A Simple One-Scale Constitutive Model for Static Liquefaction of Sand-Silt Mixtures

Instability of liquefaction is one of the major reasons which results in the failure of earth structure such as dam. The present study focuses on the simulation of static liquefaction behavior for granular materials such as sand and sand-silt mixtures. Based on micromechanical analysis of inter-particle behavior, a simple one-scale model is proposed to simulate the stress-strain response of sand; then the proposed model is extended to simulate the sand-silt mixtures using the mixture theory combining the properties of sand and silt according to their proportions. Empirical expressions are introduced to fit the critical state strength and the location of the critical state line for each mixture. Parameters of the model can be divided into two categories: the first seven parameters have the same values either with pure sand or pure silt for silt-sand with any given fines content; the other three parameters are the function of fines content and three more parameters are required to estimate their values. The predicted results of triaxial test of sand and sand-silt mixtures with different fine content, which has a good agreement with the results of laboratory tests, suggest that the proposed model can simulate static liquefaction behavior of sand and sand-silt mixtures

Childhood tuberculosis in southern Taiwan, with emphasis on central nervous system complications

Background/PurposeChildhood tuberculosis (TB) continues to be a major public health problem in Taiwan. Taiwan remains a highly endemic area despite neonatal Bacillus Calmette–Guérin (BCG) vaccination and the availability of anti-TB therapy. The presentation is highly variable and it is often difficult to make an accurate diagnosis. This study was designed to evaluate the demographic, clinical, and laboratory findings and outcomes of TB in children with emphasis on central nervous system (CNS) complications.MethodsThe medical records of 80 children diagnosed with TB at a medical center in southern Taiwan over the past 24 years (1988–2012) were reviewed.ResultsAmong them, 48.8% (39/80) had pulmonary TB, 27.5% (22/80) had isolated extrapulmonary TB, and 23.7% (19/80) had disseminated TB. Most infected cases were aged either < 4 years or > 12 years. TB contact history was found in 42.5% (34/80) cases. Fourteen (17.5%) of the cases had CNS involvement. The most common presentations were fever (85.7%), signs of increased intracranial pressure (71.4%), drowsiness (64.3%), and focal neurological signs (57.1%). The major radiological findings were tuberculoma (50%), basilar enhancement (41.6%), infarction (41.6%), hydrocephalus (16.6%), and transverse myelitis (16.6%). The case fatality of CNS TB was 14.3% and 21.4% had neurologic sequelae.ConclusionFindings suggest that positive exposure history and suspicious clinical presentations are important clues for further confirmatory laboratory and image studies in childhood TB. CNS TB usually presented as part of disseminated TB in children. Early diagnosis and treatment may lead to favorable outcomes in CNS TB

Experiences with a simple laparoscopic gastric tube construction

BACKGROUND: Minimally invasive esophagectomy (MIE) is a complex operation, and the detailed optimal surgical procedure has not been well described. Our aim was to evaluate use of a simple method of laparoscopic gastric tube construction as minimally invasive surgery for patients with esophageal cancer. METHODS: We performed a retrospective review of 26 consecutive patients who underwent MIE for esophageal cancer in the Koo Foundation Sun Yat-Sen Cancer Center between September 2009 and August 2011. Perioperative data and postoperative complications were statistically analyzed. RESULTS: The patient group consisted of 22 men and 4 women. MIE was performed successfully in all patients. The mean operative time was 430.4 ± 60.6 minutes, and the mean estimated operative blood loss was 135.0 ± 97.8 mL. There were no cases of conversion to open surgery during the procedure. The postoperative complication rate was 53.8%, and there was no surgical mortality. CONCLUSIONS: We recommend this novel method of total laparoscopic staplized formation of gastric tube to facilitate gastric pull-up

Variation Analysis of Sphygmogram to Assess Cardiovascular System under Meditation

In this article, we studied how meditation affects the characteristics of the cardiovascular system, mainly based on blood pressure waveforms (BPW). Four parameters derived from BPW include the rising slope (h1/t1), normalized height of T wave (h3/h1), normalized height of V3 valley (h4/h1) and normalized height of D wave (h5/h1), where t1 and hi, i = 1, … ,5 are quantitative features of the BPW waveform pattern. A larger value of h1/t1 reflects better heart ejection ability and aorta compliance. A larger value of h3/h1 may infer an arterial system with good elasticity. The decrease (increase) of h4/h1 parameter indicates the decrease (increase) of peripheral resistance of vessels. A larger value of h5/h1 indicates better artery elasticity and aortic valve function. In comparison with the control group, Zen-meditation practitioners have more after-meditation h1/t1, h3/h1 and h5/h1 increase, with more h4/h1 decrease, with statistical significance (P < 0.05). The observation allows us to infer that Zen meditation may effectively improve relevant characteristics of the cardiovascular system

Variation Analysis of Sphygmogram to Assess Cardiovascular System under Meditation

In this article, we studied how meditation affects the characteristics of the cardiovascular system, mainly based on blood pressure waveforms (BPW). Four parameters derived from BPW include the rising slope (h1/t1), normalized height of T wave (h3/h1), normalized height of V3 valley (h4/h1) and normalized height of D wave (h5/h1), where t1 and hi, i = 1, … ,5 are quantitative features of the BPW waveform pattern. A larger value of h1/t1 reflects better heart ejection ability and aorta compliance. A larger value of h3/h1 may infer an arterial system with good elasticity. The decrease (increase) of h4/h1 parameter indicates the decrease (increase) of peripheral resistance of vessels. A larger value of h5/h1 indicates better artery elasticity and aortic valve function. In comparison with the control group, Zen-meditation practitioners have more after-meditation h1/t1, h3/h1 and h5/h1 increase, with more h4/h1 decrease, with statistical significance (P < 0.05). The observation allows us to infer that Zen meditation may effectively improve relevant characteristics of the cardiovascular system

Long-term Characteristics of Healthcare-associated Infections in a Neonatal Intensive Care Unit

Background/PurposeHealthcare-associated infections in neonatal intensive care units (NICUs) are associated with a significant risk of morbidity and mortality. Knowledge regarding pathogens, primary sources of infection and antibiotic resistance in the NICU is essential for developing management strategies. This study aimed to analyze the long-term characteristics of healthcare-associated infections in a tertiary referral center in southern Taiwan.MethodsInfants < 30 days old, with positive blood, cerebrospinal fluid, urine or tissue fluid cultures during hospitalization in the NICU of National Cheng Kung University Hospital from July 1989 to June 2008 were included in the study.ResultsIn total, 1,417 organisms and episodes were identified during the study period. Gram-positive organisms, Gram-negative organisms and fungi constituted 923 (65.1%), 358 (25.3%) and 136 (9.6%) of the pathogens, respectively. Of the Gram-positive organisms, coagulase-negative staphylococci (51.5%), Staphylococcus aureus (34.8%) and Enterococcus spp. (6.1%) were the major pathogens; and 27% of Staphylococcus aureus isolates were oxacillin-resistant. For the Gram-negative organisms, Klebsiella pneumoniae (22%), Pseudomonas aeruginosa (21.8%), Escherichia coli (16.7%) and Enterobacter cloacae (16.7%) were dominant. Also, Candida albicans accounted for 50% of fungal infections. The most common source of infection was bloodstream infection (59.0%), and 5.6% of these were catheter-related. Skin and soft tissue infections were also frequent (26.3%).ConclusionBloodstream and skin/soft tissue infections caused by commensal species play an important role in healthcare-associated infections in the NICU. New measures should be developed in response to the changing patterns in the NICU

Clinical Outcome of Mycobacterium abscessus Infection and Antimicrobial Susceptibility Testing

Background/PurposeMycobacterium abscessus is the most resistant and rapidly growing mycobacterium and causes a wide range of clinical infectious diseases. The relationship between antimicrobial susceptibility and clinical outcome needs to be further evaluated.MethodsForty M. abscessus isolates were obtained from clinical specimens of 40 patients at the Taichung Veterans General Hospital from January 2006 to December 2008. Antimicrobial susceptibility testing was performed using the broth microdilution method according to the recommendations of the National Committee for Clinical Laboratory Standards. The clinical manifestations and outcomes were reviewed from medical records.ResultsTwenty-two patients were diagnosed with M. abscessus infection. Cough (86.3%), hemoptysis (31.8%) and fever (18.1%) were the most common symptoms. The radiographic findings included reticulonodular opacities (50.0%), consolidation (31.8%) and cavitary lesions (18.1%). The 40 isolates were susceptible to amikacin (95.0%), cefoxitin (32.5%), ciprofloxacin (10.0%), clarithromycin (92.5%), doxycycline (7.5%), imipenem (12.5%), moxifloxacin (22.5%), sulfamethoxazole (7.5%) and tigecycline (100%). The rate of treatment failure was 27.3% at the end of the 12th month after the start of treatment, although these patients were treated with a combination of clarithromycin and other antimicrobial agents.ConclusionM. abscessus is naturally susceptible to clarithromycin and amikacin, variably susceptible to cefoxitin and imipenem, and resistant to most other antimicrobial drugs. Combination therapy with clarithromycin, amikacin and other active antimicrobial agents may lead to clinical improvement; however, the rate of treatment failure is still high