Low temperature deformation mechanism of semiconductor single crystal and molding of Ge microlens array by direct electrical heating

Although deforming a silicon single crystal at a temperature of about 600 °C lower than its melting point (1414 °C) by direct electrical heating was successfully demonstrated, the mechanism has still not been fully clarified. In this paper, we propose a model for the low temperature deformation of a semiconductor single crystal by direct electrical heating. The thermographic observation during direct electrical heating reveals that the local temperature is higher at the region where dense dislocation occurred in the semiconductor single crystal by uniaxial pressing. This is interpreted in terms of the scattering of an electron by the dislocation leading to an increase in the electrical resistivity. Finally, the deformation temperature of the semiconductor single crystal apparently becomes low due to the occurrence of such hot spots. We have also demonstrated an application to mold a microlens array composed of a germanium single crystal with a focal length of 25 µm

Ultra-high temperature Soret effect in a silicate melt: SiO2 migration to cold side

The Soret effect, temperature gradient driven diffusion, in silicate melts has been investigated intensively in the earth sciences from the 1980s. The SiO2 component is generally concentrated in the hotter region of silicate melts under a temperature gradient. Here, we report that at ultra-high temperatures above approximately 3000 K, SiO2 becomes concentrated in the colder region of the silicate melts under a temperature gradient. The interior of an aluminosilicate glass (63.3SiO2-16.3Al2O3-20.4CaO(mol%)) was irradiated with a 250 kHz femtosecond laser pulse for local heating. SiO2 migrated to the colder region during irradiation with an 800 pulse (3.2 ms irradiation). The temperature analysis indicated that migration to the colder region occurred above 3060 K. In the non-equilibrium molecular dynamics (NEMD) simulation, SiO2 migrated to the colder region under a temperature gradient, which had an average temperature of 4000 K; this result supports the experimental result. SiO2 exhibited a tendency to migrate to the colder region at 2400 K in both the NEMD and experimental study. The second-order like phase transition was observed at ~ 2000-3400 K when calculated using MD without a temperature gradient. Therefore, the second-order phase transition could be related to the migration of SiO2 to colder region. However, the detailed mechanism has not been elucidated

Microscopic mechanism of structural and volume relaxation below glass transition temperature in a soda-lime silicate glass revealed by Raman spectroscopy and its first principle calculations

To elucidate the atomistic origin of volume relaxation in soda-lime silicate glass annealed below the glass transition temperature (Tg), the experimental and calculated Raman spectra were compared. By decomposing the calculated Raman spectra into a specific group of atoms, we found that the Raman peak at 1050 cm-1 corresponds to bridging oxygen with a small Si-O-Si bond angle. The experimental Raman spectra indicated that, during annealing below Tg, a homogenization reaction Q2+Q4->2Q3 proceeds in the early stage of structural relaxation. Then, the Si-O-Si units with relatively small angles decrease even in the later stages, which is first evidence of ring deformation causing volume relaxation of soda-lime silicate glass because decreasing small Si-O-Si angles corresponds to the reduce of acute O-O-O angle in a ring and can expand the space inside the rings, and Na can be inserted into the ring center. In conclusion the ring deformation and Na displacement is the origin of the volume relaxation of soda-lime silicate glass below Tg.Comment: 15 figures and 1 table for main text, 8 figures and 1 table for supplemental inf

Antiplatelet Therapy for Prevention of Thromboembolic Complications Associated with Coil Embolization of Unruptured Cerebral Aneurysms

Background: Antiplatelet agents are used during endovascular treatment of cerebral aneurysms to prevent thromboembolic complications. Objective: The aim of this study was to investigate the efficacy of clopidogrel for the prevention of thromboembolic complications during elective coil embolization of unruptured cerebral aneurysms. Methods: Sixty-three patients prospectively received oral clopidogrel 75mg/day from 3 days before and for 1 day after the procedure at our institute (Kohnan Hospital, Sendai, Japan) during 2007. Results: At 24 hours post-coiling, significantly less high-intensity areas, detected by MRI with diffusion-weighted imaging (MRI-DWI), were observed in clopidogrel-treated patients compared with a historical control cohort of aspirin (acetylsalicylic acid)-treated patients (13/63 [20.6%] vs 27/69 [39.1%]; p = 0.02), primarily due to a statistically significantly lower rate during repair of small (<10mm) lesions (p = 0.008).Also, the rate of periprocedural thromboembolic events was lower in the clopidogrel than the aspirin cohort (2/63 [3.2%] vs 5/69 [7.2%]; p = 0.3). Conclusions: Clopidogrel was generally well tolerated with no signs of hemorrhagic complications or liver dysfunction

Efficient generation of nitrogen-vacancy center inside diamond with shortening of laser pulse duration

We investigated the effect of laser pulse duration on nitrogen-vacancy (NV) center generation inside a single crystal diamond. We compared pulse durations of 40 fs (femtosecond laser) and 1 ps (picosecond laser). We found that in both cases, ensemble NV centers could be generated inside the diamond. However, the maximum photoluminescence intensity of the NV center without graphitization for the 40 fs duration was higher than that for the 1 ps duration. This indicated that the femtosecond laser was harder to graphitize diamond and could generate more NV centers without graphitization. This difference may be due to the difference in the photo-absorption process and the resulting lattice dynamics

Increased Plasma Levels of Platelet Factor 4 and β-thromboglobulin in Women with Recurrent Pregnancy Loss

Thrombosis in decidual vessels is one of the mechanisms of pregnancy loss. However, few studies have assessed the relation between platelet activation, which is known to cause of thrombosis, and recurrent pregnancy loss (RPL). We investigated platelet activation in women with RPL compared to controls by measuring plasma levels of platelet factor 4 (PF4) and β-thromboglobulin (βTG), and assessed correlations between PF4/βTG and coagulative risk factors associated with RPL. The study group included 135 women who had experienced two or more consecutive pregnancy losses. The control group included 28 age-matched healthy women who had never experienced pregnancy loss. PF4 and βTG plasma levels were significantly higher in the women with RPL than controls (PF4: 14.0 [8.0-20.0] vs. 9.0 [6.0-12.0] ng/ml, p=0.043; βTG: 42.0 [24.3-59.8] vs. 31.5 [26.6-36.4] ng/ml, p=0.002). There was a significant association between βTG and anti-phosphatidylethanolamine antibody immunoglobulin M (aPE IgM) (p=0.048). Among the women with RPL, 18 of those who were positive for PF4 (45%) and 18 of those who were positive for βTG (37%) were negative for all known coagulative risk factors associated with RPL. Measurements of PF4 and βTG may be important because they help identify women who are at risk of RPL

Tumor-specific exon creation of the HELLS/SMARCA6 gene in non-small cell lung cancer

In an attempt to identify tumor suppressor genes on chromosome 10 in non-small cell lung cancers, we isolated 10 types of splicing variants of the HELLS/ SMARCA6 gene transcripts. HELLS/SMARCA6 is a novel member of SNF2 family, which is implicated in cellular function like chromatin remodeling. Variant 1 was an alternatively spliced isoform containing an insertion of a 44-ntd intronic sequence between exons 3 and 4, giving rise to a premature termination of translation. The expression of the variant 1 was detected exclusively in the lung cancer specimens (11 of 43 cases, 26%), but was not detected in corresponding normal tissues. D10S520 marker in the proximity of the HELLS/SMARCA6 gene showed prevalent allelic loss (41%) as compared with flanking markers (25-31%). These results suggest that loss of function of HELLS/SMARCA6 by allelic loss and aberrant proteins by tumor-specific exon creation may result in epigenetic deregulation, leading the lung cells to malignancy or its progression

Effect of intracoronary thrombectomy on 30-day mortality in non-diabetic patients with acute hyperglycemia after acute myocardial infarction

SummaryBackgroundThere is limited evidence about useful therapeutic interventions for patients with acute hyperglycemia (AH) after acute myocardial infarction (AMI).MethodsWe studied 2433 consecutive non-diabetic AMI patients who underwent percutaneous coronary intervention (PCI) within 24h after the onset. Patients were divided into two groups according to the presence or absence of AH (admission serum glucose level ≥11.1mmol/l). We assessed the association between intracoronary thrombectomy and the clinical outcome in AMI patients with AH.ResultsPatients with AH had more risk factors than those without AH. The 30-day mortality rate of patients with AH was significantly higher than that of those without (11.7% vs 1.7%, p<0.001). Among patients with AH, the 30-day mortality rate was significantly lower for those with intracoronary thrombectomy than those without it (4.9% vs 17.2%, p=0.004). Among patients without AH, however, the 30-day mortality rate was similar between those with and without intracoronary thrombectomy (1.5% vs 1.9%, p=NS). Multivariate analysis showed that intracoronary thrombectomy was associated with an improved 30-day mortality rate for patients with AH (hazard ratio: HR 0.184, 95% CI 0.057–0.598, p=0.005).ConclusionsIn AMI patients with AH, intracoronary thrombectomy prior to PCI might improve the 30-day mortality rate

Singlet oxygen -derived nerve growth factor exacerbates airway hyperresponsiveness in a mouse model of asthma with mixed inflammation

Background: Refractory asthma, which is caused by several factors including neutrophil infiltration is a serious complication of bronchial asthma. We previously reported that nerve growth factor (NGF) is involved in AHR. NGF-derived induction of hyperalgesia is dependent on neutrophils; however, this relationship remains unclear in respiratory disease. In this study, we examined the roles of neutrophils and NGF in refractory asthma. Methods: Using intranasal house dust mite sensitization, we established a mouse model of asthma with mixed inflammation (Mix-in). AHR, NGF production and hyperinnervation of the lungs were examined with or without different inhibitory treatments. The levels of the singlet oxygen markers, 10- and 12-(Z,E)-hydroxyoctadecadienoic acids (HODE) in the lungs, were measured by liquid chromatography-tandem mass spectrometry. An in vitro experiment was also performed to evaluate the direct effect of singlet oxygen on NGF production. Results: NGF production and hyperinnervation were higher in Mix-in mice than in conventional eosinophilic-asthmatic mice and were positively correlated with AHR. Asthmatic parameters were inhibited by NGF neutralizing Abs and myeloperoxidase (MPO) inhibition. The 10- and 12-(Z,E)-HODEs levels were increased in the lungs and were positively correlated with MPO activity and NGF production. NGF was produced by bronchial epithelial cells in vitro upon stimulation with singlet oxygen. Conclusions: Our findings suggest that neutrophil MPO-derived singlet oxygen induces increased NGF production, leading to AHR and 10- and 12-(Z,E)-HODEs production. These findings may help to develop new therapies targeting this mechanism and to establish a new biomarker for non-type 2 and refractory asthma