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A Philips EM-200 electron microscope has been modified to incorporate two electron guns as described by Ong and Gold, for operation in the conventional (TEM) and scanning (SEM) mode.
The second gun, the SEM gun, is mounted below the viewing chamber and uses the imaging system of the microscope as the probe forming electron optic. The electrons follow essentially the same path as the image forming electrons for TEM, only in the opposite direction.
The modifications to the microscope column are designed to provide the space for the scanning coil assembly, the various detectors, and the second gun. A spacer is located above the objective lens to house the transmission electron detector, another spacer, below the objective lens, incorporates the scanning coil and a secondary electron detector.
Associations between smell identification deficits (SID) and impairments in basic cognitive domains have been shown in patients with neuropsychiatric disorders.
We analyzed social and basic cognitive deficits and SID.
To assess differences in affective decision making tasks in patients with schizophrenia-spectrum disorders, their 1st degree relatives and healthy controls. Methods: We examined 51 patients with schizophrenia-spectrum disorders (49% female, age 33.1 years, SD 11), 21 first-degree relatives (61.9% female, age 49.5 years, SD 17.6, one affected, others non-affected) and 51 matched healthy controls (49% female, age 33 years, SD 12.1). Psychopathology was evaluated using the Positive and Negative Syndrome Scale (PANSS). Subjects were administered the University of Pennsylvania Smell Identification Test (UPSIT), the Facially Expressed Emotion Labelling (FEEL) test, the spatial span subtest of the Wechsler Memory Scale-Revised (WMS-R) and the Mehrfachwahl-Wortschatz Test (MWT-B).
Patients, controls and 1st degree relatives differed in age (p = 0.000), WMS-R (p = 0.000) and FEEL scores (p = 0.007). In healthy controls, patients and 1st degree relatives FEEL correlated with age (p = 0.005, p = 0.003, p = 0.004, respectively). In patients FEEL also correlated with MWT-B (p = 0.000), UPSIT (p = 0.000) and PANSS negative scores (p = 0.016); furthermore, UPSIT correlated with MWT-B (p = 0.001). In 1st degree relatives age correlated with WMS-R (p = 0.04) and FEEL (p = 0.004), both of which inter-correlated (p = 0.006).
We found that SID, basic and social cognition, i.e. affective decision-making processes, inter-correlate in patients with schizophrenia-spectrum disorders and are partly under the influence of negative symptoms. Some of these relationships can also be seen in 1st degree relatives of patients.
Schizophrenia has often been associated with a reduced skin flush response to niacin. Blunted response suggests potential disturbance in phospholipid metabolism.
We performed niacin skin tests in patients with schizophrenia, their first-degree relatives and healthy controls.
To examine possible differences in skin flush response to niacin.
We examined 51 patients (female 49%, age 33.1 years, SD 11), with schizophrenia-spectrum disorders, 51 matched healthy controls (female 49%, age 33 years, SD 12.1), and 21 first-degree relatives (female 61,9%, age 49,5 years, SD 17,6, one affected, others non-affected). The Positive and Negative Syndrome Scale and the Mini International Neuropsychiatrie Interview were used to assess psychopathology and diagnosis, respectively. The non-invasive niacin skin flush test was used to assess vasodilatative reaction to four different concentrations of niacin on the forearms of subjects.
We found no differences in total scores on the niacin skin flush test between the three groups (p = 0.774). Mean scores were 60.27 (SD 14.2) in healthy controls, 58.84 (SD 10.2) in patients and 58.48 (SD 9.4) in first-degree relatives.
Contrary to our expectations we did not find a significantly blunted niacin skin flush reaction in patients with schizophrenia-spectrum disorders compared to healthy controls or 1st degree relatives.
Sex-related differences in smell identification have been shown in healthy subjects, however, in patients with schizophrenia these findings are still controversial.
We analyzed sex-related differences with respect to smell identification in patients with schizophrenia, their first-degree relatives and healthy controls.
To assess possible sex-related differences in smell identification.
The sample consisted of 51 patients with schizophrenia-spectrum disorders (49% female; mean age 33.1 years; SD: 11), 21 first-degree relatives (61.9% female, age 49.5 years, SD 17.6, one affected, others non-affected) ; mean age 49.5 years; SD: 17.6) and 51 matched healthy controls (49% female; mean age 33 years; SD: 12.1). The Positive and Negative Syndrome Scale (PANSS) and the Mini International Neuropsychiatric Interview (M.I.N.I.) were used to assess psychopathology and diagnosis, respectively. The University of Pennsylvania Smell Identification Test (UPSIT), a standardized, multiple- and forced-choice scratch- and sniff test consisting of 40 items, was administered to all subjects.
We found no significant differences in smell identification between the three groups (p = 0.182). Also, the female and male subgroups did not differ significantly in smell identification (p = 0.105, p = 0.387, respectively). The mean UPSIT scores were 34.4 (SD: 4.1) for healthy women (males: 33.2; SD: 3.5), 32.0 (SD: 5.1) for women with schizophrenia-spectrum disorders (males: 32.5; SD: 4.4), and 34.5 (SD: 2.6) for female first-degree relatives (males: 30.5; SD: 2.8).
We found neither significant differences in smell identification in patients with schizophrenia-spectrum disorders, their first-degree relatives or healthy controls, nor sex-related differences.
Many women experience both vasomotor menopausal symptoms (VMS) and depressed mood at midlife, but little is known regarding the prospective bi-directional relationships between VMS and depressed mood and the role of sleep difficulties in both directions.
A pooled analysis was conducted using data from 21 312 women (median: 50 years, interquartile range 49−51) in eight studies from the InterLACE consortium. The degree of VMS, sleep difficulties, and depressed mood was self-reported and categorised as never, rarely, sometimes, and often (if reporting frequency) or never, mild, moderate, and severe (if reporting severity). Multivariable logistic regression models were used to examine the bi-directional associations adjusted for within-study correlation.
At baseline, the prevalence of VMS (40%, range 13–62%) and depressed mood (26%, 8–41%) varied substantially across studies, and a strong dose-dependent association between VMS and likelihood of depressed mood was found. Over 3 years of follow-up, women with often/severe VMS at baseline were more likely to have subsequent depressed mood compared with those without VMS (odds ratios (OR) 1.56, 1.27–1.92). Women with often/severe depressed mood at baseline were also more likely to have subsequent VMS than those without depressed mood (OR 1.89, 1.47–2.44). With further adjustment for the degree of sleep difficulties at baseline, the OR of having a subsequent depressed mood associated with often/severe VMS was attenuated and no longer significant (OR 1.13, 0.90–1.40). Conversely, often/severe depressed mood remained significantly associated with subsequent VMS (OR 1.80, 1.38–2.34).
Difficulty in sleeping largely explained the relationship between VMS and subsequent depressed mood, but it had little impact on the relationship between depressed mood and subsequent VMS.
Cognition is increasingly being recognized as an important aspect of psychotic disorders and a key contributor to functional outcome. In the past, comparative studies have been performed in schizophrenia and schizo-affective disorder with regard to cognitive performance, but the results have been mixed and the cognitive measures used have not always assessed the cognitive deficits found to be specific to psychosis. A set of optimized cognitive paradigms designed by the Cognitive Neuroscience Test Reliability and Clinical Applications for Schizophrenia (CNTRACS) Consortium to assess deficits specific to schizophrenia was used to measure cognition in a large group of individuals with schizophrenia and schizo-affective disorder.
A total of 519 participants (188 with schizophrenia, 63 with schizo-affective disorder and 268 controls) were administered three cognitive paradigms assessing the domains of goal maintenance in working memory, relational encoding and retrieval in episodic memory and visual integration.
Across the three domains, the results showed no major quantitative differences between patient groups, with both groups uniformly performing worse than healthy subjects.
The findings of this study suggests that, with regard to deficits in cognition, considered a major aspect of psychotic disorder, schizophrenia and schizo-affective disorder do not demonstrate major significant distinctions. These results have important implications for our understanding of the nosological structure of major psychopathology, providing evidence consistent with the hypothesis that there is no natural distinction between cognitive functioning in schizophrenia and schizo-affective disorder.
While impaired memory and altered cortisol secretion are characteristic features of major depression, much less is known regarding the impact of antidepressant medication. We examined whether the cortisol awakening response (CAR) is increased in depressed patients with and without medication compared with healthy controls (HC) and whether CAR is associated with memory function in each group.
We examined 21 patients with major depression without medication, 20 depressed patients on antidepressant treatment, and 41 age-, sex- and education-matched healthy subjects. We tested verbal (Auditory Verbal Learning Task) and visuospatial (Rey figure) memory and measured CAR on two consecutive days.
Patient groups did not differ in severity of depression. We found a significant effect of group (p = 0.03) for CAR. Unmedicated patients exhibited a greater CAR compared with medicated patients (p = 0.04) with no differences between patient groups and HC. We found a significant effect of group for verbal (p = 0.03) and non-verbal memory (p = 0.04). Unmedicated patients performed worse compared with medicated patients and HC in both memory domains. Medicated patients and HC did not differ. Regression analyses revealed a negative association between CAR and memory function in depressed patients, but not in HC.
While in unmedicated depressed patients the magnitude of CAR is associated with impaired memory, medicated patients showed a smaller CAR and unimpaired cognitive function compared with HC. Our findings are compatible with the idea that antidepressants reduce CAR and partially restore memory function even if depressive psychopathology is still present.
In this case-control study, cases [community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), n=79] and controls [community-associated methicillin-susceptible S. aureus (CA-MSSA), n=36] were defined as a laboratory-confirmed infection in a patient with no previous hospital-associated factors. Skin and soft tissue were the predominant sites of infection, both for cases (67·1%) and controls (55·6%). Most of the cases (79·7%) and controls (77·8%) were aged <30 years. Investigations did not reveal any significant statistical differences in acquiring a CA-MRSA or CA-MSSA infection. The most common shared risk factors included overcrowding, previous antibiotic usage, existing skin conditions, household exposure to someone with a skin condition, scratches/insect bites, and exposure to healthcare workers. Similar risk factors, identified for both CA-MRSA and CA-MSSA infections, suggest standard hygienic measures and proper treatment guidelines would be beneficial in controlling both CA-MRSA and CA-MSSA in remote communities.
Much evolutionary theory assumes that parasite virulence (i.e. parasite-induced host mortality) is determined by within-host parasite reproduction and by the specific parasite genotypes causing infection. However, many other factors could influence the level of virulence experienced by hosts. We studied the protozoan parasite Ophryocystis elektroscirrha in its host, the monarch butterfly, Danaus plexippus. We exposed monarch larvae to wild-isolated parasites and assessed the effects of within-host replication and parasite genotype on host fitness measures, including pre-adult development time and adult weight and longevity. Per capita replication rates of parasites were high, and infection resulted in high parasite loads. Of all host fitness traits, adult longevity showed the clearest relationship with infection status, and decreased continuously with increasing parasite loads. Parasite genotypes differed in their virulence, and these differences were maintained across ecologically relevant variables, including inoculation dose, host sex and host age at infection. Thus, virulence appears to be a robust genetic parasite trait in this system. Although parasite loads and genotypes had strong effects on virulence, inoculation dose, host sex and age at infection were also important. These results have implications for virulence evolution and emphasize the need for a detailed understanding of specific host-parasite systems for addressing theory.
New varieties are often developed on research stations with limited farmer involvement until the final stages of testing. Recently, farmer participatory approaches have been employed to include farmers' input into breeding objectives at much earlier stages of varietal development. This paper reports on a farmer survey in Uganda to record farmer selection criteria for banana cultivars as a pre-breeding activity. From ranked data, bunch size and crop maturation time were the key selection criteria in the county's most important commercial production zones. Stand longevity, taste and crop maturation time were key factors where banana production is in decline and sale of bananas less important. Principal component analysis revealed that, nationally, stand longevity and tolerance of marginal soils were the most important criteria, probably because the larger part of overall production is for subsistence.
The East African highlands, home to more than 80 cultivated varieties of locally evolved bananas, constitute a secondary centre of banana diversity. Uganda is the leading producer and consumer of banana in the region and also enjoys the highest diversity of a group of bananas uniquely adapted to this region. These East African highland bananas comprise cooking and brewing types. The former is a staple for more than 7 million people and thus important for food security. Little is known about the distribution of the vast germplasm and this study was set up to help determine a distribution pattern and to understand the dynamics of cultivar change using farmers participatory appraisal methods. The study involved a guided interview with 120 farmers, at 24 sites throughout the banana-growing region of Uganda, to reveal cultivar diversity, proportions, distribution and preferences. Cultivar diversity ranged from 18 to 34 (mean = 26) cultivars per site, and from 4 to 22 (mean = 12.3), cultivars per individual farm. Such high diversity was attributed to a variety of end uses, better food security and the perception that each cultivar had a unique range of strengths and weaknesses. Highland banana (AAA-EA) represented 76% of total production while Kayinja (‘Pisang Awak’ subgroup) (ABB) contributed 8%; Ndiizi (’Ney Poovan’ subgroup) (AB) 7%; Kisubi (‘Ney Poovan’ subgroup) (AB) 5%; Gros Michel (‘Bogoya’) (AAA) 2%; and plantain (AAB) 2%. Although 130 highland cultivars were recorded, only 10 constituted 50% of highland banana production while 45 cultivars were found at only 1 or 2 sites. A few cultivars showed more universal distribution and it is proposed that these may be the oldest and best performing local landraces.
This paper presents an x-ray diffraction and transmission electron microscopy analysis of Al1−xInxAs grown by molecular beam epitaxy. Two samples grown on (001) InP at temperatures of 370 and 400 °C are characterized. The first, which contains a high density of twin lamellae, exhibits triple-period short-range ordering with a rather short correlation range normal to the (111) planes. Within these (individual) planes, the concentration, however, is uniform over a considerably greater distance, leading to a highly anisotropic scattering. This is the first observation of triple-period short-range ordering in a sample that exhibits 2 × 1 surface reconstruction. The second sample exhibits CuPt-type short-range ordering with scattering that is significantly streaked, suggestive of lamellar-shaped ordered domains. Both samples contain high densities of stacking faults leading to additional sharp streaking along symmetry-allowed 〈111〉 directions.
An In0.25Ga0.75Sb/InAs strained-layer superlattice, grown by molecular-beam epitaxy (MBE) on a GaSb substrate, has been characterized by four-circle x-ray diffractometry. This system, proposed by Maliot and Smith for ir detection application, is challenging because of the two group V species and the likelihood of cross-incorporation of the different elements during growth, leading possibly to interdiffusion and thus, to a more diffuse interface. High-resolution x-ray diffraction (XRD) profiles were obtained about several reciprocal lattice points in order to extract a reliable set of structural parameters. The profiles were then successfully modeled by computer simulation. The presence of many sharp higher-order satellite reflections in the XRD profiles is a measure of the high quality of the superlattices. The normal and lateral structural coherence was also measured and will be discussed.
This paper describes examination of in-service coating degradation in land based gasturbine blades by means of a small punch testing (SP) method and scanning Auger microprobe(SAM). SP tests on coated specimens with unpolished surfaces indicated large variations ofthe mechanical properties because of the surface roughness and curvature in gas turbine blades, SP tests on polished specimens better characterized the mechanical degradation of bladecoatings. The coated specimens greatly softened and the room temperature ductility of thecoatings and substrates tended to decrease with increasing operation time. The ductile-brittletransition temperature of the coatings shifted to higher temperatures during the bladeoperation. From SAM analyses on fracture surfaces of unused and used blades, it has beenshown that oxidation and sulfidation near the coating surface, which control the fractureproperties, result from high temperature environmental attack.
Studies of diamond heteroepitaxy on silicon indicate that C-C surface species act as nucleation precursors. We have investigated the conversion of the Si(100) 2×1 surface to SiC using C2H4 to obtain an understanding of how C-C species may be formed and to determine the effect of an O-adlayer on enhancing or selecting the reaction channel which leads to these species. Under appropriate conditions, the interaction between C2H4 and the clean silicon surface yields both SiC and C-C species. The presence of an O-adlayer significantly reduces the activity of silicon and enhances the formation of sp2 and sp3 C-C species. These results provide key insights into diamond nucleation conditions in conventional growth processes.
Small punch (SP) tests on single grained titanium aluminide (Ti-48 at.%Al) specimens with 12° and 80° lamellar orientations with respect to the tensile stress axis were conducted at 1123 K in air. Brittle cracks readily extended through the thickness in the 80° lamellar structure. In a SP specimen with the 12° lamellar structure load-interrupted at the strain of 0.43%, surface cracks with the depth of 15–25 μm were formed along lamellar boundaries. Local oxidation behavior on partly sputtered surfaces in the load-interrupted 12° lamellar specimen was examined using scanning Auger microprobe (SAM). Oxygen enriched regions were observed near cracks and some lamellar layers. The mechanisms of high temperature oxygen-induced cracking are discussed in terms of the local oxidation near cracks and lamellar boundaries.