Yung-Wei Chen

The 90-day mortality and the subsequent renal recovery in critically ill surgical patients requiring acute renal replacement therapy.

BACKGROUND Particular attention should be paid to postoperative patients that suffer from severe acute kidney injury (AKI) requiring renal replacement therapy (RRT). METHODS This multicenter prospective observational study included 342 patients with postoperative AKI requiring RRT from January 2002 to December 2006. RESULTS There were 137 (40%) survivors at 90 days after the commencement of RRT. Independent predictors of 90-day mortality were older age, presence of sepsis, status post-cardiopulmonary resuscitation, necessity of continuous renal replacement therapy (CRRT), requirement of total parenteral nutrition, lower body mass index, higher Sequential Organ Failure Assessment score, and higher serum lactate level at the commencement of RRT. Further analysis among the survivors showed that lower serum creatinine at intensive care unit admission, lower Simplified Acute Physiology Score II and inotropic equivalent score at the commencement of RRT, and using CRRT were independent predictors for subsequent renal recovery. CONCLUSIONS The development of AKI requiring RRT in postoperative critical patients represents a substantial risk for mortality and morbidity.

Sustained low-efficiency dialysis versus continuous veno-venous hemofiltration for postsurgical acute renal failure

BACKGROUND In postsurgical acute renal failure patients with moderate unstable hemodynamics or fluid overload, the choice of dialysis modality is difficult. This study was performed to compare the outcomes between the sustained low-efficiency dialysis (SLED) and continuous veno-venous hemofiltration (CVVH) in these patients. METHODS Sequential postsurgical acute renal failure patients undergoing acute dialysis with CVVH (2002-2003), or SLED (2004-2005) as a result of severe fluid overload or moderately unstable hemodynamics were analyzed. Multivariate analyses of comorbidity, disease severity before initiating dialysis, biochemical measurements, and hemodynamic parameters for 3 days after the first dialysis session were performed by fitting multiple logistic regression models to predict patients 30-day after hospital discharge (AHD) mortality. RESULTS Among the 101 recruited patients, 38 received SLED and the rest received CVVH. The 30-day AHD mortality was 62.4%. The independent risk factors of 30-day AHD mortality included older age (P = .008), lower first postdialysis mean arterial pressure (MAP) (P = .021), higher first postdialysis blood urea nitrogen level (P = .009), and absence of a history of hypertension (P = .002). A further linear regression analysis found that dialysis using SLED was associated with higher first postdialysis MAP (P = .003). CONCLUSIONS Among the postsurgical patients requiring acute dialysis with severe fluid overload or moderately unstable hemodynamics, the patients treated with SLED had a higher first postdialysis MAP than those treated with CVVH, which led to lower mortality. Further multicenter randomized clinical trials of larger sample size are needed to compare the effects of SLED and CVVH on the outcomes of postsurgical acute dialysis patients.

Surface plasmon enhanced energy transfer between type I CdSe/ZnS and type II CdSe/ZnTe quantum dots

Fluorescence resonant energy transfer (FRET) has been investigated between donor-acceptor pairs of type I CdSe/ZnS and type II CdSe/ZnTe quantum dots (QDs). An Au nanoparticles assisted FRET enhancement was clearly demonstrated. It is found that the efficiency of the energy transfer depends on the excitation wavelength and is largest when in resonance with the Au surface plasmon mode. With the large tunability of the emission intensity in near infrared region, our finding paves an excellent route for creating highly efficient optoelectronic devices and bioimaging labels derived from type II QDs.

A Modified Sequential Organ Failure Assessment Score to Predict Hospital Mortality of Postoperative Acute Renal Failure Patients Requiring Renal Replacement Therapy

Background: A predictive model for hospital mortality in postoperative acute renal failure (ARF) patients requiring renal replacement therapy (RRT) may aid clinicians’ therapeutic decision-making and research design. Methods: A prospective observational study of 398 postoperative ARF patients requiring RRT was conducted in four hospitals. The derivation cohort consisted of 334 patients recruited between January 2002 and December 2005. The validation cohort consisted of 64 patients recruited between January 2006 and December 2006. Results: The hospital mortality rates for the derivation and validation cohorts were 65.6 and 62.5%, respectively. A modified Sequential Organ Failure Assessment (SOFA) score was constructed at the commencement of RRT by a formula of serum lactate level (mM) + 2 × (generic SOFA score) + 3 × (age per decade) + 8 (if mechanical circulatory support required) + 10 (if total parenteral nutrition required) + 11 (if status postcardiopulmonary resuscitation) + 13 (if positive sepsis sign). The area under the receiver operating characteristic curve of the model for the derivation and validation cohorts was 0.804 and 0.839, respectively. Conclusion: This validated score at dialysis commencement might assist clinicians in estimating hospital mortality, planning future clinical trials, and providing quantitative guidance for decision making in postoperative ARF patients requiring RRT.

Enhancement of random lasing through fluorescence resonance energy transfer and light scattering mediated by nanoparticles

A simple approach for the enhancement of random lasing based on fluorescence resonance energy transfer and light scattering mediated by nanoparticles is reported. To illustrate our working principle, ZnO nanorods decorated with TiO2 nanoparticles were chosen as an example. It is shown that the random laser action of ZnO nanorods can be significantly improved by the assistance of TiO2 nanoparticles. Moreover, due to the inherent nature of higher refractive index of TiO2 than ZnO, the TiO2 nanoparticles can serve efficiently as better nanoscatterers, which can promote the formation of closed-loop paths. Our strategy provided here is very useful for the future development of high efficiency optoelectronic devices.

Strain response of high mobility germanium n-channel metal-oxide-semiconductor field-effect transistors on (001) substrates

Well-behaved Ge n-channel metal-oxide-semiconductor field-effect transistors on (001) substrates with dispersion-free, high on/off ratio, and high peak mobility are demonstrated. The interface trap density is effectively reduced down to 5 × 1011 cm−2 eV−1 near midgap by GeO2 passivation using rapid thermal oxidation, resulting in high peak mobility of ∼1050 cm2/Vs. The fast roll-off of the mobility at high electric field is probably due to the large surface roughness scattering. By applying uniaxial 〈110〉 tensile strain (0.08%) on 〈110〉 channel direction, the best mobility enhancement (12%) can be achieved. The calculated strain responses with proper stress configurations are consistent with experimental results.

Electron scattering in Ge metal-oxide-semiconductor field-effect transistors

The electron mobility of n-channel metal-oxide-semiconductor field-effect transistors using Ge/GeO2/Al2O3 gate stack on (001) Ge substrates is analyzed theoretically and experimentally. Phonon scattering, Coulomb scattering, and interface roughness scattering are taken into account. The Ge peak mobility exceeding Si universal in our device by a factor of 1.3 is due to the reduction of Coulomb scattering of the interface states. As compared to Si, the faster roll-off of the Ge mobility at the effective field larger than 0.3 MV/cm is due to larger interface roughness scattering.

Tunable photoluminescence and photoconductivity in ZnO one-dimensional nanostructures with a second below-gap beam

Tunable photoluminescence (PL) and photoconductivity (PC) with a second below-gap beam were demonstrated on ZnO nanorods and nanoribbons. We found that both PL and PC could be quenched as the second beam was applied to the nanostructures, and this behavior was excluded from thermal effect by comparing the phonon replica spectra with that from heating the sample directly. The most quenching effect occurred near the defect transition located at 520 nm. The underlying mechanism of the quenching behavior was attributed to the defect transition between different states of oxygen vacancies. Size-dependence measurement lets us know that the effect occurs near the surface of nanostructures, and the power-dependent measurement further confirms the underlying mechanism we proposed.

EUV degradation of high performance Ge MOSFETs

High energy 13.5 nm EUV (~92 eV) induced Ge MOSFET degradation is reportedly for the first time. The degradation of threshold voltage, subthreshold swing, and channel mobility is attributed to the generation of interface traps and oxide fixed charges. Much more severe degradation of S.S. on nFETs as compared to pFETs suggests that acceptor type Dit in the upper half of Ge bandgap are generated by EUV radiation. ΔQit may originate from the dangling bonds at interface. Positive ΔQf is due to the fixed charges of oxygen vacancy. The generation of bulk defects in Ge increases the drain leakage current, leading to the reduction of current on/off ratio.