80 research outputs found

    Low-Load Metal-Assisted Catalytic Etching Produces Scalable Porosity in Si Powders

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    The recently discovered low-load metal-assisted catalytic etching (LL-MACE) creates nanostructured Si with controllable and variable characteristics that distinguish this technique from the conventional high-load variant. LL-MACE employs 150 times less metal catalyst and produces porous Si instead of Si nanowires. In this work, we demonstrate that some of the features of LL-MACE cannot be explained by the present understanding of MACE. With mechanistic insight derived from extensive experimentation, it is demonstrated that (1) the method allows the use of not only Ag, Pd, Pt, and Au as metal catalysts but also Cu and (2) judicious combinations of process parameters such as the type of metal, Si doping levels, and etching temperatures facilitate control over yield (0.065−88%), pore size (3−100 nm), specific surface area (20−310 m2·g−1), and specific pore volume (0.05−1.05 cm3·g−1). The porous structure of the product depends on the space-charge layer, which is controlled by the Si doping and the chemical identity of the deposited metal. The porous structure was also dependent on the dynamic structure of the deposited metal. A distinctive comet-like structure of metal nanoparticles was observed after etching with Cu, Ag, Pd, and, in some cases, Pt; this structure consisted of 10−50 nm main particles surrounded by smaller (\u3c5 nm) nanoparticles. With good scalability and precise control of structural properties, LL-MACE facilitates Si applications in photovoltaics, energy storage, biomedicine, and water purification

    Paneelikeskustelu ortodoksisen kirkkokunnan asetuksen ja pappiskoulutuksen juhlaseminaarissa "1918 ja ortodoksit": ItÀ-Suomen yliopisto 20.4.2018

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    Pre- and postdiagnosis growth failure, adult short stature, and untreated growth hormone deficiency in radiotherapy-treated long-term survivors of childhood brain tumor

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    PurposeGrowth failure is common in radiotherapy-treated long-term survivors of pediatric brain tumors, but studies on longitudinal growth in this patient group are lacking. Here, the aim was to assess the changes in growth patterns before and after brain tumor diagnosis, the adult height, and the risk factors for compromised growth. The incidence and treatment practices of growth hormone deficiency were analyzed.MethodsA cohort of 73 survivors of childhood brain tumor (median age 27.2 years, range 16.2 to 43.8 years) was studied after a median follow-up period of 20.4 years from diagnosis (IQR 14.9 to 22.9 years). Patients were treated in five university hospitals in Finland between 1970 and 2008. Growth curves, final height, and patient- and disease-related risk factors for compromised growth during different growth periods were analyzed. Laboratory analyses for IGF-1 and IGFBP-3 were performed at the follow-up.ResultsGrowth failure was evident at diagnosis, with a mean height decline of -0.6 SDS (standard deviation score) from birth (95% CI -1.15 to -0.05). Mean height SDS decline after the diagnosis was -1.09 SDS (95%CI -1.51 to -0.66). At follow-up, 37% of the study subjects (27/73) had true short stature (height ConclusionLongitudinal growth impairment was common in radiotherapy-treated survivors of childhood brain tumor, resulting in compromised adult height. Loss of growth potential was evident already at diagnosis and further accelerated by the treatments. At young adulthood, unrecognized growth hormone deficiency was common.</p

    Pre- And postdiagnosis growth failure, adult short stature, and untreated growth hormone deficiency in radiotherapy-treated long-term survivors of childhood brain tumor

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    Purpose Growth failure is common in radiotherapy-treated long-term survivors of pediatric brain tumors, but studies on longitudinal growth in this patient group are lacking. Here, the aim was to assess the changes in growth patterns before and after brain tumor diagnosis, the adult height, and the risk factors for compromised growth. The incidence and treatment practices of growth hormone deficiency were analyzed. Methods A cohort of 73 survivors of childhood brain tumor (median age 27.2 years, range 16.2 to 43.8 years) was studied after a median follow-up period of 20.4 years from diagnosis (IQR 14.9 to 22.9 years). Patients were treated in five university hospitals in Finland between 1970 and 2008. Growth curves, final height, and patient- and disease-related risk factors for compromised growth during different growth periods were analyzed. Laboratory analyses for IGF-1 and IGFBP-3 were performed at the follow-up. Results Growth failure was evident at diagnosis, with a mean height decline of -0.6 SDS (standard deviation score) from birth (95% CI -1.15 to -0.05). Mean height SDS decline after the diagnosis was -1.09 SDS (95%CI -1.51 to -0.66). At follow-up, 37% of the study subjects (27/73) had true short stature (height < -2 SDS). The mean height deficit corrected for target height was -1.9 SDS (95% CI -1.45 to -2.40). Growth failure was associated with the age at diagnosis, corticosteroid dose, radiotherapy modality and mean dose of irradiation in the thalamic area. Low IGF-1 level (below -2.0 SDS) was found in 32% (23/72), and untreated growth hormone deficiency in 40% (29/72) of the subjects. Conclusion Longitudinal growth impairment was common in radiotherapy-treated survivors of childhood brain tumor, resulting in compromised adult height. Loss of growth potential was evident already at diagnosis and further accelerated by the treatments. At young adulthood, unrecognized growth hormone deficiency was common.publishedVersionPeer reviewe

    Neurocognitive impairment, employment, and social status in radiotherapy-treated adult survivors of childhood brain tumors

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    Background. Little is known of the cognitive functions, employment, and social status in adult survivors of childhood brain tumor (BT). We aimed to determine the long-term neurocognitive profile of radiotherapy-treated adult survivors of childhood BT and the relationship between cognitive functions and employment and social status. Methods. Neurocognitive profiles of survivors were assessed in a Finnish national cohort of 71 radiotherapy-treated survivors of childhood BT (median follow-up time: 21 years [range: 5-33 years]) using a cross-sectional design. Neurocognitive outcomes were compared to control (n = 45) and normative values. Tumor- and treatment-related data were collected from the patient files. Information on employment and social status was gathered. Results. Survivors' (median age: 27 years [range: 16-43 years]) median verbal and performance intelligence quotient (IQ) was 90 (range: 49-121) and 87 (range: 43-119), respectively. The cognitive domains with the greatest impairment were executive functions (median z score, 3.5 SD [range: -25.0 to 1.3 SD]), and processing speed and attention (median z score, -2.5 SD [range: -24.9 to 0.5 SD]). Executive functions were associated with employment, educational level, living independently, having an intimate relationship, and having a driving license. Processing speed and attention were related to educational level, living independently, having an intimate relationship, and having a driving license. Performance IQ was associated with educational level and employment status. Working memory was associated with educational level and living independently. Conclusions. Radiotherapy-treated adult survivors of childhood BT experience significant neurocognitive impairment, which is associated with difficulties related to employment and social status.Peer reviewe

    Colonic Delivery of α-Linolenic Acid by an Advanced Nutrient Delivery System Prolongs Glucagon-Like Peptide-1 Secretion and Inhibits Food Intake in Mice

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    ScopeNutrients stimulate the secretion of glucagon-like peptide-1 (GLP-1), an incretin hormone, secreted from enteroendocrine L-cells which decreases food intake. Thus, GLP-1 analogs are approved for the treatment of obesity, yet cost and side effects limit their use. L-cells are mainly localized in the distal ileum and colon, which hinders the utilization of nutrients targeting GLP-1 secretion. This study proposes a controlled delivery system for nutrients, inducing a prolonged endogenous GLP-1 release which results in a decrease food intake.Methods and Resultsα-Linolenic acid (αLA) was loaded into thermally hydrocarbonized porous silicon (THCPSi) particles. In vitro characterization and in vivo effects of αLA loaded particles on GLP-1 secretion and food intake were studied in mice. A total of 40.4 ± 3.2% of loaded αLA is released from particles into biorelevant buffer over 24 h, and αLA loaded THCPSi significantly increased in vitro GLP-1 secretion. Single-dose orally given αLA loaded mesoporous particles increased plasma active GLP-1 levels at 3 and 4 h and significantly reduced the area under the curve of 24 h food intake in mice.ConclusionsαLA loaded THCPSi particles could be used to endogenously stimulate sustain gastrointestinal hormone release and reduce food intake.</p

    Late vertebral side effects in long-term survivors of irradiated childhood brain tumor

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    Purpose: Long-term side effects of the treatments are common in survivors of irradiated pediatric brain tumors. Ionizing radiation in combination with surgery and chemotherapy during childhood may reduce vertebral height and bone mineral density (BMD), and cause growth failure. The aim of this study was to evaluate the late consequences of tumor treatments on vertebrae in survivors of childhood brain tumors.Methods: 72 adult survivors (mean age 27.8 years, standard deviation 6.7) of irradiated childhood brain tumor were studied by spinal magnetic resonance imaging (MRI) for vertebral abnormalities from the national cohort of Finland. Patients were treated in five university hospitals in Finland between the years 1970 and 2008. Subject height and weight were measured and body mass index (BMI) was calculated. The morphology and height/ depth ratio of the vertebrae in the middle of the kyphotic thoracic curvature (Th8) and lumbar lordosis (L3) were examined. Vertebrae were analyzed by Genant's semiquantative (SQ) method and spinal deformity index (SDI) was calculated. BMD was measured by using dual X-ray absorptiometry.Results: 4.2% (3/72) of the patients had undiagnosed asymptomatic vertebral fracture and 5.6% (4/72) of patients had radiation- induced decreased vertebral body height. Male patients had flatter vertebrae compared with females. Patient age at the time of irradiation, BMI and irradiation area correlated to vertebral morphology differentially in males and females. BMD had no association with the vertebral shape. Patients who had received craniospinal irradiation were shorter than the general population.Conclusion: Childhood brain tumor survivors had a high number of vertebral abnormalities in young adulthood. Irradiation was associated with abnormal vertebral morphology and compromised final height. Male gender may predispose vertebrae to the side effects of irradiation.</div

    Early fecal microbiota composition in children who later develop celiac disease and associated autoimmunity

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    Objectives: Several studies have reported that the intestinal microbiota composition of celiac disease (CD) patients differs from healthy individuals. The possible role of gut microbiota in the pathogenesis of the disease is, however, not known. Here, we aimed to assess the possible differences in early fecal microbiota composition between children that later developed CD and healthy controls matched for age, sex and HLA risk genotype.Materials and methods: We used 16S rRNA gene sequencing to examine the fecal microbiota of 27 children with high genetic risk of developing CD. Nine of these children developed the disease by the age of 4 years. Stool samples were collected at the age of 9 and 12 months, before any of the children had developed CD. The fecal microbiota composition of children who later developed the disease was compared with the microbiota of the children who did not have CD or associated autoantibodies at the age of 4 years. Delivery mode, early nutrition, and use of antibiotics were taken into account in the analyses.Results: No statistically significant differences in the fecal microbiota composition were found between children who later developed CD (n = 9) and the control children without disease or associated autoantibodies (n = 18).Conclusions: Based on our results, the fecal microbiota composition at the age of 9 and 12 months is not associated with the development of CD. Our results, however, do not exclude the possibility of duodenal microbiota changes or a later microbiota-related trigger for the disease.</p
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