Electron beam induced tunneling magnetoresistance in spatially confined manganite bridges

Certain manganites exhibit rich and technologically relevant transport properties which can often be attributed to the existence and changes of the intrinsic electronic phase competition within these materials. Here we demonstrate that a scanning electron beam can be used to artificially create domain configurations within La_0.3Pr_0.4Ca_0.3MnO₃ thin film microbridges that results in novel magneto-transport effects. In particular, the electron beam preferentially produces insulating regions within the narrow film and can be used to create a configuration consisting of ferromagnetic metallic domains separated by a potential barrier. This arrangement enables the spin-dependent tunneling of charge carriers and can produce large switching tunneling magnetoresistance effects which were initially absent. Hence, this work describes a new and potentially powerful method for engineering the electronic phase domains in manganites to generate functional transport properties that are important for spintronic devices.

Severity of acute and chronic urticaria correlates with D-dimer level, but not C-reactive protein or total IgE

BACKGROUND

Although various scoring systems for measuring urticaria severity have been introduced, most rely on subjective criteria. Therefore, additional objective criteria such as laboratory markers would be helpful adjuncts in making this assessment.

AIM

To evaluate the usefulness of three laboratory markers [D-dimer, C-reactive protein (CRP), and total IgE] in assessing disease severity of both acute urticaria (AU) and chronic urticaria (CU).

METHODS

We conducted a retrospective analysis of 94 patients with urticaria. Correlations between the aforementioned laboratory markers and the Urticaria Activity Score (UAS) were calculated.

RESULTS

A substantial proportion of patients with urticaria (acute 43.5%; chronic 39.6%) had an increased D-dimer level. Additionally, there was a significant correlation between D-dimer level and UAS (AU r = 0.60, P < 0.001; CU r = 0.37, P < 0.05). However, there was no significant correlation between UAS and either CRP or total IgE.

CONCLUSIONS

D-dimer level could be used as a marker of disease severity for both AU and CU. However, CRP and total IgE are not as reliable in predicting disease severity.

Toward successful migration to computerized physician order entry for chemotherapy

BACKGROUND

Computerized physician order entry (cpoe) systems allow for medical order management in a clinical setting. Use of a cpoe has been shown to significantly improve chemotherapy safety by reducing the number of prescribing errors. Usability of these systems has been identified as a critical factor in their successful adoption. However, there is a paucity of literature investigating the usability of cpoe for chemotherapy and describing the experiences of cancer care providers in implementing and using a cpoe system.

METHODS

A mixed-methods study, including a national survey and a workshop, was conducted to determine the current status of cpoe adoption in Canadian oncology institutions, to identify and prioritize knowledge gaps in cpoe usability and adoption, and to establish a research agenda to bridge those gaps. Survey respondents were representatives of cancer care providers from each Canadian province. The workshop participants were oncology clinicians, human factors engineers, patient safety researchers, policymakers, and hospital administrators from across Canada, with participation from the United States.

RESULTS

A variety of issues related to implementing and using a cpoe for chemotherapy were identified. The major issues concerned the need for better understanding of current practices of chemotherapy ordering, preparation, and administration; a lack of system selection and procurement guidance; a lack of implementation and maintenance guidance; poor cpoe usability and workflow support; and other cpoe system design issues. An additional three research themes for addressing the existing challenges and advancing successful adoption of cpoe for chemotherapy were identified: The need to investigate variances in workflows and practices in chemotherapy ordering and administrationThe need to develop best-practice cpoe procurement and implementation guidance specifically for chemotherapyThe need to measure the effects of cpoe implementation in medical oncology.

CONCLUSIONS

Addressing the existing challenges in cpoe usability and adoption for chemotherapy, and accelerating successful migration to cpoe by cancer care providers requires future research focusing on workflow variations, chemotherapy-specific cpoe procurement needs, and implementation guidance needs.

Novel anti-apoptotic mechanism of A20 through targeting ASK1 to suppress TNF-induced JNK activation

The zinc-finger protein A20 has crucial physiological functions as a dual inhibitor of nuclear factor-κB (NF-κB) activation and apoptosis in tumor necrosis factor (TNF) receptor 1 signaling pathway. Although the molecular basis for the anti-NF-κB function of A20 has been well elucidated, the anti-apoptotic function of A20 is largely unknown. Here, we report a novel mechanism underlying the anti-apoptotic function of A20: A20 blocks TNF-induced apoptosis through suppression of c-jun N-terminal kinase (JNK) by targeting apoptosis signal-regulating kinase1 (ASK1). First, the ectopic expression of A20 drastically inhibits TNF-induced JNK activation and apoptosis in multiple cell types including those deficient of NF-κB activation. Unexpectedly, the blunting effect of A20 on TNF-induced JNK activation is not mediated by affecting the TNFR1 signaling complex formation. Instead, A20 interacts with ASK1, an important MAPKK kinase in the JNK signaling cascade. More importantly, overexpression of wild-type A20, but not of mutant A20 (ZnF4; C624A, C627A), promotes degradation of the ASK1 through the ubiquitin-proteasome system. Taken together, the results from this study reveal a novel anti-apoptotic mechanism of A20 in TNF signaling pathway: A20 binds to ASK1 and mediates ASK1 degradation, leading to suppression of JNK activation and eventually blockage of apoptosis.

Patterns of nurse-physician communication and agreement on the plan of care

BACKGROUND

Interdisciplinary communication is critically important to provide safe and effective care, yet it has been inadequately studied for hospitalised medical patients. Our objective was to characterise nurse-physician communication and their agreement on patients' plan of care.

METHODS

During a one-month period, randomly selected hospitalised patients, their nurses and their physicians were interviewed. Nurses and physicians were asked to identify one another, whether communication had occurred, and about six aspects of the plan of care. Two internists rated nurse-physician agreement on aspects of the plan of care as none, partial or complete agreement. Measures included the percentage of nurses and physicians able to identify one another and reporting communication and the percentage of nurse-physician pairs in agreement on aspects of the plan of care.

RESULTS

310 (91%) and 301 (88%) of 342 eligible nurses and physicians completed interviews. Nurses correctly identified patients' physicians 71% of the time and reported communicating with them 50% of the time. Physicians correctly identified the patients' nurses 36% of the time and reported communicating with them 62% of the time. Physicians and nurses showed no agreement on aspects of the plan of care ranging from 11% for planned procedures to 42% for medication changes.

CONCLUSIONS

Nurses and physicians did not reliably communicate with one another and were often not in agreement on the plan of care for hospitalised medical patients.

Role of the M3 muscarinic acetylcholine receptor in beta-cell function and glucose homeostasis

The release of insufficient amounts of insulin in the presence of elevated blood glucose levels is one of the key features of type 2 diabetes. Various lines of evidence indicate that acetylcholine (ACh), the major neurotransmitter of the parasympathetic nervous system, can enhance glucose-stimulated insulin secretion from pancreatic beta-cells. Studies with isolated islets prepared from whole body M(3) muscarinic ACh receptor knockout mice showed that cholinergic amplification of glucose-dependent insulin secretion is exclusively mediated by the M(3) muscarinic receptor subtype. To investigate the physiological relevance of this muscarinic pathway, we used Cre/loxP technology to generate mutant mice that lack M(3) receptors only in pancreatic beta-cells. These mutant mice displayed impaired glucose tolerance and significantly reduced insulin secretion. In contrast, transgenic mice overexpressing M(3) receptors in pancreatic beta-cells showed a pronounced increase in glucose tolerance and insulin secretion and were resistant to diet-induced glucose intolerance and hyperglycaemia. These findings indicate that beta-cell M(3) muscarinic receptors are essential for maintaining proper insulin secretion and glucose homeostasis. Moreover, our data suggest that enhancing signalling through beta-cell M(3) muscarinic receptors may represent a new avenue in the treatment of glucose intolerance and type 2 diabetes.

Polymer confinement and bacterial gliding motility

Cyanobacteria and myxobacteria use slime secretion for gliding motility over surfaces. The slime is produced by the nozzle-like pores located on the bacteria surface. To understand the mechanism of gliding motion and its relation to slime polymerization, we have performed molecular dynamics simulations of a molecular nozzle with growing inside polymer chains. These simulations show that the compression of polymer chains inside the nozzle is a driving force for propulsion. There is a linear relationship between the average nozzle velocity and the chain polymerization rate with a proportionality coefficient dependent on the geometric characteristics of the nozzle such as its length and friction coefficient. This minimal model of the molecular engine was used to explain the gliding motion of bacteria over surfaces.

Synthesis and reactivity of an efficient 1,2-dehydrocarborane precursor, phenyl[o-(trimethylsilyl)carboranyl]iodonium acetate

The reaction of [o-(trimethylsilyl)carboranyl]lithium with IPh(OAc)2 in diethyl ether affords an efficient 1,2-dehydro-o-carborane precursor 4: the facile 2 + 4 cycloaddition of 4 with dienes in the presence of the desilylating agent is reported.

Quadriceps muscle deoxygenation during functional electrical stimulation in adults with spinal cord injury

STUDY DESIGN

Cross-sectional study comparing healthy subjects with age and gender matched subjects with spinal cord injury (SCI, injury levels from C5 to T12).

OBJECTIVES

To compare the acute cardiorespiratory responses and muscle oxygenation trends during functional electrical stimulation (FES) cycle exercise and recovery in the SCI and healthy subjects exercising on a mechanical cycle ergometer.

SETTING

Seven volunteers in each group participated in one exercise test at the Rick Hansen Center, University of Alberta, Edmonton, Canada.

METHODS

Both groups completed a stagewise incremental test to voluntary fatigue followed by 2 min each of active and passive recovery. Cardiorespiratory responses were continuously monitored using an automated metabolic cart and a wireless heart rate monitor. Tissue absorbency, an index of muscle oxygenation, was monitored non-invasively from the vastus lateralis using near infrared spectroscopy.

RESULTS

The healthy subjects showed significant (P<0.05) increases in the oxygen uptake (VO2), heart rate (HR) and ventilation rate (VE) from rest to maximal exercise. The SCI subjects showed a twofold increase in VO2 (P>0.05), a threefold increase in VE (P<0.05) and a 5 beats/min increase in HR (P>0.05) from the resting value. The SCI subjects demonstrated a lesser degree (P<0.05) of muscle deoxygenation than the healthy subjects during the transition from rest to exercise. Regression analysis indicated that the rate of decline in muscle deoxygenation with respect to the VO2 was significantly (P<0.05) faster in the SCI subjects compared to healthy subjects.

CONCLUSIONS

FES exercise in SCI subjects elicits: (a) modest increases in the cardiorespiratory responses when compared to resting levels; (b) lower degree of muscle deoxygenation during maximal exercise, and (c) faster changes in muscle deoxygenation with respect to the VO2 during exercise when compared to healthy subjects.