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Toward the development of a new parent-rating for insomnia, this multi-site qualitative study explored sleep problems and related impacts in children with autism spectrum disorder (ASD) and their families. To ensure content validity of the measure, we conducted six focus groups with caregivers (N = 25) of 24 children (age 3 to 18 years) with ASD. Based on parent report, all children had a history of mild or greater insomnia. The focus group transcripts were systematically coded to identify major themes. Verbatim comments from caretakers were used to generate 134 candidate items. Further review by the research team and an expert panel followed by individual cognitive interviews with 12 parents reduced the item bank to 40. The thematic analysis of focus group transcripts identified 7 categories: (1) Trouble falling asleep; (2) trouble staying asleep; (3) early morning waking; (4) bedtime routines; (5) parental strategies for bedtime management; (6) impact of sleep problems on the child; and (7) impact of sleep problems on the family. The Flesch Kincaid Grade Level of the 40-item version was 7.2 (seventh grade reading level). Insomnia in children with ASD shares features in common with insomnia in the general pediatric population. However, perhaps owing to autistic features such as insistence on sameness, sensory sensitivities, communication impairments, insomnia in children with ASD appears to have unique behavioral manifestations. Content validity and item clarity of the 40-item bank were supported by expert panel review and cognitive interviews with caregivers of children with ASD. [ABSTRACT FROM AUTHOR]

The present theoretical work addresses the study of the formation of a positive Antihydrogen ion in a single charge exchange reaction where a positronium (ground or excited state) interacts with a ground state antihydrogen atom, being embedded in a dense Debye plasma. The calculations are carried out in the frame work of a Coulomb distorted eikonal approximation. The result shows that Ps (3s) is the most interesting state to enhance the -μH+ production at the energy close to the reaction threshold. Regarding the Debye screening, it may be inferred that in lower energy regime, the screening effect enhances the TCS for the 1s and 2s states while reduces the same for the 2p and 3s states of Ps. [ABSTRACT FROM AUTHOR]

The anisotropy in resonant tunneling transport through an electrostatic barrier in monolayer black phosphorus either in presence or in absence of an oscillating potential is studied. Non-perturbative Floquet theory is applied to solve the time dependent problem and the results obtained are discussed thoroughly. The resonance spectra in field free transmission are Lorentzian in nature although the width of the resonance for the barrier along the zigzag (Г–Y) direction is too thinner than that for the armchair (Г–X) one. Resonant transmission is suppressed for both the cases by the application of oscillating potential that produces small oscillations in the transmission around the resonant energy particularly at low frequency range. Sharp asymmetric Fano resonances are noted in the transmission spectrum along the armchair direction while a distinct line shape resonance is noted for the zigzag direction at higher frequency of the oscillating potential. Even after the angular average, the conductance along the Г–X direction retains the characteristic Fano features that could be observed experimentally. The present results are supposed to suggest that the phosphorene electrostatic barrier could be used successfully as switching devices and nano detectors. [ABSTRACT FROM AUTHOR]

We investigate theoretically the effect of a time dependent oscillating potential on the transport property of the Dirac Fermion through a monolayer graphene electrostatic barrier under the influence of the Rashba spin orbit interaction. The time dependent problem is solved in the frame work of the non-perturbative Floquet approach. It is noted that the dynamic condition of the barrier may be controlled by tuning the Rashba parameter. Introduction of the spin orbit interaction causes splitting of the Fano resonance (FR), a characteristic feature in photon assisted tunneling. The separation between the spin split FR's gives an indirect measure of the fine structure of the quasi-hole bound state inside the barrier. The present findings on the Rashba splitting of the FR and its external control by tuning the oscillating field parameters might have potential for applications in spintronic devices, especially in the spin field effect transistors. The spin polarization of different Floquet sidebands is found to be quite sensitive to the spin-pseudospin interaction. [ABSTRACT FROM AUTHOR]

The influence of an external intense laser field on the tunneling transport (ballistic) of the Dirac fermions through a monolayer graphene electrostatic barrier is studied in the framework of the Floquet approach for a continuous wave, linearly polarized, monochromatic laser. The Klein tunneling is shown to be suppressed by the irradiation of a strong laser field, arising due to breaking of chiral symmetry. The symmetric nature of the field free angular transmission spectrum around the normal to the well-barrier interface is destroyed due to the additional coupling between the pseudo-spin and the time dependent vector potential. The energy distribution of the tunneling spectrum displays Fano resonance which is absent for a laser assisted conventional electrostatic barrier but similar to the case of quantum well structures, providing an optical tool to identify field free quasi bound states inside the graphene nanostructures. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to review the outcomes of thyroid surgery in children operated for both benign and malignant conditions.Patients and Method: Demography, clinical features, and surgical outcomes were noted retrospectively for operations performed during the last 23 years. Results were analyzed using Fisher exact test and Woolf (logit) method with p value < 0.05 considered as significant.Results: In total, 61 children (43 girls and 18 boys) underwent thyroidectomy for benign (70%) and malignant (30%) conditions. Median follow-up period was 1.4 years. In the benign group, 84% children had Graves disease and 16% had other conditions. In this study, 42% children had total, 22% had near-total, 27% had subtotal, and 9% had type 2 hemithyroidectomy. In the malignant group, 50% had multiple endocrine neoplasia, 33% had papillary, 11% had follicular cancer, and 6% had B-cell lymphoma. Fifty percent children had prophylactic thyroidectomy, 44% had total thyroidectomy plus lymphadenectomy, and 6% had hemithyroidectomy. At the time of surgery, children with benign conditions were older than those with malignancy (median, 12 vs. 7.5 years). There were no incidents of postoperative bleeding or infection. Hypocalcemia was significantly more frequent in the malignant group (39 vs. 9%, p value = 0.01). The type of recurrent laryngeal nerve (RLN) injury was more serious in the benign group (one bilateral and one unilateral permanent injury) than in the malignant group (transient hoarseness in three). Overall rate of complications was higher for operations for malignancy (56 vs. 28%, p value = 0.07). In Graves disease, the subtotal thyroidectomies had a recurrence of 30% but no recurrence was seen following total or near-total thyroidectomy group (p value = 0.01). There was no recurrence in the malignant group. Children operated after 2000 were younger than those operated before 2000 (median age, 9 vs. 14 years). Malignant conditions were more common in children operated after 2000 in comparison to before 2000 (55 vs. 10%).Conclusion: Benign conditions are commonest indications for thyroid surgery in children but the incidence of surgery for malignant conditions is rising. Overall rate of complications, especially hypocalcemia, is higher after surgery for malignancy but all cases of permanent RLN injury were in benign group. Total or near total thyroidectomy prevents recurrence of thyrotoxicosis and is an operation of choice for Graves disease. [ABSTRACT FROM AUTHOR]

Aim The practice of routine or selective interval appendicectomy (IA) following successful conservative treatment of appendix mass is a matter of debate. Predictors of recurrence may be elucidated by correlating demographic and disease course data with high risk histology obtained at IA. Material and Methods Children having undergone IA between 2002 and 2012 were identified. Histology of specimens were reviewed by two clinicians and categorised as low or high risk of recurrence. Demographic and treatment course data was analysed using Fishers exact for nominal and Mann-Whitney U test for continuous data, to demonstrate association with histological risk. Results Thirty-nine children were identified, median age 11 years (range 3-15) and weight 37kg (9 -77Kg). We report recurrence of symptoms in 33%. Seventy-two percent had histologically high risk of recurrence. Demographic data was comparable between the two groups. Predictors of high risk included: palpation of a clear abdominal mass on initial exam (PPV 83%), ultrasound findings of a clearly visualised appendix phlegmon (OR 5.25, p=0.038) or faecolith (OR 2.25, p=0.35), recurrence of symptoms and readmission (OR 2.4, 2.3 p=0.3, p=0.29). Conclusion Only ultrasound appearance of clearly defined appendix phlegmon reached statistical significance to predict outcome. This information can be used in counselling families following successful conservative treatment of an appendix mass. [ABSTRACT FROM AUTHOR]

Abstract: The scattering of a bound Frohlich large polaron in the presence of a coulomb impurity center as well as a linearly polarized laser field is studied. The differential (DCS) as well as the momentum transfer cross sections (MTCS) and the conductivity depend remarkably on the electron–phonon coupling ( ) and the strength of the coulomb impurity ( ). The strongly bound polaron is found to be reluctant to contribute to the conductivity which is justified physically. The curves for MTCS and conductivity verses and appear to be complementary, indicating the possibility of controlling the mobility and thereby conductivity by varying one of the parameters. This behavior indicates the possibility of optimizing the composition of optoelectronic materials where laser is the dominant source of excitation. [Copyright &y& Elsevier]

Purpose The aim of this study was to find out the outcome of "thoracoscopic sympathectomy" (TS) for palmar hyperhidrosis (PH) in children. To our knowledge, this is the largest experience of TS from the United Kingdom. Method All patients who underwent TS for PH during the past 21 years were studied retrospectively. Results A total of 85 procedures were done in 44 children. Ratio of female tomale was 4:1. Median age at operation was 12.8 years. Types of operations performed were as follows: bilateral T2-T3 sympathectomy in 87% (38/44), bilateral T2-T5 sympathectomy in 9% (4/44), and right-sided thoracoscopic (left-sided done open) in 1% (0.5/44); operation was not possible in 3% (1.5/44) of cases. No chest drains were used. Median postoperative stay was 2 days (range 1 to 5).Median follow-up time was 1.3 years (range 0.2 to 4.7 years). Only problematic patients were followed up for longer. During followup, 21% (9/44) developed severe hyperhidrosis of other parts of body. Seven percent (3/44) of patients developed severe axillary hyperhidrosis (AH) and required T4-T5 sympathectomy later on at a median age of 14.4 years (range 11 to 16 years). Another 9% (4/44) patients developed severe plantar hyperhidrosis. Severe hyperhidrosis of the whole body was seen in 5% (2/44) of the patients. Postoperative complications were seen in 47% (21/44) of the patients. They were as follows: postoperative pain (needing > 48 hours hospital stay) in 18% (8/44); transient Horner syndrome in 18% (8/44-right 5, left 3); and recurrence of PH in 11% (5/44) of cases. In the recurrence group, 7% (3/44) were unilateral (right 2, left 1) and 5% (2/44) were bilateral. Redo operations were performed in 11% (5/44) of cases. Median time to redo was 2.6 years (range 8 months to 4.2 years). All three unilateral recurrent patients underwent respective sided redo. In the bilateral recurrence group (2/44), one patient had bilateral redo (remained dry), whereas the other patient underwent only right-sided operation (remained dry), as that sided operation was difficult and so the other side was not tried. Final Outcomes The final outcomes were recurrence 3.5% (3/85-right 2, left 1) and technically failed operation 3.5% (3/85-both sides 1, one side 1). Success rate for thoracoscopic sympathetectomy was 93% (79/85) overall. Conclusion TS for PH is a safe and feasible operation in children. It is successful in the majority; however, the procedure is not trouble free. [ABSTRACT FROM AUTHOR]

Aim: To review our practice of Meckel's Tc-99m pertechnetate scans over 18 years with regard to indications for the test, sensitivity and specificity in our particular referral patients' population. Materials and methods: This is a retrospective review of Meckel's scans performed in two paediatric tertiary care teaching hospitals from April 1993 to March 2011 and followed up till October 2011. The scan was performed according to published international guidelines. 183 patients were included in this study. We classified the patients into two groups: group 1, which included 77 patients (42 %) presenting with painless per rectum bleeding, and group 2, which included 106 patients (58 %) presenting with other non-specific symptoms (e.g. abdominal pain, possibly associated with nausea and/or vomiting, failure to thrive). Data were analysed using Chi square test, considering P value less than 0.05 as significant. The age of the patients ranged from 4 days to 16.5 years (median 3 years). Results: 161 of the total 183 children on the study (88 %) had a negative Meckel's scan, and 22 children (12 %) had a positive scan. In the group with a positive Meckel's scan (22 children), all patients underwent surgical exploration and ectopic gastric mucosa was found in 17 cases (77 %, true positives). In the remaining 5 cases (23 %), there was no evidence of ectopic gastric mucosa (false positives). Within the group with a negative scan, 8 children (5 %) underwent surgery; only 1 child had a ectopic gastric mucosa detected following surgery (false negative). In other 52 children (32 %) of the group with a negative Meckel's scan, an endoscopy was done, which showed a normal result in 21 children and was abnormal in 31 children. Of the remaining 101 (63 %) children with a negative Meckel's scan, 74 children (46 %) improved without any further intervention. In 13 cases (8 %), other pathologies were identified. The sensitivity and specificity of the Meckel's scan for ectopic gastric mucosa were 94 and 97 %, respectively. The Meckel's scan was positive in 26 % of the patients of group 1 and in only 2 % patients of group 2. The difference between the two groups was highly significant [ P < 0.0001 (Yates-corrected Chi square); odds ratio 18 (Woolf-logit method 95 % CI)]. Conclusion: The Meckel's scan retains a high diagnostic accuracy in children for detecting a Meckel's diverticulum with ectopic gastric mucosa within it, when performed according to the recommended guidelines. The test yields its highest positive result in children presenting with significant per rectum bleeding. [ABSTRACT FROM AUTHOR]

The present theoretical model deals with the transmission property of the Dirac fermions in the Floquet sidebands for the laser radiated graphene nanostructure. The laser assisted structure behaves as a tunneling barrier that leads to asymmetric transmission around the normal to the interface and is capable to confine the massless Dirac particles in a monolayer graphene strip. The absence of the Klein tunneling and the presence of a large number of controlling parameters would make the time dependent vector potential barrier superior over the electrostatic and magnetic barriers towards the opto-electronic device fabrication. [ABSTRACT FROM AUTHOR]

The asymmetric Fano resonances (FRs) are noted for the first time in the coherent ballistic transmission spectrum of bilayer graphene tunneling structures. This characteristic tunneling transmission that occurs particularly at small glancing incidence mainly arises due to the quadratic dispersion of chiral charge carriers. The Fano line shape is found to be highly sensitive with respect to the direction of incidence of the charge carriers, the applied homogeneous electric field, as well as to the barrier height and width. The absence of the FR at normal incidence is in accordance with the conservation of chirality of the Dirac fermions in bilayer graphene. The sharp antiresonance at the center of the tunneling band arising due to destructive interference between the electron and the holelike states might be responsible for high negative differential conductivity (NDC) in bilayer graphene. [ABSTRACT FROM AUTHOR]

The dynamics of the electron impact multiphoton ionization of a He atom in the presence of an intense laser field ( n $\gamma _e$, 2 e) is studied theoretically for laser polarization ( $\vert\vert^l$) and perpendicular ( $\bot^r$) to the incident momentum. The triple differential (TDCS) as well as the double differential (DDCS) cross sections are studied for the coplanar asymmetric geometry. The results are compared with the only available kinematically complete experiment at high incident energy (1000 eV). Significant laser modification (enhancement) is noted due to multiphoton effects in the present binary and recoil peak intensities of the TDCS for both the geometries, in qualitative agreement with the experiment. In the single photon case, the net effect of the laser field is to suppress the field free (FF) TDCS as well as the DDCS in the zeroth order approximation of the ejected electron wave function (CV), while in the first order (MCV), the cross sections are found to be enhanced. The CV multiphoton cross sections obey the famous Kroll Watson (KW) sum rule while the latter does not hold good in the corresponding MCV approximation. [ABSTRACT FROM AUTHOR]

Fragmentation of ground state ortho-positronium (Ps) in collision with Li ion (Li+) is studied in the framework of post-collisional Coulomb distorted eikonal approximation (CDEA), giving special emphasis on the dynamics of the electron loss to the continuum (ELC) that occurs when the electron (e) and the positron (e+) are very close to each other in the velocity space (ve ≈ vp). The present model takes account of the two-centre effect on the ejected e which is crucial for a proper description of the ELC phenomena. Both the fully differential cross-section (TDCS) and the doubly differential cross-section (DDCS) (energy spectra) are investigated at intermediate and high incident energies. A broad distinct ELC peak centred around ve ≈ vp is noted in the e energy spectrum in contrast to the sharp ELC peak for a heavy projectile, corroborating the experimental findings. Two salient features are noted in the present study: (i) the shift of the e DDCS peak (summed over e+ angles) towards higher ejection energy with respect to half the residual energy of the system, (ii) comparison of the e and e+ energy spectra reflect a strong e-e+asymmetry with respect to the ratio ve=vp = 1. Both these features are in qualitative agreement with the experimental observations due to Armitage et al for Ps-He atom system and could be attributed to the post-collisional two-centre effect on e due to its parent nucleus (e+) and the screened target ion. Two different wave functions of the Li ion are chosen in order to test the sensitivity of the present results with respect to the choice of the wave function. [ABSTRACT FROM AUTHOR]

The importance of the excited states of Positronium (Ps) in the formation cross sections (both differential and total) of the negative hydrogen ion (H-) are investigated theoretically for the charge transfer reaction, Ps (n = 1, 2) + H ↦ e+ + H- for a wide range of incident energies (e.g., threshold – 500 eV). The calculations are performed in the frame work of a qualitative model, the post collisional Coulomb modified eikonal approximation (CMEA). A comparative study is also made between the capture from ground and excited states of the Ps. The present CMEA model takes account of higher order effects which is essential for a rearrangement process where the first Born type approximation (Coulomb Born for the ionic case) is not supposed to be adequate. At low incident energies, the excited states of Ps (2s, 2p) are found to play a dominant role in the H- formation cross sections. Significant deviations are noted between the present CMEA and the Coulomb Born (CBA) results even at very high incident energies (e.g., Ei = 500 eV), indicating the importance of higher order effects. At high incident energies the present CMEA differential cross section (DCS) exhibits a double peak structure which is totally absent in the CBA and could again be attributed to higher order effects. [ABSTRACT FROM AUTHOR]

Biliary atresia (BA) is a cholangiodestructive disease affecting biliary tract, which ultimately leads to cirrhosis, liver failure and death if not treated. The incidence is higher in Asian countries than in Europe. Up to 10% of cases have other congenital anomalies, such as polysplenia, asplenia, situs inversus, absence of inferior vena cava and pre-duodenal portal vein, for which we have coined the term Biliary Atresia Splenic Malformation (BASM) syndrome. For these infants the aetiology lies within the first trimester of gestation. For others affected with BA, aetiology is more obscure and perinatal destruction of fully-formed ducts perhaps by the action of hepatotropic viruses has been suggested. Whatever the cause, the lumen of the extrahepatic duct is obliterated at a variable level and this forms the basis for the commonest classification (Types I, II, III). All patients with BA present with varying degree of conjugated jaundice, pale non-pigmented stools and dark urine. Key diagnostic tests include ultrasonography, biochemical liver function tests, viral serology, and (in our centre) a percutaneous liver biopsy. In some centres, duodenal intubation and measurement of intralumenal bile is the norm. Currently BA is being managed in two stages. The first stage involves the Kasai operation, which essentially excises all extrahepatic biliary remnants leaving a transected portal plate, followed by biliary reconstruction using a Roux loop onto that plate as a portoenterostomy. If bile flow is not restored by Kasai procedure or life-threatening complications of cirrhosis ensue then consideration should be given to liver transplantation as a second stage. The outcome following the Kasai operation can be assessed in two ways: clearance of jaundice to normal values and the proportion who survive with their native liver. Clearance of jaundice (<2 mg/dL or <34 μmol/L) after Kasai has been reported to be around 60%, whereas five years survival with native liver ranges from 40% to 65%. [ABSTRACT FROM AUTHOR]

Abstract: A new series of group 6 carbonyl complexes of N-[(2-pyridyl)methyliden]-α (or β)-aminonaphthalene (α/β-NaiPy) are described in this work. The complexes are formulated as cis-[M(CO)4(α/β-NaiPy)] by elemental, mass and other spectroscopic data. The complexes show emission spectra at room temperature and their quantum yield lies between 0.4 and 0.5. All the complexes exhibit negative solvatochromism. Cyclic voltammetry shows metal centred oxidation and ligand reductions. [Copyright &y& Elsevier]

Abstract: Background: Opiate use in pregnancy is on the increase. There are a number of complications associated with this problem but current data from UK centres are sparse. Design: A retrospective study. Setting: A North of England Hospital. Methods: Maternal and neonatal case records were studied and a standard data set completed. Main outcome measures: Maternal and neonatal outcomes were classified by the woman''s drug usage at the end of pregnancy. Results: One hundred and ten babies born to 108 women were studied and 41% had evidence of previous exposure to the hepatitis C virus. Women who took heroin in later pregnancy were significantly more likely than women who were stabilised on methadone to have a baby who needed morphine (40% versus 19%), had higher mean maximum neonatal abstinence scores (NAS) (5.8 versus 4.7) and stayed in the neonatal unit significantly longer (mean 17.2 days versus 11.8days). There were two neonatal deaths and the overall rate of prematurity was 29%. Conclusions: The outcome for pregnancy in women who use opiates is complicated by high rates of prematurity and neonatal death. Women who used heroin in later pregnancy had babies who developed more severe NAS and needed a longer hospital stay than women who used only methadone. [Copyright &y& Elsevier]

Pyrethroid-based mosquito repellents (MR) are commonly used to protect humans against mosquito vector. New born babies and children are often exposed to pyrethroids for long periods by the use of liquid vaporizers. Occupational and experimental studies indicate that pyrethroids can cause clinical, biochemical and neurological changes, and that exposure to pyrethroids during organogenesis and early developmental period is especially harmful. The neurotoxicity caused by MR has aroused concern among public regarding their use.In the present study, the effect of exposure of rat pups during early developmental stages to a pyrethroid-based MR (allethrin, 3.6% w/v, 8 h per day through inhalation) on blood–brain barrier (BBB) permeability was investigated. Sodium fluororescein (SF) and Evan’s blue (EB) were used as micromolecular and macromolecular tracers, respectively. Exposure during prenatal (gestation days 1–20), postnatal (PND1–30) and perinatal (gestation days 1–20+PND1–30) periods showed significant increase in the brain uptake index (BUI) of SF by 54% (P<0.01), 70% (P<0.001), 79% (P<0.001), respectively. This increase persisted (68%, P<0.01) even 1 week after withdrawal of exposure (as assessed on PND37). EB did not exhibit significant change in BBB permeability in any of the group. The results suggest that MR inhalation during early prenatal/postnatal/perinatal life may have adverse effects on infants leading to central nervous system (CNS) abnormalities, if a mechanism operates in humans similar to that in rat pups. [Copyright &y& Elsevier]

Bihar is one of the major states of India, being located almost in the middle of the Gangetic Plain. The Ganga River divides the state in two parts, the northern region being known as North Bihar. It is the playground of many rivers originating in Nepal, which characteristically carry water during the monsoon season far beyond their carrying capacities, with resulting massive silting and silt loads. The rivers have meandered in the past and changed their courses, leaving many natural depressions later converted into oxbow lakes. The lakes are fed by rainwater and monsoon river flows. These wetlands are present in large numbers in North Bihar, having served many useful purposes. Although they were nature's own initiative at flood control, this important function is now seriously impaired because of a number of natural and man-made reasons. In short, these wetlands are dying, and climate change is likely to compound and worsen the situation. Long-term temperature and rainfall data related to the region were statistically analysed in this study. The results indicated that, while the temperature was increasing, the rainfall exhibited a declining trend. Analysis of the rainfall data used in this study indicated that they were consistent. The finding highlights the potential future danger and justifies a comprehensive research effort directed to obtaining definitive results. Indeed, a quick assessment, and adoption of remedial measures without delay, is imperative for the future of this aquatic system. [ABSTRACT FROM AUTHOR]

Abstract: The tunneling escape rate is calculated on the basis of ballistic miniband transport of electron in the presence of external electric field. The variation of the miniband escape rate is reported as functions of barrier and well widths as well as the externally applied bias. Interesting features with regard to the electric field modulation are observed in the semiconductor heterostructures with small barrier and well widths. For the system with constant periodic length, the maximum confinement of carriers is found for the well width almost equal to half of the barrier width. [Copyright &y& Elsevier]

Authors report an 11-month-old female child, who presented with recurrent episodes of colicky abdominal pain and diarrhea. An abdominal ultrasound revealed small bowel intussusception. She was also noted to have a thick walled gall bladder and a solitary gallstone. Further investigations confirmed the diagnosis of coeliac disease. The combination of small bowel intussusception, coeliac disease and cholelithiasis is unique and has not been reported in the literature. [ABSTRACT FROM AUTHOR]

The well-known asymmetric Fano resonances that results from the quantum interference between the discrete and the continuum states are noted for the first time in the ballistic transmission spectrum of the bilayer graphene tunneling structures. This unconventional tunneling transmission, in stark contrast to the monolayer graphene and to the conventional heterostructures, arises due to the quadratic dispersion of the chiral charge carriers. If the Klein tunneling (the phenomenon for normal incidence) is an unusual characteristic of the massless chiral particles, then the Fano tunneling (the phenomenon for low glancing incidence) would be the specialty for the massive chiral particles. The characteristic features of the Fano line shape are found to be highly sensitive to the direction of incidence of the charge carriers, the applied homogeneous electric field, and to the barrier height. The sharp anti-resonance at the center of the tunneling band arising due to the destructive interference between the electron and the holelike states could probably be responsible for the high negative differential conductance (NDC) in the bilayer graphene. The tunneling conductance in the double barrier structure exhibits a resonant peak with a sharp NDC region for the Fermi energy less than or equal to half of the barrier height. The present findings might have great implications in the preparation of NDC-based devices using bilayer graphene nanostructures. [ABSTRACT FROM AUTHOR]

Pyloric duplication is the rarest duplication in gastrointestinal tract. Only seven cases have been reported so far in the English literature. In most cases pre-operative diagnosis was not made. We present such a case in a 9-day-old baby, presenting with non-bilious vomiting since birth. The diagnosis was made pre-operatively by ultrasonography, which is a good investigation for pre-operative diagnosis. The case was operated successfully without opening the pyloric canal. [ABSTRACT FROM AUTHOR]

We investigate theoretically the transmission of electrons through a pair of δ-function magnetic barriers in graphene in presence of external monochromatic, linearly polarized and CW laser field. The transmission coefficients are calculated in the framework of non-perturbative Floquet theory using the transfer matrix method. It is noted that the usual Fabry–Perot oscillations in transmission through the graphene magnetic barriers with larger inter barrier separation takes the shape of beating oscillations in presence of the external laser field. The laser assisted transmission spectra are also found to exhibit the characteristic Fano resonances (FR) for smaller values of the inter barrier separation. The appearance of the perfect node in the beating oscillation and the asymmetric Fano line shape can be controlled by varying the intensity of the laser field. The above features could provide some useful and potential information about the light - matter interactions and may be utilized in the graphene based optoelectronic device applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] Importance of 1H-2(Phenylazo) imidazole (PaiH) molecule is discussed. [•] Interaction of PaiH with silver nano particles is possibly through theN3 atom. [•] Concentration dependent dark isomerisation (trans-to-cis) is suggested. [•] DFT calculations are in good agreement with experimental results. [ABSTRACT FROM AUTHOR]

The dynamics of the complete breakup process in an Ortho Ps-He system including electron loss to the continuum (ELC) is studied where both the projectile and the target get ionized simultaneously. The process is essentially a four body problem and the present model takes account of the two centre effect on the electron ejected from the Ps-atom which is crucial for a proper description of the ELC phenomena. The calculations are performed in the framework of Coulomb distorted eikonal approximation. The exchange effect between the target and the projectile electron is taken into account in a consistent manner. Interesting features are noted in the dynamics (FDCS) for both the electrons belonging to the target and the projectile. A distinct broad ELC peak is noted in the fully differential cross sections (FDCS) for the Ps electron. The exchange effect is found to play a dominant role in the FDCS both quantitatively and qualitatively depending on the kinematics. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of HgX2 (X=Cl, Br, I) with 1-alkyl-2-{(o-thioalkyl)phenylazo}imidazole (SRaaiNR′) in MeOH-ethyleneglycol mixture has synthesised [Hg(SRaaiNR′)X2]. The structure of the products has been established by microanalytical and spectral (IR, UV–Vis, 1H NMR) data, and a distorted Td-geometry has been confirmed by a single crystal X-ray diffraction study of [Hg(SMeaaiNEt)I2] (SMeaaiNEt=1-ethyl-2-{(o-thiomethyl)phenylazo}imidazole). The UV light irradiation in CH3CN solution of the complexes shows E-to-Z (E and Z refer to trans and cis-configurations) isomerisation of the coordinated SRaaiNR′ ligand about the –N bond. The rate of isomerisation follows: [Hg(SRaaiNR′)Cl2]<[Hg(SRaaiNR′)Br2]<[Hg(SRaaiNR′)I2]. The quantum yields (ϕE → Z ) of the isomerisation of the complexes are lower than those of the free ligands. These may be due to increased mass and rotor volume of the complexes. The electronegativity sequence of X (I

Abstract: A theoretical model is proposed to study the ballistic electron transport for a quasi-periodic multibarrier structure where two different barrier shapes are arranged according to the Thue–Morse sequence. Important tunneling features are revealed form such arrangements. It is noted that the tunneling band spectrum could be fragmented by tailoring the shape of the barriers in the structure. Results for the transmission coefficients and the current densities are compared with the corresponding periodic and single shape barrier arrangements. The quasi-periodic structure consisting of the rectangular and triangular barrier shapes is suggested to be more suitable for the electronic and opto-electronic devices due to its high negative differential conducting effect. [Copyright &y& Elsevier]

Abstract: Dynamics of the Dirac fermions, in particular the transmission coefficient and the resonant tunneling lifetime are studied across a bilayer graphene electrostatic double barrier structure modulated by an in plane homogeneous electric field. Asymmetric Fano type resonances are noted for the first time in the transmission spectrum of the bilayer graphene nanostructures and are found to be highly sensitive to the direction of incidence of the charge carriers and the applied homogeneous electric field. The effect of the external field on the extended and the evanescent modes is also analysed. Resonant tunneling lifetime is found to be highly anisotropic in nature. The chiral carriers are either accelerated or decelerated by the electric field depending on the energy of the quasi-bound states, the angle of incidence and the magnitude of the applied field. Effects of the external field on the localization of the chiral carriers are also discussed. [Copyright &y& Elsevier]

Abstract: The effects of the external homogeneous electric field on the transmission coefficient and the ballistic conductance are studied theoretically for an electron across a graphene double barrier structure. The Klein transmission is noted for the normal to near normal incidence only. The electrons are found to be confined by the external static electric field for the glancing incidence and not for the normal incidence. Although the conductance profile for the lower barrier widths is almost sinusoidal in nature, some interesting features occur for the higher barrier width of the structure. The oscillations in the below barrier conductance are greatly suppressed by the external field. Some negative differential conducting regions are also noted, being quite sensitive to the Fermi energy of the system. [Copyright &y& Elsevier]

The dynamics of the electron impact multiphoton ionization of a hydrogen atom in the presence of an intense laser field (e, n γ e) has been studied theoretically for laser polarization parallel ( $\vert \vert^{l}$) and perpendicular (⊥r) to the incident momentum, with a view to comparing (qualitatively) the results with the recent kinematically complete experiments of Höhr et al. [Phys. Rev. Lett. 94, 153201 (2005)] for the He target. Significant laser modifications are noted in the present doubly (DDCS) and the fully differential multiphoton cross sections (TDCS) for both the geometries ( $\vert \vert^{l}$ and ⊥r). For most of the explored kinematics (chosen in accordance with the experiment), the present binary peak intensity of the laser-assisted multiphoton TDCS is significantly enhanced with respect to the field free ones, in qualitative agreement with the experiment. Importance of the multiphoton effects is also studied. The multiphoton cross sections in the zeroth order approximation of the ejected electron wavefunction (CV) obeys the Kroll Watson sum rule while it does not hold good in the corresponding first order approximation (MCV). [ABSTRACT FROM AUTHOR]

Abstract: A new series of Cr(0)- and Mo(0)-carbonyl complexes of 1-alkyl-2-(naphthyl-α/β-azo)imidazoles (α/β-NaiR′) are described in this work. The complexes are formulated cis-[M(CO)4(α/β-NaiR′)] by elemental, mass and other spectroscopic data. The complexes are stable and exhibit emission spectra at room temperature. Cyclic voltammetry shows two metal centred oxidations, M+/M0 and M2+/M+, and two ligand centred reductions, azo/azo− and azo−/azo=. [Copyright &y& Elsevier]

Reaction of ctc-OsBr2(RaaiR′)2 [RaaiR′=1-alkyl-2-(arylazo)imidazole, p-R-C6H4-N&z.dbnd6;N-C3H2-NN-1-R′, where R=H (a), Me (b), Cl (c) and R′=Me (2), Et (3) and CH2Ph (4)] with 2,2′-bipyridine (bpy) in presence of AgNO3 in EtOH followed by the addition of NH4PF6 afforded a mixed ligand complex [Os(bpy)(RaaiR′)2](PF6)2. The structure of the complex, in one case [Os(bpy)(MeaaiMe)2](PF6)2 · 4H2O, has been confirmed by X-ray crystallography. The complexes are diamagnetic (low spin d6, s=0) and they show intense MLCT transition in the visible region (480–525 nm) and a weak transition at longer wavelength (>850 nm) in CH3CN solution. Cyclic voltammetry of the complexes show two metal oxidation, Os(II)/Os(III) at 0.72–0.76 V and Os(III)/Os(IV) at 1.34–1.42 V and three successive ligand reductions. [Copyright &y& Elsevier]

1-Alkyl-2-(naphthyl-(α/β)-azo)imidazole [α-NaiR (2)/β-NaiR (3); R=Me (a), Et (b), CH2Ph (c)] are N,N′-bidentate chelating ligands. The structure of 1-ethyl-2-(naphthyl-α-azo)imidazolium hexaflurophosphate has been confirmed by single crystal X-ray structure study and shows supramolecular geometry through non-covalent interactions (C–H⋯F, C–H⋯π, π⋯π). Mercury(II) complexes of the formula Hg(NaiR)Cl2 (4/5) have been synthesised and characterised by spectral (IR, UV–Vis and 1H and 13C NMR) studies. α-NaiR has been used to synthesise organomercury derivatives, Hg(α-NaiR–H)Cl (6) and the site of mercuration has been supported by charge density calculation using a semi-empirical PM3 technique. [Copyright &y& Elsevier]

Using a computerised analysis, the cardiotocograph (CTG) from women who use methadone ( n= 25) when compared with women who do not use methadone ( n= 25) showed a significant reduction in the fetal heart baseline rate, with a significant reduction in number of accelerations and episodes of high variation. The short-term variation, number of decelerations and episodes of low variation were not different between the two groups. The time taken to meet the standardised criteria was not different, and it is possible that a computer-assisted CTG analysis could be more accurate than a naked eye interpretation. [ABSTRACT FROM AUTHOR]

Charge transport through a rectangular vector potential barrier modulated by a continuum laser in monolayer phosphorene is studied theoretically in the ballistic regime along the line of Floquet formalism. Laser free transmission profile displays strong directional behavior exhibiting collimation depending on the incident energy and width of the barrier. However, the application of laser, polarized along the zig-zag direction, creates a sharp anti-resonance in the transmission spectrum and reveals a strong light matter interaction due to broken symmetry in presence of the magnetic vector potential. Transmission properties through a vector barrier are found to be sensitive particularly for lower frequency and higher intensity of the laser. For a thin barrier, the laser assisted conductance is suppressed remarkably in contrast to its oscillatory nature for a thicker one. • Tunneling through a driven phosphorene vector barrier is studied for the first time. • Laser with linear polarization can be used to control the tunneling transmission. • Characteristic Fano anti-resonances are noted in the transmission. • Suppression in the conductance is noted particularly for the lower width of the barrier. [ABSTRACT FROM AUTHOR]

Photochromism, a fast reversible structural change even at less than a femto second order upon irradiation of light, is largely influenced by the environment such as, polarity of media, existence of non-covalent interactions, hydrogen bonding etc. In this work, the micelle environment has been imposed on [Cu(RaaiR')2]ClO4 and [Ag(RaaiR')2]NO3 (RaaiR' = 1-alkyl- 2-(arylazo)imidazole) in MeOH solution using Triton-X-100 (CMC, 108 ± 1.16 at 298 K), CTAB (CMC, 51.64 ± 1.04 at 298 K) and SDS (CMC, 207.01 ± 1.51 at 298 K). 1-alkyl-2-(arylazo)imidazole undergoes trans-to-cis and vice-versa isomerization about –N=N- bond upon light irradiation. The quantum yield (Φt→c) of the photoisomerization follows the order - nonionic micelle (Triton-X-100) > Cationic micelle (CTAB) > no micelle > anionic micelle (SDS). The cis-to-trans isomerization is a thermally induced process. The activation energy of cis-to-trans isomerization is calculated by controlled temperature (298–313 K) experiment. Triton-X-100 and CTAB amplify the activation energy of cis → trans thermal isomerization while SDS reduces it. [ABSTRACT FROM AUTHOR]

The transmission coefficient and the ballistic conductance are studied theoretically for a Dirac fermion through the graphene periodic magnetic barriers modulated by a homogeneous in-plane electric field. The transmission is highly asymmetric for zero and low biased conditions of the system. In contrast, it turns out to be symmetric in case of strongly modulated (by electric field) magnetic barriers and becomes independent of the number of barriers due to the predominant Klein tunneling effect. Interesting electric field effects are noted on the angular transmission properties of the chiral carriers. The conductivity profile exhibits some negative differential conducting regions, the number and the sharpness of the regions being intimately related to the number of barriers and the Fermi energy of the system. [ABSTRACT FROM AUTHOR]

Graphical abstract Phosphino bridged Ag(I) complex of 1-alkyl-2-(arylazo)imidazole is structurally characterized and UV light irradiation initiates trans -to- cis isomerisation. Reverse is also carried out by heat treatment. Rate of photoisomerisation of free ligand is faster than coordinated ligand which may be due to higher molar mass of the associated photochrome. Highlights • Diphenylphosphino bridging Ag(I)-dimer complex of arylazoimidazoles. • Single crystal X-ray structure of one of the complexes was established. • Coordinated arylazoimidazole undergoes UV-light irradiated photoisomerisation. • Free ligand shows higher rate of trans -to- cis photoisomerisation that that of complex phase. • Reverse process, cis -to- trans isomerisation is thermally controlled. Abstract The coordinated 1-alkyl-2-(arylazo)imidazole (RaaiR/) in [Ag(μ-dppm)(RaaiR/)] 2 (PF 6) 2 (dppm, bis-(diphenylphosphino)methane) undergoes light induced trans -to- cis isomerization about N N bond. The quantum yields (ϕ t→c) of trans -to- cis isomerization of coordinated RaaiR/ in the complex is lower than the free ligand data. The reverse transformation, cis -to- trans , is carried out at different temperatures (298–313 K) and activation energy (E a) has been calculated. It is found that E a (free ligands) > E a (coordinated ligand in the complexes). The structures of the complexes have been established by spectral (UV–Vis, IR, and 1H NMR) data. One of the complexes, [Ag(μ-dppm)(HaaiEt)] 2 (PF 6) 2 has been structurally confirmed by single crystal X-ray diffraction study. [ABSTRACT FROM AUTHOR]

Transmission profiles in bilayer graphene are studied theoretically through a rectangular vector potential (magnetic) barrier with and without the presence of an oscillatory potential. Unlike the electrostatic barrier, the Fano resonances (FR) are noted in the transmission spectra both for normal and glancing incidences due to non-conservation of chirality for a static vector barrier. The results for normal incidence indicate that the cloaking effect is a manifestation of the chirality conservation in charge transport through bilayer graphene scalar barriers. It is also noted that the aforesaid FR for a static vector barrier might disappear (photon induced electronic cloaking effect) due to the predominant photon exchange processes in presence of an external oscillating potential. The study of Fano resonances in transmission spectrum is in high demand in respect of localization of charge carriers in graphene nano structures for its potential applications in digital device fabrications. [ABSTRACT FROM AUTHOR]