Rupture of a flow aneurysm secondary to spontaneous extracranial to intracranial revascularisation in the posterior fossa following radiation-induced vasculopathy for cerebellar tumour.

Paediatric patients receiving cranial irradiation therapy for brain tumours are at increased risk of cerebrovascular complications. Radiation-induced moyamoya syndrome (MMS) is a well-recognised complication of this. We present a case of an 8-year-old boy with a history of medulloblastoma, who underwent surgical excision followed by post-operative adjuvant oncological treatment. Six years later, he developed cerebellar/intraventricular haemorrhage. He underwent an emergency external ventricular drain (EVD) insertion followed by posterior fossa suboccipital craniotomy. On dural opening, an abnormal vessel was visualised on the surface of the right cerebellar hemisphere, which was not disturbed. No obvious abnormalities were identified intra-operatively. Cerebral catheter angiography confirmed the presence of a right-sided occipital artery (OA) to posterior inferior cerebellar artery (PICA) extracranial to intracranial (EC-IC) bypass with a zone of the distal PICA territory supplied by this EC-IC bypass. A presumed flow aneurysm originated from the bypass in the distal PICA, identified as cause for the haemorrhage. We highlight a rare cause for intracranial haemorrhage in this cohort of patients. Children who have undergone radiotherapy may have exquisitely sensitive cerebral vasculature and need careful vigilance and evaluation for vasculopathic complications following spontaneous haemorrhage.

Moyamoya disease in a European setting: a Danish population-based study.

BACKGROUND AND PURPOSE: The incidence of moyamoya disease (MMD) in Europe is not well known. In those affected, the risk of brain hemorrhage is considered low. The present study aimed to investigate the incidence and clinical presentation of MMD in the Danish population. METHODS: Eligible patients were identified in the Danish National Patient Register from 1994 to 2017. We collected clinical and radiological data from individual patient records from neurological, neurosurgical and paediatric units across Denmark. The diagnosis was validated according to established criteria. We also extracted basic demographic data on the cohort from the Danish Civil Registration System. RESULTS: A total of 52 patients fulfilled the diagnostic criteria for MMD. Most patients were native Danes and only 15% had an East Asian background. The ratio of female to male patients was 1.8, and the incidence had two peaks: one in childhood and another in young middle age. Until 2007, MMD was only diagnosed sporadically. From 2008 onwards, the incidence rate was 0.07 per 100 000 person-years (95% confidence interval 0.05-0.09 per 100 000 person-years). The most common mode of presentation was ischaemic stroke (33%), followed by hemorrhage (23%), headache (17%) and transient ischaemic attack (14%). CONCLUSIONS: Moyamoya disease is rare in Denmark, but is associated with a considerable risk of hemorrhage. Thus, MMD should be considered in the evaluation for ischaemic as well as hemorrhagic stroke paediatric and middle-aged Caucasians.

Novel biallelic SZT2 mutations in 3 cases of early-onset epileptic encephalopathy.

The seizure threshold 2 (SZT2) gene encodes a large, highly conserved protein that is associated with epileptogenesis. In mice, Szt2 is abundantly expressed in the central nervous system. Recently, biallelic SZT2 mutations were found in 7 patients (from 5 families) presenting with epileptic encephalopathy with dysmorphic features and/or non-syndromic intellectual disabilities. In this study, we identified by whole-exome sequencing compound heterozygous SZT2 mutations in 3 patients with early-onset epileptic encephalopathies. Six novel SZT2 mutations were found, including 3 truncating, 1 splice site and 2 missense mutations. The splice-site mutation resulted in skipping of exon 20 and was associated with a premature stop codon. All individuals presented with seizures, severe developmental delay and intellectual disabilities with high variability. Brain MRIs revealed a characteristic thick and short corpus callosum or a persistent cavum septum pellucidum in each of the 2 cases. Interestingly, in the third case, born to consanguineous parents, had unexpected compound heterozygous missense mutations. She showed microcephaly despite the other case and previous ones presenting with macrocephaly, suggesting that SZT2 mutations might affect head size.

Charge transport mechanisms in sol-gel grown La0.7Pb0.3MnO3/LaAlO3 manganite films.

In this communication, structural, microstructural, transport and magnetotransport properties are reported for La0.7Pb0.3MnO3/LaAlO3 (LPMO/LAO) manganite films having different thicknesses. All the films were irradiated with 200 MeV Ag+15 swift heavy ions (SHI). Films were grown using the sol-gel method by employing the acetate precursor route. Structural measurements were carried out using the X-ray diffraction (XRD) method at room temperature, while atomic force microscopy (AFM) was performed for the surface morphology. Temperature dependent resistivity under different applied magnetic fields for all the films shows metal to insulator transition at temperature TP. In addition to the metal to insulator transition at TP, the films also exhibit low temperature resistivity upturn behavior. Resistivity, TP and upturn behavior are highly influenced by the film thickness, applied magnetic field and irradiation. To understand the nature of charge transport for the low temperature resistivity behavior and metallic and insulating (semiconducting) regions, various models and mechanisms have been verified and the most suitable mechanism has been found for each region in the resistivity curves. Magnetoresistance (MR) is affected by temperature, film thickness and irradiation. MR behavior has been understood in terms of combined and separate contributions from grains and grain boundaries in the films.

Correction: Charge transport mechanisms in sol-gel grown La0.7Pb0.3MnO3/LaAlO3 manganite films.

Correction for 'Charge transport mechanisms in sol-gel grown La0.7Pb0.3MnO3/LaAlO3 manganite films' by Eesh Vaghela et al., Phys. Chem. Chem. Phys., 2017, DOI: 10.1039/c6cp07730g.

Assessment of body force effects in flow condensation, part II: Criteria for negating influence of gravity.

This study concerns the development of a set of mechanistic criteria capable of predicting the flow conditions for which gravity independent flow condensation heat transfer can be achieved. Using FC-72 as working fluid, a control-volume based annular flow model is solved numerically to provide information regarding the magnitude of different forces acting on the liquid film and identify which forces are dominant for different flow conditions. Separating the influence of body force into two components, one parallel to flow direction and one perpendicular, conclusions drawn from the force term comparison are used to model limiting cases, which are interpreted as transition points for gravity independence. Experimental results for vertical upflow, vertical downflow, and horizontal flow condensation heat transfer coefficients are presented, and show that, for the given test section, mass velocities above 425 kg/m2 s ensure gravity independent heat transfer. Parametric evaluation of the criteria using different assumed values of mass velocity, orientation, local acceleration, and exit quality show that the criteria obey physically verifiable trends in line with those exhibited by the experimental results. As an extension, the separated flow model is utilized to provide a more sophisticated approach to determining whether a given configuration will perform independent of gravity. Results from the model show good qualitative agreement with experimental results. Additionally, analysis of trends indicate use of the separated flow model captures physics missed by simpler approaches, demonstrating that use of the separated flow model with the gravity independence criteria constitute a powerful predictive tool for engineers concerned with ensuring gravity independent flow condensation heat transfer performance.

Disrupted nitric oxide signaling due to GUCY1A3 mutations increases risk for moyamoya disease, achalasia and hypertension.

Moyamoya disease (MMD) is a progressive vasculopathy characterized by occlusion of the terminal portion of the internal carotid arteries and its branches, and the formation of compensatory moyamoya collateral vessels. Homozygous mutations in GUCY1A3 have been reported as a cause of MMD and achalasia. Probands (n = 96) from unrelated families underwent sequencing of GUCY1A3. Functional studies were performed to confirm the pathogenicity of identified GUCY1A3 variants. Two affected individuals from the unrelated families were found to have compound heterozygous mutations in GUCY1A3. MM041 was diagnosed with achalasia at 4 years of age, hypertension and MMD at 18 years of age. MM149 was diagnosed with MMD and hypertension at the age of 20 months. Both individuals carry one allele that is predicted to lead to haploinsufficiency and a second allele that is predicted to produce a mutated protein. Biochemical studies of one of these alleles, GUCY1A3 Cys517Tyr, showed that the mutant protein (a subunit of soluble guanylate cyclase) has a significantly blunted signaling response with exposure to nitric oxide (NO). GUCY1A3 missense and haploinsufficiency mutations disrupt NO signaling leading to MMD and hypertension, with or without achalasia.

Impurity metallic conduction below the critical concentration of metal-insulator transition in Fe1-xCoxSi.

Analysis on very detailed measurements of resistivity (ρ) and thermoelectric power (S) of magnetic impurity (Co) substituted iron silicide (FeSi) has been presented in this report. The impurity valence electrons of Co dominate the whole physical properties at low temperatures below 35 K, below the critical concentrationxc(≈0.02). The negative thermopower and the positive slope in the resistivity at low temperatures are exciting and show that the system is not entirely insulator below the critical concentration of metal-insulator transition (xc). So, due to the external impurity electrons, the system's magnetic ground state could change considerably compared to the parent compound FeSi. This report may help unveil the interesting low-temperature transport properties betweenx= 0 andx= 0.04 (Fe1-xCoxSi). Two band model and variable range hopping model were employed to explain the low-temperature electrical and thermal transport properties.

Surgical revascularisation for childhood moyamoya.

PURPOSE: Children with moyamoya disease/syndrome (MM) have a high rate of recurrent arterial ischaemic stroke (AIS) and associated neurological morbidity; surgical revascularisation (SR) has the potential to prevent this. Here we describe our experience of SR for childhood mm. METHODS: This study is a retrospective review of case notes and radiology of children with moyamoya who underwent SR at our centre. RESULTS: Seventy-three children with MM and who had SR were identified, with median age at presentation of 4.75 years (range 0.6-14.5). Children with >1 AIS or transient ischaemic attack (TIA) and who had not infarcted the whole territory of the diseased carotid artery were offered SR, with the primary aim of preventing further AIS. One hundred and thirty-four SR procedures were undertaken: 82 indirect (62.4 %) and 49 (37.6 %) direct procedures with 3 second SR procedures following initial SR. Median age at surgery was 7.3 (1-18.2) years. There was no perioperative mortality. One anticoagulated child developed an intracranial haemorrhage on the fifth post-operative day. Median duration of follow-up was 34 (5-166) months. Three children (4.1 %) had recurrent AIS (one silent) after SR; two with sickle cell disease had intracranial haemorrhage 1.5 and 11 months post-SR. TIAs improved in 42 out of 53 (79.2 %). CONCLUSION: Our experience of SR for paediatric MM is comparable to other large series. SR is safe, and the rate of recurrent AIS after SR is lower than would be anticipated, on the basis of known natural history of MM. There was no observed difference in outcome of recurrent AIS for direct versus indirect procedures in this series.

High-pressure homogenization of raw and pasteurized milk modifies the yield, composition, and texture of queso fresco cheese.

High-pressure homogenization (HPH) of milk was studied as an alternative processing operation in the manufacturing of queso fresco cheese. Raw and pasteurized (65°C for 30 min) milks were subjected to HPH at 0, 100, 200, and 300 MPa and then used to manufacture queso fresco. The cheeses were evaluated for yield, moisture content, titratable acidity, nitrogen content, whey protein content, yield force, yield strain, and tactile texture by instrumental or trained panel analyses. The combination of HPH and thermal processing of milk resulted in cheeses with increased yield and moisture content. The net amount of protein transferred to the cheese per kilogram of milk remained constant for all treatments except raw milk processed at 300 MPa. The highest cheese yield, moisture content, and crumbliness were obtained for thermally processed milk subjected to HPH at 300 MPa. The principal component analysis of all measured variables showed that the variables yield, moisture content, and crumbliness were strongly correlated to each other and negatively correlated to the variables yield strain, protein content (wet basis), and sensory cohesiveness. It is suggested that the combination of thermal processing and HPH promotes thermally induced denaturation of whey protein, together with homogenization-induced dissociation of casein micelles. The combined effect results in queso fresco containing a thin casein-whey matrix that is able to better retain sweet whey. These results indicate that HPH has a strong potential for the manufacture of queso fresco with excellent yield and textural properties.

A robust nitridation technique for fabrication of disordered superconducting TiN thin films featuring phase slip events.

Disorder induced phase slip (PS) events appearing in the current voltage characteristics (IVCs) are reported for two-dimensional TiN thin films produced by a robust substrate mediated nitridation technique. Here, high temperature annealing of Ti/Si3N4 based metal/substrate assembly is the key to produce majority phase TiN accompanied by TiSi2 & elemental Si as minority phases. The method itself introduces different level of disorder intrinsically by tuning the amount of the non-superconducting minority phases that are controlled by annealing temperature (Ta) and the film thickness. The superconducting critical temperature (Tc) strongly depends on Ta and the maximum Tc obtained from the demonstrated technique is about 4.8 K for the thickness range ~ 12 nm and above. Besides, the dynamics of IVCs get modulated by the appearance of intermediated resistive steps for decreased Ta and the steps get more prominent for reduced thickness. Further, the deviation in the temperature dependent critical current (Ic) from the Ginzburg-Landau theoretical limit varies strongly with the thickness. Finally, the Tc, intermediate resistive steps in the IVCs and the depairing current are observed to alter in a similar fashion with Ta and the thickness indicating the robustness of the synthesis process to fabricate disordered nitride-based superconductor.

Unconventional impurity band conduction and carrier dynamics in Ni substituted FeSi.

Analysis of the resistivity, thermoelectric power, and heat capacity of Fe1-x Ni x Si is presented in this report. In-spite of Ni having two extra valence electrons as compared to Fe, the physical properties are observed to be dominated by holes. In this report, we have explained this unusual hole dominant scenario by a modified two narrow-band model. According to this model, the impurity electrons which are nearer to conduction band get shifted towards lower energy level thereby leaving holes around the Fermi level, and hence a hole dominated scenario at low temperatures. Due to this hole like density of states around the Fermi level, the nickel substitution could only produce a weak ferromagnetic behavior. Such a picture may assist in understanding the thermopower of similar systems i.e. Ni substituted on Fe site, such as Fe2-x Ni x VAl. We have also found that the activation energy derived from resistivity and thermoelectric power decreases with increasing Ni concentration.

Anomalous magnetic properties of RCrTiO5 (R = Dy and Ho) compounds.

We have investigated the nature of magnetic ground state of RCrTiO5 (R = Dy and Ho) through dc magnetization and heat capacity measurements. Due to the strong competition between the Cr3+ and R 3+ sublattice moments, several intriguing phenomena have been observed when the magnetic state is probed at low field. In both the systems, the Cr3+ sublattice undergoes a long-range antiferromagnetic ordering below ∼139 K with a weak ferromagnetic (FM) moment perpendicular to c axis as evident from the hysteresis in M(H) curve. At low fields ([Formula: see text]150 Oe), the zero-field-cooled magnetization shows that the FM component of Cr3+ spin and R 3+ moments align in the opposite direction with respect to each other and the net moment aligns in the opposite direction to the applied field in the temperature range 136-16 K for DyCrTiO5 and below 128 K for HoCrTiO5. For both the samples, the strong coupling between the two magnetic sublattices is manifested in the temperature dependence of coercive field. Another interesting phenomenon, the spin reorientation transition, has been observed below [Formula: see text] K, where the easy axis of FM moment of Cr3+ starts to rotate from one crystallographic axis toward another in DyCrTiO5 but no such transition has been observed in HoCrTiO5. The other members of RCrTiO5 series do not show such kinds of interesting magnetic properties.

Effect of zinc oxide doping on the structural and optical characterization of nanostructured molybdenum oxide films.

Undoped and zinc oxide (ZnO) doped molybdenum oxide (MoO3) films were prepared by RF magnetron sputtering technique. The influence of doping and post annealing temperature on the structural and optical properties of these films were investigated systematically using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-VIS spectroscopy and photoluminescence spectroscopy (PL). The XRD patterns indicate the presence of stoichiometric orthorhombic alpha-MoO3 phase in the annealed (573 and 673 K) undoped molybdenum oxide films and in ZnO doped molybdenum oxide film (annealed at 673 K). The crystalline grain size in the films was investigated using Debye Scherrer formula and corrected using Hall-Williamson equation. The SEM and AFM images revealed the distribution of nano leafs, nanorods and nanograins. Nanorods of length 1.4 microm and diameter 149 nm can be observed in ZnO doped films. The optical band gap energy was found to increase with increase in annealing temperature and particle size. These nanostructures show a room temperature PL emission in the UV and visible region.

Transport and magnetotransport studies on Sol-Gel grown nanostructured La0.7Pb0.3MnO3 manganites.

Sol-Gel synthesis offers relatively inexpensive scale processing of mixed oxide materials with a good control over the stoichiometry and morphology which helps to tailor the required materials on atomic scale to suit specific applications. Nanophasic polycrystalline samples of La0.7Pb0.3MnO3 (LPMO) manganites having perovskite type structure synthesized by novel Sol-Gel technique using acetate precursor route were sintered at various temperatures in the range 950-1150 degrees C for studying the effect of grain size modifications on their structural, transport and magnetotransport properties. X-ray diffraction (XRD) studies show that the samples exhibit rhombohedral structure crystallizing in space group R-3C. Microstructural investigations using Scanning Electronic Microscopy (SEM), Atomic Force Microscopy (AFM) and Lateral Force Microscopy (LFM) measurements reveal the observation of secondary grain growth behavior starting in the sample sintered at 1000 degrees C. The d.c. four probe resistivity measurements with and without applied magnetic field in the temperature range of 2-380 K, show the effect of secondary grain growth on the magnetoresistance (MR) behavior of LPMO manganites. The microstructural studies show the atomic scale engineering at nanoscale which is reflected in the improvement of surface to volume ratio (D(-1)) which in turn modifies the physical properties of samples under investigation. All the samples exhibit resistivity minima at approximately 30 K which can be explained in terms of e-e interaction at 0 Tesla field. There is a correlation between the parameters derived from e-e scattering model and the secondary grain growth present in the samples. The results of the microstructural and MR measurements on the nanostructured LPMO manganites have been discussed in detail.

Synthesis of nanoscale copper nitride thin film and modification of the surface under high electronic excitation.

Nanoscale (approximately 90 nm) Copper nitride (Cu3N) films are deposited on borosilicate glass and Si substrates by RF sputtering technique in the reactive environment of nitrogen gas. These films are irradiated with 200 MeV Au15+ ions from Pelletron accelerator in order to modify the surface by high electronic energy deposition of heavy ions. Due to irradiation (i) at incident ion fluence of 1 x 10(12) ions/cm2 enhancement of grains, (ii) at 5 x 10912) ions/cm2 mass transport on the films surface, (iii) at 2 x 10(13) ions/cm2 line-like features on Cu3N/glass and nanometallic structures on Cu3N/Si surface are observed. The surface morphology is examined by atomic force microscope (AFM). All results are explained on the basis of a thermal spike model of ion-solid interaction.

Grain size effect on lattice of ni nanocrystals prepared through polyol method.

Nanocrystalline nickel powders were prepared with grain size 'd' in the range 40-100 nm diameters through polyol method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used for characterization. XRD of the prepared samples consistently matched with standard fcc structure of nickel without any impurity peak. Detailed analysis and calculations using Scherrer equation for (111) peak revealed systematic increase in line width and peak shifting towards lower diffraction 2theta angles with decrease in nickel to ethylene glycol mole ratio. Different values of d estimated from various peaks of each sample suggested associated microstrains in the nanograins. Values of d estimated from X-ray diffraction patterns were compared with those obtained from atomic force microscopy and scanning electron microscopy results, and discussed. Observed lattice expansion is explained, on the basis of a theoretical model of linear elasticity.

Quantum phase transition and non-Fermi liquid behavior in Fe1-x Co x Si (x ⩾ 0.7).

We report on the nature of electron correlations in Fe1-x Co x Si ([Formula: see text]) using combined results of magnetization, specific heat and transport properties. Doping driven quantum critical point is observed to occur at [Formula: see text]. The magnetically unstable regime is identified to be centered around [Formula: see text] [[Formula: see text]]. The emergence of non-Fermi liquid behaviors in x = 0.8 (near to ferromagnetic quantum critical point) and x = 0.9 (disorder-induced) compositions are discussed on the basis of the power-law dependence of susceptibility [Formula: see text] ([Formula: see text] for x = 0.8 and 0.55 for x = 0.9), specific heat [Formula: see text] ([Formula: see text] for x = 0.8 and 0.9) and resistivity [Formula: see text] ([Formula: see text] for x = 0.8 and 1.38 for x = 0.9). Further, a comprehensive classification of doping dependent physical properties of Fe1-x Co x Si is presented in the revisited temperature-composition (T-x) phase diagram.