An all phosphorene lattice nanometric spin valve.

Phosphorene is a unique semiconducting two-dimensional platform for enabling spintronic devices integrated with phosphorene nanoelectronics. Here, we have designed an all phosphorene lattice lateral spin valve device, conceived via patterned magnetic substituted atoms of 3d-block elements at both ends of a phosphorene nanoribbon acting as ferromagnetic electrodes in the spin valve. Through First-principles based calculations, we have extensively studied the spin-dependent transport characteristics of the new spin valve structures. Systematic exploration of the magnetoresistance (MR) of the spin valve for various substitutional atoms and bias voltage resulted in a phase diagram offering a colossal MR for V and Cr-substitutional atoms. Such MR can be directly attributed to their specific electronic structure, which can be further tuned by a gate voltage, for electric field controlled spin valves. The spin-dependent transport characteristics here reveal new features such as negative conductance oscillation and switching of the sign of MR due to change in the majority spin carrier type. Our study creates possibilities for the design of nanometric spin valves, which could enable integration of memory and logic elements for all phosphorene 2D processors.

Orbital leiomyoma presenting as inverse globe retraction syndrome: a unique presentation of a rare disease.

Inverse globe retraction syndrome is a rare ocular motility disorder characterized by limited abduction, with globe retraction and up- or downshoots on attempted abduction, differentiating it from globe retraction due to Duane retraction syndrome, seen on attempted adduction. It can be congenital or acquired. We report the case of a 3-year-old girl who presented with classical features of inverse globe retraction syndrome secondary to an underlying orbital tumor involving the medial rectus muscle. Incisional biopsy confirmed the diagnosis of a leiomyoma. At 10 months' follow-up, vision, ocular alignment, and ocular motility had improved.

Bi-stimuli assisted engineering and control of magnetic phase in monolayer CrOCl.

Magnetic phase control and room temperature magnetic stability in two-dimensional (2D) materials are indispensable for realising advanced spintronic and magneto-electronic functions. Our current work employs first-principles calculations to comprehensively study the magnetic behaviour of 2D CrOCl, uncovering the impact of strain and electric field on the material. Our studies have revealed that uniaxial strain leads to the feasibility of room temperature ferromagnetism in the layer and also detected the occurrence of a ferromagnetic → antiferromagnetic phase transition in the system, which is anisotropic along the armchair and zigzag directions. Beyond such a strain effect, the coupling of strain and electric field leads to a remarkable enhancement of the Curie temperature (Tc) ∼ 450 K in CrOCl. These predictions based on our detailed simulations show the prospect of multi-stimuli magnetic phase control, which could have great significance for realizing magneto-mechanical sensors.

Spin-selective response tunability in two-dimensional nanomagnet.

Recent reports on the two-dimensional (2D) material CrOCl revealed magnetic ordering and spin polarisation with Curie Temperature T c ∼ 160 K, values higher than most diluted magnetic semiconductors. Here, we investigate the uniaxial and biaxial strain-dependent electronic and transport properties of CrOCl monolayer using first-principles based calculations. The calculated Young's modulus indicates high mechanical flexibility for the application of high strain. Our study shows that strain can induce phase changes from a bipolar magnetic semiconductor → half metal → magnetic metal in the material, leading to interesting spin-resolved conductance with 100% spin filtering. Furthermore, the current-voltage (I-V) response showed conductance fluctuations, characterised by peak to valley ratio and switching efficiency offering high strain assisted tunability. Overall, CrOCl shows a highly anisotropic behaviour with the material displaying 100% spin polarisation in the tensile strain region. The electronic, transport and mechanical properties indicate that CrOCl is a versatile 2D material with multi-phase capabilities having promising applications for future nanospintronic devices.

High efficiency spin filtering in magnetic phosphorene.

Phosphorene has a unique set of characteristics such as a semiconducting nature, good carrier mobility and low-spin orbit coupling aspects which makes it a highly prospective two dimensional material for cross-hybrid architectures in nanoelectronics, spintronics, and optoelectronics. In the spintronic context, the creation of a stable magnetic order in phosphorene can be immensely beneficial for designing phosphorene spin circuits. In this work, we present high efficiency spin filtering behaviour in magnetically rendered phosphorene. First, we calculate the effect of doping various 3d block elements in phosphorene to introduce a stable magnetic order. Next, by varying doping concentrations in distinct doping configurations, an extensive phase diagram has been obtained depicting the presence of various electronic and magnetic states. This allows us to achieve a high magnetisation in the presence of various transition metal atoms, with a spin polarisation of ∼100% in half-metallic regimes. The transport behaviour reveals a map of the spin injection efficiency showing enhancement with doping concentration and reaching a perfect spin filtering capacity of ∼100% in the presence of Ti, Cr, Mn, Co, and Fe atoms. The present results offer new insights into engineered designs of multi-functional phosphorene spintronic circuits.

Electronic phase-crossover and room temperature ferromagnetism in a two-dimensional (2D) spin lattice.

Tuning of system properties such as electronic and magnetic behaviour through various engineering techniques is necessary for optoelectronic and spintronic applications. In our current work, we employ first-principles methodologies along with Monte-Carlo simulations to comprehensively study the electronic and magnetic behaviour of 2-dimensional (2D) Cr2Ge2Te6 (T c = 61 K), uncovering the impact of strain and electric field on the material. In the presence of strain, we were able to achieve high temperature magnetic ordering in the layer along with observable phase crossover in the electronic state of the system, where the system exhibited transference from semiconducting to half-metallic state. Finally, on coupling strain and electric field remarkable increase in Curie temperature (T c) ∼ 331 K (above 5-fold enhancement from pristine configuration) was observed, which is very well above room temperature. Our inferences have shed light on a relatively new type of coupling method involving strain and electric field which may have tremendous implications in the development of 2D spintronic architecture.

Dramatic magnetic phase designing in phosphorene.

Phosphorene is a unique two-dimensional semiconductor that exhibits huge potential for nanoelectronic, optoelectronic and spintronic applications and their cross-hybrid electronics. In particular, creation of magnetic phases in phosphorene selectively can provide a multitude of opportunities for developments in 2D spintronic circuits. Doping phosphorene with transition metal atoms can induce sustainable magnetic ordering, making it a diluted magnetic system, however, the viability of high temperature magnetic phases and potential control remain unanswered. In this work, using first-principles calculations, we uncover the impact of doping phosphorene with various 3d block elements (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) in increasing order of atomic number at various levels of doping. Such an extensive study helps us to find the doping conditions that lead to remarkable feasibility of ferromagnetism and antiferromagnetism up to a strikingly large temperature ∼1150 K, evaluated by mean field theory. The doping concentration and atom type can be used to systematically tune the phases from ferromagnetic and antiferromagnetic to non-magnetic ground states. Our work provides new guidelines for engineering multi-functional spintronic components using phosphorene as a base material for all-phosphorene spintronics.

Enzymatic single-chain antibody tagging: a universal approach to targeted molecular imaging and cell homing in cardiovascular disease.

RATIONALE: Antibody-targeted delivery of imaging agents can enhance the sensitivity and accuracy of current imaging techniques. Similarly, homing of effector cells to disease sites increases the efficacy of regenerative cell therapy while reducing the number of cells required. Currently, targeting can be achieved via chemical conjugation to specific antibodies, which typically results in the loss of antibody functionality and in severe cell damage. An ideal conjugation technique should ensure retention of antigen-binding activity and functionality of the targeted biological component. OBJECTIVE: To develop a biochemically robust, highly reproducible, and site-specific coupling method using the Staphylococcus aureus sortase A enzyme for the conjugation of a single-chain antibody (scFv) to nanoparticles and cells for molecular imaging and cell homing in cardiovascular diseases. This scFv specifically binds to activated platelets, which play a pivotal role in thrombosis, atherosclerosis, and inflammation. METHODS AND RESULTS: The conjugation procedure involves chemical and enzyme-mediated coupling steps. The scFv was successfully conjugated to iron oxide particles (contrast agents for magnetic resonance imaging) and to model cells. Conjugation efficiency ranged between 50% and 70%, and bioactivity of the scFv after coupling was preserved. The targeting of scFv-coupled cells and nanoparticles to activated platelets was strong and specific as demonstrated in in vitro static adhesion assays, in a flow chamber system, in mouse intravital microscopy, and in in vivo magnetic resonance imaging of mouse carotid arteries. CONCLUSIONS: This unique biotechnological approach provides a versatile and broadly applicable tool for procuring targeted regenerative cell therapy and targeted molecular imaging in cardiovascular and inflammatory diseases and beyond.

The effectiveness of microballoon angioplasty in treating middle cerebral artery occlusion beyond the bifurcation.

BACKGROUND AND PURPOSE: PTA effectively treats vasospasm and arterial disease in peripheral, coronary, and large proximal cerebral vessels but rarely reaches small vessels like the distal MCA beyond the bifurcation. Our purpose was to evaluate the safety and efficacy of PTA for distal MCA occlusions in acute ischemic stroke. MATERIALS AND METHODS: Seven patients had strokes in branches of their MCAs. Following diagnostic angiography, all received microballoon angioplasty and various combinations of IA alteplase (rtPA), abciximab, and/or nitroglycerin. Two also underwent stent placement. Comprehensive retrospective review of the patients' records was performed. Patients' NIHSS scores were reassessed before discharge. Recanalization was evaluated by angiography after treatment and at follow-up. RESULTS: PTA was successfully performed in 7 patients without treatment-associated intracerebral hemorrhage. Two patients received distal MCA angioplasty as a secondary intervention: 1 following failed treatment with a Merci retriever and the other after successful removal of proximal clot with a Merci retriever. One patient did not recover from the initial ischemic event despite an excellent angiographic result. Complete recanalization (modified TIMI grade 4) was achieved in 4 patients and near-complete recanalization with mild flow deficit (modified TIMI grade 3), in 3 patients. CONCLUSIONS: PTA of the distal MCA with a microballoon is safe and effective for acute ischemic stroke. This case series demonstrates that endovascular treatment beyond the MCA bifurcation can dramatically reverse neurologic deficits.

Steroids in full term infants with respiratory failure and pulmonary hypertension due to meconium aspiration syndrome.

Persistent pulmonary hypertension of the newborn (PPHN) due to meconium aspiration syndrome (MAS), has a high morbidity and mortality especially in centres with limited access to extra-corporeal membrane oxygenation or nitric oxide therapy. In such a setting, we conducted a pilot study to evaluate the effect of dexamethasone on severe respiratory failure with PPHN due to MAS with a view to exploring possible justification for randomised controlled trials in similar patients. We prospectively managed a consecutive case series of 14 infants over a 3-year period with the above mentioned diagnosis, who were ventilated and with an oxygenation index >25. Dexamethasone was commenced in a dose of 0.5 mg/kg per day and given for up to a maximum of 9 days in a reducing schedule. Differences between time points were analysed using analysis of variance for repeated measures. The mean age of commencing dexamethasone was 79.9 h. There was a rapid, significant improvement (P < 0.05) in the respiratory status in 13 of these infants after commencing dexamethasone, allowing weaning from the ventilator and eventual extubation at a mean age of 8.7 days. One infant died. Two infants had infective episodes. Conclusion. Dexamethasone, if started early in infants with respiratory failure and persistent pulmonary hypertension of the newborn due to meconium aspiration syndrome may be effective in improving gas exchange, and possibly avoiding extra-corporeal membrane oxygenation. A randomised controlled trial of using dexamethasone early in similar patients and setting is warranted.

Effects of smoking on health care costs.

Smoking is the leading preventable cause of death in the United States. The US Centers for Disease Control and Prevention (CDC) estimate that smoking kills approximately 419,000 people in the United States each year. Cigarette smoking is the nation's leading cause of premature mortality, and is responsible for one-third of all deaths among working-age Americans. Smoking cigarettes is both psychologically and physiologically addictive. Smoking is an important risk factor for cardiovascular diseases, especially coronary artery disease, stroke, carcinoma of the lung, chronic bronchitis, chronic obstructive pulmonary disease, and emphysema. It also increases the risk for peripheral vascular disease and is associated with cancers of the larynx, oral cavity, esophagus, pancreas, and urinary bladder. Smoking by pregnant women can cause adverse health effects on their babies, like low birth weight and preterm delivery; increases the risk of miscarriage; and has also been found to be an important cause of sudden infant death syndrome. Careless smoking also can cause severe burn injuries and death. Many of these adverse effects of smoking occur in "second-hand" smokers.

Regulatory role of the 3' untranslated region of luteinizing hormone receptor: effect on mRNA stability.

Posttranscriptional regulation of luteinizing hormone receptor (LHR) mRNA has a significant role in regulating cell surface receptor expression during ovarian cycle. In order to gain insight into the mechanism of posttranscriptional regulation, the cis-acting elements in the 3' untranslated region (3' UTR) of LHR mRNA were examined by transfection studies followed by measurements of the receptor expression and receptor mRNA half-life. The results show that the inhibitory effect exerted by the 3.51 kb 3' UTR of the LHR resides in the distal 1.98 kb region. Half-life measurement of LHR mRNA showed that the inhibitory effect of the 3' UTR was due to a decrease in receptor mRNA stability. Deletion studies revealed that the entire 1.98 kb region is required for LHR mRNA destabilization. Although the 3.51 kb 3' UTR of LHR contains 11 AUUUA motifs, their removal had no effect on mRNA stability or receptor expression. Thus, although AUUUA motifs have been implicated in mRNA stability, these motifs do not appear to play an inhibitory role in LHR expression. The 3' UTR of LHR was also able to decrease the expression of a reporter gene indicating that the inhibitory effect of 3' UTR is not unique to the open reading frame of LHR. The present studies show that the distal 1.98 kb portion of the 3' UTR exerts an inhibitory effect on the expression of LHR by decreasing the receptor mRNA half-life. The inhibitory effect of 3' UTR might play a role in the maintenance of the steady state levels of the receptor mRNA under different physiological states.

A trial of baby check scoring system to identify high-risk infants in a polyclinic in Oman.

The baby check score card was used in a busy polyclinic to identify babies with different grades of illness attending as out-patients. A total of 90 paediatric patients in the age group 1 to 6 months were screened during February to June 1995. These patients were seen by the junior physicians. They filled in the score card and graded the illness, as they perceived, into well or mild, moderate, and severe. The scores, as described by the original authors, were then assigned to the various signs and symptoms recorded in the score card, by the investigators. The total scores obtained were correlated with the grades of illness (grade 1-well or mild, grade 2-moderate, and grade 3-severe). The scores ranged from 0 to 41. Forty-three cases were well or mildly ill; 41 moderately ill; and six seriously ill. The scores generally correlated with the grades of illness. Those with lower scores had milder illness and were sent home with reassurance. Six cases who were seriously ill all scored over 20 and were referred for tertiary care. The scoring system appeared to be fairly accurate in identifying high-risk infants. It could be used as a valuable tool for screening infants for severity of illness with reasonable accuracy in our set-up.