Forming a Photoluminescent Layer on Another Surface in the Dark through Lasering of N-Type Silicon in an Electrolyte

Photoetching of n-type silicon induces a photoluminescent (PL) layer containing nanocrystals on the irradiated surface, usually through band gap absorption (wavelength <1100 nm). Here, we demonstrate the formation of a PL layer restricted to the backside surface, not the irradiated surface, by using a 1064 nm Nd:YAG laser. A nanoscale structure of the PL layer is achieved by merely modifying the electrolyte concentration without adding oxidants. To illustrate the working principle, we submit the hypothesis of a quasi-pn structure based on the theory of a quasi-Fermi level. Because of the "injection current" effect due to the quasi-pn structure, the hole current promoted by free-carrier absorption flows toward the backside surface, leading to anodization. This result is remarkable because anodization of n-type silicon is very hard to achieve with just an etchant in the dark.

Pre-treatment quality of life as a predictor of distant metastasis-free survival and overall survival in patients with head and neck cancer who underwent free flap reconstruction

PURPOSE

This study examined the prognostic associations of pre-treatment quality of life (QoL) with overall survival (OS) and distant metastasis-free survival (DFMS) among patients with head and neck cancer (HNC) who underwent free flap reconstruction.

METHODS

A cohort of 127 HNC patients who received free flap reconstruction between November 2010 and June 2014 at a hospital were recruited. Pre-treatment QoL was measured by the University of Washington Quality of Life Questionnaire, which contains six physical domains, including speech, swallowing, appearance, saliva, taste and chewing, as well as the six social-emotional domains of pain, activity, recreation, shoulder, mood, and anxiety. Cox regression analyses were performed.

RESULTS

Results showed that pre-treatment QoL was predictive of OS and DMFS. Of the domains, swallowing, chewing, speech, taste, saliva, pain and shoulder were demonstrated to be significant predictors of OS. Additionally, swallowing, chewing, speech, pain and activity were demonstrated making significant contributions to DMFS.

CONCLUSION

Our data supported that physical domains of pre-treatment QoL were predictors for OS and DFMS in HNC patients with free-flap reconstruction. Longitudinal studies are warranted to clarify the prognostic abilities of social-emotional domains. Information on pre-treatment QoL should be taken into account to individualize care plan for these patients, and hence prolong their survival.

Optimal C2 concentration of cyclosporin corrected with good efficacy and safety in Asian kidney transplant recipients

INTRODUCTION

Calcineurin inhibitors (CNI) are known for their renal toxicity. Lower CNI exposure is a reasonable option to mitigate potential CNI-induced renal toxicity. Herein we have presented our long-term results after lower cyclosporine (CsA) exposure in the first year.

MATERIALS AND METHODS

Between 1997 and 2004, 63 renal transplant recipients received CsA-based immunosuppression. CsA dosing was adjusted according to the 2-hour whole blood concentration (C2) level. We retrospectively reviewed acute rejection and graft survivals rates, as well as whole blood C2 levels.

RESULTS

Review of serial mean C2 concentrations at 1, 2, 3, 6, and 12 months after transplantation were 1341, 1241, 1191, 1059, and 927 ng/mL, respectively. These levels were slightly lower than those suggested by the Consensus for C2 levels by Levy et al in 2002, namely, 1600 to 2000 ng/mL (mean, 1700); 1400 to 1600 ng/mL (mean, 1500); 1200 to 1400 ng/mL (mean, 1300); 1000 to 1200 ng/mL (mean, 1100), and 800 to 1000 ng/mL (mean, 900), respectively. Acute rejection rate at 3 months and 1 year are 17.5% and 23.8%. Graft survival at 1 year was 97% and at 5 years, 89%. Two patient were lost to fulminant hepatitis and acute myocardial infarction during the first year, which were not associated with underimmunosuppression.

CONCLUSION

Appropriate CsA C2 levels may be lower among Taiwanese. Our C2 dosing strategy resulted in good outcomes with acceptable side effects in our single-center experience. Appropriate CsA C2 levels for Asians deserve more attention in trials of larger scale; most reference levels are presently concluded from studies of Caucasians.

Acute lobar nephronia in a renal allograft: a case report and literature review

We report a diabetic renal transplant recipient who presented with fever and right lower quadrant abdominal pain. Acute appendicitis was considered initially and she underwent emergent appendectomy. However, persistent symptoms postoperatively made us perform an imaging study to identify the problems. Abdominal and pelvic computed tomography disclosed several focal wedge-shaped lesions of low attenuation in the renal allograft. Acute lobar nephronia was successfully managed with parenteral antibiotics. The patient recovered without any sequela. A renal allograft in the right iliac fossa complicates the diagnosis among acute renal infection, malignancy, acute rejection, and even acute appendicitis. Biopsy of the renal allograft is sometimes needed due to clinically ambiguous imaging results. In this report, we not only detail the clinical course of such a rare case, but also review the previous 3 cases of acute lobar nephronia in renal allografts in the literature.

The impact of human ABO blood groups on human xenoreactive antibody-mediated cytotoxicity and the protective effect of human decay-accelerating factors exogene on swine endothelium

Swine tissue can express antigens similar to human A/B blood types. We evaluated whether the variation in human blood type influences the human xenoreactive antibody-mediated cytotoxicity and modifies the protective effect of human decay-accelerating factor (hDAF) exogene, a complement activation regulator, on swine endothelium.

METHODS

Pig aortic endothelial cells were harvested form normal and hDAF transgenic pigs. Cellular viability was evaluated with an MTT assay.

RESULTS

As compared with that of other human blood types, human serum from blood type O donors induced more prominent cytotoxicity on swine endothelial cells both from hDAF transgenic or normal pigs (P < .05). In addition, this difference of xenoreactive antibody-induced cytotoxicity between treatment with O and other human blood type sera was more evident in hDAF transgenic swine endothelial cells than those of normal pigs (P < .05). The hDAF exogene can significantly protect the endothelial cells from human xenoreactive antibody-mediated cytotoxicty when treated with human serum from AB blood type (P < .05). Our data demonstrated that human ABO blood type significantly affected human xenoreactive antibody-induced cytotoxicity, which may modulate the protective effect of hDAF exogene expression on swine endothelial cells.

Acute and chronic phase platelet aggregability studies in Chinese patients after implantation of a permanent transvenous pacemaker

It has been suggested that the incidence of thromboembolic events always increases in patients after insertion of a transvenous pacemaker. Blood samples from twenty consecutive patients (fifteen males and five females) before and after pacemaker implantation was retained for platelet aggregability studies which were analyzed separately with ADP, collagen, epinephrine and arachidonic acid. The maximal amplitude of platelet aggregatory curve was detected by an aggregometer. The samples collected the day before pacemaker implantation (day 0) were used as self-control. Day 1 and day 3 after pacemaker implantation were defined as the acute phase, while day 30 was defined as the chronic phase. The maximal amplitude of platelet aggregatory curve was observed to be lowest on day 1 and then return to normal on day 3 and day 30. The results of platelet aggregability, however, showed no significant difference (P>0.05) between self-control and post-implantation samples. In conclusion, there was no significant change in platelet aggregability for either acute or chronic phases after pacemaker implantation. Antiplatelet medications may not be necessary for the prevention of thromboembolic events after the implantation of a pacemaker.

Neurite outgrowth and growth cone morphology on micropatterned surfaces

The quantitative effects of micropatterned laminin surfaces on neurite outgrowth and growth cone morphology were investigated. Using microlithography, 20- or 30-micron-wide laminin stripes were applied to the surface of a glass coverslip, alternating with BSA-coated glass stripes of the same dimension. Growth on these surfaces was strongly biased in the direction parallel to the stripes, but the mean length of outgrowth was reduced relative to that on uniform laminin surfaces. Growth cones were slightly more elongated on micropatterned surfaces than on controls and were aligned with the pattern. These results provide a starting point for examining the fundamental effects of micropatterned surfaces on neurite outgrowth and ways in which these may be useful in controlling and guiding neurite outgrowth for biotechnological applications.

Influence of hydroxyapatite particle size on bone cell activities: an in vitro study

Over the past decade, a large number of biomaterials have been proposed as artificial bone fillers for repairing bone defects. The material most widely used in clinical medicine is hydroxyapatite. The aim of our investigation was to study the effect of hydroxyapatite size mechanism on osteoblasts. The osteoblasts were cultured in vitro with 0.1% (1 mg/mL) of various sized hydroxyapatite particles (0.5-3.0, 37-63, 177-250, and 420-841 microm) for 1 h, 3 h, 1 day, 3 days, and 7 days. The results showed that adding hydroxyapatite particles to osteoblast cultures can significantly affect osteoblast cell count. Osteoblast populations decreased significantly. Osteoblast mean surface areas also changed significantly. Transforming growth factor-beta1 (TGF-beta1) concentrations in culture medium decreased significantly with the addition of hydroxyapatite particles. Prostaglandin E2 (PGE2) concentrations in medium increased significantly. The changes in TGF-beta1 and PGE2 concentration were more significant and persisted longer in smaller-particle groups. The inhibitory effects of hydroxyapatite particles on osteoblast cell cultures were mediated by the increased synthesis of PGE2. Caution should be exercised before using a hydroxyapatite product which could easily break down into fine particles.

Biocompatibility and osteoconductivity of the pyrost bone substitutes

The purpose of this study was to re-evaluate the bone regeneration power and the in vitro biocompatibility of the Pyrost bone substitute. Twenty-four adult New Zealand White rabbits were used. Bony defect over both iliac crest and mid-diaphyseal portion of the ulna bone were created. Appropriate sized-block of Pyrost bone substitute were implanted. Four of the animals were killed at each postoperative month to evaluate its bone regeneration power by histologic study. The Pyrost bones were co-cultured with osteoblasts to evaluate its biocompatibility. The results showed that Pyrost bone substitute was quite stable and incorporated well with active bone regeneration. The Pyrost heal better at the iliac crest than at the ulnar defect. The Pyrost was compatible to the osteoblasts. Osteoblasts had successfully seeded and mitotically expanded on the porous surface of the Pyrost bone graft. The result showed that Pyrost bone obviously exerts an intense stimulus on osteo-regeneration in the presence of osteoblasts. We consider Pyrost to be an alternate to the conventional preserved allografts that is occasionally necessary.