and in the basal fraction. In the murine prostate, Trop2 shows progenitor characteristics such as localization to the region of the gland proximal to the urethra and enrichment for sphere-forming and colony-forming cells. Trop2 subfractionates the basal cells into 2 populations, both of which express characteristic basal cell markers by quantitative PCR. However, only the basal cells expressing high levels of Trop2 were able to efficiently form spheres in vitro. In the human prostate, where Sca-1 is not expressed, sphere-forming progenitor cells were also isolated based on high expression of Trop2 and CD49f. Trop2-expressing murine basal cells could regenerate prostatic tubules in vivo, whereas the remaining basal cells had minimal activity. Evidence was found for basal, luminal, and neuroendocrine cells in prostatic tubules regenerated from Trop2
hi
basal cells. In summary, functionally distinct populations of cells exist within the prostate basal compartment and an epithelial progenitor can give rise to neuroendocrine cells in vivo.
The efficacy of conservative management after conization in patients with stage IA1 microinvasive cervical carcinoma
Authors: LEE SHIN WHA , KIM YONG‐MAN , SON WOO‐SEOK , YOU HANG‐JO , KIM DAE‐YEON , KIM JONG‐HYEOK , KIM YOUNG‐TAK , NAM JOO‐HYUN
Published: December 2008

Objective. To investigate the efficacy of conization followed by conservative management for treating stage IA1 microinvasive carcinoma of the uterine cervix. Design/Setting. Retrospective study. Population. Seventy‐five patients treated for stage IA1 microinvasive carcinoma of the cervix. Patients underwent conization followed by hysterectomy (Group 1, 53 patients), or were followed by conservative management (Group 2, 22 patients). Methods. Medical and histopathological record review. Results. For Group 1, pathology results showed that 30 had no residual tumor, one had cervical intraepithelial neoplasia (CIN) I, 11 had CIN III/cervical carcinoma in situ (CIS), nine had microinvasive carcinomas, and one had an invasive carcinoma (outcome for one patient not recorded). For Group 2, secondary procedures involved only cervical smears for 12 (48%) patients, of whom nine had normal cytology, one had low‐grade squamous intraepithelial lesion and two had high‐grade squamous intraepithelial lesions. For 13 (52%) patients in Group 2, secondary procedures involved repeat conization on whom six had no residual tumor, one had CIN II, four CIN III/CIS, and two microinvasive carcinoma and a negative resection margin. Therefore, conization followed by conservative management was an effective treatment for 90.9% (20/22) of Group 2. In neither group was recurrence recorded. There was no relation between lymphovascular invasion and follow‐up cytology or pathology results, or between resection margin status and follow‐up examination results. Conclusion. Conization alone with careful follow‐up appears to be an effective and safe treatment for patients with stage IA1 microinvasive carcinoma of the uterine cervix, regardless of resection margins status or lymphovascular invasion.
Predicting the binding preference of transcription factors to individual DNA k-mers
Authors: Alleyne Trevis M. , Peña-Castillo Lourdes , Badis Gwenael , Talukder Shaheynoor , Berger Michael F. , Gehrke Andrew R. , Philippakis Anthony A. , Bulyk Martha L. , Morris Quaid D. , Hughes Timothy R.
Published: December 2008

Motivation: Recognition of specific DNA sequences is a central mechanism by which transcription factors (TFs) control gene expression. Many TF-binding preferences, however, are unknown or poorly characterized, in part due to the difficulty associated with determining their specificity experimentally, and an incomplete understanding of the mechanisms governing sequence specificity. New techniques that estimate the affinity of TFs to all possible k-mers provide a new opportunity to study DNA–protein interaction mechanisms, and may facilitate inference of binding preferences for members of a given TF family when such information is available for other family members.

Results: We employed a new dataset consisting of the relative preferences of mouse homeodomains for all eight-base DNA sequences in order to ask how well we can predict the binding profiles of homeodomains when only their protein sequences are given. We evaluated a panel of standard statistical inference techniques, as well as variations of the protein features considered. Nearest neighbour among functionally important residues emerged among the most effective methods. Our results underscore the complexity of TF–DNA recognition, and suggest a rational approach for future analyses of TF families.

Contact:  t.hughes@utorotno.ca

Supplementary information:  Supplementary data are available at Bioinformatics online.
Trends and Outcomes of Malignant Hyperthermia in the United States, 2000 to 2005
Authors: Rosero Eric B. , Adesanya Adebola O. , Timaran Carlos H. , Joshi Girish P.
Published: December 2008

Background

Malignant hyperthermia (MH) is a potentially fatal pharmacogenetic disorder with an estimated mortality of less than 5%. The purpose of this study was to evaluate the current incidence of MH and the predictors associated with in-hospital mortality in the United States.

Methods

The Nationwide Inpatient Sample, which is the largest all-payer inpatient database in the United States, was used to identify patients discharged with a diagnosis of MH during the years 2000-2005. The weighted exact Cochrane-Armitage test and multivariate logistic regression analyses were used to assess trends in the incidence and risk-adjusted mortality from MH, taking into account the complex survey design.

Results

From 2000 to 2005, the number of cases of MH increased from 372 to 521 per year. The occurrence of MH increased from 10.2 to 13.3 patients per million hospital discharges (P = 0.001). Mortality rates from MH ranged from 6.5% in 2005 to 16.9% in 2001 (P < 0.0001). The median age of patients with MH was 39 (interquartile range, 23-54 yr). Only 17.8% of the patients were children, who had lower mortality than adults (0.7% vs. 14.1%, P < 0.0001). Logistic regression analyses revealed that risk-adjusted in-hospital mortality was associated with increasing age, female sex, comorbidity burden, source of admission to hospital, and geographic region of the United States.

Conclusions

The incidence of MH in the United States has increased in recent years. The in-hospital mortality from MH remains elevated and higher than previously reported. The results of this study should enable the identification of areas requiring increased focus in MH-related education.
Activation of p38 Mitogen-activated Protein Kinase in Spinal Microglia Contributes to Incision-induced Mechanical Allodynia
Authors: Wen Yeong-Ray , Suter Marc R. , Ji Ru-Rong , Yeh Geng-Chang , Wu Yen-Sheng , Wang Kuo-Ching , Kohno Tatsuro , Sun Wei-Zen , Wang Chia-Chuan
Published: December 2008

Background

Recent studies have implicated the activation of stress-activated mitogen-activated protein kinase (MAPK) p38 in spinal microglial cells for development of neuropathic and inflammatory pain. The aim of the present study was to investigate whether phosphorylation of p38 (p-p38) also mediates mechanical allodynia and thermal hyperalgesia induced by plantar incision.

Methods

After rats received a plantar incision surgery, mechanical allodynia and thermal hyperalgesia were determined by von Frey filaments and radiant heat, respectively, and the number of p-p38 immunoreactive cells in the dorsal horn was quantified to determine p38 activation at different time points after incision. The p38 inhibitor FR167653 was administered intrathecally 30 min before hind paw plantar incision to determine the role of p38 in postoperative pain.

Results

A significant increase in number of p-p38 immunoreactive cells was observed in the ipsilateral L4-5 spinal dorsal horn from 1 h to 3 days after the incision. p-p38 was found predominantly in microglia. However, microglial activation (assessed by OX-42 upregulation) was not evident until 3 days after plantar incision. Intrathecal pretreatment of FR167653 attenuated incision-induced mechanical allodynia from 1 h to day 2 and significantly reduced activation of p38 in the dorsal horn 1 day after plantar incision. However, FR167653 only inhibited heat hyperalgesia at an early time point.

Conclusions

Plantar incision-induced mechanical allodynia can be prevented by the p38 inhibitor. Our results suggest that p38 activation in spinal microglia play a role in incision-induced mechanical allodynia in rats. Therefore, p38 inhibition may be useful in treating postsurgical pain.
Comparison of Continuous Infusion versus Automated Bolus for Postoperative Patient-controlled Analgesia with Popliteal Sciatic Nerve Catheters
Authors: Taboada Manuel , Rodríguez Jaime , Bermudez Maria , Amor Marcos , Ulloa Beatriz , Aneiros Francisco , Sebate Sergi , Cortés Joaquin , Alvarez Julian , Atanassoff Peter G.
Published: December 2008

Background

This investigation was designed to compare a new methodology of automated regular bolus with a continuous infusion of local anesthetic for continuous popliteal sciatic block; both regimens were combined with patient-controlled analgesia (PCA).

Methods

Fifty patients undergoing hallux valgus repair were randomly allocated to receive an infusion of 0.125% levobupivacaine administered through a popliteal catheter as an automated regular bolus (n = 25) or as a continuous infusion (n = 25), both combined with PCA. Postoperative pain scores, incremental doses delivered by the PCA, local anesthetic consumed per hour, and the need for rescue tramadol analgesia were recorded.

Results

Both dosing regimens provided similar postoperative analgesia. Consumption of local anesthetic (5.14 ml/h, 5-5.75 ml/h) and dose request from the PCA (1, 0-5.4) was lower in the automated bolus group as compared to the continuous infusion group (5.9 ml/h, 5.05-7.8 ml/h; doses by PCA: 6.5, 0-20.5; P < 0.05). The need for rescue tramadol was similar in the two groups.

Conclusion

In continuous popliteal sciatic block, local anesthetic administered as an automated regular bolus in conjunction with PCA provided similar pain relief as a continuous infusion technique combined with PCA; however, the new dosing regimen reduced the need for additional PCA and the overall consumption of local anesthetic.
YmdB: a stress-responsive ribonuclease-binding regulator of E. coli RNase III activity
Authors: Kim Kwang-sun , Manasherob Robert , Cohen Stanley N.
Published: December 2008

The broad cellular actions of RNase III family enzymes include ribosomal RNA (rRNA) processing, mRNA decay, and the generation of noncoding microRNAs in both prokaryotes and eukaryotes. Here we report that YmdB, an evolutionarily conserved 18.8-kDa protein of Escherichia coli of previously unknown function, is a regulator of RNase III cleavages. We show that YmdB functions by interacting with a site in the RNase III catalytic region, that expression of YmdB is transcriptionally activated by both cold-shock stress and the entry of cells into stationary phase, and that this activation requires the σ-factor-encoding gene, rpoS. We discovered that down-regulation of RNase III activity occurs during both stresses and is dependent on YmdB production during cold shock; in contrast, stationary-phase regulation was unperturbed in ymdB-null mutant bacteria, indicating the existence of additional, YmdB-independent, factors that dynamically regulate RNase III actions during normal cell growth. Our results reveal the previously unsuspected role of ribonuclease-binding proteins in the regulation of RNase III activity.
Protein phosphatase PP1 is required for normal DNA methylation in Neurospora
Authors: Adhvaryu Keyur K. , Selker Eric U.
Published: December 2008

Covalent modifications of histones integrate intracellular and extracellular cues to regulate the genome. H3 Lys 9 methylation (H3K9me) can direct heterochromatin formation and DNA methylation, while phosphorylation of H3 Ser 10 (H3S10p) drives gene activation and chromosome condensation. To examine the relationship between H3S10p, H3K9me, and DNA methylation in Neurospora crassa, we built and tested mutants of the putative H3S10 phosphatase, PP1. A PP1-impaired mutant showed increased H3S10p and selective reduction of methylation of H3K9 and DNA. Similarly, amino acid substitutions of H3S10 abolished methylation of H3K9 and DNA. Thus, H3S10 dephosphorylation by PP1 is required for DNA methylation of some loci.
Dynamic regulation of Pdx1 enhancers by Foxa1 and Foxa2 is essential for pancreas development
Authors: Gao Nan , LeLay John , Vatamaniuk Marko Z. , Rieck Sebastian , Friedman Joshua R. , Kaestner Klaus H.
Published: December 2008

The onset of pancreas development in the foregut endoderm is marked by activation of the homeobox gene Pdx1 (IPF1). Pdx1 is essential for the expansion of the pancreatic primordium and the development of endocrine islets. The control of Pdx1 expression has been only partially elucidated. We demonstrate here that the winged-helix transcription factors Foxa1 and Foxa2 co-occupy multiple regulatory domains in the Pdx1 gene. Compound conditional ablation of both Foxa1 and Foxa2 in the pancreatic primordium results in complete loss of Pdx1 expression and severe pancreatic hypoplasia. Mutant mice exhibit hyperglycemia with severely disrupted acinar and islet development, and die shortly after birth. Assessment of developmental markers in the mutant pancreas revealed a failure in the expansion of the pancreatic anlage, a blockage of exocrine and endocrine cell differentiation, and an arrest at the primitive duct stage. Comparing their relative developmental activity, we find that Foxa2 is the major regulator in promoting pancreas development and cell differentiation. Using chromatin immunoprecipitations (ChIP) and ChIP sequencing (ChIPSeq) of fetal pancreas and islet chromatin, we demonstrate that Foxa1 and Foxa2 predominantly occupy a distal enhancer at −6.4 kb relative to the transcriptional start site in the Pdx1 gene. In addition, occupancy of the well-characterized proximal Pdx1 enhancer by Foxa1 and Foxa2 is developmental stage-dependent. Thus, the regulation of Pdx1 expression by Foxa1 and Foxa2 is a key early event controlling the expansion and differentiation of the pancreatic primordia.
Talk is cheap—cross-talk in establishment, maintenance, and readout of chromatin modifications
Authors: Fischle Wolfgang
Published: December 2008

The functionality of a cell’s genome is controlled epigenetically on the level of chromatin. Multiple post-translational modifications of histone proteins together with DNA methylation play a key role in directing distinct functional states of chromatin. As it emerges, many epigenetic marks on the chromatin platform do not act independently, but cross-talk with each other. In this issue of Genes & Development, Adhvaryu and Selker (3391-3396) provide novel insights into an intricate regulatory network involving histone phosphorylation, histone methylation, and DNA methylation.
ASYMMETRIC LEAVES2-LIKE19/LATERAL ORGAN BOUNDARIES DOMAIN30andASL20/LBD18Regulate Tracheary Element Differentiation inArabidopsis
Authors: Soyano Takashi , Thitamadee Siripong , Machida Yasunori , Chua Nam-Hai
Published: December 2008

ASYMMETRIC LEAVES2 (AS2)/LATERAL ORGAN BOUNDARIES DOMAIN (LBD) family proteins are plant-specific nuclear proteins, and genes encoding several family members have been implicated in plant development. We investigated the function of two members of the Arabidopsis thaliana AS2/LBD family, AS2-LIKE19 (ASL19)/LBD30 and ASL20/LBD18, which encode homologous proteins. Both ASL19 and ASL20 were expressed in immature tracheary elements (TEs), and the expression was dependent on VASCULAR-RELATED NAC-DOMAIN PROTEIN6 (VND6) and VND7, which are transcription factors required for TE differentiation. Overexpression of ASL19 and ASL20 induced transdifferentiation of cells from nonvascular tissues into TE-like cells, similar to those induced upon VND6/7 overexpression. By contrast, aberrant TEs were formed when a cDNA encoding a fusion protein of ASL20 with an artificial repressor domain (ASL20-SRDX) was expressed from its native promoter. These results provide evidence that ASL proteins positively regulate TE differentiation. In transgenic plants overexpressing both ASL19 and ASL20, the xylem-deficient phenotype caused by the expression of dominant-negative versions of VND6/7 proteins was not rescued. However, ectopic expression of VND7 was detected in plants overexpressing ASL20. Moreover, VND genes and their downstream targets were downregulated in ASL20-SRDX plants. Therefore, ASL20 appears to be involved in a positive feedback loop for VND7 expression that regulates TE differentiation-related genes.
Association between CRHR1 polymorphism and improved lung function in response to inhaled corticosteroid in patients with COPD
Authors: KIM Woo J. , SHEEN Seung S. , KIM Tae‐Hyung , HUH Jin W. , LEE Ji‐Hyun , KIM Eun‐Kyung , LEE Jin H. , LEE Sang‐Min , LEE Sangyeub , LIM Seong Y. , SHIN Tae R. , YOON Ho I. , OH Yeon‐Mok , LEE Sang D.
Published: December 2008

Background and objective:  Inhaled corticosteroids are used to treat COPD and asthma. An association between sequence variants in the corticotrophin‐releasing hormone receptor 1 (CRHR1) gene and improved lung function in asthmatics treated with inhaled corticosteroids was reported recently. This study investigated the association between the change in lung function in response to inhaled corticosteroids and single‐nucleotide CRHR1 polymorphisms in patients with COPD.

Methods:  COPD patients (n = 87) with a positive smoking history were recruited from the pulmonary clinics of 11 hospitals in Korea. Patients were treated with fluticasone propionate and salmeterol for 12 weeks and lung function was measured at baseline and after the 12‐week treatment. Eighty‐four of the 87 subjects were successfully genotyped.

Results:  Seventy‐one patients with the wild‐type GG genotype and 13 patients with the heterozygous GT genotype in rs242 941 were evaluated. After 12‐week treatment, the change in FEV1 was significantly higher in patients with wild‐type GG genotype (6.0 ± 0.8% of predicted FEV1) than in GT heterozygotes (−0.8 ± 1.8, P = 0.003).

Conclusions:  Improved FEV1 following inhaled corticosteroid and a long‐acting β2‐agonist was associated with CRHR1 genetic polymorphism in patients with COPD.
Evaluation of transcutaneous CO2 responses following acute changes in PaCO2 in healthy subjects
Authors: FUKE Satoshi , MIYAMOTO Kenji , OHIRA Hiroshi , OHIRA Megumi , ODAJIMA Nao , NISHIMURA Masaharu
Published: December 2008

Background and objective:  Transcutaneous blood gas‐monitoring systems with miniaturized SpO2 (peripheral blood oxygen saturation)/PCO2 combined sensors (TOSCATM) have been widely used. There are no reports of the inter‐ and intra‐individual variability in transcutaneous measurements of PaCO2 (PtcCO2) in response to acute progressive changes in PaCO2. This study examined inter‐ and intra‐individual variability of PtcCO2 measurements under semi‐steady‐state conditions, and characterized the behaviour of PtcCO2 in response to acute progressive changes in PaCO2.

Methods:  Subjects breathed mixed gases through a mouthpiece connected to an automatic arterial blood gas controller. Using end‐tidal PCO2 and PO2 as guides, PaCO2 was controlled to increase and/or decrease between baseline and ≥ 60 mm Hg, in a stepwise (n = 9) or progressive fashion (n = 6). Arterial blood was sampled when needed.

Results:  Intra‐individual correlation coefficients between PtcCO2 and PaCO2 were excellent in all subjects (0.971–0.989); however, the slope of the regression line varied among subjects (1.040–1.335). Bias and limits of agreement (± 2 SD from bias) between PtcCO2 and PaCO2 were −1.8 mm Hg and −7.7 to 4.1 mm Hg. Changes in PtcCO2 in response to acute progressive changes in PaCO2 also varied among subjects.

Conclusion:  The PtcCO2 measurement system allows reliable estimation of PaCO2 in a given subject. However, caution is needed when comparing absolute values between subjects or when acute changes in PaCO2 occur.
Aetiologies and outcomes of diffuse alveolar haemorrhage presenting as acute respiratory failure of uncertain cause
Authors: JIN Sang‐Man , YIM Jae‐Joon , YOO Chul‐Gyu , KIM Young‐Whan , HAN Sung‐Koo , SHIM Young‐Soo , LEE Sang‐Min
Published: December 2008

Background and objective:  Connective tissue diseases are the most common disorders causing diffuse alveolar haemorrhage (DAH) confirmed by open lung biopsy. However, it is not known whether these diseases are also the most common causes of DAH in patients presenting with the features of ARDS/acute lung injury (ALI). This study evaluated the frequency of concomitant disease in patients with ARDS/ALI and DAH.

Methods:  The sampling frame comprised all patients in a tertiary referral hospital diagnosed with ARDS/ALI and who underwent BAL between January 2000 and July 2006. The medical records of those patients who had BAL fluid findings compatible with DAH were reviewed.

Results:  Of the 97 patients diagnosed with ARDS/ALI and who underwent BAL, 27 had BAL fluid findings compatible with DAH. Sixteen of the 27 patients did not have connective tissue diseases (59%); of these 12 patients had concomitant haematological malignancies or solid tumours. Of the seven patients who presented with DAH and no known underlying disease, only two were subsequently diagnosed with a connective tissue disorder. The in‐hospital mortality rate was 55% and 63% for patients with DAH with and without connective tissue diseases, respectively (P = 0.710).

Conclusions:  The majority of patients with DAH presenting with the features of ARDS/ALI did not have underlying connective tissue diseases. Concomitant malignancies were found frequently in these patients. The outcome did not differ between patients with DAH with or without connective tissue diseases.
Obstructive bronchiolar disease identified by CT in the non‐transplant population: Analysis of 29 consecutive cases
Authors: PARAMBIL Joseph G. , YI Eunhee S. , RYU Jay H.
Published: December 2008

Background and objective:  Obstructive bronchiolar disease or constrictive bronchiolitis, particularly in non‐transplant patients, is poorly understood. This study identified the associated diseases, presenting features, and clinical course of obstructive bronchiolar disease identified by CT in the non‐transplant adult population.

Methods:  Retrospective single‐centre study of 29 consecutive patients clinically diagnosed to have an obstructive bronchiolar disease based on the presence of respiratory symptoms and abnormal CT findings consisting of mosaic perfusion pattern with air trapping.

Results:  The median age was 54 years (range, 25–80 years); 20 were women (69%) and four patients (14%) had a smoking history. All 29 patients presented with respiratory symptoms, predominantly dyspnoea. The most common cause of obstructive bronchiolar disease was rheumatoid arthritis (34%). Other causes included hypersensitivity pneumonitis, multiple carcinoid tumorlets, Sjögren's syndrome, paraneoplastic pemphigus, inflammatory bowel disease and Swyer–James syndrome. The underlying cause was not identifiable in nine patients (31%), that is, cryptogenic constrictive bronchiolitis. An obstructive pattern was seen on pulmonary function testing in most patients (86%) with the exception of those with hypersensitivity pneumonitis and extreme obesity. Management usually included corticosteroid therapy, inhaled and oral, and bronchodilator therapy. Additional medications included macrolides, cytotoxic agents and other immunomodulator therapy. Pharmacologic therapy did not provide improvement in pulmonary function in the majority of patients but the follow‐up data were limited.

Conclusions:  Diverse causes and underlying diseases are associated with obstructive bronchiolar disease diagnosed radiologically in the non‐transplant adult population. Rheumatoid arthritis‐associated and cryptogenic constrictive bronchiolitis are found in over one‐half of these patients. Most patients with obstructive bronchiolar disease do not appear to improve with currently available therapy.
Pulmonary alveolar proteinosis in a patient with Behcet's disease
Authors: UCHIYAMA Michihiro , NAGAO Tsuyoshi , HATTORI Aritoshi , FUJII Tatsuya , ICHIWATA Toshio , NAKATA Koh , TANI Kenzaburo , HAYASHI Takuya
Published: December 2008

Secondary pulmonary alveolar proteinosis (PAP) has been described in several clinical settings that can be grouped into three main categories: infections of the lung; haematological malignancies and other conditions that alter the patient's immune status; and exposure to inhaled chemicals and minerals. Recent studies reported that anti‐granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) antibody was present in the serum of patients with idiopathic PAP but not in patients with secondary PAP or in normal subjects. The present report describes the interesting case of a patient with Behcet's disease and PAP. The absence of anti‐GM‐CSF antibodies in this patient suggested a diagnosis of secondary PAP.
Endogenous catecholamine stimulates alveolar fluid clearance in rats with acute pancreatitis
Authors: XU Jin , WANG Zheng , MA Gang , SAGAWA Motoyasu , SHIMAZAKI Miyako , UEDA Yoshimichi , SAKUMA Tsutomu
Published: December 2008

Background and objective:  Acute pancreatitis causes pulmonary oedema with the accumulation of fluid in the alveolar spaces, possibly due to reduced clearance. This study tested the hypothesis that acute pancreatitis decreases alveolar fluid clearance in a rat model of pulmonary oedema during acute pancreatitis.

Methods:  Acute pancreatitis was induced by a retrograde injection of 5% taurocholate sodium (0.2 mL) into the common bile duct. The lungs were isolated 4, 24 and 48 h after the induction of acute pancreatitis and alveolar fluid clearance was measured in the absence of pulmonary perfusion.

Results:  Alveolar fluid clearance increased to 31.0 ± 3.5% of instilled volume/h in rats with acute pancreatitis for 4 h compared with 17.3 ± 1.0% of instilled volume/h in sham rats (P < 0.01), then returned to the control level 48 h after acute pancreatitis (16.0 ± 4.1% of instilled volume/h). In contrast, the lung water to dry lung weight ratio decreased maximally 24 h after acute pancreatitis (P < 0.01), then returned to the control level 48 h after acute pancreatitis. The plasma epinephrine levels increased to 25‐fold higher in rats with acute pancreatitis for 4 h than in sham rats without acute pancreatitis. Prazosin (an α1‐adrenergic antagonist, 10−4 mol/L), yohimbine (an α2‐adrenergic antagonist, 10−4 mol/L) or a bilateral adrenalectomy inhibited the increase in part, a combination of prazosin (10−4 mol/L) and yohimbine (10−4 mol/L) completely inhibited the increase in alveolar fluid clearance in rats after acute pancreatitis for 4 h, whereas propranolol (a β‐adrenergic antagonist, 10−4 mol/L) had no effect.

Conclusions:  Endogenous catecholamine stimulates α‐adrenoceptors and increases alveolar fluid clearance in rats with acute pancreatitis.