Optimally enhanced optical emission in laser-induced breakdown spectroscopy by combining spatial confinement and dual-pulse irradiation

In laser-induced breakdown spectroscopy (LIBS), a pair of aluminum-plate walls were used to spatially confine the plasmas produced in air by a first laser pulse (KrF excimer laser) from chromium (Cr) targets with a second laser pulse (Nd:YAG laser at 532 nm, 360 mJ/pulse) introduced parallel to the sample surface to re-excite the plasmas. Optical emission enhancement was achieved by combing the spatial confinement and dual-pulse LIBS (DP-LIBS), and then optimized by adjusting the distance between the two walls and the interpulse delay time between both laser pulses. A significant enhancement factor of 168.6 for the emission intensity of the Cr lines was obtained at an excimer laser fluence of 5.6 J/cm(2) using the combined spatial confinement and DP-LIBS, as compared with an enhancement factor of 106.1 was obtained with DP-LIBS only. The enhancement mechanisms based on shock wave theory and reheating in DP-LIBS are discussed.

Interleukin-8 (IL-8) over-production and autocrine cell activation are key factors in monomethylarsonous acid [MMA(III)]-induced malignant transformation of urothelial cells

The association between chronic human exposure to arsenicals and bladder cancer development is well recognized; however, the underlying molecular mechanisms have not been fully determined. We propose that inflammatory responses can play a pathogenic role in arsenic-related bladder carcinogenesis. In previous studies, it was demonstrated that chronic exposure to 50 nM monomethylarsenous acid [MMA(III)] leads to malignant transformation of an immortalized model of urothelial cells (UROtsa), with only 3 mo of exposure necessary to trigger the transformation-related changes. In the three-month window of exposure, the cells over-expressed pro-inflammatory cytokines (IL-1β, IL-6 and IL-8), consistent with the sustained activation of NFKβ and AP1/c-jun, ERK2, and STAT3. IL-8 was over-expressed within hours after exposure to MMA(III), and sustained over-expression was observed during chronic exposure. In this study, we profiled IL-8 expression in UROtsa cells exposed to 50 nM MMA(III) for 1 to 5 mo. IL-8 expression was increased mainly in cells after 3 mo MMA(III) exposure, and its production was also found increased in tumors derived from these cells after heterotransplantation in SCID mice. UROtsa cells do express both receptors, CXCR1 and CXCR2, suggesting that autocrine cell activation could be important in cell transformation. Supporting this observation and consistent with IL-8 over-expression, CXCR1 internalization was significantly increased after three months of exposure to MMA(III). The expression of MMP-9, cyclin D1, bcl-2, and VGEF was significantly increased in cells exposed to MMA(III) for 3 mo, but these mitogen-activated kinases were significantly decreased after IL-8 gene silencing, together with a decrease in cell proliferation rate and in anchorage-independent colony formation. These results suggest a relevant role of IL-8 in MMA(III)-induced UROtsa cell transformation.

Unusual causes of carpal tunnel syndrome: space occupying lesions

Space occupying lesions found at surgery caused or contributed to carpal tunnel syndrome in 23 of 779 patients operated for carpal tunnel syndrome from January 1999 to December 2008. The mean age of these 23 patients was 52.9 years, and in patients who had a local swelling or palpable mass, ultrasonography or magnetic resonance imaging (MRI) was done. All had open release of the transverse carpal ligament and lesions were removed. Histopathology showed tophaceous gout in 10 men, tenosynovitis in seven patients and tumors in eight. The tumors included ganglion cysts in two, lipoma in three and fibroma of the tendon sheath in one. The neurological symptoms subsided after surgery in all. In patients with gout, one had an infected wound and another had recurrence of symptoms 1 year after later. Carpal tunnel syndrome caused by a space occupying lesion is rare and more complicated than idiopathic carpal tunnel syndrome.

Measurements of the anisotropic in-plane resistivity of underdoped FeAs-based pnictide superconductors

We systematically investigated the in-plane resistivity anisotropy of electron-underdoped EuFe(2-x)Co(x)As(2) and BaFe(2-x)Co(x)As(2) and hole-underdoped Ba(1-x)K(x)Fe(2)As(2). Large in-plane resistivity anisotropy was found in the former samples, while tiny in-plane resistivity anisotropy was detected in the latter ones. When it is detected, the anisotropy starts above the structural transition temperature and increases smoothly through it. As the temperature is lowered further, the anisotropy takes a dramatic enhancement through the magnetic transition temperature. We found that the anisotropy is universally tied to the presence of T-linear behavior of resistivity. Our results demonstrate that the nematic state is caused by electronic degrees of freedom, and the microscopic orbital involvement in the magnetically ordered state must be fundamentally different between the hole- and electron-doped materials.

Microsomal prostaglandin E synthase-1 promotes hepatocarcinogenesis through activation of a novel EGR1/β-catenin signaling axis

Microsomal prostaglandin E synthase-1 (mPGES-1) is a key enzyme that couples with cyclooxygenase-2 (COX-2) for the production of PGE₂. Although COX-2 is known to mediate the growth and progression of several human cancers including hepatocellular carcinoma (HCC), the role of mPGES-1 in hepatocarcinogenesis is not well established. This study provides novel evidence for a key role of mPGES-1 in HCC growth and progression. Forced overexpression of mPGES-1 in two HCC cell lines (Hep3B and Huh7) increased tumor cell growth, clonogenic formation, migration and invasion, whereas knockdown of mPGES-1 inhibited these parameters, in vitro. In a SCID mouse tumor xenograft model, mPGES-1 overexpressed cells formed palpable tumors at earlier time points and developed larger tumors when compared to the control (p<0.01); in contrast, mPGES-1 knockdown delayed tumor development and reduced tumor size (p<0.01). Mechanistically, mPGES-1-induced HCC cell proliferation, invasion and migration involve PGE₂ production and activation of early growth response 1 (EGR1) and β-catenin. Specifically, mPGES-1-derived PGE₂ induces the formation of EGR1-β-catenin complex, which interacts with TCF4/LEF1 transcription factors and activates the expression of β-catenin downstream genes. Our findings depict a novel crosstalk between mPGES-1/PGE₂ and EGR1/β-catenin signaling that is critical for hepatocarcinogenesis.

Measurement of GSTP1 promoter methylation in body fluids may complement PSA screening: a meta-analysis

BACKGROUND

Prostate-specific antigen (PSA) screening has low specificity. Assessment of methylation status in body fluids may complement PSA screening if the test has high specificity.

METHOD

The purpose of this study was to conduct a meta-analysis of the sensitivity and specificity for prostate cancer detection of glutathione-s-transferase-π (GSTP1) methylation in body fluids (plasma, serum, whole blood, urine, ejaculate, and prostatic secretions). We conducted a comprehensive literature search on Medline (Pubmed). We included studies if they met all four of the following criteria: (1) measurement of DNA methylation in body fluids; (2) a case-control or case-only design; (3) publication in an English journal; and (4) adult subjects. Reviewers conducted data extraction independently using a standardised protocol. Twenty-two studies were finally included in this paper. Primer sequences and methylation method in each study were summarised and evaluated using meta-analyses. This paper represents a unique cross-disciplinary approach to molecular epidemiology.

RESULTS

The pooled specificity of GSTP1 promoter methylation measured in plasma, serum, and urine samples from negative-biopsy controls was 0.89 (95% CI, 0.80-0.95). Stratified analyses consistently showed a high specificity across different sample types and methylation methods (include both primer sequences and location). The pooled sensitivity was 0.52 (95% CI, 0.40-0.64).

CONCLUSIONS

The pooled specificity of GSTP1 promoter methylation measures in plasma, serum, and urine was excellent and much higher than the specificity of PSA. The sensitivity of GSTP1 was modest, no higher than that of PSA. These results suggest that measurement of GSTP1 promoter methylation in plasma, serum, or urine samples may complement PSA screening for prostate cancer diagnosis.

UV light emitting transparent conducting tin-doped indium oxide (ITO) nanowires

Multifunctional single crystalline tin-doped indium oxide (ITO) nanowires with tuned Sn doping levels are synthesized via a vapor transport method. The Sn concentration in the nanowires can reach 6.4 at.% at a synthesis temperature of 840 °C, significantly exceeding the Sn solubility in ITO bulks grown at comparable temperatures, which we attribute to the unique feature of the vapor-liquid-solid growth. As a promising transparent conducting oxide nanomaterial, layers of these ITO nanowires exhibit a sheet resistance as low as 6.4 Ω/[Symbol: see text] and measurements on individual nanowires give a resistivity of 2.4 × 10(-4) Ω cm with an electron density up to 2.6 × 10(20) cm(-3), while the optical transmittance in the visible regime can reach ∼ 80%. Under the ultraviolet excitation the ITO nanowire samples emit blue light, which can be ascribed to transitions related to defect levels. Furthermore, a room temperature ultraviolet light emission is observed in these ITO nanowires for the first time, and the exciton-related radiative process is identified by using temperature-dependent photoluminescence measurements.

Functional expression of P2X4 receptor in capillary endothelial cells of the cochlear spiral ligament and its role in regulating the capillary diameter

The cochlear lateral wall generates the endocochlear potential (EP), which creates a driving force for the hair cell transduction current and is essential for normal hearing. Blood flow at the cochlear lateral wall is critically important for maintaining the EP. The vulnerability of the EP to hypoxia suggests that the blood flow in the cochlear lateral wall is dynamically and precisely regulated to meet the changing metabolic needs of the cochlear lateral wall. It has been reported that ATP, an important extracellular signaling molecule, plays an essential role in regulating cochlear blood flow. However, the cellular mechanism underlying ATP-induced regional blood flow changes has not been investigated. In the current study, we demonstrate that 1) the P2X4 receptor is expressed in endothelial cells (ECs) of spiral ligament (SL) capillaries. 2) ATP elicits a characteristic current through P2X4 on ECs in a dose-dependent manner (EC(50) = 0.16 mM). The ATP current has a reversal potential at ∼0 mV; is inhibited by 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepin-2-one (5-BDBD), LaCl(3), pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid) tetrasodium salt hydrate (PPADS), and extracellular acidosis; and is less sensitive to α,β-methyleneadenosine 5'-triphosphate (α,β-MeATP) and 2'- and 3'-O-(4-benzoyl-benzoyl) adenosine 5'-triphosphate (BzATP). 3) ATP elicits a transient increase of intracellular Ca(2+) in ECs. 4) In accordance with the above in vitro findings, perilymphatic ATP (1 mM) caused dilation in SL capillaries in vivo by 11.5%. N(ω)-nitro-l-arginine methyl ester hydrochloride (l-NAME), a nonselective inhibitor of nitric oxide synthase, or 5-BDBD, the specific P2X4 inhibitor, significantly blocked the dilation. These findings support our hypothesis that extracellular ATP regulates cochlear lateral blood flow through P2X4 activation in ECs.

Mechanisms Causing Capacity Loss on Long Term Storage in NiMH System

Capacity recovery after long term storage and loaded storage is a critical issue with the NiMH system since its inception. A measurable loss in capacity is observed when cells are stored for long periods of time or discharged deeply to zero volts. The different mechanisms that are known to cause self discharge and capacity loss after storage and loaded storage will be the focus of this paper. Capacity loss after long term storage involves two main events. One is self discharge which causes the open circuit voltage(OCV) of the cell to drop. Self discharge is caused by decomposition of NiOOH, migration of metal ions and possible degradation of separator. Self discharge can be prevented by using separators which are stable at high temperatures and pH and have good ion trapping capability. Various separator types and treatments can play an important role in inhibiting metal ions from migrating thus reducing self discharge. Self discharge during storage causes a severe suppression in the voltage of the foam positive electrode. This drop in voltage causes a breakdown of the cobalt conductive network in the nickel positive electrode. Reduction of high valence cobalt(III) which forms the electrode's conductive network takes place at these low voltages. A permanent breakdown in the conductive network results in low efficiency of the cell on consecutive charge and discharge cycles. In addition, the cobalt in its lower valence states can migrate away from the electrode into the separator causing shorts. These events effect the charge and discharge efficiency of these cells thereby resulting in capacity loss. Various mechanisms causing self discharge which affect capacity recovery after long term storage and loaded storage are discussed in this paper.

Effect of capsaicin on potassium conductance and electromotility of the guinea pig outer hair cell

Capsaicin, the classic activator of TRPV-1 channels in primary sensory neurons, evokes nociception. Interestingly, auditory reception is also modulated by this chemical, possibly by direct actions on outer hair cells (OHCs). Surprisingly, we find two novel actions of capsaicin unrelated to TRPV-1 channels, which likely contribute to its auditory effects in vivo. First, capsaicin is a potent blocker of OHC K conductances (I(K) and I(K,n)). Second, capsaicin substantially alters OHC nonlinear capacitance, the signature of electromotility - a basis of cochlear amplification. These new findings of capsaicin have ramifications for our understanding of the pharmacological properties of OHC I(K), I(K,n) and electromotility and for interpretation of capsaicin pharmacological actions.

Rotavirus infection in adult small intestine allografts: a clinicopathological study of a cohort of 23 patients

Rotavirus enteritis (RVE) is increasingly recognized as a cause of small bowel allograft dysfunction but its significance in adult patients is unknown. We have studied 23 adult small bowel transplant patients aged 19.8-59 years (mean = 38.2 years), who were presented with diarrhea and tested positive for rotavirus by enzyme-linked immunosorbent assay methods. Serial follow-up biopsies, as well as clinical data, are documented and analyzed. These patients were followed up for an average of 168 days (range 33-534 days). Mean time of rotavirus diagnosis from transplant day was 794 days (range 38-2907 days). Self-limited diarrhea lasting 6-13 days (mean = 9 days) was the main presentation. Sixteen (69.6%) patients developed acute cellular rejection either concurrently with (i.e. six patients) or after (10 patients) RVE, often characterized by prominent mucosal plasmacytosis at an average of 22 days (range 0-94 days) from the day RVE was diagnosed. One-third of patients with acute rejection (i.e. five out of 16) required muromonab-CD3 rescue therapy. Two patients experienced graft loss (one from chronic rejection, another from sepsis). Rotavirus infection is a cause of diarrhea in adult small bowel transplant patients. The infection appeared to trigger cellular rejection that was associated with mucosal plasmacytosis, and sometimes required aggressive rescue therapy.

Tunable magnetic interaction at the atomic scale in oxide heterostructures

We report on a systematic study of a number of structurally identical but chemically distinct transition metal oxides in order to determine how the material-specific properties such as the composition and the strain affect the properties at the interface of heterostructures. Our study considers a series of structures containing two layers of ferromagnetic SrRuO₃, with antiferromagnetic insulating manganites sandwiched in between. The results demonstrate how to control the strength and relative orientation of interfacial ferromagnetism in correlated electron materials by means of valence state variation and substrate-induced strain, respectively.