Enhancing Amplification in Compliant Mechanisms: Optimization of Plastic Types and Injection Conditions.

This study surveys the impacts of injection parameters on the deformation rate of the injected flexure hinge made from ABS, PP, and HDPE. The flexure hinges are generated with different filling time, filling pressure, filling speed, packing time, packing pressure, cooling time, and melt temperature. The amplification ratio of the samples between different injection parameters and different plastic types is measured and compared to figure out the optimal one with a high amplification ratio. The results show that the relationship between the input and output data of the ABS, PP, and HDPE flexure hinges at different injection molding parameters is a linear relation. Changing the material or many injection molding parameters of the hinge could lead to a great impact on the hinge's performance. However, changing each parameter does not lead to a sudden change in the input and output values. Each plastic material has different optimal injection parameters and displacement behaviors. With the ABS flexure hinge, the filling pressure case has the greatest amplification ratio of 8.81, while the filling speed case has the lowest value of 4.81. With the optimal injection parameter and the input value of 105 µm, the ABS flexure hinge could create a maximum average output value of 736.6 µm. With the PP flexure hinge, the melt temperature case achieves the greatest amplification ratio of 6.73, while the filling speed case has the lowest value of 4.1. With the optimal injection parameter and the input value of 128 µm, the PP flexure hinge could create a maximum average output value of 964.8 µm. The average amplification ratio values of all injection molding parameters are 6.85, 5.41, and 4.01, corresponding to ABS, PP, and HDPE flexure hinges. Generally, the ABS flexure hinge has the highest amplification ratios, followed by the PP flexure hinge. The HDPE flexure hinge has the lowest amplification ratios among these plastic types. With the optimal injection parameter and the input value of 218 µm, the HDPE flexure hinge could create a maximum average output value of 699.8 µm. The results provide more insight into plastic flexure hinges and broaden their applications by finding the optimal injection parameters and plastic types.

Effect of Initial Vancomycin Dose and Creatinine Clearance on the Attainment of Target Trough Concentration in Children.

BACKGROUND: Vancomycin is a glycopeptide antibiotic that is used to treat serious grampositive infections. However, therapeutic drug monitoring for vancomycin is not performed routinely in Vietnam in clinical practices. Monitoring of serum vancomycin concentration or trough levels is necessary to ensure the efficacy and safety of vancomycin therapy. OBJECTIVE: This study aims to determine the impact of initial vancomycin dose and creatinine clearance on target trough attainment in hospitalized Vietnamese children. METHODS: A prospective study with patients who received vancomycin for at least three days was conducted. Subsequently, demographic data, clinical diagnosis, vancomycin dosage, and serum creatinine levels were recorded. The vancomycin trough level was collected and creatinine clearance and adjusted vancomycin doses were calculated. RESULTS: A total of 40 eligible patients were enrolled. Patients' mean age, body weight, and height were 1.4 years old, 9.8 kg, and 75.5 cm, respectively. The mean vancomycin dose was 55.83 ± 19.34 mg/kg/day. The mean creatinine clearance was 80.18 ± 29.14 ml/min. The median trough level was 11.09 (7.84 - 16.46) µg/ml. There was no significant difference in the mean initial and the adjusted vancomycin doses (p = 0.062). However, there were statistically significant differences of initial (p = 0.004) or adjusted doses (p = 0.016) between groups of creatinine clearance. The trough vancomycin concentration was not statistically significant (p = 0.406) between these groups. CONCLUSION: Target trough vancomycin level may be associated with creatinine clearance but did not proportionally correspond to the vancomycin dose. Therefore, monitoring vancomycin trough levels is necessary to achieve the target trough and to ensure vancomycin efficacy and safety in treating severely infected Vietnamese children.

Neutralizing Antibodies against Enteroviruses in Patients with Hand, Foot and Mouth Disease.

Hand, foot and mouth disease (HFMD) is an emerging infection with pandemic potential. Knowledge of neutralizing antibody responses among its pathogens is essential to inform vaccine development and epidemiologic research. We used 120 paired-plasma samples collected at enrollment and >7 days after the onset of illness from HFMD patients infected with enterovirus A71 (EV-A71), coxsackievirus A (CVA) 6, CVA10, and CVA16 to study cross neutralization. For homotypic viruses, seropositivity increased from <60% at enrollment to 97%-100% at follow-up, corresponding to seroconversion rates of 57%-93%. Seroconversion for heterotypic viruses was recorded in only 3%-23% of patients. All plasma samples from patients infected with EV-A71 subgenogroup B5 could neutralize the emerging EV-A71 subgenogroup C4. Collectively, our results support previous reports about the potential benefit of EV-A71 vaccine but highlight the necessity of multivalent vaccines to control HFMD.

Classifying prostate cancer patients based on total prostate-specific antigen and free prostate-specific antigen features by support vector machine.

AIMS OF STUDY: In this work, we enhanced the role of prostate-specific antigen (PSA) test by examining the relation between free PSA (fPSA) and total PSA (tPSA) value and other biological information such as age and volume of prostate. Our primary goal is to find an approach that improves the sensitivity but still give a reasonable specificity. SUBJECTS AND METHODS: We proposed a new approach to predict the prostate cancer (PCa) based on tPSA, fPSA, age, and prostate volume by using combination of statistical techniques and support vector machine (SVM). Our approach detected PCa based on following two steps: Classifying patients into normal or abnormal group by means of SVM method and then predicting which patients in abnormal group with PCa. RESULTS: The sensitivity of our system was 95.1%, whereas the specificity was acceptable (84.6%). The positive biopsy rate was 58% while the unnecessary biopsy rate was 15.4%. We further developed a program to assist clinicians in predicting PCa. CONCLUSIONS: Applying SVM not only improved the performance of PSA test in screening and detecting PCa but also explored some molecular information. Based on the information, we can discover more knowledge about cancer disease.

Factors associated with nosocomial SARS-CoV transmission among healthcare workers in Hanoi, Vietnam, 2003.

BACKGROUND: In March of 2003, an outbreak of Severe Acute Respiratory Syndrome (SARS) occurred in Northern Vietnam. This outbreak began when a traveler arriving from Hong Kong sought medical care at a small hospital (Hospital A) in Hanoi, initiating a serious and substantial transmission event within the hospital, and subsequent limited spread within the community. METHODS: We surveyed Hospital A personnel for exposure to the index patient and for symptoms of disease during the outbreak. Additionally, serum specimens were collected and assayed for antibody to SARS-associated coronavirus (SARS-CoV) antibody and job-specific attack rates were calculated. A nested case-control analysis was performed to assess risk factors for acquiring SARS-CoV infection. RESULTS: One hundred and fifty-three of 193 (79.3%) clinical and non-clinical staff consented to participate. Excluding job categories with < 3 workers, the highest SARS attack rates occurred among nurses who worked in the outpatient and inpatient general wards (57.1, 47.4%, respectively). Nurses assigned to the operating room/intensive care unit, experienced the lowest attack rates (7.1%) among all clinical staff. Serologic evidence of SARS-CoV infection was detected in 4 individuals, including 2 non-clinical workers, who had not previously been identified as SARS cases; none reported having had fever or cough. Entering the index patient's room and having seen (viewed) the patient were the behaviors associated with highest risk for infection by univariate analysis (odds ratios 20.0, 14.0; 95% confidence intervals 4.1-97.1, 3.6-55.3, respectively). CONCLUSION: This study highlights job categories and activities associated with increased risk for SARS-CoV infection and demonstrates that a broad diversity of hospital workers may be vulnerable during an outbreak. These findings may help guide recommendations for the protection of vulnerable occupational groups and may have implications for other respiratory infections such as influenza.