35 research outputs found
Microwave-Assisted Topochemical Manipulation of Layered Oxide Perovskites: From Inorganic Layered Oxides to Inorganic-Organic Hybrid Perovskites and Functionalized Metal-Oxide Nanosheets
Developing new materials with desired properties is a vital component of emerging technologies. Functional hybrid compounds make an important class of advanced materials that let us synergistically utilize the key features of the organic and inorganic counterparts in a single composite, providing a very strong tool to develop new materials with ”engineered” properties. The research presented here, summarizes efforts in the development of facile and efficient methods for the fabrication of three- and two-dimensional inorganic-organic hybrids based on layered oxide perovskites. Microwave radiation was exploited to rapidly fabricate and modify new and known materials. Despite the extensive utilization of microwaves in organic syntheses as well as the fabrication of the inorganic solids, the work herein was among the first reported that used microwaves in topochemical modification of the layered oxide perovskites. Our group specifically was the first to perform rapid microwave-assisted reactions in all of the modification steps including proton exchange, grafting, intercalation, and exfoliation, which decreased the duration of multi-step modification procedures from weeks to only a few hours. Microwave-assisted grafting and intercalation reactions with n-alkyl alcohols and n-alkylamines, respectively, were successfully applied on double-layered Dion-Jacobson and Ruddlesden-Popper phases (HLaNb2O7, HPrNb2O7, and H2CaTa2O7), and with somewhat more limited reactivity, applied to triple-layered perovskites (HCa2Nb3O10 and H2La2Ti3O10). Performing neutron diffraction on n-propoxy-LaNb2O7, structure refinement of a layered hybrid oxide perovskite was then tried for the first time. Furthermore, two-dimensional hybrid oxides were efficiently prepared from HLnNb2O7 (Ln = La, Pr), HCa2Nb3O10, HCa2Nb2FeO9, and HLaCaNb2MnO10, employing facile microwave-assisted exfoliation and post-exfoliation surface-modification reactions for the first time. A variety of surface groups, saturated or unsaturated linear and cyclic organics, were successfully anchored onto these oxide nanosheets. Properties of various functionalized metal-oxide nanosheets, as well as the polymerization of some monomer-grafted nanosheets, were then investigated for the two-dimensional hybrid systems
Movement disorders in systemic autoimmune diseases: Clinical spectrum, ancillary investigations, pathophysiological considerations
With the advances in neuroimmunology especially due to the discovery of new neuronal antibodies, the recognition of treatable antibody-related movement disorders has recently received much attention. In contrast, the identification and characterisation of movement disorders associated with systemic autoimmune diseases remains a substantially unexplored area. Beyond the classic few associations such as chorea and antiphospholipid syndrome, or ataxia and coeliac disease, movement disorders have been reported in association with several systemic autoimmune diseases, however a clear image of clinical phenotypes, investigations, and treatment outcomes in these conditions has never been drawn. In this review, we analyse data from approximately 300 cases and summarise the epidemiological, clinical and diagnostic features of movement disorders associated with systemic autoimmune diseases, and the available knowledge about treatment and outcomes. We highlight that movement disorders in systemic autoimmune conditions are frequently the only or among a few presenting manifestations and are mostly treatable disorders responding to immunotherapy or dietary modifications. We point out the pertinent combination of clinical features and investigations which can suggest the underlying autoimmune nature of these movement disorders, and thus address the most appropriate treatment
Effect of Group and Individual Breeding on Performance, Blood Parameters, Ruminal Fermentation, Behavior and Health of Dairy Calves
Introduction: In most dairy farms, calves are housed individually during the milk-feeding period and will only introduce to social groups after weaning. Individual housing can help keep calves healthy by reducing disease transmission and incidence behavioral problems such as cross-sucking as well as providing individual feeding and health-care of the calf. Nevertheless, individual rearing systems through lack of social contact can compromise the welfare of the calf. Calves are social animals, thus keeping calves in groups can promote more normal social behavior. Also, social housing results in decreased labor costs associated with calf rearing, increased solid feed intake, weight gains, and less fear of novel social situations. Despite all the performance and behavioral advantages in calves with social housing compared to individually housing, there are concerns about the close relationship between calves and the risk of disease transmission. It has been reported a higher frequency of diarrhea in socially housed calves compared with individually housed calves at week 3. Thereby the risk of morbidity and mortality can be reduced if calves are grouped after 3 weeks of age onwards. Also, no considerable differences were observed for social behaviors between calves housed together from birth compared with those housed together from 3 week of life. Research is needed to establish best practices to rear the calves whilst improving the welfare, health, and growth of dairy calves. Therefore the aim of this experiment was to investigate the effect of individual or group housing (from 4 weeks) on performance, blood parameters, ruminal fermentation, behavior, and health of dairy calves.Materials and Methods: A total of 32 Holstein calves were separated from their dams immediately after birth, weighed, and placed in individual pens. Then at 28 ± 2 d, calves were randomly assigned to either an individual pen (n = 16 calves, 1.5×2 m2) or group pen (4 calves/pen, n = 16 calves, 3×4 m2). All calves were offered a step-up/step-down method of milk feeding (4, 6, 8, 6, 4, and 2 L/d) and weaned at d 63. The study finished when calves reached 90 d of age. Feed intake was determined daily. Calves were weighed at birth, 28, 63, and 90 d of the age. Body measurements including body length, body girth, withers height, heart girth, hip height, and hip width of the calves were measured at the start and end of the study. Blood samples were collected at d 4 before and d 4 after weaning for measurement of glucose, cholesterol, and BUN concentration. Behavior parameters (playing, cross-sucking, grooming, and non-nutritive oral behavior) were monitored by visual observations of all calves at the 60 and 89 d of age for a period of 24 h. Calf health was checked every day for fecal scoring, general appearance scoring, and respiratory scoring. Also, diarrhea and pneumonia diagnoses and treatment of calves were recorded. On 50 and 80 d of age, ruminal fluid samples were collected from male calves for the measurement of pH and analysis of volatile fatty acids.Results and Discussion: There was no significant difference between housing for starter intake, total dry matter intake, and ADG during pre-weaning, post-weaning, and the total period of the study. Also, BW (birth, 28, 63, and 90 d) and skeletal growth (initial and final of the study) were not affected by housing. We observed no housing effect on glucose and BUN plasma, however, cholesterol concentration was greater in individual calves than group calves at pre- and post-weaning, which is probably related to the greater stress of individual calves than group calves during weaning. Ruminal pH, total VFA concentration, the concentration of acetate, propionate, butyrate, iso-butyrate, isovalerate, valerate, and acetate to propionate ratio in ruminal fluid were similar between treatments. There was no difference between treatments for the frequency and number of days with general appearance (score ≥2), diarrhea (score ≥3), and pneumonia, as well as medicated days for both diarrhea and pneumonia during the pre-weaning, post-weaning, and total period of the experiment, indicating that calves, in general, were healthy. These results are probably attributed to good management of colostrum feeding, bedding, hygiene, regular health monitoring and disease diagnosis, and small group size. In the current study, non-nutritive oral behaviors were greater in individual calves than group calves during pre-weaning. However, cross-sucking, grooming, and playing activities were greater in group calves than individual calves during pre-weaning. During post-weaning, behaviors were not affected by housing. Behavioral results show that group housing improves the welfare of calves at weaning.Conclusion: In general, the results showed that type of housing (group or individual) did not affect performance, rumen fermentation, and health of calves. While group housing can lead to improving the welfare of calves (increase the play and grooming, and decrease the non-nutritive oral behaviors).We suggested that calves can be grouped in good health if housing is properly managed
Refining the Deep Brain Stimulation Target within the Limbic Globus Pallidus Internus for Tourette Syndrome
BACKGROUND: Deep brain stimulation (DBS) in patients with severe, refractory Tourette syndrome (TS) has demonstrated promising but variable results thus far. The thalamus and anteromedial globus pallidus internus (amGPi) have been the most commonly stimulated sites within the cortico-striato thalamic circuit, but an optimal target is yet to be elucidated. OBJECTIVES: This study of 15 patients with long-term amGPi DBS for severe TS investigated whether a specific anatomical site within the amGPi correlated with optimal clinical outcome for the measures of tics, obsessive compulsive behaviour (OCB), and mood. METHODS: Validated clinical assessments were used to measure tics, OCB, quality of life, anxiety, and depression before DBS and at the latest follow-up (17-82 months). Electric field simulations were created for each patient using information on electrode location and individual stimulation parameters. A subsequent regression analysis correlated these patient-specific simulations to percentage changes in outcome measures in order to identify any significant voxels related to clinical improvement. RESULTS: A region within the ventral limbic GPi, specifically on the medial medullary lamina in the pallidum at the level of the AC-PC, was significantly associated with improved tics but not mood or OCB outcome. CONCLUSIONS: This study adds further support to the application of DBS in a tic-related network, though factors such as patient sample size and clinical heterogeneity remain as limitations and replication is required
Face perception enhances insula and motor network reactivity in Tourette syndrome
Tourette syndrome is a neurodevelopmental disorder, characterised by motor and phonic tics. Tics are typically experienced as avolitional, compulsive, and associated with premonitory urges. They are exacerbated by stress and can be triggered by external stimuli, including social cues like the actions and facial expressions of others. Importantly, emotional social stimuli, with angry facial stimuli potentially the most potent social threat cue, also trigger behavioural reactions in healthy individuals, suggesting that such mechanisms may be particularly sensitive in people with Tourette syndrome. Twenty-one participants with Tourette syndrome and 21 healthy controls underwent functional magnetic resonance imaging while viewing faces wearing either neutral or angry expressions to quantify group differences in neural activity associated with processing social information. Simultaneous video recordings of participants during neuroimaging enabled us to model confounding effects of tics on task-related responses to the processing of faces. In both Tourette syndrome and control participants, face stimuli evoked enhanced activation within canonical face perception regions, including the occipital face area and fusiform face area. However, the Tourette syndrome group showed additional responses within the anterior insula to both neutral and angry faces. Functional connectivity during face viewing was then examined in a series of psychophysiological interactions. In Tourette syndrome participants, the insula showed functional connectivity with a set of cortical regions previously implicated in tic generation: the pre-supplementary motor area, premotor cortex, primary motor cortex, and the putamen. Furthermore, insula functional connectivity with the globus pallidus and thalamus varied in proportion to tic severity, while supplementary motor area connectivity varied in proportion to premonitory sensations, with insula connectivity to these regions increasing to a greater extent in patients with worse symptom severity. In addition, the occipital face area showed increased functional connectivity in Tourette syndrome participants with posterior cortical regions, including primary somatosensory cortex, and occipital face area connectivity with primary somatosensory and primary motor cortices varied in proportion to tic severity. There were no significant psychophysiological interactions in controls. These findings highlight a potential mechanism in Tourette syndrome through which heightened representation within insular cortex of embodied affective social information may impact the reactivity of subcortical motor pathways, supporting programmed motor actions that are causally implicated in tic generation. Medicinal and psychological therapies that focus on reducing insular hyper-reactivity to social stimuli may have potential benefit for tic reduction in people with Tourette syndrome
Microwave-Assisted Topochemical Manipulation of Layered Oxide Perovskites: From Inorganic Layered Oxides to Inorganic-Organic Hybrid Perovskites and Functionalized Metal-Oxide Nanosheets
Developing new materials with desired properties is a vital component of emerging technologies. Functional hybrid compounds make an important class of advanced materials that let us synergistically utilize the key features of the organic and inorganic counterparts in a single composite, providing a very strong tool to develop new materials with ”engineered” properties. The research presented here, summarizes efforts in the development of facile and efficient methods for the fabrication of three- and two-dimensional inorganic-organic hybrids based on layered oxide perovskites. Microwave radiation was exploited to rapidly fabricate and modify new and known materials. Despite the extensive utilization of microwaves in organic syntheses as well as the fabrication of the inorganic solids, the work herein was among the first reported that used microwaves in topochemical modification of the layered oxide perovskites. Our group specifically was the first to perform rapid microwave-assisted reactions in all of the modification steps including proton exchange, grafting, intercalation, and exfoliation, which decreased the duration of multi-step modification procedures from weeks to only a few hours. Microwave-assisted grafting and intercalation reactions with n-alkyl alcohols and n-alkylamines, respectively, were successfully applied on double-layered Dion-Jacobson and Ruddlesden-Popper phases (HLaNb2O7, HPrNb2O7, and H2CaTa2O7), and with somewhat more limited reactivity, applied to triple-layered perovskites (HCa2Nb3O10 and H2La2Ti3O10). Performing neutron diffraction on n-propoxy-LaNb2O7, structure refinement of a layered hybrid oxide perovskite was then tried for the first time. Furthermore, two-dimensional hybrid oxides were efficiently prepared from HLnNb2O7 (Ln = La, Pr), HCa2Nb3O10, HCa2Nb2FeO9, and HLaCaNb2MnO10, employing facile microwave-assisted exfoliation and post-exfoliation surface-modification reactions for the first time. A variety of surface groups, saturated or unsaturated linear and cyclic organics, were successfully anchored onto these oxide nanosheets. Properties of various functionalized metal-oxide nanosheets, as well as the polymerization of some monomer-grafted nanosheets, were then investigated for the two-dimensional hybrid systems
The Use of Deep Brain Stimulation in Tourette Syndrome
Tourette syndrome (TS) is a childhood neurobehavioural disorder, characterised by the presence of motor and vocal tics, typically starting in childhood but persisting in around 20% of patients into adulthood. In those patients who do not respond to pharmacological or behavioural therapy, deep brain stimulation (DBS) may be a suitable option for potential symptom improvement. This manuscript attempts to summarise the outcomes of DBS at different targets, explore the possible mechanisms of action of DBS in TS, as well as the potential of adaptive DBS. There will also be a focus on the future challenges faced in designing optimized trials
Inter and intra-Rater Reliability of Accuracy of Testicular volume Evaluation (IRRATE): a simulation study
Background: The measurement of testicular volume is a practical and inexpensive method of pubertal staging in adolescents. Traditionally, volume is measured using orchidometers or calipers, the most widely used of which is the Prader Orchidometer. However, there is conflicting evidence of its use with regards to reliability in different hands.
Objectives: To determine the accuracy of the Prader orchidometer in measuring testicular volume, by comparing the resultant measurement with the actual testicular volumes. Information on inter-observer and intra-observer variation was obtained for 16 investigators. Furthermore, the effect of factors such as clinical experience, gender and training in using an orchidometer on the accuracy of testicular volume measurement were investigated.
Methods: A total of 16 investigators were asked to measure a range of 4 testicular volumes, attached via prosthesis to child-sized mannequins. The volume of each testis was measured independently using the Prader Orchidometer. A proportion of investigators also repeated testicular volume measurements, blinded by measurements obtained by other investigators.
Results: The mean testicular volume measured by 16 examiners for 4 sizes at 20ml, 10ml, 5ml and 3ml. There were 4 male investigators and 12 female investigators. Fischer’s exact test found males to be significantly more accurate at measuring testicular volume than females (P =0.04).
Chi-squared values were measured at each volume and showed no significant difference between those with clinical paediatric endocrine experience compared with those with no experience. Inter-observer reliability was measured using coefficient of variation due to our sample size of 16. This showed no significant difference between investigators measuring each testicular volume. However, it showed that larger volume testicles were more likely to be accurately measured compared to smaller volumes. Results showed that the 20ml volume had the smallest variability of 0.109 and 0.130 for right and left respectively ad the 3ml volume had a higher variation at 0.456 and 0.559 for right and left testicles respectively. Interestingly, variation was higher at all volumes in the left testicle. Furthermore, the 5ml volume has an unexpectedly low variability which may be attributed to its link with puberty and the need for endocrinologists to be skilledat identifying this particular volume due it’s clinical relevance. 7 people were trained vs 9 untrained in using orchidometers. Orchidometer training R20 A
3 B
10 C
5 D
L20 A
3 B
10 C
5 D
% accuracy trained
3/7
42.9
2/7
28.6
5/7
71.4
2/7
28.6
6/7
85.7
FE:
4/7
57.1
FE:
6/7
85.7
FE:
2/7
28.6
FE:
%accuracy not trained
7/9
77.8
2/9
22.2
3/9
33.3
2/9
22.2
5/9
55.6
3/9
33.3
3/9
33.3
2/9
22.2
FE
0.302
1.00
0.315
1.00
0.308
0.615
0.060
1.000
Fischer’s exact: does having orchidometer training affect accuracy of results- not significant.
Conclusion
In conclusion, it was found that measurement of testicular volumes on paediatric testicular models is subject to great/little inter/intra-observer variation. The data suggests that there is a clinical need for formal training in testicular volume measurement as there is currently no established training in place. As a result, the innovative, custom-made testicular models for this study could have a role in simulation training as an educational tool
Rapid Topochemical Modification of Layered Perovskites via Microwave Reactions
An effective microwave
approach to the topochemical modification of different layered oxide
perovskite hosts is presented where cation exchange, grafting, and
intercalation reactions with acid, <i>n</i>-alkyl alcohols,
and <i>n</i>-alkylamines, respectively, are successfully
carried out. Microwave-assisted proton exchange reactions involving
double- and triple-layered Dion–Jacobson and Ruddlesden–Popper
perovskite family members, RbLnNb<sub>2</sub>O<sub>7</sub> (Ln = La,
Pr), KCa<sub>2</sub>Nb<sub>3</sub>O<sub>10</sub>, Li<sub>2</sub>CaTa<sub>2</sub>O<sub>7</sub>, and Na<sub>2</sub>La<sub>2</sub>Ti<sub>3</sub>O<sub>10</sub>, were found to be quite efficient, decreasing reaction
times from several days to ≤3 h. Grafting and intercalation
reactions involving double-layered perovskites were also quite rapid
with full conversions occurring in as fast as an hour. Interestingly,
triple-layered hosts were found to show different behavior; when complete
intercalations were possible, grafting reactions were limited at best.
Utilization of this rapid synthetic approach could help facilitate
the fabrication of new organic–inorganic hybrids