The origin ofhigh hydraulic resistance for filter cakes ofdef ormable particles: cell-bed deformation or surface-layer effect?

This study reports a numerical approach for modeling the hydraulic resistance ofa filter cake ofdef ormable cells. First, a mechanical and osmotic model that describes the volume fraction ofsolids in a bed ofyeast cells as a function ofthe compressive pressure it experiences is presented. The effects ofpressure on the compressibility ofyeast cells beds were further investigated both by filtration experiments and by centrifugal experiments based on the multiple speed equilibrium sediment height technique. When comparing the latter measurements with compression model calculations, we observed that the method based on centrifugal experiments suffers from rapid relaxation of the compressed bed. Concerning the filtration experiments, specific resistance ofwell-defined bed ofcells were calculated by a combination of the compression model with a formulation for hydraulic resistivity developed using the Lattice Boltzmann method. We further explain the experimental values observed for the hydraulic resistance ofcell beds, assuming that the first layer ofcells in contact with the membrane partially blocks the membrane area open to flow. In such a case, the blocked area seems to be a constant fraction of the normal cell–cell contact area

Lunar laser ranging in infrfared at hte Grasse laser station

For many years, lunar laser ranging (LLR) observations using a green wavelength have suffered an inhomogeneity problem both temporally and spatially. This paper reports on the implementation of a new infrared detection at the Grasse LLR station and describes how infrared telemetry improves this situation. Our first results show that infrared detection permits us to densify the observations and allows measurements during the new and the full Moon periods. The link budget improvement leads to homogeneous telemetric measurements on each lunar retro-reflector. Finally, a surprising result is obtained on the Lunokhod 2 array which attains the same efficiency as Lunokhod 1 with an infrared laser link, although those two targets exhibit a differential efficiency of six with a green laser link

Stronger diversity effects with increased environmental stress : a study of multitrophic interactions between oak, powdery mildew and ladybirds

Recent research has suggested that increasing neighbourhood tree species diversity may mitigate the impact of pests or pathogens by supporting the activities of their natural enemies and/or reducing the density of available hosts. In this study, we attempted to assess these mechanisms in a multitrophic study system of young oak (Quercus), oak powdery mildew (PM, caused by Erysiphe spp.) and a mycophagous ladybird (Psyllobora vigintiduo-punctata). We assessed ladybird mycophagy on oak PM in function of different neighbourhood tree species compositions. We also evaluated whether these species interactions were modulated by environmental conditions as suggested by the Stress Gradient Hypothesis. We adopted a complementary approach of a field experiment where we monitored oak saplings subjected to a reduced rainfall gradient in a young planted forest consisting of different tree species mixtures, as well as a lab experiment where we independently evaluated the effect of different watering treatments on PM infections and ladybird mycophagy. In the field experiment, we found effects of neighbourhood tree species richness on ladybird mycophagy becoming more positive as the target trees received less water. This effect was only found as weather conditions grew drier. In the lab experiment, we found a preference of ladybirds to graze on infected leaves from trees that received less water. We discuss potential mechanisms that might explain this preference, such as emissions of volatile leaf chemicals. Our results are in line with the expectations of the Natural Enemies Hypothesis and support the hypothesis that biodiversity effects become stronger with increased environmental stress

PERBANDINGAN DAMPAK KESEHATAN ANTARA ROKOK ELEKTRIK DENGAN ROKOK KONVENSIONAL: STUDI META-ANALISIS

Perilaku merokok merupakan masalah kesehatan masyarakat yang paling umum dan menjadi perhatian global saat ini. Di seluruh dunia, pengguanaan tembakau menyebabkan lebih dari 7 juta kematian per tahun. Perokok sendiri dibagi menjadi dua berdasarkan jenis dan bentuk rokok yang dikonsumsi yakni rokok konvensional dan rokok elektrik. Rokok elektrik dianggap lebih aman daripada rokok konvensional atau tembakau karena tidak mengandung tar dan karbon monoksida. Namun, penelitian lain menemukan bahwa rokok elektrik tetap memiliki kandungan nikotin dan bahan kimia lain yang dapat berbahaya bagi kesehatan. Tujuan dari penelitian ini adalah untuk mengetahui perbandingan dampak kesehatan antara rokok elektrik dan rokok konvensional melalui pendekatan meta-analisis. Metode yang digunakan adalah meta-analisis dengan menganalisis data dari berbagai studi yang relevan. Hasil menunjukan bahwa ukuran efek dampak kesehatan dari kedua jenis rokok tergolong kecil, dengan nilai effect size antara 0,12 hingga 0,32, dan perbedaan tidak signifikan secara statistik (p-velue = 0,58) model efek acak digunakan dalam analisis akibat heterogenitas yang cukup tinggi antar studi. Meskipun rokok elektrik sering dianggap lebih aman, dampak kesehatan dari kedua jenis rokok tersebut tidak signifikan. Pemerintah dan lembaga kesehatan disarankan untuk memperkatat regulasi terhadap rokok elektrik, termasuk, termasuk pengawasan kandungan kimia dan nikotin. Edukasi kepada masyarakat tentang potensi risiko keduajenis rokok juga diperlukan

VARX Granger Analysis: Modeling, Inference, and Applications

Complex systems, such as brains, markets, and societies, exhibit internal dynamics influenced by external factors. Disentangling delayed external effects from internal dynamics within these systems is often challenging. We propose using a Vector Autoregressive model with eXogenous input (VARX) to capture delayed interactions between internal and external variables. While this model aligns with Granger's statistical formalism for testing "causal relations", the connection between the two is not widely understood. Here, we bridge this gap by providing fundamental equations, user-friendly code, and demonstrations using simulated and real-world data from neuroscience, physiology, sociology, and economics. Our examples illustrate how the model avoids spurious correlation by factoring out external influences from internal dynamics, leading to more parsimonious explanations of the systems. We also provide methods for enhancing model efficiency, such as L2 regularization for limited data and basis functions to cope with extended delays. Additionally, we analyze model performance under various scenarios where model assumptions are violated. MATLAB, Python, and R code are provided for easy adoption: https://github.com/lcparra/var

Identification of metabolic engineering targets through analysis of optimal and sub-optimal routes

Identification of optimal genetic manipulation strategies for redirecting substrate uptake towards a desired product is a challenging task owing to the complexity of metabolic networks, esp. in terms of large number of routes leading to the desired product. Algorithms that can exploit the whole range of optimal and suboptimal routes for product formation while respecting the biological objective of the cell are therefore much needed. Towards addressing this need, we here introduce the notion of structural flux, which is derived from the enumeration of all pathways in the metabolic network in question and accounts for the contribution towards a given biological objective function. We show that the theoretically estimated structural fluxes are good predictors of experimentally measured intra-cellular fluxes in two model organisms, namely, Escherichia coli and Saccharomyces cerevisiae. For a small number of fluxes for which the predictions were poor, the corresponding enzyme-coding transcripts were also found to be distinctly regulated, showing the ability of structural fluxes in capturing the underlying regulatory principles. Exploiting the observed correspondence between in vivo fluxes and structural fluxes, we propose an in silico metabolic engineering approach, iStruF, which enables the identification of gene deletion strategies that couple the cellular biological objective with the product flux while considering optimal as well as sub-optimal routes and their efficiency.This work was supported by the Portuguese Science Foundation [grant numbers MIT-Pt/BS-BB/0082/2008, SFRH/BPD/44180/2008 to ZS] (http://www.fct.pt/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Yeasts as biocatalysts in the stereoselective reduction of acetophnone

Fil: Decarlini, M. F. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Manzoni, C. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Medici, E. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Vazquez, A. M. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Aimar, M. L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Química. Cátedra de Química Aplicada; Argentina.The asymmetric reduction of prochiral ketones represents a pivotal transformation for the production of chiral alcohols. Several of them are considered as key starting materials in obtaining of pharmaceuticals. Nowadays, bio-reductions are an important component of organic synthesis for the production of drugs. In this sense, microorganisms are considered an outstanding tool for the obtaining of these chiral building blocksFil: Decarlini, M. F. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Manzoni, C. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Medici, E. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Vazquez, A. M. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Aimar, M. L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Química. Cátedra de Química Aplicada; Argentina.Otras Ciencias Química

In vivo magnetic resonance spectroscopy in the brain of Cdkl5 null mice reveals a metabolic profile indicative of mitochondrial dysfunctions

Mutations in the X‐linked CDKL5 gene cause CDKL5 deficiency disorder (CDD), a severe neurodevelopmental condition mainly characterized by infantile epileptic encephalopathy, intellectual disability, and autistic features. The molecular mechanisms underlying the clinical symptoms remain largely unknown and the identification of reliable biomarkers in animal models will certainly contribute to increase our comprehension of CDD as well as to assess the efficacy of therapeutic strategies. Here, we used different Magnetic Resonance (MR) methods to disclose structural, functional, or metabolic signatures of Cdkl5 deficiency in the brain of adult mice. We found that loss of Cdkl5 does not cause cerebral atrophy but affects distinct brain areas, particularly the hippocampus. By in vivo proton‐MR spectroscopy (MRS), we revealed in the Cdkl5 null brain a metabolic dysregulation indicative of mitochondrial dysfunctions. Accordingly, we unveiled a significant reduction in ATP levels and a decrease in the expression of complex IV of mitochondrial electron transport chain. Conversely, the number of mitochondria appeared preserved. Importantly, we reported a significant defect in the activation of one of the major regulators of cellular energy balance, the adenosine monophosphate‐activated protein kinase (AMPK), that might contribute to the observed metabolic impairment and become an interesting therapeutic target for future preclinical trials. In conclusion, MRS revealed in the Cdkl5 null brain the presence of a metabolic dysregulation suggestive of a mitochondrial dysfunction that permitted to foster our comprehension of Cdkl5 deficiency and brought our interest towards targeting mitochondria as therapeutic strategy for CDD

Control of Panicum maximum in sugar cane with preemergence herbicides

Avaliou-se a eficácia dos herbicidas imazapic, imazapyr e pendimethalin, aplicados em pré-ernergência na cultura da cana-de-açúcar, para controle de capim-colonião (Panicum maximum Jacq.).O trabalho foi realizado na Usina São Carlos, Jaboticabal-SP, em solo de classe textural argilosa. O delineamento experimental utilizado foi o de blocos ao acaso com quatro repetições. Os tratamentos foram: imazapic (73,5 e 98 g/ha), imazapyr (122 e 147 g/ha), imazapic+pendimethalin (50+ 1000 e 60+ 1200 g/ha) e pendimethalin (1200 g/ha), além das testemunhas capinada e sem capinas. Para aplicação dos herbicidas foi utilizado um pulverizador costal, à pressão constante (mantida por ar comprimido) de 2,8 kg/cm-, com bicos de jato plano ("leque") DG 11002 e consumo de calda equivalente a 250 l/ha. A variedade de cana-de-açúcar utilizada foi a RB 72454, 3°corte. Tanto o imazapic como o imazapyr proporcionaram resultados considerados muito pobres no controle de P maximum. A mistura de imazapic + pendimethalin apresentou excelente desempenho no controle desta espécie, podendo ser utilizada na menor dose testada. O pendimethalin isolado (1200 g/ha) foi levemente inferior às misturas, mas com resultados ainda considerados muito bons, podendo também ser recomendado para a cultura.The major problem with the sugar cane crop is weed competition, specially Panicum maximum Jacq., which is a very agressive plant. The trial was carried out at Usina São Carlos (a sugar will), in Jaboticabal-SP, during 1998/1999 aiming to study imazapyr and imazapic herbicides, sprayed alone in preemergence, or imazapic in mixture with pendimethalin, for P maximum control. The experimental design was a randomized block with nine treatments and four replications. The treatments were: controls (with and without weeds), imazapic (73.5 and 98 g/ha), imazapyr (122 and 147 g/ha): imazapic+pendimethalin (50+ 1000 and 60+ 1200 g/ha) and pendimethalin (1200 g/ha) at preemergence. The herbicides were applied with a manual sprayer, with constant pressure of 2.8 kg/crrf and jet nozzles with descontinuous deposition (DG11002), using 250 Ilha of the herbicide solution. The sugar-cane variety used was RB 72454. The best preemergence weed control was observed with imazapic+pendimethalim in ali treatments 126 days after application. The postemergence treatment cannot be used because they caused high crop toxicity. The herbicide mixture (imazapic+pendimethalin) showed low efficiency in ali tested treatments