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.

[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.

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.

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.

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.

Defining the autism minimum candidate gene region on chromosome 7.

Previous genetic and cytogenetic studies provide evidence that points to one or more autism susceptibility genes residing on chromosome 7q (AUTS1, 115-149 cM on the Marshfield map). However, further localization using linkage analysis has proven difficult. To overcome this problem, we examined the Collaborative Linkage Study of Autism (CLSA) data-set to identify only the families potentially linked to chromosome 7. Out of 94, 47 families were identified and 17 markers were used to generate chromosomal haplotypes. We performed recombination breakpoint analysis to determine if any portion of the chromosome was predominately shared across families. The most commonly shared region spanned a 6 cM interval between D7S501 and D7S2847. Additional markers at 1 cM intervals within this region were genotyped and association and recombination breakpoint analysis was again performed. Although no significant allelic association was found, the recombination breakpoint data points to a shared region between D7S496-D7S2418 (120-123 cM) encompassing about 4.5 Mb of genomic DNA containing over 50 genes.

Linkage disequilibrium at the Angelman syndrome gene UBE3A in autism families.

Autistic disorder is a neurodevelopmental disorder with a complex genetic etiology. Observations of maternal duplications affecting chromosome 15q11-q13 in patients with autism and evidence for linkage and linkage disequilibrium to markers in this region in chromosomally normal autism families indicate the existence of a susceptibility locus. We have screened the families of the Collaborative Linkage Study of Autism for several markers spanning a candidate region covering approximately 2 Mb and including the Angelman syndrome gene (UBE3A) and a cluster of gamma-aminobutyric acid (GABA(A)) receptor subunit genes (GABRB3, GABRA5, and GABRG3). We found significant evidence for linkage disequilibrium at marker D15S122, located at the 5' end of UBE3A. This is the first report, to our knowledge, of linkage disequilibrium at UBE3A in autism families. Characterization of null alleles detected at D15S822 in the course of genetic studies of this region showed a small (approximately 5-kb) genomic deletion, which was present at somewhat higher frequencies in autism families than in controls.

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.

Myeloid commitment shifts toward monocytopoiesis after thermal injury and sepsis.

OBJECTIVE: To demonstrate enhanced bone marrow monocytopoiesis in response to thermal injury and sepsis and to provide a mechanism for this observation. SUMMARY BACKGROUND DATA: Although monocyte activation and the resultant dysregulated cytokine production are now the accepted hallmarks of systemic inflammatory response syndrome, no information is available on the status of bone marrow monocyte production under injury conditions; neither has the balance between the two arms of myelopoiesis (monocytopoiesis and granulocytopoiesis) been delineated. METHODS: Peripheral blood absolute neutrophil and monocyte counts were determined 72 hours after the initial injury in sham, burn, and burn sepsis mice. Colony-forming potential in response to colony-stimulating factors (granulocyte, macrophage, and granulocyte/macrophage) was determined in both total nucleated and monocyte progenitor enriched bone marrow cells. Dual color flow cytometry was used to document the distribution pattern of monocyte progenitors. Macrophage colony-stimulating factor receptor density in monocyte progenitors was assessed by 125I macrophage colony-stimulating factor binding assay. RESULTS: Burn sepsis induced circulating monocytosis and granulocytopenia. Colony-forming assays demonstrated an increase in the growth potential of monocyte progenitors and a significant decrease in granulocyte progenitors after burn and burn sepsis. Flow cytometric analysis of early (ER-MP12) and late (ER-MP20) monocyte progenitors showed an increase in monocyte lineage growth in burn sepsis. Radioligand binding assay demonstrated an increase in macrophage colony-stimulating factor receptor expression in monocyte progenitors in burn sepsis. CONCLUSIONS: The data validate the premise that enhanced monocytopoiesis in thermal injury and sepsis results from an imbalance in myelopoiesis that is driven by the increased expression of macrophage colony-stimulating factor receptor.

On the detection of linkage in multiple data sets: a comparison of various statistical approaches.

We contrast the pooling of multiple data sets with the compound HLOD (HLOD-C) and the posterior probability of linkage (PPL), two approaches that have been shown to have more power in the presence of genetic heterogeneity. We also propose and evaluate several multipoint extensions.

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.

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.

The importance of watching our weights: how the choice of weights for non-independent sib pairs can dramatically alter results.

Handling non-independent sib pairs in families with multiple affected sibs presents a problem in likelihood-based nonparametric linkage analyses. We contrast the more stable partial-likelihood solution in MAPMAKER/SIBS with the extremely variable partial-likelihood approach used in ASPEX, and the potential inflation of lods when the problem is ignored as in BETA.

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.

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.

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.

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.

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.

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.