Evaluation of the Martin et al. (1975) Pore Pressure Build Up Model Using Laboratory Test Data

Liquefaction has occurred during numerous earthquakes and it has caused damages and catastrophic failures. This phenomenon takes place due to the excess pore pressure development in loose saturated granular soils. Researchers have attempted to predict these phenomena (excess pore water pressure and liquefaction) using constitutive modeling and numerical approaches. In this paper, a numerical modeling procedure is presented to predict the seismic excess pore water pressure using a fully coupled effective stress analysis. A few cyclic and monotonic element tests and a level ground centrifuge test conducted during VELACS project were utilized to calibrate the numerical models. The Mohr-Coulomb elastic-perfectly plastic and the Martin et. al. (1975) excess pore water pressure build up models were concurrently incorporated in the analysis. This study focuses on a reasonable step by step procedure in order to adjust and obtain the calibration parameters of these models. Comparing the excess pore pressure buildup time histories of the numerical and experimental models (both element and centrifuge tests) showed that the Martin et al. (1975) models can be used in the numerical assessment of excess pore water pressure with an acceptable degree of preciseness

Evaluation of bacterial and fungal contamination in the health care workers? hands and rings in the intensive care unit

Introduction. Nosocomial infections remain a major challenge to the health care system and result in significant mortality, morbidity, and economic burden. Intensive care unit (ICU) patients are at great risk of acquiring nosocomial infections. The objective of this study was to determine the contamination rate (bacterial and fungal) of the health care workers? (HCWs?) hands and ring in ICU. Methods. All health care workers were screened during the day shift in Emam hospital ICU. After obtaining informed consent, convenience samples of HCWs? hands and rings were cultured on specific media during their routine work hours, always after a patient care episode. The fungal and bacterial isolates were identified using standard microbiological procedures. Results. A total of 40 subjects were selected in this study (28females, 12males). The rate of contamination of hands and rings was observed in 73.1%. Most of isolates are known to cause nosocomial infections which included: 23% staphylococci, 7.9% Klebsiella spp., 4.7% Enterobacter spp., 3.9% Escherichia coli, 3.1% Acinetobacter spp., 2.3% Pseudomonas spp., and 27.7% were colonized with fungi. The fungal isolates were 16.6% Candida spp., 3.9% Rhodotorula spp., 3.1% Aspergillus niger, and 3.9% Aspergillus flavus. Conclusion. According to these results HCWs? hands and their rings were contaminated with various types of microorganisms. Medical and hospital personals must follow careful hand-washing techniques to minimize transmission of disease and should remove rings, watches, and bracelets before washing their hands and entering the ICU

Analisa Pengaruh Jumlah Sirip Pada Coil Radiant Cooling Terhadap Performa Pendingin

Baru-baru ini, beberapa penelitian membahas penghematan energi yang dapat dicapai oleh radiant cooling system dan diperoleh bahwa sistem pendinginan radiasi dapat menghemat energi pengguna sekitar 40 dibandingkan dengan sistem pendinginan konvensional. Salah satu cara untuk meningkatkan performa pendinginan dari coil radiant cooling adalah dengan menambahkan sirip pada pipa-pipa yang digunakan dalam sistem tersebut. Untuk melakukan analisa pengaruh jumlah sirip pada coil radiant cooling terhadap performa pendinginan, dapat dilakukan dengan melakukan pengukuran suhu udara di sekitar pipa dengan menggunakan atau tanpa menggunakan sirip. Dalam penelitian menggunakan metode percobaan alat pendingin langsung dan penelitian kepustakaan ini untuk mengetahui pengaruh jumlah sirip pada coil radiant cooling terhadap performa pendinginan dan memberikan rekomendasi yang berguna untuk pengembangan coil radiant cooling yang lebih efektif dalam pendinginan. Hasil laju perpindahan panas ini didapatkan dari perhitungan data yang paling rendah pada sirip 10 dengan nilai 21.164 kj/kg dan untuk paling tinggi pada sirip 4 dengan nilai 23.077 kj/kg. Hasil nilai laju perpindahan panas ini menunjukan pada sirip 4 paling tinggi dibandingkan variasi sirip 6, 8, dan 10 disebabkan oleh perbedaan suhu dinding evaporator yang tinggi membuat proses pendinginan melalui media air menjadi lebih cepat. Dari data perhitungan COP di didapat nilai yang berbeda-beda dikarenakan pengaruh dari koefisien konveksi termal yang di pengaruhi oleh perbedaan jumlah sirip yang digunakan. Pada variasi jumlah sirip 10 lebih efisien dikarenakan nilai COP berbanding terbalik dengan biaya operasional, apabila COP lebih tinggi maka biaya operasional yang dikeluarkan akan menjadi lebih rendah Pengaruh variasi jumlah sirip pada radiant cooling terhadap performa kinerja mesin pendingin adalah pada penelitian ini bisa di lihat pada nilai Efficiency energy ratio (EER) dimana pada jumlah sirip 10 dengan nilai 22,64 paling tinggi daripada variasi jumlah sirip 4, 6, 8. Kata Kunci: Radiant Cooling, Jumlah Sirip, COP, EE

The Influence of Pearlite Volume Fraction on Rayleigh Wave Propagation in A572 Grade 50 Steel

The acoustoelastic effect is the interaction between ultrasonic wave velocity and stress. To estimate the stress a perturbation signal is introduced and the shift in time of flight is measured at the receiving location. In addition to the stress, the wave velocity can be affected by the amount of phases in the material’s microstructure. This study investigates the changes in Rayleigh wave velocity for A572 grade 50 steel as a function of stress and pearlite phase volume fraction. In order to obtain different amounts of pearlite the samples are heat treated at 970 °C for time durations of 30 min, 1 hour, 2 hours and 4 hours and then furnace cooled. The acoustoelastic coefficient for 0.5 and 1 MHz perturbation frequency is calculated by uniaxial loading of each heat treated plate while measuring ultrasonic wave velocity. The results are compared for pearlite phase volume fraction obtained from optical microscopy and hardness measurements

The lifelong maintenance of mesencephalic dopaminergic neurons by Nurr1 and engrailed

Specific vulnerability and degeneration of the dopaminergic neurons in the substantia nigra pars compacta of the midbrain is the pathological hallmark of Parkinson’s disease. A number of transcription factors regulate the birth and development of this set of neurons and some remain constitutively expressed throughout life. These maintenance transcription factors are closely associated with essential neurophysiological functions and are required ultimately for the long-term survival of the midbrain dopaminergic neurons. The current review describes the role of two such factors, Nurr1 and engrailed, in differentiation, maturation, and in normal physiological functions including acquisition of neurotransmitter identity. The review will also elucidate the relationship of these factors with life, vulnerability, degeneration and death of mesencephalic dopaminergic neurons in the context of Parkinson’s disease

Ultrasound-enhanced ocular delivery of dexamethasone sodium phosphate: An in vivo study

Background The eye\u27s unique anatomy and its physiological and anatomical barriers can limit effective drug delivery into the eye. Methods An in vivo study was designed to determine the effectiveness and safety of ultrasound application in enhancing drug delivery in a rabbit model. Permeability of a steroid ophthalmic drug, dexamethasone sodium phosphate, was investigated in ultrasound- and sham-treated cases. For this study, an eye cup filled with dexamethasone sodium phosphate was placed on the cornea. Ultrasound was applied at intensity of 0.8 W/cm2 and frequency of 400 or 600 kHz for 5 min. The drug concentration in aqueous humor samples, collected 90 min after the treatment, was determined using chromatography methods. Light microscopy observations were done to determine the structural changes in the cornea as a result of ultrasound application. Results An increase in drug concentration in aqueous humor samples of 2.8 times (p \u3c 0.05) with ultrasound application at 400 kHz and 2.4 times (p \u3c 0.01) with ultrasound application at 600 kHz was observed as compared to sham-treated samples. Histological analysis showed that the structural changes in the corneas exposed to ultrasound predominantly consisted of minor epithelial disorganization. Conclusions Ultrasound application enhanced the delivery of an anti-inflammatory ocular drug, dexamethasone sodium phosphate, through the cornea in vivo. Ultrasound-enhanced ocular drug delivery appears to be a promising area of research with a potential future application in a clinical setting

Wavefront-guided laser-assisted subepithelial keratectomy in low myopia, myopic astigmatism and high myopia

AIM: To compare the safety, efficacy, predictability, stability and complications of wavefront-guided laser-assisted subepithelial keratectomy (LASEK) in low myopia, myopic astigmatism and high myopia correction. METHODS: A retrospective analysis of 416 eyes were assigned to 3 groups: 159 eyes with low myopia (LM) and mean refractive spherical equivalent (MRSE) of -3.68±1.33 dioptre (D); 161 eyes with myopic astigmatism (MA) and MRSE of -5.99±2.24D and mean cylinder of 2.41±1.07D; and 96 eyes with high myopia (HM) and MRSE of -7.41±0.80D. After an epithelial flap creation, a wavefront-based excimer laser ablation was performed. Safety, efficacy, predictability and stability were evaluated at day 10, 2, 6 and 12mo postoperatively. RESULTS: At 12mo, the MRSE was -0.36±0.31D in LM group, 0.15±0.41D in MA group and 0.58±0.68D in HM group. The uncorrected visual acuity (UCVA) was 20/20 in 90.60 of patients in LM group, 78.90 in MA group and 67 in HM group. Efficacy indices were 0.98, 1.04 and 0.92 in LM, MA and HM groups, respectively. Safety indices were 1.00, 1.07 and 1.05 in LM, MA and HM respectively. Five eyes (3.1) in the LM group gained 1 line. Forty-four eyes (27.3) in MA gained 1-3 lines and eighteen eyes (19.2) of HM group gained 1-2 lines of BSCVA. Only 2 eyes in LM group developed corneal haze. There were not statistically significant differences in efficacy and safety indices amongst three groups. CONCLUSION: Wavefront-guided LASEK is an effective and safe procedure for the treatment of LM, MA, and HM.although in myopic astigmatism the predictability, efficacy and safety indices had been better. ©, 2015, International Journal of Ophthalmology (c/o Editorial Office). All right reserved

Improved delivery of voriconazole to Aspergillus fumigatus through solid lipid nanoparticles as an effective carrier

Novel voriconazole-loaded solid lipid nanoparticles (VRC-SLNs) were prepared via probe-ultrasonication method, and the resultant nanoparticles were tested on A. fumigatus. Voriconazole-loaded solid lipid nanoparticles were prepared using the probe ultrasonication technique. Photon correlation spectroscopy (PCS) was used to determine the average particle size and zeta potential of SLN formulations. Transmission electron microscopy was also used to determine the morphology of solid lipid nanoparticles. To determine MIC for all SLN formulations against strains of Aspergillus the Clinical and Laboratory Standards Institute guidelines was followed. The results showed that SLNs containing voriconazole exhibited almost spherical shape with a diameter and zeta potential of 286.6 ± 4.7 nm and −15 ± 4.1 mV respectively. This novel formulation of VRC led to a significant reduction in MICs for all Aspergillus either VRC-susceptible or VRC-resistant isolates (P < 0.05). The MIC50 drug concentration was obtained as 0.015 μg/ml for both VRC-susceptible strains of A. fumigates while it was 0.25 μg/ml against VRC (p < 0.05). VRC-resistant strains showed a MIC50 of 0.015 μg/ml as well. These novel drug formulations may increase the bioavailability through an increase in the dissolution rate of voriconazole. This study showed, for the first time, VRC-SLNs can be employed as an effective delivery systems for VRC on A. fumigatus isolates