335 research outputs found

    Atomic and magnetic structures of (CuCl)LaNb2_2O7_7 and (CuBr)LaNb2_2O7_7: Density functional calculations

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    The atomic and magnetic structures of (CuXX)LaNb2_2O7_7 (XX=Cl and Br) are investigated using the density-functional calculations. Among several dozens of examined structures, an orthorhombic distorted 2×22\times 2 structure, in which the displacement pattern of XX halogens resembles the model conjectured previously based on the empirical information is identified as the most stable one. The displacements of XX halogens, together with those of Cu ions, result in the formation of XX-Cu-XX-Cu-XX zigzag chains in the two materials. The nearest-neighbor interaction within the zigzag chains are determined to be antiferromagnetic (AFM) for (CuCl)LaNb2_2O7_7 but ferromagnetic (FM) for (CuBr)LaNb2_2O7_7. On the other hand, the first two neighboring interactions between the Cu cations from adjacent chains are found to be AFM and FM respectively for both compounds. The magnitudes of all these in-plane exchange couplings in (CuBr)LaNb2_2O7_7 are evaluated to be about three times those in (CuCl)LaNb2_2O7_7. In addition, a sizable AFM inter-plane interaction is found between the Cu ions separated by two NbO6_6 octahedra. The present study strongly suggests the necessity to go beyond the square J1J2J_1-J_2 model in order to correctly account for the magnetic property of (CuX)X)LaNb2_2O7_7.Comment: 24 pages, 7 figure

    Bacteremic pneumonia caused by Nocardia veterana in an HIV-infected patient

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    SummaryDisseminated Nocardia veterana infection has rarely been reported. We describe the first reported case of N. veterana bacteremic pneumonia in an HIV-infected patient. The isolate was confirmed by 16S rRNA sequencing analysis. The patient initially responded well to trimethoprim–sulfamethoxazole treatment (minimum inhibitory concentration 0.25μg/ml), but died of ventilator-associated pneumonia

    Estimation of measurement uncertainty caused by surface gradient for a white light interferometer

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    Although the Scanning White Light Interferometer can provide measurement results with sub-nanometer resolution, the measurement accuracy is far from perfect. The surface roughness and surface gradient have significant influence on the measurement uncertainty since the corresponding height differences within a single CCD pixel cannot be resolved. This paper presents an uncertainty estimation method for estimating the measurement uncertainty due to the surface gradient of the workpiece. The method is developed based on the mathematical expression of an uncertainty estimation model which is derived and verified through a series of experiments. The results show that there is a notable similarity between the predicted uncertainty from the uncertainty estimation model and the experimental measurement uncertainty, which demonstrates the effectiveness of the method. With the establishment of the proposed uncertainty estimation method, the uncertainty associated with the measurement result can be determined conveniently

    Reversine suppresses oral squamous cell carcinoma via cell cycle arrest and concomitantly apoptosis and autophagy

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    <p>Abstract</p> <p>Background</p> <p>The effective therapies for oral cancer patients of stage III and IV are generally surgical excision and radiation combined with adjuvant chemotherapy using 5-Fu and Cisplatin. However, the five-year survival rate is still less than 30% in Taiwan. Therefore, evaluation of effective drugs for oral cancer treatment is an important issue. Many studies indicated that aurora kinases (A, B and C) were potential targets for cancer therapies. Reversine was proved to be a novel aurora kinases inhibitor with lower toxicity recently. In this study, the potentiality for reversine as an anticancer agent in oral squamous cell carcinoma (OSCC) was evaluated.</p> <p>Methods</p> <p>Effects of reversine on cell growth, cell cycle progress, apoptosis, and autophagy were evaluated mainly by cell counting, flow cytometry, immunoblot, and immunofluorescence.</p> <p>Results</p> <p>The results demonstrated that reversine significantly suppressed the proliferation of two OSCC cell lines (OC2 and OCSL) and markedly rendered cell cycle arrest at G2/M stage. Reversine also induced cell death via both caspase-dependent and -independent apoptosis. In addition, reversine could inhibit Akt/mTORC1 signaling pathway, accounting for its ability to induce autophagy.</p> <p>Conclusions</p> <p>Taken together, reversine suppresses growth of OSCC via multiple mechanisms, which may be a unique advantage for developing novel therapeutic regimens for treatment of oral cancer in the future.</p

    Bacteremic pneumonia caused by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae: Appropriateness of empirical treatment matters

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    BackgroundClinical information about bacteremic pneumonia caused by extended-spectrum beta-lactamase (ESBL)-producing organism is limited.MethodsA retrospective study was conducted at two medical centers in Taiwan. From May 2002 to August 2010, clinical information and outcome of adults with bacteremic pneumonia caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae were analyzed. The primary outcome is the 30-day mortality.ResultsA total of 111 patients with bacteremic pneumonia caused by E. coli (37 patients, 33.3%) and K. pneumoniae (74, 66.7%) were identified. Their mean age was 69.2 years and 51.4% were male patients. Fifty-seven (51.3%) episodes were classified as hospital-acquired infections, 19 (17.1%) as health-care-associated infections, and four (3.6%) as community-acquired infections. Fifty-one (45.9%) patients received appropriate empiric antimicrobial therapy. The 30-day mortality rate was 40.5% (45 patients). In the multivariate analysis, several independent risk factors, including rapidly fatal underlying disease [odds ratio (OR), 5.75; 95% confidence interval (CI), 1.54–21.48; p = 0.009], severe sepsis (OR, 4.84; 95% CI, 1.55–15.14; p = 0.007), critical illness (OR, 4.28; 95% CI, 1.35–13.57; p = 0.013), and receipt of appropriate empirical therapy (OR, 0.19; 95% CI, 0.07–0.55; p = 0.002), were associated with 30-day mortality. The survival analysis consistently found that individuals with appropriate empiric therapy had a higher survival rate (log-rank test, p < 0.001).ConclusionESBL-producing bacteremic pneumonia, especially health-care-associated infections, often occurred in adults with comorbidities. Appropriate empirical therapy was associated with a favorable outcome

    A study of real-time spindle error compensation in single-point diamond turning of optical micro-structured patterns on precision rollers

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    Micro-structured patterns are widely used in optics since the optical performance can be significantly improved in many applications [1]. One of the most common methods to fabricate the micro-structure is using Single-Point Diamond Turning on Precision Rollers [2]. The accuracy requirement of the Precision Rollers is stringent because the dimension of the microstructure is very small (pitch lengths and depths 10-100μm) and surface finishing is ultra-smooth (Ra<3nm) [2]. In order to achieve this level of accuracy, the manufacturing errors of the machine tool are required to be reduced while error compensation methods are needed to be developed. Spindle errors can be classified as synchronous error and asynchronous error [3]. Synchronous error occurs at integer times of spindle rotation frequency and can be represented as repeatable error while asynchronous error occurs at noninteger times of spindle rotation frequency and can be represented as non-repeatable error. Most of the existing error compensation techniques are based on offline error compensation methods (OECM) which can only compensate the synchronous error [4,5]. The asynchronous error is fluctuating without a predictable value and it is different from the synchronous error so it cannot be eliminated using OECM. One of the most promising methods to compensate the asynchronous error is real-time error compensation method (RECM). Some researchers have studied the RECM and their results showed that it was effective to enhance the machine accuracy [6,7]. However, most of the previous research work is focused on the machine tools with a relatively low accuracy and there is relatively few studies focused on the Single-Point Diamond Turning. Kim and Kim developed a feed-forward control of fast tool servo system for real-time correction of spindle error for diamond turning of flat surfaces [8]. A capacitive displacement sensor was used to measurement the spindle axial error motion and the motion error was compensated using a fast tool servo. A flatness of 0.1μm was achieved with a 100mm diameter aluminum specimen. However, the study only considered the axial error, when it is diamond turned on precision rollers, both the radial error and axial error have to be compensated. This paper attempts to investigate the RECM in Single-Point Diamond Turning of Optical Microstructured Patterns on Precision Rollers. The radial error and axial error were simulated and the compensated results of OECM and RECM were presented considering both synchronous errors and asynchronous errors in radial and axial directions. The results of OECM and RECM were also compared and discussed. Furthermore, the effects of time delay in RECM were studied. An adaptive time-series modeling method was also proposed to predict the realtime error to reduce the time delay effect of RECM. The results show that the RECM is effective and promising to further improve the accuracy of the Single-Point Diamond Turning Precision Rollers

    Effects of Growth Hormone Treatment on Height, Weight, and Obesity in Taiwanese Patients with Prader-Willi Syndrome

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    BackgroundInformation regarding the efficacy of growth hormone (GH) therapy in Asian Prader-Willi syndrome (PWS) patients is lacking. We report our experience with GH treatment in children with PWS in Taiwan.MethodsForty-six PWS patients (27 males, 19 females; age range, 1 year 4 months to 13 years 7 months) who received and/or who are currently receiving GH treatment (0.1 IU/kg/day subcutaneously) for a period from 1 year to 3 years were retro-spectively analyzed. We evaluated height, weight, body mass index (BMI) and Rohrer index, before and after GH treatment.ResultsAfter patients had received GH for 1, 2 and 3 years, a significant improvement in mean height standard deviation score (SDS) was noted from −1.24 to −0.31 (p <0.01), 0.00 (p <0.001) and −0.26 (p <0.001), respectively. Mean BMI SDS decreased significantly from 1.93 to 1.13 (p <0.05) after 1 year of treatment; however, no significant changes were observed afterward. Mean Rohrer index decreased significantly, from 224.2 to 186.6 (p <0.001), 178.9 (p <0.001) and 169.3 (p <0.001). No significant gender or genotype pattern differences were noted among the 4 parameters examined.ConclusionThis 3-year, retrospective study indicates that PWS patients benefit from GH therapy in height increase and improved body composition

    Reciprocal regulation of MicroRNA-99a and insulin-like growth factor I receptor signaling in oral squamous cell carcinoma cells

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    BACKGROUND: MicroRNAs (miRNAs), small noncoding RNA molecules can function as oncogenes or tumor suppressors in tumorigenesis. Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers worldwide with a 5-year survival rate of approximately 50%. METHODS: The expression of microRNA-99a (miR-99a) in OSCC tissues and cell lines was investigated using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis. The functions of miR-99a in migration/invasion and lung colonization were determined by transwell and tail vein injection assays, respectively. Specific targets of miR-99a were determined by software prediction, correlation with target protein expression, and luciferase reporter assay. The signaling pathways involved in regulation of miR-99a were investigated using the kinase inhibitors. RESULTS: We observed reduced levels of miR-99a, identified as one of the most downregulated miRNA in OSCC and all tested OSCC cell lines compared to normal oral keratinocytes. Ectopic miR-99a expression in OSCC cells markedly reduced migration and invasion in vitro as well as lung colonization in vivo. When evaluating the specific targets of miR-99a, we found that ectopic miR-99a expression downregulates insulin-like growth factor 1 receptor (IGF1R) protein and that the expression of miR-99a correlates negatively with IGF1R protein in OSCC cells. Insertion of the 3′UTR of IGF1R mRNA into the 3′UTR of a reporter gene markedly reduced luciferase activity in OSCC cells expressing miR-99a, suggesting that miR-99a reduces luciferase activity by targeting the 3′UTR of IGF1R mRNA. When evaluating the mechanisms of miR-99a downregulation, we observed the upregulation of miR-99a expression in serum-starved conditions and its suppression in response to insulin-like growth factor (IGF1) stimulation. Inhibitors of phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) kinase inhibited IGF1-induced suppression of miR-99a, suggesting the negative regulation of miR-99a expression by IGF1R signaling. CONCLUSION: Overall, results indicate that miR-99a functions as a tumor metastasis suppressor in OSCC cells and mutually regulates IGF1R expression in a reciprocal regulation

    Improved Breath Phase and Continuous Adventitious Sound Detection in Lung and Tracheal Sound Using Mixed Set Training and Domain Adaptation

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    Previously, we established a lung sound database, HF_Lung_V2 and proposed convolutional bidirectional gated recurrent unit (CNN-BiGRU) models with adequate ability for inhalation, exhalation, continuous adventitious sound (CAS), and discontinuous adventitious sound detection in the lung sound. In this study, we proceeded to build a tracheal sound database, HF_Tracheal_V1, containing 11107 of 15-second tracheal sound recordings, 23087 inhalation labels, 16728 exhalation labels, and 6874 CAS labels. The tracheal sound in HF_Tracheal_V1 and the lung sound in HF_Lung_V2 were either combined or used alone to train the CNN-BiGRU models for respective lung and tracheal sound analysis. Different training strategies were investigated and compared: (1) using full training (training from scratch) to train the lung sound models using lung sound alone and train the tracheal sound models using tracheal sound alone, (2) using a mixed set that contains both the lung and tracheal sound to train the models, and (3) using domain adaptation that finetuned the pre-trained lung sound models with the tracheal sound data and vice versa. Results showed that the models trained only by lung sound performed poorly in the tracheal sound analysis and vice versa. However, the mixed set training and domain adaptation can improve the performance of exhalation and CAS detection in the lung sound, and inhalation, exhalation, and CAS detection in the tracheal sound compared to positive controls (lung models trained only by lung sound and vice versa). Especially, a model derived from the mixed set training prevails in the situation of killing two birds with one stone.Comment: To be submitted, 31 pages, 6 figures, 5 table
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