Cationic-vacancy-induced room-temperature ferromagnetism in transparent, conducting anatase Ti1-xTaxO2 (x~0.05) thin films

We report room-temperature ferromagnetism (FM) in highly conducting, transparent anatase Ti(1-x)Ta(x)O(2) (x∼0.05) thin films grown by pulsed laser deposition on LaAlO(3) substrates. Rutherford backscattering spectrometry (RBS), X-ray diffraction, proton-induced X-ray emission, X-ray absorption spectroscopy (XAS) and time-of-flight secondary-ion mass spectrometry indicated negligible magnetic contaminants in the films. The presence of FM with concomitant large carrier densities was determined by a combination of superconducting quantum interference device magnetometry, electrical transport measurements, soft X-ray magnetic circular dichroism (SXMCD), XAS and optical magnetic circular dichroism, and was supported by first-principles calculations. SXMCD and XAS measurements revealed a 90 per cent contribution to FM from the Ti ions, and a 10 per cent contribution from the O ions. RBS/channelling measurements show complete Ta substitution in the Ti sites, though carrier activation was only 50 per cent at 5 per cent Ta concentration, implying compensation by cationic defects. The role of the Ti vacancy (V(Ti)) and Ti(3+) was studied via XAS and X-ray photoemission spectroscopy, respectively. It was found that, in films with strong FM, the V(Ti) signal was strong while the Ti(3+) signal was absent. We propose (in the absence of any obvious exchange mechanisms) that the localized magnetic moments, V(Ti) sites, are ferromagnetically ordered by itinerant carriers. Cationic-defect-induced magnetism is an alternative route to FM in wide-band-gap semiconducting oxides without any magnetic elements.

Gellan gum capped silver nanoparticle dispersions and hydrogels: cytotoxicity and in vitro diffusion studies

The preparation of highly stable water dispersions of silver nanoparticles using the naturally available gellan gum as a reducing and capping agent is reported. Further, exploiting the gel formation characteristic of gellan gum silver nanoparticle incorporated gels have also been prepared. The optical properties, morphology, zeta potential and long-term stability of the synthesized silver nanoparticles were investigated. The superior stability of the gellan gum-silver nanoparticle dispersions against pH variation and electrolyte addition is revealed. Finally, we studied the cytotoxicity of AgNP dispersions in mouse embryonic fibroblast cells (NIH3T3) and also evaluated the in vitro diffusion of AgNP dispersions/gels across rat skin.

Effect of pre-bypass methylprednisolone on post-operative renal function following correction of atrial septal defect under cardiopulmonary bypass

Conventional open heart surgery with cardiopulmonary bypass (CPB) are associated with transient post-operative renal dysfunction which is caused by systemic inflammatory response induced by CPB. Corticosteroids are administered to attenuate the systemic inflammatory response. The purpose of this study was to compare the effects of pre-bypass and post-bypass methylprednisolone on postoperative renal function after correction of ASD under CPB. Forty (40) patients were selected in the University cardiac centre of BSMMU undergoing ASD correction under CPB. Patients were randomized into two group to receive pre-bypass (Group A) or post-bypass (Group B) methylprednisolone 30mg/kg. Markers of glomerular function (BUN, serum creatinine, creatinine clearance) and damage (micro-albuminuria) and tubular function (glucosuria) were evaluated 24 hours after operation. Transient impairment of glomerular and tubular function of kidney was observed in patients those received post-bypass metylprednisolone (Group B) while Group A patients shown no significant difference between baseline and post-operative renal function. Use of pre-bypass methylprednisolone has a protective effect on post-operative renal function after correction of ASD under CPB.

Metal-insulator transition in SrTiO(3-x) thin films induced by frozen-out carriers

We report optical, electrical and magnetotransport properties of oxygen deficient SrTiO(3) (SrTiO(3-x)) thin films fabricated by pulsed laser deposition technique. The oxygen vacancies (O(vac)) in the thin film are expected to be uniform. By comparing its electrical properties to those of bulk SrTiO(3-x), it was found that O(vac) in bulk SrTiO(3-x) is far from uniform over the whole material. The metal-insulator transition (MIT) observed in the SrTiO(3-x) film was found to be induced by the carrier freeze-out effect. The low temperature frozen state can be reexcited by Joule heating, electric and intriguingly magnetic field.

A modified Gaines procedure for spondyloptosis

We present an illustrative case using a modification of the Gaines procedure for the surgical management of patients with spondyloptosis. It involves excision of the inferior half of the body of L5 anteriorly combined with posterior reduction and fusion.

New Insights into Hyperglycemia-induced Molecular Changes in Microvascular Cells

Hyperglycemia is the most prevalent characteristic of diabetes and plays a central role in mediating adverse effects on vascular cells during the progression of diabetic vascular complications. In diabetic microangiopathy, hyperglycemia induces biochemical and molecular changes in microvascular cells that ultimately progress to retinal, renal, and neural complications and extends to other complications, including advanced periodontal disease. In this review, we describe changes involving basement membrane thickening, tissue remodeling, gap junctions, inflammation, cytokines, and transcription factors, and their effects on the pathogenesis of diabetic microvascular complications. The majority of the changes described relate to retinal microangiopathy, since ultrastructural, structural, and biochemical alterations have been well-characterized in this tissue.

Natriuretic peptides and heart failure in the patient with chronic kidney disease: a review of current evidence

Natriuretic peptides such as brain natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) are commonly used in the diagnosis and evaluation of heart failure. However, their utility in patients with chronic kidney disease (CKD) is less clear as renal dysfunction itself can be associated with elevated concentrations of these biomarkers. Given the high prevalence of left ventricular hypertrophy and left ventricular systolic dysfunction in patients with CKD, diagnosis or exclusion of heart failure becomes important in this population. Most studies to date indicate that upward adjustment of diagnostic cut points preserves the usefulness of both BNP and NT-proBNP in the CKD patient, with similar clinical performance of each biomarker. We review the role of natriuretic peptide in heart failure in the setting of chronic renal disease.

Progress in chip-scale photonic sensing

Chip-scale integrated planar photonic sensing systems for portable diagnostics and monitoring are emerging, as photonic components are integrated into systems with silicon (Si), Si complementary metal-oxide semiconductor, and fluidics. This paper reviews progress in these areas. Medical and environmental applications, candidate photonic sensors, integration methodologies, integrated subsystem demonstrations, and challenges facing this emerging field are discussed in this paper.

X-ray absorption near-edge structure of GaN with high Mn concentration grown on SiC

By means of x-ray absorption near-edge structure (XANES) several Ga(1-x)Mn(x)N (0.03<x<0.09) layers have been analyzed. The Mn-doped GaN samples consisted of different epilayers grown by molecular beam epitaxy on [0001] SiC substrates. The low mismatch between GaN and SiC allows for a good quality and homogeneity of the material. The measurements were performed in fluorescence mode around both the Ga and Mn K edges. All samples studied present a similar Mn ionization state, very close to 2+, and tetrahedral coordination. In order to interpret the near-edge structure, we have performed ab initio calculations using the full potential linear augmented plane wave method as implemented in the Wien2k code. The calculations show the appearance of a Mn bonding [Formula: see text] band localized in the gap region, and the corresponding anti-bonding state [Formula: see text], which seem to be responsible for the double structure which appears at the pre-edge absorption region. The shoulders and main absorption peak of the XANES spectra are attributed to transitions from the Mn(1s) band to the conduction bands, which are partially dipole allowed because of the Mn(4p) contribution to these bands.

Dose-finding study of NKTR-102 in combination with cetuximab

e13503

Background: NKTR-102 is an advanced polymer conjugate of irinotecan with broad single agent activity and a unique pharmacokinetic (pk) profile. The apparent half-life of the active metabolite SN-38 in patients (pts) administered NKTR-102 is approximately 50 days. NKTR-102 in combination with cetuximab was evaluated in pts with refractory solid tumors to define the maximum tolerated dose (MTD). Methods: NKTR-102 was infused over 90 minutes every 3 weeks per cycle. Cetuximab was infused over 2 hours at 400mg/m2 on day 1 followed by a weekly 1 hour infusion at 250mg/m2. Cohorts of 3 -12 pts were treated with escalating doses of NKTR- 102. MTD was established based on the dose limiting toxicities observed in cycle 1 and safety data from subsequent cycles. Serial plasma samples were collected throughout the study for PK analysis. Results: Eighteen pts were enrolled: main tumor types include colon (5), pancreas (4), rectal (2), breast (2), gastric (1), other (4). Pts received 100 mg/m2 (12) or 125 mg/m2 (6) of NKTR-102 for a median of 2.5 cycles (range 1 to 11+). At 125 mg/m2, 3 pts had G3 diarrhea, 1 in cycle 1; 2 in cycle 2. At 100mg/m2, 1 pt had G3 diarrhea in cycle 1 and a further pt had G4 fatigue in cycle 2. Other G3 toxicities for all patients in both dose groups include nausea (3), vomiting (3) and neutropenia (2). No G3 rash was reported. Partial responses (PR) were observed in 3 pts at 100 mg/m2: confirmed (rectal, colorectal) and unconfirmed (gastric). Another pt with pancreatic cancer had a decrease in CA19–9 from 2000 at baseline to 157 U/ml with associated symptomatic benefit. NKTR-102 resulted in sustained exposure to SN-38 with no evidence of PK drug interactions between NKTR-102 and cetuximab. Conclusions: NKTR-102 shows evidence of clinical antitumor activity in combination with cetuximab. Toxicity is manageable; diarrhea and neutropenia are dose limiting. The recommended dose of NKTR-102 with cetuximab is 100mg/m2 every three weeks. Data support further evaluation of this combination in appropriate tumor types.

[Table: see text]

Exploring the relationship between physiological measures of cochlear and brainstem function

OBJECTIVE

Otoacoustic emissions and the speech-evoked auditory brainstem response are objective indices of peripheral auditory physiology that are used clinically for assessing hearing function. While each measure has been extensively explored, their interdependence and the relationships between them remain relatively unexplored.

METHODS

Distortion product otoacoustic emissions (DPOAEs) and speech-evoked auditory brainstem responses (sABRs) were recorded from 28 normal-hearing adults. Through correlational analyses, DPOAE characteristics were compared to measures of sABR timing and frequency encoding. Data were organized into two DPOAE (Strength and Structure) and five brainstem (Onset, Spectrotemporal, Harmonics, Envelope Boundary, and Pitch) composite measures.

RESULTS

DPOAE Strength shows significant relationships with sABR Spectrotemporal and Harmonics measures. DPOAE Structure shows significant relationships with sABR Envelope Boundary. Neither DPOAE Strength nor Structure is related to sABR Pitch.

CONCLUSIONS

The results of the present study show that certain aspects of the speech-evoked auditory brainstem responses are related to, or covary with, cochlear function as measured by distortion product otoacoustic emissions.

SIGNIFICANCE

These results form a foundation for future work in clinical populations. Analyzing cochlear and brainstem function in parallel in different clinical populations will provide a more sensitive clinical battery for identifying the locus of different disorders (e.g., language based learning impairments, hearing impairment).

Total ankle replacement in patients with significant pre-operative deformity of the hindfoot

We carried out 123 consecutive total ankle replacements in 111 patients with a mean follow-up of four years (2 to 8). Patients with a hindfoot deformity of up to 10° (group A, 91 ankles) were compared with those with a deformity of 11° to 30° (group B, 32 ankles). There were 18 failures (14.6%), with no significant difference in survival between groups A and B. The clinical outcome as measured by the post-operative American Orthopaedic Foot and Ankle Surgeons score was significantly better in group B (p = 0.036). There was no difference between the groups regarding the post-operative range of movement and complications. Correction of the hindfoot deformity was achieved to within 5° of neutral in 27 ankles (84%) of group B patients. However, gross instability was the most common mode of failure in group B. This was not adequately corrected by reconstruction of the lateral ligament.

Total ankle replacement can safely be performed in patients with a hindfoot deformity of up to 30°. The importance of adequate correction of alignment and instability is highlighted.