Multilayer gas cells for sub-Doppler spectroscopy

We have carried out theoretical research on ultra-high resolution spectroscopy of atoms (or molecules) in the suggested cell with a series of plane-parallel thin gas layers between spatially separated gas regions of this cell for optical pumping and probing. It is shown the effective velocity selection of optically pumped atoms because of their specific transit time and collisional relaxation in such a cell, which lead to narrow sub-Doppler resonances in absorption of the probe monochromatic light beam. Resolution of this spectroscopic method is analyzed in cases of stationary and definite nonstationary optical pumping of atoms by the broadband radiation versus geometrical parameters of given cells and pumping intensity. The suggested multilayer gas cell is the compact analog of many parallel atomic (molecular) beams and may be used also as the basis of new compact optical frequency standards of high accuracy.Comment: 12 pages, 4 figure

Mapping the landscape of metabolic goals of a cell

Genome-scale flux balance models of metabolism provide testable predictions of all metabolic rates in an organism, by assuming that the cell is optimizing a metabolic goal known as the objective function. We introduce an efficient inverse flux balance analysis (invFBA) approach, based on linear programming duality, to characterize the space of possible objective functions compatible with measured fluxes. After testing our algorithm on simulated E. coli data and time-dependent S. oneidensis fluxes inferred from gene expression, we apply our inverse approach to flux measurements in long-term evolved E. coli strains, revealing objective functions that provide insight into metabolic adaptation trajectories.MURI W911NF-12-1-0390 - Army Research Office (US); MURI W911NF-12-1-0390 - Army Research Office (US); 5R01GM089978-02 - National Institutes of Health (US); IIS-1237022 - National Science Foundation (US); DE-SC0012627 - U.S. Department of Energy; HR0011-15-C-0091 - Defense Sciences Office, DARPA; National Institutes of Health; R01GM103502; 5R01DE024468; 1457695 - National Science Foundatio

Large-Eddy Simulation of Pollutant Dispersion from a Ground-Level Area Source Over Urban Street Canyons with Irreversible Chemical Reactions

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Acclimation responses of gill ionocytes of red tilapia (Oreochromis mossambicus × O. niloticus) to water salinity and alkalinity

To understand the acclimation strategies of red tilapia to different environments, this study aimed to evaluate different responses of red tilapia (O. mossambicus × O. niloticus) to salinity (10-30‰), alkalinity (1-3 gL^-1 NaHCO3) and salinity and alkalinity (10/1-30/3 ‰/gL^-1 NaHCO3) environments. Localization, type, size, and numeration of gill ionocytes were investigated on the same specimens by scanning electron microscopy (SEM) and immunohistochemistry (IHC) with antibodies of Na+/K+-ATPase (NKA), Na+/K+/2Cl-contransporter (NKCC), cystic fibrosis transmembrane conductance regulator (CFTR) and carbonic anhydrase (CA). Ionocytes were only located on filaments conducted by SEM. Four types of ionocytes namely pit, convex, concave and transitory types were determined morphologically by their apical openings of which concave and transitory type were not present in freshwater (FW) and saltwater (SW) fish (10). Both ionocytes size and number increased with elevated stress levels. In comparison to FW, density of ionotypes increased to about 4.75, 3.00 and 3.44 fold in SW (30), AW (3) and S&AW (30/3) respectively. Immunoreactive cells on gill filaments confirmed branchial distribution of ionocytes. Immunoreaction of NKA, NKCC and CA appeared in FW except for CFTR while they all appeared in SW (30), AW (3) and S&AW (30/3)

Dental Biofilm and Laboratory Microbial Culture Models for Cariology Research

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Effect of Silver Diamine Fluoride and Potassium Iodide Treatment on Secondary Caries Prevention and Tooth Discolouration in Cervical Glass Ionomer Cement Restoration

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Prevention of secondary caries by silver diamine fluoride

Purpose: This study aimed to investigate the use of 38% silver diamine fluoride (SDF) as a treatment for preventing secondary caries in glass ionomer cement (GIC) and composite resin (CR) restorations. Methods: Six extracted human sound premolars were collected. Four cavities (4 × 2 × 2 mm3) were prepared on each premolar and then allocated to the following restoration groups: group 1, SDF conditioning and GIC restoration; group 2, GIC restoration; group 3, SDF conditioning and CR restoration; and group 4, CR restoration. After thermal cycling and sterilisation, the teeth were soaked in a 5% sucrose solution containing Streptococcus mutans and Lactobacillus acidophilus for 28 days. Micro-computed tomography was used to study demineralisation. The outer lesion depth (OLD) and wall lesion depth (WLD) of the tooth–restoration interface were measured. The OLD and WLD were directly related to the extent of secondary caries. Two-way analysis of variance was used to analyse the effects of SDF conditioning and restorative materials on OLD. Results: The mean ± standard deviation OLD values were 156 ± 45 μm, 235 ± 33 μm, 153 ± 20 μm and 232 ± 24 μm for groups 1–4, respectively. The OLD was less in restorations with SDF conditioning (P < 0.001) than in those without SDF conditioning. No interaction effect on OLD was found between the restorative materials and SDF conditioning (P = 0.062). The WLD was detected only in groups 3 and 4. Clinical significance: Conditioning with 38% SDF can increase resistance of GIC and CR restorations to secondary caries.postprin

A Review of the Common Models Used in Mechanistic Studies on Demineralization-Remineralization for Cariology Research

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Paediatric Over-the-Counter (OTC) Oral Liquids Can Soften and Erode Enamel

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Effects of Neurotrophin-3 Plasmids on Myocyte Apoptosis and Ca²⁺-ATPase Content in the Muscle After Nerve Injury in Rats

We estimated the influence of plasmids with DNA carrying the neurotrophin-3 (NT-3) gene on apoptosis in the gastrocnemius muscle and content of Ca²⁺-ATPase in the latter after sciatic nerve injury. Sixty adult Wistar rats were randomly divided into the saline (control) and NT-3 groups. The related indices, such as expression of caspase-3 protein, the rate of apoptosis in the muscle evaluated using a TUNEL technique, and the level of Ca²⁺-ATPase estimated using Western blot, were observed. Expression of caspase-3 protein was elevated at different post-operative times after peripheral nerve injury; NT-3 expression and the rate of muscle cell apoptosis decreased, whereas the level of Ca²⁺-ATPase in the sarcoplasmic reticulum increased; significant differences were observed compared with the saline group (P < 0.05). The mitigation mechanism of NT-3 on muscle atrophy after peripheral nerve injury is expressed as inhibition of caspase-3 gene expression, increase in the Ca²⁺-ATPase level, and reduction in the rate of muscle apoptosis.Ми вивчали вплив плазмід із ДНК, що несе ген нейротрофіну-3 (NT-3), на апоптоз міоцитів у m. gastrocnemius та вміст Ca²⁺-ATФази в цьому м’язі після перерізання сідничного нерва. 60 дорослих щурів лінії Вістар були рандомізовано поділені на контрольну (введення фізіологічного розчину) та NT-3-групи. Оцінювали відповідні показники – експресію протеїну каспази-3, рівень апоптозу в м’язі (з використанням TUNEL-методики) та рівень Ca²⁺-ATФази (з використанням Вестерн-блотингу). Експресія білка каспази-3 в різні часові інтервали після пошкодження периферичного нерва була підвищеною; експресія NT-3 та рівень апоптозу м’язових клітин були знижені, а вміст Ca²⁺-ATФази в саркоплазматичному ретикулумі – підвищеним. Відмінності цих показників щодо таких у контрольній групі були вірогідними (P < 0.05). Обмежуючі впливи NT-3 на процес м’язової атрофії після пошкодження периферичного нерва виявлялись як інгібування експресії гена каспази-3, підвищення вмісту Ca²⁺-ATФази та зниження інтенсивності апоптозу в м’язі