Distance dependence of energy transfer from InGaN quantum wells to graphene oxide

We report the distance-dependent energy transfer from an InGaN quantum well to graphene oxide (GO) by time-resolved photoluminescence (PL). A pronounced shortening of the PL decay time in the InGaN quantum well was observed when interacting with GO. The nature of the energy-transfer process has been analyzed, and we find the energy-transfer efficiency depends on the 1/d² separation distance, which is dominated by the layer-to-layer dipole coupling.

Chlorpyrifos is associated with slower serum cholinesterase recovery in acute organophosphate-poisoned patients

PURPOSE

Organophosphate poisoning (OPP) accounts for 200,000 deaths annually in developing countries. Serum cholinesterase (SChE) is of diagnostic value in patients with OPP and is checked repeatedly during the course of treatment. This study aimed to investigate the recovery pattern in patients with OPP using linear mixed models.

METHODS

Using a retrospective cohort study design, we included 212 adult OPP patients who had visited the emergency department (ED) in a tertiary medical center between 2000 and 2010. One hundred and thirty-one patients were available for analysis, as 81 patients did not meet the criteria and were excluded. Information regarding basic personal characteristics, initial vital signs and severity scores, laboratory data, type and amount of organophosphate ingested, treatment, and serial SChE values was collected. A random coefficient model with a random intercept and a random slope of time were added to address the dynamic relationships of SChE with time and other associated factors.

RESULTS

The initial SChE activity and recovery rates varied among patients with OPP. The type of organophosphate, the first SChE activity, and the initial APACHE II score were significantly related to the SChE recovery trend. Chlorpyrifos and methamidophos had significantly slower and faster SChE recovery rates, respectively, than other organophosphates. Sex, dose of Pralidoxim (2-PAM), and delay in obtaining medical assistance did not significantly affect SChE recovery.

CONCLUSIONS

This study demonstrated the pattern and associated correlates of SChE activity recovery in patients with acute OPP. Chlorpyrifos appeared to have a slower SChE activity recovery rate than other organophosphates.

Capnography: An Accurate Method to Assess the Position of the Feeding Tube in a Porcine Model

Objective

To test the accuracy of capnography in the differential placement of feeding tubes into the trachea versus the oesophagus.

Method

Nineteen pigs were anesthetised, and feeding tubes were placed into their tracheas and oesophagi. A naïve examiner attached a capnography to the tube and evaluated the presence or absence of flow waveforms on the capnography. In the next step experiment, we gave 20 intentional oesophageal ventilations to the animals to create a distended stomach. The feeding tubes were reinserted, and examined by a naïve examiner by capnography.

Results

Capnography demonstrated continuous flow waveforms for the feeding tubes placed in the tracheas, but no waveforms were observed for those placed in the oesophagi. In the next step experiment, we found the same results.

Conclusion

Capnography can be used to accurately determine the placement of tracheal versus oesophageal feeding tubes based on the presence or absence of flow waveforms.

Stroke volume variation derived by arterial pulse contour analysis is a good indicator for preload estimation during liver transplantation

BACKGROUND

Accurate determination of preload during liver transplantation is essential. Continuous right ventricular end diastolic volume index (RVEDVI) has been shown to be a better preload indicator during liver transplantation than the filling pressures. However, recent evidence has shown that dynamic variables, in this case stroke volume variation (SVV), are also good indicators of preload responsiveness. In this study, we evaluated the correlation between SVV, which we derived from arterial pulse contour analysis and RVEDVI.

METHODS

In this study, we looked for possible relationships between SVV obtained through FloTrac/Vigileo monitor, central venous pressure (CVP), pulmonary arterial occlusion pressure (PAOP), and RVEDVI in 30 patients undergoing liver transplantation. Measurements were taken at 11 defined points during different phases across liver transplantation. Each set of measurement was taken during a steady state, which means at least 15 minutes elpased after any changes occured in either the infusion rate of catecholamines or ventilator settings. Pearson's test was used for correlation estimation.

RESULTS

There was a statistically significant (P<.01) relationship between SVV and RVEDVI with a correlation coefficient of -0.87. The correlations between CVP (r=0.42), PAOA (r=0.46), and RVEDVI were less strong.

CONCLUSION

We conclude that SVV is a good indicator for preload estimation during liver transplantation. A higher SVV value is associated with a more hypovolemic fluid status.

Probable Blastomyces dermatitidis infection in a young rat

A 21-week-old male untreated control SHR/NCrlNarl rat was found dead during an experiment. Grossly, pulmonary lesions were characterized by multifocal to coalescing firm gray-white nodules randomly scattered on the surface. Microscopically, bronchopneumonia was found with pyogranulomas containing neutrophils, macrophages, and numerous thick-walled yeast cells. Yeast cells, 5 to 25 μm in diameter, with no branching of hyphae were observed by staining with hematoxylin and eosin, Diff-Quik, and periodic acid-Schiff. Furthermore, polymerase chain reaction (PCR) using panfungal and nested PCR primers were used for detection of Blastomyces dermatitidis DNA in the lung tissue. After sequencing and matching with DNA sequences in the GenBank, the sample showed a similarity of 94.6% and 97% to Ajellomyces dermatitidis (B. dermatitidis), respectively. On the basis of these results, probable pulmonary blastomycosis was diagnosed. The origin of the infection in the colony rat is undetermined.

Hemodynamics of portal venous stenosis before and after treatment in pediatric liver transplantation: evaluation with Doppler ultrasound

AIM

The aim of this study was to evaluate portal vein stenosis (PVS) in pediatric liver transplantation (PLT) using Doppler ultrasound (DUS) before and after interventional management for hemodynamic changes.

MATERIALS AND METHODS

From 2000 to 2010, we encountered 11 PVS cases among 180 PLT that were evaluated using DUS and computed tomography (CT) angiography (CTA); all underwent portal stenting. DUS was used to monitor portal hemodynamics. For the diagnosis of PVS, we investigated multiple parameters including stenotic size (SS), stenotic ratio (SR) (SR [%]=PRE-SS/PRE [PRE=stenotic size]), portal flow velocity ratio (VR) (VR=VS/PRE [PRE=velocity at prestenotic site; VS=peak velocity at stenotic site]), spleen size, and platelet count.

RESULTS

The incidence of PVS was 5.6% (11/180). The PV was 2.5 mm using DUS and 2.7 mm using CTA. The average SR was 65% fitting the criterion. Low prestenotic portal flow<12 cm/sec and high peak velocity in the stenotic segment (up to 147 cm/sec) were observed in 6 cases. The VR value was high at 7.5:1 and there was splenomegaly with thrombocytopenia. After portal vein stenting, hyperperfusion occurred might after reopening the stenosis: the flow increased to an average of 34 cm/sec and then flow decreased slowly to a stable level 2 weeks later. The size of the spleen decreased from 17 to 12 cm and the thrombocytopenia also improved with platelet counts increasing from 67×10(3) to 178×10(3)/μl at 2 months follow-up. The changes in portal flow, portal vein size, spleen size, and platelet count were significant (P<.05).

CONCLUSION

PVS is diagnosed using DUS by increased intrahepatic PV dilatation, peak flow at the stenotic site, discrepant VR. Early portal stenting showed a better prognosis. DUS is essential and effective for hemodynamic monitoring and management of PVS.

A program to interest medical students in Changhua, Taiwan in the incorporation of visual arts in medicine

INTRODUCTION

Visual arts have been used to facilitate the teaching of the United States Accreditation Council for Graduate Medical Education (ACGME) competencies used in some countries. Some medical students may not appreciate the usefulness of incorporating arts in medical education. Therefore, arts programs that can interest medical students are necessary. We initiated and evaluated a visual arts program at the Changhua Christian Hospital in Changhua, Taiwan, with an aim to give the students a short review of visual arts and to interest them in the incorporation of arts in medicine.

METHODS

A total of 110 students in clerkship or internship participated in a visual arts program with emphasis on medicine-related visual arts. Content analysis of the data from the notes made by the instructor from direct observation of students; descriptions during discussions and the written feedback from students at the end of the program was used to evaluate the effect of the program. Anonymous questionnaires were also used for self-assessment of students.

RESULTS

Qualitative analysis of the data revealed that the course was interesting to students. Themes emerged including its helpfulness to students in interpreting paintings, enhanced empathy, increased cultural awareness, enhanced observational skills, better team work, listening and communication skills and reduced stress. Ratings on the questionnaire showed similar results. Moreover, students had an increase in their confidence and desire to interpret paintings.

CONCLUSION

The structured visual arts program, with emphasis on medicine-related visual arts and other humanities subjects, was able to attract the attention of medical students. It might be helpful to improve the required skills of ACGME competencies, but further studies are needed to support these conclusions.

Changes in gene transcription and protein expression involved in the response of Agrobacterium sp. ATCC 31749 to nitrogen availability during curdlan production

The changes in transcription of genes involved in nitrogen metabolism and curdlan biosynthesis, and total protein expression were firstly analyzed to define the responses of Agrobacterium sp. ATCC 31749 to nitrogen source availability during curdlan fermentation. The transcription of all nitrogen metabolism and regulation genes increased significantly under nitrogen limitation. The genes of carbon (exoC) and nitrogen (ntrB, ntrC, and nifR) metabolism showed distinctive transcriptional responses to nitrogen limitation. Their relative expression level was increased by 14, 9, 7 and 7-fold, respectively. Two-dimentional electrophoresis (2-DE) revealed that the expression of 14 proteins were elevated and 6 proteins were down-regulated significantly under nitrogen starvation. Furthermore, 4 proteins (GroEL, ABC transporter, Atu1730 and enoyl-acyl carrier protein reductase) in which the expression level changed significantly were identified. The results showed that Agrobacterium sp. regulates its carbon flux and nitrogen assimilation effectively for better survival.

Discovery of two novel HLA-B alleles, B*46:13:03 and B*15:189, in two Taiwanese volunteer bone marrow donors by sequence-based typing

We report here two novel HLA-B alleles, B*46:13:03 and B*15:189, discovered in two Taiwanese volunteer bone marrow donors. The sequence of B*15:189 has a nucleotide sequence possibly derived from a recombination event between HLA-B*39:01:01 and B*15:01:01:01, while the origin of the sequence B*46:13:03 was less obvious to postulate, considering the low frequency of B*46:13 in the general population and the silent mutations involved. Our report here adds further HLA polymorphism to the growing lists of HLA-B*46 and HLA-B*15 and provides an additional HLA information for donor search programme for patients undergoing transplant.

Oriental HLA-A*11:90 detected in a Taiwanese cord blood sample and the haplotype in association with A*11:90 allele

We report here an HLA-A allele, A*11:90, found in a Taiwanese cord blood sample using DNA sequence-based typing (SBT) protocol after observing an anomalous reaction pattern in a sequence-specific oligonucleotide (SSO) typing exercise. The sequence of A*11:90 is identical to A*11:01:01, the most predominant A*11 variant in Taiwanese, in exon 2 but differs from A*11:01:01 in exon 3 by two nucleotide substitutions at codon 163 (c.487C>G and c.488G>A), resulting R163E. In comparison with the sequence of A*11:02:01, the second most predominant subtype of A*11 in Taiwanese A*11:90 has one nucleotide difference at codon 19 (c.55A>G) in exon 2 resulting K19E and two nucleotides variations at codon 163 (c.487C>G and c.488G>A) in exon 3 resulting R163E. HLA-A*11:90-B*40:02-DRB1*11:01 is the deduced probable HLA haplotype in association with A*11:90. The generation of A*11:90 is thought to involve a DNA recombination event between alleles A*11:01:01 and A*80:01 where A*80:01 donated a fragment of the DNA sequence (from n.t. 487 to n.t. 497) to the recipient sequence of A*11:01:01.

Detection of two HLA-A alleles, A*31:30 and A*26:20, in two Taiwanese volunteer bone marrow donors by sequence-based typing

We here report detection of a novel sequence of HLA-A*31:30 and a confirmatory sequence of HLA*26:20 from two Taiwanese individuals. The sequence of A*31:30 is identical to that of A*31:01:02 in exons 2 and 3, except one nucleotide (n.t.) substitution c.539T > G resulting in p.Leu180Trp. The sequence of A*26:20 is identical to A*26:01:01 in exons 2 and 3, except a segment of the sequence from n.t. 78 to n.t.102. The mismatched sequence segment is identical to a sequence segment of A*02:03:01, suggesting that the formation of A*26:20 was resulted from a DNA recombination event between A*26:01:01 and A*02:03:01 sequences. A*26:20 differs from A*26:01:01 with c.98A > T resulting in p.Tyr33Phe.

Energy transfer from InGaN quantum wells to Au nanoclusters via optical waveguiding

We present the first observation of resonance energy transfer from InGaN quantum wells to Au nanoclusters via optical waveguiding. Steady-state and time-resolved photoluminescence measurements provide conclusive evidence of resonance energy transfer and obtain an optimum transfer efficiency of ~72%. A set of rate equations is successfully used to model the kinetics of resonance energy transfer.

Atorvastatin or transgenic expression of TFPI inhibits coagulation initiated by anti-nonGal IgG binding to porcine aortic endothelial cells

BACKGROUND

Intravascular thrombosis remains a barrier to successful xenotransplantation. Tissue factor (TF) expression on porcine aortic endothelial cells (PAECs), which results from their activation by xenoreactive antibodies (Abs) to Galα1,3Gal (Gal) and subsequent complement activation, plays an important role.

OBJECTIVES

The present study aimed to clarify the role of Abs directed against nonGal antigens in the activation of PAECs to express functional TF and to investigate selected methods of inhibiting TF activity.

METHODS

PAECs from wild-type (WT), α1,3-galactosyltransferase gene-knockout (GT-KO) pigs, or pigs transgenic for CD46 or tissue factor pathway inhibitor (TFPI), were incubated with naïve baboon serum (BS) or sensitized BS (with high anti-nonGal Ab levels). TF activity of PAECs was assessed.

RESULTS

Only fresh, but not heat-inactivated (HI), naïve BS activated WT PAECs to express functional TF. Similarly, PAECs from CD46 pigs were resistant to activation by naïve BS, but not to activation by fresh or HI sensitized BS. HI sensitized BS also activated GT-KO PAECs to induce TF activity. TF expression on PAECs induced by anti-nonGal Abs was inhibited if serum was pretreated with (i) an anti-IgG Fab Ab or (ii) atorvastatin, or (iii) when PAECs were transgenic for TFPI.

CONCLUSIONS

Anti-nonGal IgG Abs activated PAECs to induce TF activity through a complement-independent pathway. This implies that GT-KO pigs expressing a complement-regulatory protein may be insufficient to prevent the activation of PAECs. Genetic modification with an 'anticoagulant' gene (e.g. TFPI) or a therapeutic approach (e.g. atorvastatin) will be required to prevent coagulation dysregulation after pig-to-primate organ transplantation.

Atorvastatin or transgenic expression of TFPI inhibits coagulation initiated by anti-nonGal IgG binding to porcine aortic endothelial cells

BACKGROUND

Intravascular thrombosis remains a barrier to successful xenotransplantation. Tissue factor (TF) expression on porcine aortic endothelial cells (PAECs), which results from their activation by xenoreactive antibodies (Abs) to Galα1,3Gal (Gal) and subsequent complement activation, plays an important role.

OBJECTIVES

The present study aimed to clarify the role of Abs directed against nonGal antigens in the activation of PAECs to express functional TF and to investigate selected methods of inhibiting TF activity.

METHODS

PAECs from wild-type (WT), α1,3-galactosyltransferase gene-knockout (GT-KO) pigs, or pigs transgenic for CD46 or tissue factor pathway inhibitor (TFPI), were incubated with naïve baboon serum (BS) or sensitized BS (with high anti-nonGal Ab levels). TF activity of PAECs was assessed.

RESULTS

Only fresh, but not heat-inactivated (HI), naïve BS activated WT PAECs to express functional TF. Similarly, PAECs from CD46 pigs were resistant to activation by naïve BS, but not to activation by fresh or HI sensitized BS. HI sensitized BS also activated GT-KO PAECs to induce TF activity. TF expression on PAECs induced by anti-nonGal Abs was inhibited if serum was pretreated with (i) an anti-IgG Fab Ab or (ii) atorvastatin, or (iii) when PAECs were transgenic for TFPI.

CONCLUSIONS

Anti-nonGal IgG Abs activated PAECs to induce TF activity through a complement-independent pathway. This implies that GT-KO pigs expressing a complement-regulatory protein may be insufficient to prevent the activation of PAECs. Genetic modification with an 'anticoagulant' gene (e.g. TFPI) or a therapeutic approach (e.g. atorvastatin) will be required to prevent coagulation dysregulation after pig-to-primate organ transplantation.

Unstable spiral modes in disk-shaped galaxies

The mechanisms for the maintenance and the excitation of trailing spiral modes of density waves in diskshaped galaxies, as proposed by Lin in 1969 and by Mark recently, are substantiated by an analysis of the gas-dynamical model of the galaxy. The self-excitation of the unstable mode in caused by waves propagating outwards from the corotation circle, which carry away angular momentum of a sign opposite to that contained in the wave system inside that circle. Specifically, a simple dispersion relationship is given as a definite integral, which allows the immediate determination of the pattern frequency and the amplification rate, once the basic galactic model is known.

Discrete spiral modes in disk galaxies: Some numerical examples based on density wave theory

Discrete growing spiral modes are calculated, on the basis of principles of stellar dynamics, according to the recently developed asymptotic theory of density waves for spiral structure in galaxies. From the growth rates obtained, it appears likely that several spiral modes coexist in a given disk galaxy. General properties of these modes are described for two galaxy models, and some of their important observational implications are discussed.