Quantitative measurement of combustion gases in harsh environments using NDIR spectroscopy

The global climate change calls for a more environmental friendly use of energy and has led to stricter limits and regulations for the emissions of various greenhouse gases. Consequently, there is nowadays an increasing need for the detection of exhaust and natural gases. This need leads to an ever-growing market for gas sensors, which, at the moment, is dominated by chemical sensors. Yet, the increasing demands to also measure under harsh environmental conditions pave the way for non-invasive measurements and thus to optical detection techniques. Here, we present the development of a non-dispersive infrared absorption spectroscopy (NDIR) method for application to optical detection systems operating under harsh environments.Comment: 10 pages, 8 figure

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http://tartu.ester.ee/record=b2661982~S

Systemic chemotherapy decreases brain glucose metabolism

Objective: Cancer patients may experience neurologic adverse effects, such as alterations in neurocognitive function, as a consequence of chemotherapy. The mechanisms underlying such neurotoxic syndromes remain poorly understood. We here describe the temporal and regional effects of systemically administered platinum-based chemotherapy on glucose metabolism in the brain of cancer patients. Methods: Using sequential FDG-PET/CT imaging prior to and after administration of chemotherapy, we retrospectively characterized the effects of intravenously administered chemotherapy on brain glucose metabolism in a total of 24 brain regions in a homogenous cohort of 10 patients with newly diagnosed non-small-cell lung cancer. Results: Significant alterations of glucose metabolism were found in response to chemotherapy in all gray matter structures, including cortical structures, deep nuclei, hippocampi, and cerebellum. Metabolic changes were also notable in frontotemporal white matter (WM) network systems, including the corpus callosum, subcortical, and periventricular WM tracts. Interpretation Our data demonstrate a decrease in glucose metabolism in both gray and white matter structures associated with chemotherapy. Among the affected regions are those relevant to the maintenance of brain plasticity and global neurologic function. This study potentially offers novel insights into the spatial and temporal effects of systemic chemotherapy on brain metabolism in cancer patients

Impact of gut hormone FGF-19 on type-2 diabetes and mitochondrial recovery in a prospective study of obese diabetic women undergoing bariatric surgery

Background: The ileal-derived hormone, fibroblast growth factor 19 (FGF-19), may promote weight loss and facilitate type-2 diabetes mellitus remission in bariatric surgical patients. We investigated the effect of different bariatric procedures on circulating FGF-19 levels and the resulting impact on mitochondrial health in white adipose tissue (AT). Methods: Obese and type-2 diabetic women (n = 39, BMI > 35 kg/m2) undergoing either biliopancreatic diversion (BPD), laparoscopic greater curvature plication (LGCP), or laparoscopic adjustable gastric banding (LAGB) participated in this ethics approved study. Anthropometry, biochemical, clinical data, serum, and AT biopsies were collected before and 6 months after surgery. Mitochondrial gene expression in adipose biopsies and serum FGF-19 levels were then assessed. Results: All surgeries led to metabolic improvements with BPD producing the greatest benefits on weight loss (↓30%), HbA1c (↓28%), and cholesterol (↓25%) reduction, whilst LGCP resulted in similar HbA1c improvements (adjusted for BMI). Circulating FGF-19 increased in both BPD and LGCP (χ2(2) = 8.088; P = 0.018), whilst, in LAGB, FGF-19 serum levels decreased (P = 0.028). Interestingly, circulating FGF-19 was inversely correlated with mitochondrial number in AT across all surgeries (n = 39). In contrast to LGCP and LAGB, mitochondrial number in BPD patients corresponded directly with changes in 12 of 14 mitochondrial genes assayed (P < 0.01). Conclusions: Elevated serum FGF-19 levels post-surgery were associated with improved mitochondrial health in AT and overall diabetic remission. Changes in circulating FGF-19 levels were surgery-specific, with BPD producing the best metabolic outcomes among the study procedures (BPD > LGCP > LAGB), and highlighting mitochondria in AT as a potential target of FGF-19 during diabetes remission

Rationalization of excited-state tuning through ultrafast transient absorption and vibrational coherence spectroscopy

Photophysical and-chemical processes make use of light as strongly quantized energy source, rendering mechanisms possible, which involve excited states that are thermally unavailable. This puts them at the heart of many exciting and promising technologies from photovoltaics to photocatalysis and photodynamic therapy. In this work, several strategies to tuning these excited states are rationalized by ultrafast transient absorption and impulsive vibrational spectroscopy, applied to two different classes of samples. Firstly, the excited-state dynamics of two iron(II) complexes are investigated for the tuning effect of solvent choice and ligand design. They toggle on and off the involvement of metal-centered (MC) excited states acting as loss channels for desired metal-to-ligand charge transfer (MLCT) states. Impulsive vibrational spectroscopy is established as suitable method for identifying MLCT-MC transitions in [Fe(bpy)(CN)4]2-, a well-known reference sample. The method is then applied to an iron(II)N-heterocyclic carbene complex and identifies an ultrafast MLCT-MC branching in this promising dye-sensitizer candidate. Secondly, the photophysics and -chemistry of triphenylamine is thoroughly investigated for the influences of solvent, the oxygen content therein and enforced planarity. In n-hexane, triphenylamine is converted to N-phenylcarbazole, with oxygen playing an intricate double role. The conversion is stopped completely by planarization due to the cancellation of p-orbital preorientation. In chloroform, ultrafast electron transfer to the solvent dominates the photochemistry, producing the radical cation leading to chromophore dimerization

Hereditary factors and weight loss

Otyłość jest przewlekłą chorobą, wynikającą z długotrwałej nadwyżki w bilansie energetycznym, spowodowanej wieloma różnorodnymi czynnikami, zarówno genetycznymi, jak i środowiskowymi. Otyłość jest istotną przyczyną chorobowości i śmiertelności w krajach rozwiniętych. Wprowadzenie skutecznych strategii prewencji oraz walki z otyłością powinno być głównym celem opieki zdrowotnej na całym świecie. Utrata, a następnie utrzymanie odpowiedniej masy ciała zależy od wielu, współdziałających ze sobą czynników genetycznych, metabolicznych, psychobehawioralnych i środowiskowych. Odpowiedź na programy powodujące utratę masy ciała świadczy o dużej różnorodności poszczególnych jednostek. Natomiast czynniki predysponujące do utraty masy ciała są nieznane. Ostatnio nastąpił duży postęp w badaniu genetycznie uwarunkowanej otyłości. Opisano już ponad 400 genów kandydatów otyłości. W niniejszym artykule zebrano dostępne dane na temat dziedzicznych czynników wpływających na utratę i utrzymanie masy ciała. W badaniu przeprowadzonym wśród bliźniaków i ich rodzin udowodniono, że otyłość ściśle wiąże się z genotypem. Na wynik postępowania zmniejszającego masę ciała wpływa polimorfizm kilku genów kandydatów otyłości. Niestety, w niektórych dotąd przeprowadzonych badaniach uzyskano dwuznaczne wyniki. Niewątpliwie należy poświęcić więcej uwagi nawykowemu jedzeniu jako głównemu czynnikowi, od którego zależy utrzymanie odpowiedniej masy ciała po schudnięciu, co jest także, nawet w znacznym stopniu, uwarunkowane genetycznie. Osiągnięcie zmniejszenia masy ciała w czasie leczenia otyłości zależy także od zmian w ekspresji genów powodujących otyłość i leptynę indukowanej różnego rodzaju czynnikami środowiskowymi, takimi jak pożywienie oraz aktywność fizyczna. Należy przeprowadzić bardziej wnikliwe badania zależności między genami, kandydatami otyłości oraz czynnikami psychobehawioralnymi i środowiskowymi w celu lepszego zrozumienia uzyskiwanych wyników postępowania redukującego masę ciała w coraz bardziej sprzyjającym otyłości otoczeniu.Obesity is a chronic disease of multifactorial origin arising from a long-term energy imbalance, in which both genetic and environmental factors may be involved. Obesity is an important cause of morbidity and mortality in developed countries. Implementation of effective strategies in prevention and management of obesity should become a major target in the health care systems worldwide. Weight loss and maintenance depend on the interaction of genetic, metabolic, psychobehavioral and environmental factors. Responsiveness to weight reduction programmes shows a wide interindividual variation and reliable weight loss predictors have not been available. Major advances have been made recently in the study of genetics of obesity with more than 400 candidate obesity genes being characterized. This paper summarizes available data on the involvement of hereditary factors in weight loss and maintenance. Twin and family studies demonstrated that the weight loss is strongly controlled by genotype. Polymorphisms in several obesity candidate genes was shown to influence the outcome of weight management. However, several studies yield ambiguous results. It should considered that the eating behaviour as a major predictor of weight loss maintenance is also significantly genetically determined. Weight loss achieved in response to obesity treatment might also be influenced by changes in obesogenic and/or leptogenic genes expression induced by environmental factors such as the type of ingested nutrient and level of physical activity. More comprehensive studies on interaction between candidate obesity genes, psychobehavioral factors and environmental factors are needed for better understanding the outcome of weight management in our increasingly obesogenic environment

Impact of gut hormone FGF-19 on type-2 diabetes and mitochondrial recovery in a prospective study of obese diabetic women undergoing bariatric surgery

The ileal-derived hormone, fibroblast growth factor 19 (FGF-19), may promote weight loss and facilitate type-2 diabetes mellitus remission in bariatric surgical patients. We investigated the effect of different bariatric procedures on circulating FGF-19 levels and the resulting impact on mitochondrial health in white adipose tissue (AT).Obese and type-2 diabetic women (n = 39, BMI > 35 kg/m2) undergoing either biliopancreatic diversion (BPD), laparoscopic greater curvature plication (LGCP), or laparoscopic adjustable gastric banding (LAGB) participated in this ethics approved study. Anthropometry, biochemical, clinical data, serum, and AT biopsies were collected before and 6 months after surgery. Mitochondrial gene expression in adipose biopsies and serum FGF-19 levels were then assessed.All surgeries led to metabolic improvements with BPD producing the greatest benefits on weight loss (↓30%), HbA1c (↓28%), and cholesterol (↓25%) reduction, whilst LGCP resulted in similar HbA1c improvements (adjusted for BMI). Circulating FGF-19 increased in both BPD and LGCP (χ2(2) = 8.088; P = 0.018), whilst, in LAGB, FGF-19 serum levels decreased (P = 0.028). Interestingly, circulating FGF-19 was inversely correlated with mitochondrial number in AT across all surgeries (n = 39). In contrast to LGCP and LAGB, mitochondrial number in BPD patients corresponded directly with changes in 12 of 14 mitochondrial genes assayed (P  LGCP > LAGB), and highlighting mitochondria in AT as a potential target of FGF-19 during diabetes remission