A comparison of the ethanol sensing properties of α-iron oxide nanostructures prepared via the sol-gel and electrospinning techniques.

Haematite (α-Fe2O3) nanostructures were synthesized via a Pechini sol-gel method (PSG) and an electrospinning (ES) technique. Their texture and morphology were investigated by scanning and transmission electron microscopy. α-Fe2O3 nanoparticles were obtained by the PSG method, whereas fibrous structures consisting of interconnected particles were synthesized through the ES technique. The crystallinity of the α-Fe2O3 nanostructures was also studied by means of x-ray diffraction and Raman spectroscopy. Gas-sensing devices were fabricated by printing the synthesized samples on ceramic substrates provided with interdigitated Pt electrodes. The sensors were tested towards low concentrations of ethanol in air in the temperature range (200-400 °C). The results show that the α-Fe2O3 nanostructures exhibit somewhat different gas-sensing properties and, interestingly, their sensing behaviour is strongly temperature-dependent. The availability of active sites for oxygen chemisorption and the diffusion of the analyte gas within the sensing layer structure are hypothesized to be the key factors responsible for the different sensing behaviour observed.

Optimized CVD production of CNT-based nanohybrids by Taguchi robust design.

Taguchi's robust design method is for the first time employed to optimize many aspects of the production of nanohybrids based on C nanotubes by iron-catalyzed chemical vapor deposition in i-C4H10 + H2 atmosphere. By analyzing the outcomes of the catalytic process in terms of selectivity, carbon yield, purity and crystalline arrangement of the hybrid-forming nanotubes, the influence is ranked of the following parameters: synthesis temperature (500-700 degrees C), support material (alumina, magnesia or sodium-exchanged montmorillonite), calcination- (450-750 degrees C) and reduction-(500-700 degrees C) temperatures of the 15 wt% Fe-catalyst. In the experiments initially performed for this purpose, the growth process had, on average, scarce selectivity (2 in a scale 1-5) and poor yield (130 wt%); carbonaceous deposits exhibited unsatisfactory graphitization degree (Raman D/G intensity ratio > 1.5) and contained large amounts of metal impurities (14 wt%) and amorphous carbon (5 wt%). The indications emerging from Taguchi approach to the process optimization are critically examined. The experimental conditions chosen for carrying out test experiments allow achieving excellent selectivity (5) or large yield (760 wt%), hybrids with well-graphitized nanotubes (D/G intensity ratio < 0.6), nearly free of metallic (0.3 wt%) or amorphous (0.4 wt%) inclusions, with consequent possibility of satisfying the different requisites that the specific application to be addressed may require.

Growth and analysis of C nanotubes on ceramic polymer-additives.

C nanotubes are synthesized by catalytic route on ceramic supports (Al2O3, MgO and CaO), usually utilized for polymer reinforcing/flame-retardancy, aiming at nanotube-based hybrid preparation. Chemical vapor deposition is carried out in i-C4H10+H2 atmosphere over 17 wt% Fe-catalysts upon different conditions. In order to clarify the influence of support material, calcination (450 degrees C or 750 degrees C) and reduction temperature (500 degrees C or 600 degrees C) of the catalysts, and synthesis temperature (600 degrees C or 700 degrees C), catalysts utilized and nanotubes obtained are systematically investigated by the use of several analysis techniques (electron microscopy, X-ray diffraction, thermo-gravimetry and Raman spectroscopy). The results obtained show that, in the considered range of variation, support material is the most influential parameter. The most catalytically active alumina supports allow achieving higher yields, but involve larger metallic inclusions and lower crystalline quality. Remaining supports behave oppositely. The reasons for such differences are discussed in the light of the current assessments on the nanotube growth and the results obtained are compared with those available in literature for similar catalysts.

Scaling laws for multi-walled carbon nanotube growth by catalyzed chemical vapor deposition.

The synthesis of C nanotubes by catalyzed chemical vapor deposition at 600 degrees C is investigated, using yield and purity degree of C deposits to monitor the reaction outcome. From the reaction, carried out in C4H10-H2-He environment over Al2O3 supported Fe catalysts, multi-walled C nanotubes are attained, which, after purification, are analyzed by routinely-used diagnostics techniques. In order to clarify the role of the growth parameters, various experiments are performed changing flow rates of reactive gases, as well as, amount, metal load and reduction temperature of Fe/Al2O3 catalysts in the ranges 15-90 cc/min, 0.25-2.00 g, 10-40 wt% and 500-700 degrees C, respectively. Correspondingly, carbon yield varies between 47 wt% and 913 wt%, while purity degree between 56 wt% and 93 wt%. Owing to the lack of any correlation between these changes, it is initially quite difficult to envisage the effect, produced by any change of the growth conditions, on the final reaction outcome. The problem is solved by applying a semi-empirical approach, through which the "original" growth variables are combined to give dimensionless arguments (scaling laws for the reaction parameters), able to account for all the variation of yield and purity in the ranges considered. As final result, the growth issue can be easily predicted because carbon yield and purity degree can be approximated through very simple functions of the "new" process variables.

Influence of carbon source and Fe-catalyst support on the growth of multi-walled carbon nanotubes.

Catalytic activity of iron based catalysts in the production of multi-walled carbon nanotubes (MWCNTs) has been investigated. The effect of the carbon source (ethane or isobutane), catalyst support (Al2O3 or SiO2), iron loading, catalyst reduction temperature and reaction temperature on yield and quality of carbon products has been examined. The structural and morphological properties of catalyst and carbon products obtained have been analyzed by means of scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy (RS), thermogravimetric analysis (TGA) and X-ray powder diffraction (XRD). The iron-based catalysts supported on alumina seem to be efficient systems for the production of carbon nanotubes from chemical vapor deposition (CVD) of isobutane with very interesting yields. The opportune calibration of reaction parameters, such as iron loading and reaction temperature, can in fact drive the synthesis toward the formation of high quality CNTs.

Personality and language characteristics in parents from multiple-incidence autism families.

Several studies have suggested that the genetic liability for autism may be expressed in non-autistic relatives of autistic probands, in behavioral characteristics that are milder but qualitatively similar to the defining features of autism. We employ a variety of direct assessment approaches to examine both personality and language in parents ascertained through having two autistic children (multiple-incidence autism parents) and parents of Down syndrome probands. Multiple-incidence autism parents had higher rates of particular personality characteristics (rigidity, aloofness, hypersensitivity to criticism, and anxiousness), speech and pragmatic language deficits, and more limited friendships than parents in the comparison group. The implications of these findings for future genetic studies of autism are discussed.

Assessing risk for the Tourette spectrum of disorders among first-degree relatives of probands with Tourette syndrome.

Previous studies have indicated that genetic investigations of Tourette syndrome (TS) should focus on a phenotype that includes not only TS, but chronic tics (CT) and obsessive-compulsive disorder (OCD) as well. These studies have shown that sex may play a role in determining which of the disorders in the TS spectrum is expressed in a susceptible individual. Female relatives of TS probands far more often express OCD, while male relatives more often express TS or CT. Data from the Yale Family Study of TS were used to model risk to first-degree relatives of probands with TS for a variety of TS disease phenotypes. Risk to relatives was modeled using multivariate Cox regression analysis, a method appropriate for assessing risk when there is correlation among disease onsets. This is the first known application of this method to family data. The study identified two proband characteristics that increase the risk for disease onset among both male and female relatives for all TS spectrum disorders, lending credence to the hypothesis that TS spectrum disorders share a common etiology. These were a relatively younger age-at-onset, and no experience of simple motor tics. The predictive ability of two additional factors varied by both sex and disease phenotype. These characteristics, i.e., proband onset with compulsive tics, and proband onset with range, appear to increase risk primarily in female relatives, and for the OCD part of the spectrum.

Incorporating language phenotypes strengthens evidence of linkage to autism.

We investigated the effect of incorporating information about proband and parental structural language phenotypes into linkage analyses in the two regions for which we found the highest signals in our first-stage affected sibling pair genome screen: chromosomes 13q and 7q. We were particularly interested in following up on our chromosome 7q finding in light of two prior reports of linkage of this region to developmental language disorder, since one of the diagnostic criteria for autism is absent or abnormal language development. We hypothesized that if the language phenotype were genetically relevant to linkage at the chromosome 7q locus, then incorporating parents phenotypes would increase the signal at that locus, and most of the signal would originate from the subset of families in which both probands had severe language delay. The results support these hypotheses. The linkage signals we obtained on chromosome 7q as well as at least one signal on chromosome 13q are mainly attributable to the subgroup of families in which both probands had language delay. This became apparent only when the parents' history of language-related difficulties was also incorporated into the analyses. Although based on our data, we were not able to distinguish between epistasis or heterogeneity models, we tentatively concluded that there may be more than one autism susceptibility locus related to language development.

An autosomal genomic screen for autism. Collaborative linkage study of autism.

Autism is a severe neurodevelopmental disorder defined by social and communication deficits and ritualistic-repetitive behaviors that are detectable in early childhood. The etiology of idiopathic autism is strongly genetic, and oligogenic transmission is likely. The first stage of a two-stage genomic screen for autism was carried out by the Collaborative Linkage Study of Autism on individuals affected with autism from 75 families ascertained through an affected sib-pair. The strongest multipoint results were for regions on chromosomes 13 and 7. The highest maximum multipoint heterogeneity LOD (MMLS/het) score is 3.0 at D13S800 (approximately 55 cM from the telomere) under the recessive model, with an estimated 35% of families linked to this locus. The next highest peak is an MMLS/het score of 2.3 at 19 cM, between D13S217 and D13S1229. Our third highest MMLS/het score of 2.2 is on chromosome 7 and is consistent with the International Molecular Genetic Study of Autism Consortium report of a possible susceptibility locus somewhere within 7q31-33. These regions and others will be followed up in the second stage of our study by typing additional markers in both the original and a second set of identically ascertained autism families, which are currently being collected. By comparing results across a number of studies, we expect to be able to narrow our search for autism susceptibility genes to a small number of genomic regions. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:609-615, 1999.

Are schizophrenic men at higher risk for developmental deficits than schizophrenic women? Implications for adult neuropsychological functions.

This study tested the hypothesis that schizophrenic men would be at a greater risk than schizophrenic women for exhibiting a history of developmental problems in childhood and would exhibit more neuropsychological deficits as adults. The study was a secondary analysis of data that were collected in 1981-83. The sample consisted of 49 DSM-III schizophrenic patients (57% male/43% female), who were generally in the early stages of the disorder. All subjects received a neurodevelopmental and clinical/diagnostic interview and a neuropsychological battery of tests, including measures of intelligence, abstract reasoning, memory, sustained attention, executive function, language skills, and motor ability. Latent class analysis was used to identify gender differences in subclasses of schizophrenia. The groups were then compared on neuropsychological function. Results indicated that schizophrenics with histories of early developmental problems exhibited significantly more neuropsychological dysfunction as adults than did other schizophrenics, and they were more likely to be men. Impairment in this group was evident in the areas of verbal ability, attention, abstraction, motor function, and verbal and nonverbal learning and memory, with verbal tasks being relatively more impaired.

Impact of maternal depression on ratings of comorbid depression in adolescents with attention-deficit/hyperactivity disorder.

OBJECTIVE: To assess the degree to which indirect maternal reports of comorbid major depression (MD) in adolescents with and without attention-deficit/hyperactivity disorder (ADHD) were influenced by the mother's personal history of MD. METHOD: Bivariate regression was used to model the impact of maternal depression on the direct and indirect report of MD in ADHD (n = 150) and non-ADHD (n = 123) subjects. The dependent variable (i.e., risk for MD) was modeled as a function of the main effect of ADHD, the main effect of reporter, their interaction, and higher-order interactions with maternal depression. RESULTS: There was a significant interaction between maternal depression and the effect of reporter exclusively in non-ADHD control subjects. ADHD continued to be a significant risk factor for MD independent of maternal reporting or maternal depression. CONCLUSIONS: The potential distortion of indirect interviews by depressed mothers may be stronger in community than in clinical settings and does not account for the increased risk for MD in referred adolescents with ADHD.

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.

Tourette's syndrome: what are the influences of gender and comorbid obsessive-compulsive disorder?

OBJECTIVE: To explore the influence of gender and comorbid obsessive-compulsive disorder (OCD) on the phenomenology of Tourette's syndrome (TS). METHOD: TS proband groups defined by gender and comorbid OCD status were compared on a variety of sociodemographic variables, clinical characteristics, and perinatal complications. RESULTS: Compared to females, males more often onset with rage and had ever experienced any form of simple tics. Females onset with compulsive tics more often than males. Probands with comorbid OCD were more likely than those without OCD to onset with complex tics. Delivery complications, especially forceps deliveries, were associated with being male and with having OCD. Fetal exposure to relatively high levels of coffee, cigarettes, or alcohol predicted OCD in TS probands. Diagnosis of TS occurred at later ages among females than among males. Males and females displayed different age distributions. CONCLUSIONS: Males and females tend to experience different kinds of symptoms at onset. However, the overall experience of TS appears to be similar for both groups. Perinatal brain injury is implicated in the etiology of TS in some boys. Early brain injury may cause or exacerbate the development of OCD in some TS sufferers.

The role of gender in identifying subtypes of schizophrenia: a latent class analytic approach.

Past literature suggests that schizophrenic men and women may be at different risks for developing different subtypes of schizophrenia. This hypothesis was tested using data from the well-known retrospective cohort family studies, the Iowa 500 and the Iowa non-500. The sample consisted of 171 male and 161 female DSM-III schizophrenic patients and 713 of their first-degree relatives. First, bivariate tests for gender differences were conducted regarding family morbidity, age of onset, premorbid history, season of birth, and expression of deficit and affective symptoms. Restricted maximum likelihood latent class analysis was then used to test whether there was a subgroup of schizophrenic men who were more likely to have a low familial risk for schizophrenia or schizophrenia spectrum disorders, deficit symptoms, poor premorbid history, and birth in the winter months, suggesting possible early environmental insults, compared to schizophrenic women. Results showed that although men were more likely to meet these criteria, women also met them, thus suggesting gender differences in the prevalence of the subtype. Schizophrenic women were more likely to express a form of the illness characterized by dysphoria, persecutory delusions, and a higher family morbidity risk for schizophrenia than schizophrenic men. Results for spectrum disorders among relatives were equivocal with regard to gender.

Finding specific genes that cause autism: a combination of approaches will be needed to maximize power.

Although autism is clearly inherited, it may be challenging to find the genes involved: The mechanism of inheritance is unknown, families with an autistic child are usually small, parent-child pairs are rare, and a fairly large number of genes may be involved, some or all of which may have a small effect on the phenotype. We discuss several strategies for finding genes, all of which may be used in combination to find the relevant genes.

Self-mutilation and suicide attempt: distinguishing features in prisoners.

Nonlethal forms of self-injury are often discussed together with suicide attempts as though they belonged on a continuum of self-harm. Both types of self-injury are common in prisons, which have a predominantly male population; however, most studies of nonlethal self-injury have been done with female subjects. This exploratory study tested the hypothesis that prisoners who injured themselves without intending to die would differ clinically from prisoners who had attempted suicide. Inmates admitted to the prison unit of a public hospital for treatment of self-inflicted wounds or who had a history of previous self-injury were administered a standardized intake protocol by the first author, which included asking about their intent at the time they injured themselves. Patients were classified as self-mutilators or suicide attempters on the basis of intent. Fifteen patients reported that they had attempted to take their own lives, while 16 reported other reasons for harming themselves. Suicide attempt was associated with adult affective disorder 13/15 versus 2/16 mutilators); self-mutilation with a history of childhood hyperactivity (12/16 versus 1/15 suicide attempters) and a mixed dysthymia/anxiety syndrome that began in childhood or early adolescence (9/16). Prison self-mutilators and suicide attempters had very different clinical presentations and histories. The history of childhood hyperactivity in self-mutilators deserves further study in both correctional and noncorrectional populations.

[Epidemiology of CKD in Italy and prevention strategies]. / Epidemiologia della malattia renale cronica in italia e strategie per la prevenzione.

Although chronic kidney disease (CKD) is a major health problem worldwide; it is not adequately considered in the strategies for the prevention of non-communicable diseases. To plan properly preventive strategies in our country, we need to know what is the prevalence of CKD, the risk factors, the level of awareness for the diagnosis, the referral to specialists nephrologists and the prognosis of patients followed in primary care. The prevalence of CKD, adjusted for age and gender, is 6.3% and the major independent risk factors are represented by old age, arterial hypertension, obesity, diabetes, cardiovascular disease and smoking . The awareness of the diagnosis in our country in 2003 is underestimated and nephrology referral for individuals with glomerular filtration (GF) under 60 ml / min was only 10%. The prognosis of patients, followed exclusively in primary care, worsens progressively for values of GF under 45 ml / min, both as need for substitutive treatment and mortality, compared with patients of stage I and II. To improve the management of CKD, it would be useful to set up an electronic database on our national territory by a network among laboratories, primary care, and nephrologists. An example of this organization is Great Britain that evidences encouraging results in the treatment and prevention of this debilitating disease.

Prostaglandin E2 receptor antagonist (SC-19220) treatment restores the balance to bone marrow myelopoiesis after burn sepsis.

BACKGROUND: Although prostaglandin E2 (PGE2) has been shown to be immunosuppressive, its role in the development of specific bone marrow myeloid lineages after thermal injury and sepsis has yet to be elucidated. The purpose of this study was to demonstrate that alterations in bone marrow progenitor proliferation favoring monocytopoiesis in burn sepsis can be restored by blocking the cellular interactions of PGE2. METHODS: A murine model of burn sepsis with and without treatment with SC-19220, a PGE2 receptor antagonist, was used to determine peripheral monocyte and neutrophil counts as well as the colony forming potential of colony-stimulating factor responsive bone marrow progenitors. RESULTS: Burn sepsis augmented the growth of the early colony-forming unit granulocyte-macrophage and monocyte progenitors and the number of circulating monocytes, whereas granulocyte progenitors and circulating neutrophils demonstrated an opposite response. Treatment with SC-19220 nearly reversed these alterations. CONCLUSION: These data indicate that abrogating PGE2's actions during burn sepsis can restore the balance in bone marrow granulocyte and monocyte production, further consolidating the pivotal role PGE2 plays in the pathogenesis of burn sepsis.