Vacuum-deposited thin film porous ZnO-metal oxide hybrid systems for microsupercapacitor applications with Ir/IrO2in ZnO as a new, high-performance electrode.

We fabricate porous nanostructured 1µm thick ZnO-metal/metal oxide hybrid material thin films using a unique approach utilizing physical vapor deposition with postdeposition annealing. We study Pt, Pd, Ru, Ir and Sn as the metals and find they all form hybrid structures, however with differing physical and electrochemical properties. We investigate their applicability in microsupercapacitor electrodes in a LiCl aqueous electrolyte and find that the ZnO hybrid with Ir exhibits the highest capacitances. We follow with optimization and more detailed material studies of the ZnO-Ir hybrid showing that a significant amount of Ir is present in the material in the form of metallic Ir and indiffused Ir, while IrO2is also present in the nanoscale. We obtain electrodes with 5.25 mF · cm-2capacitance with 90% retention over 10 000 charge/discharge cycles in an aqueous LiCl electrolyte, which is better than the reported values for other Ir-based hybrids. Finally, we showed that the electrodes provide 2.64 mF · cm-2in a symmetric device with an operating voltage of 0.8 V. With this report, we discuss the influence of both Ir and IrO2on the capacitance, underlining the synergistic effect, and show them as promising inorganic matterials for integration with other supercapacitor electrodes.

Highly transparent supercapacitors based on ZnO/MnO2 nanostructures.

The recent rapid development of transparent electronics, notably displays and control circuits, requires the development of highly transparent energy storage devices, such as supercapacitors. The devices reported to date utilize carbon-based electrodes for high performance, however at the cost of their low transparency around 50%, insufficient for real transparent devices. To overcome this obstacle, in this communication highly transparent supercapacitors were fabricated based on ZnO/MnO2 nanostructured electrodes. ZnO served as an intrinsically transparent skeleton for increasing the electrode surface, while MnO2 nanoparticles were applied for high capacitance. Two MnO2 synthesis routes were followed, based on the reaction of KMnO4 with Mn(Ac)2 and PAH, leading to the synthesis of ß-MnO2 with minority α-MnO2 nanoparticles and amorphous MnO2 with embedded ß-MnO2, respectively. The devices based on such electrodes showed high capacitances of 2.6 mF cm-2 and 1.6 mF cm-2, respectively, at a scan rate of 1 mV s-1 and capacitances of 104 µF cm-2 and 204 µF cm-2 at a very high rate of 1 V s-1, not studied for transparent supercapacitors previously. Additionally, the Mn(Ac)2 devices exhibited very high transparencies of 86% vs. air, far superior to other transparent energy storage devices reported with similar charge storage properties. This high device performance was achieved with a non-acidic LiCl gel electrolyte, reducing corrosion and handling risks associated with conventional highly concentrated acidic electrolytes, enabling applications in safe, wearable, transparent devices.

Room temperature sputter deposited catalyst-free nanowires with wurtzite/zinc blende ZnO superstructure and their application in electromechanical nanogenerators on polymer and paper substrates.

Catalyst-free growth of ZnO nanowires using reactive magnetron sputtering at room temperature is reported. We discuss the growth of the nanowires using reactive magnetron sputtering as a function of argon and oxygen flow values changing at a set ratio of 10:2. A transition from nanostructured Zn to nanowire ZnO growth is observed at 20 sccm Ar and 4 sccm O2. Densification and improved alignment of the nanowires is visible for increasing flow values up to 50 sccm Ar and 10 sccm O2. Nanowires exhibit stacking fault regions of zinc blende ZnO in wurtzite ZnO. The regions encompass the whole width of the nanowires and their quantum well behavior is manifested in the photoluminescence spectra. The nanowires were subsequently deposited on paper and PET substrates and electromechanical nanogenerators were fabricated. Manual pressing and depressing of the devices induced voltages of 50 µV and 2 µV for the devices on PET and paper substrates, respectively.

Depth measurements of etch-pits in GaN with shape reconstruction from SEM images.

The method, which allows shape reconstruction by reading the intensity from the scanning electron microscopy image, is presented and discussed in details. The method is applied to read the morphology of etch-pits, which were formed on the GaN surface by etching in molten KOH-NaOH eutectic mixture to delineate dislocations. The etch-pit depth distributions are obtained and used to determine densities of pits related to screw, mixed or edge-type dislocations. The results are compared with atomic force microscopy.

Selective etching of dislocations in GaN and quantitative SEM analysis with shape-reconstruction method.

Due to the differences in etch-pit morphologies, chemical etching offers a possibility to determine densities of dislocations in respect to their type. In the present paper we propose a method, which implements a simple shape-from-shading procedure, i.e. with results derived from image brightness dependence on surface slope. It allows estimation of etch-pit depth distributions from scanning electron microscopy micrographs. This method is used to obtain depth distributions from GaN surface after etching in molten KOH-NaOH eutectic mixture. Depth distributions are used to estimate densities of etch-pits related to a given dislocation type. The distributions are compared with dislocation densities determined with transmission electron microscopy.

Buried amorphous-layer impact on dislocation densities in silicon.

The impact of amorphous layers on dislocation densities in silicon piezo-resistors was investigated by means of transmission electron microscopy and chemical etching. Mechanical bevel polishing at a shallow angle and selective etching were applied to assess the dislocation depth distributions. It was found that, despite the presence of additional defects after recrystallization, the initial presence of a buried amorphous layer reduced, after annealing, the dislocation density in the depletion region of a p-n junction, compared with the case of a shallower, surface amorphous layer.

Predictors of cognitive test patterns in autism families.

In a case-control study of cognitive performance, tests of intelligence, reading, spelling, and pragmatic language were administered to the parents and siblings of 90 community-ascertained probands with autism (AU group) and to the parents and siblings of 40 similarly ascertained probands with trisomy 21 Down syndrome (DS group). The two samples were comparable for age and parents' education; both groups were well-educated and had above-average intelligence. AU parents scored slightly but significantly lower on the WAIS-R Full Scale and Performance IQ, on two subtests (Picture Arrangement and Picture Completion), and on the Word Attack Test (reading nonsense words) from the Woodcock-Johnson battery. There were no differences between AU and DS siblings. As in earlier studies, AU parents, more often than DS parents, reported a history of early language-related cognitive difficulties; we were not able to replicate this in siblings. AU parents who reported such difficulties scored significantly lower on Verbal IQ, spelling, and the nonsense reading test. AU parents without a history of early language-related cognitive difficulties often had a Verbal IQ that exceeded Performance IQ by more than one standard deviation. AU siblings with early language-related difficulties had similar findings: lower Verbal IQ, poorer spelling, and poorer reading scores, compared to AU siblings without such a history. Parents with a positive history also scored worse on a measure of pragmatic language,the Pragmatic Rating Scale, but not on measures of social-related components of the broader autism phenotype. We propose that cognitive differences in a subset of autism family members are manifestations of the language-related component of the broader autism phenotype, and separate from the social-related component. This is consistent with the hypothesis that there are several genes that may interact to cause autism which segregate independently and have distinguishable manifestations in family members. The hypothesis would be further supported by finding different patterns of genetic loci linked to autism in families where one or both parents has language difficulties.

Macrocephaly in children and adults with autism.

OBJECTIVE: To explore the frequency and onset of macrocephaly in autism and its relationship to clinical features. METHOD: Head circumferences at birth, during early childhood, and at the time of examination were studied in a community-based sample of autistic children and adults. The authors investigated whether head circumference at the time of examination was associated with clinical features. RESULTS: Fourteen percent of the autistic subjects had macrocephaly: 11% of males and 24% of females. In most, the macrocephaly was not present at birth; in some it became apparent in early and middle childhood as a result of increased rate of head growth. A small relationship was noted between head circumference percentile and less severe core features of autism. Neither macrocephaly nor head circumference percentile was associated with nonverbal IQ, verbal status, seizure disorder, neurological soft signs or minor physical anomalies in the autistic subjects. CONCLUSION: Macrocephaly is common in autism and usually is not present at birth. Rates of head growth may be abnormal in early and middle childhood in some (37%) children with autism. Macrocephaly does not define a homogeneous subgroup of autistic individuals according to clinical features.

Personality characteristics of the parents of autistic individuals.

Personality characteristics of 87 parents of autistic probands and 38 parents of Down's syndrome probands were examined using a standardized personality interview. Using best-estimate ratings derived from subject and informant interviews, parents of autistic individuals were rated significantly higher than controls on three characteristics: aloof, untactful and undemonstrative. When ratings were based on interviews with subjects only, parents of autistic probands were rated as significantly more aloof, untactful and unresponsive. There were no significant differences between parent groups on ratings based on informant interviews only. The implications of these findings for future family studies of autism are discussed.

The etiology of autism: pre-, peri- and neonatal factors.

OBJECTIVE: To examine pre-, peri-, and neonatal factors in autism using composite optimality scores. METHOD: Pre-, peri-, and neonatal composite optimality scores were examined in 39 autistic subjects and 39 randomly matched sibling controls using a modification of the Gillberg Optimality Scale (Modified-GOS). Scores were based on best-estimate ratings of maternal interviews and medical records. Rules for best-estimate ratings were derived from a study of agreement between these two sources. RESULTS: Significant differences in optimality between autistic probands and their siblings were not present after adjustment for "maternal parity." Examination of specific variables revealed that only maternal parity differed significantly between autistic subjects and randomly matched sibling controls, reflecting an excess of first and fourth born among the autistic subjects. CONCLUSION: The findings of this study suggest that previous reports of an association between optimality and autism are a result of failure to adjust for birth order.

Social language use in parents of autistic individuals.

Social language use (pragmatics) in parents of autistic individuals and controls was compared. Autism parents displayed atypical pragmatic behaviours more often than controls. Preliminary factor analysis suggested three parsimonious groupings of pragmatic abnormalities: Disinhibited Social Communication, Awkward/Inadequate Expression, and Odd Verbal Interaction. The pragmatic features observed in some autism parents are milder but conceptually similar to the social language deficits of autism. Possible reasons for familial aggregation of pragmatic language deficits are discussed.

The prevalence of fragile X in a sample of autistic individuals diagnosed using a standardized interview.

The study examined 75 autistic individuals who met DSM-III-R criteria for autistic disorder at 5 years of age. Diagnosis was based on information elicited using a standardized interview for autism. Two of 75 (2.7%) autistic subjects expressed the fragile X marker (Xq27.3) in 40% of cells counted and had other affected family members. Two additional subjects expressed the fragile X anomaly at low rates (1%). These rates are compared with those reported in other studies. Methodological differences, which may underlie the varying rates reported across studies, are discussed.

Psychiatric disorders in the parents of autistic individuals.

Eighty-one parents of 42 autistic probands and 34 parents of 18 Down syndrome probands were examined using a semistructured, investigator-based version of the Schedule for Affective Disorders and Schizophrenia Lifetime Version to estimate the lifetime risk of psychiatric disorder. The lifetime prevalence rate of anxiety disorder was significantly greater in parents of autistic probands than in parents of Down syndrome probands. The lifetime prevalence rate of major depressive disorder, while not significantly different in cases and controls, may be high in the parents of autistic probands (27%) in comparison with populations rates.

A family history study of neuropsychiatric disorders in the adult siblings of autistic individuals.

The family history method was used to obtain developmental, social, and psychiatric histories on the 67 adult siblings of 37 autistic probands. Two of 67 siblings (3.0%) were autistic, three siblings (4.4%) had severe social dysfunction and isolation, 10 (15%) had cognitive disorders, and 10 (15%) had received treatment for affective disorder. This study is the first to investigate the frequency of disorders in the adult siblings of autistic probands. These results suggest aggregation of a variety of neuropsychiatric disorders in the siblings of autistic individuals.