ALBERT

Beschreibung: Fluid flow patterns and associated concentration fields in Y-mixers are investigated using lattice Boltzmann method (LBM) -based models. The focus lies on the impact of mixing angle on flow and concentration fields, which is varied between acute (θ = 10°) and obtuse (θ = 130°) angles. Residence time distributions are determined to study the effect of the angles on mixing and velocity patterns, in particular, different flow regimes, namely, stratified laminar, vortex and engulfment. The results from the simulations are validated with literature data and found to be in good agreement. Maximum mixing occurs in the 100 o -obtuse angle Y-mixer, attributed to the extensive engulfment of flows in the mixing channel.

Beschreibung: Pretreatment of lignocellulosic biomass is essential for overcoming its inherent recalcitrance prior to enzymatic hydrolysis and fermentation of its carbohydrate components into biofuels and bioproducts. Among the myriad of existing pretreatment methods, the hot water pretreatment with no-chemical usage is a particularly attractive approach due to its fewer safety and environmental concerns, as well as relative low cost. The hydronium ions dissociated from water at elevated temperatures can catalyze the deconstruction of lignocellulosic biomass into fermentable sugars, digestible cellulose, and lignin fragments. However, a prohibitive amount of sugar degradation products particularly generating in conventional batch systems limit the efficiency of hot water pretreatment. Although the advanced continuous reaction systems like flowthrough systems are prone to reduce the sugar degradation compounds thereby enhancing the sugar recovery, excessive water consumption accompanied with the over dilute sugar streams still impede the implementation of hot water pretreatment to be an economical viable pathway. These limitations of hot water pretreatment are considered to be associated with the scant attention of water-biomass interaction mechanism, as well as the engineering aspects regarding kinetic modeling and reactor configurations. Thus, extrapolating this information from scattered literatures would play a vital role to complete the comprehensive understanding of the hot water pretreatment. This review aims to fill in the blank of those critical factors influencing hot water pretreatment of lignocellulosic biomass, in terms of chemistry and engineering fundamentals to understand the correct axiomatic approaches needed to advance this technology. In particular, various reactor configurations and kinetic models are evaluated herein to explore the optimization strategies of hot water pretreatment toward application.

Beschreibung: Beet Armyworm, Spodoptera exigua is a herbivorous moth and a serious pest of many economically important plants, which are used as food sources. Because of rigorous standards of food quality, usage of synthetic insecticides in crop protection, against pests, is limited. Solanaceae plant extracts may be a relatively cheap source of efficient natural insecticides that can limit usage of synthetic substances. Their biological activity is not fully known. In particular, ultrastructural studies, using transmission electron microscopy, are not usual. In the present article we describe the effects of sublethal concentrations of tomato and potato leaf extracts against S. exigua . Acute lethal effects were not observed. Both extracts exerted similar effects within midgut and fat body cells. Midgut cells were not significantly altered while fat body cells showed prominent swelling of nuclear envelope and endoplasmic reticulum, vacuolization of mitochondria and fusion of fat droplets. These changes were much more intensive within groups exposed to potato than tomato extracts at highest concentration at least. Light microscopy was used to observe and document developmental alterations of S. exigua exposed to potato and tomato leaf extracts. Potato leaf extracts significantly decreased hatching success and caused morphological malformations of imagoes. Among them, malformations of wings were the most prominent. Interestingly, these effects were not observed within populations exposed to tomato extracts at highest concentration at least.

Beschreibung: During the past years cost pressure on the European chemical companies grew dramatically by increased competition from low-labor-cost BRIC countries on the one side and the U.S., favored by decreased energy costs due to shale gas exploitation, on the other side. Raising costs for energy consumption and wages come on top. Lonza, as a mid-sized chemical company located in a high-income-country, faced the need of cost reduction long time before and established highly efficient procedures in both, development and production, with the aim to decrease costs and already successfully applied since years. The paper describes some of the applied techniques in detail and shows their potential in terms of time and cost reduction. Furthermore, Lonza works with great emphasis on future solutions.

Beschreibung: Solid-liquid extraction using a laboratory robot, where anthocyanins are leached from dried red vine leaves ( vitis vinifera ), is evaluated with respect to precision and accuracy. The solid handling of the robot results in standard deviations between ± 0.6 and ± 1.8 depending on the particle size (max. 630 µm). For liquid handling standard deviations are from ± 0.8 to ± 2.6 depending on the volatility of the solvents. The validated, fully automated natural plant extraction-robot shows yields based on dry matter from 1.3 % to 0.8 %, 1.15 % to 0.55 % and 0.4 to 0.15 % for methanol, water (HCl, pH = 2.5) and ethanol and is improving with increasing particle size. Manually performed extraction kinetics experiments are compared with the robot and indicate a variance of 0.1 %. With respect to process intensification, a comparison of yields obtained by microwave and ultrasonic supported extraction in comparison to laboratory robot shaking and stirred single-stage batch experiments was performed.

Beschreibung: Aerial view of pipes of the thermal power plant. © Nickolay Vinokurov/Shutterstock

Beschreibung: Surface ultrastructure of the gills of the angler catfish Chaca chaca was investigated to unravel the adaptive modifications associated with the feeding ecology of the fish. The fish is often found in mud or in soft substrates where they remain buried both for protection and to feed. Gill rakers present on the gill arch in most fish species are absent in this fish. The absence of gill rakers are associated with the feeding habit of the fish and is considered to facilitate the swallowing of captured prey smoothly without any hindrance. Highly corrugated surface of the gill arch and gill filaments could be associated to retain water/mucus to prevent dessicassion of the fish. Papillae like epithelial protuberances each bearing a taste bud at its summit toward the pharyngeal side of the gill arch is associated with the sorting of the food. Large number of mucous goblet cells on the gill arch epithelium are considered to secret copious mucus to lubricate the prey for easy swallowing. In C. chaca the gill septa between gill filaments are reduced. This could enhance the flexibility and permit the free movement of the gill filaments. Extensive secondary lamellae and infrequent mucous goblet cells on secondary lamellae are associated to increase the surface area to enhance efficiency of gaseous exchange.

Beschreibung: In the present research, different adhesive techniques were used to set up fillings with composite resins. After the application of etch and rinse or self etch adhesive technique, marginal adaptation of composite fillings was estimated by the length of margins without gaps, and by the microretention of resin in enamel and dentin. The study material consisted of 40 extracted teeth. Twenty Class V cavities were treated with 35% phosphorous acid and restored after rinsing by Adper Single Bond 2 and Filtek Ultimate - ASB/FU 3M ESPE composite system. The remaining 20 cavities were restored by Adper Easy One - AEO/FU 3M ESPE composite system. Marginal adaptation of composite fillings was examined using a scanning electron microscope (SEM). The etch and rinse adhesive technique showed a significantly higher percentage of margin length without gaps (in enamel: 92.5%, in dentin: 57.3%), compared with the self-etch technique with lower percentage of margin length without gaps, in enamel 70.4% ( p  〈 .001), and in dentin-22.6% ( p  〈 .05). In the first technique, microretention was composed of adhesive and hybrid layers as well as resin tugs in interprismatic spaces of enamel, while the dentin microretention was composed of adhesive and hybrid layers with resin tugs in dentin canals. In the second technique, resin tugs were rarely seen and a microgap was dominant along the border of restoration margins. The SEM analysis showed a better marginal adaptation of composite resin to enamel and dentin with better microretention when the etch and rinse adhesive procedure was applied.

Beschreibung: The purpose of this study was to compare total-etch, self-etch, and selective etching techniques on the marginal microleakage of Class V composite restorations prepared by Er:YAG laser and bur. Class V cavities prepared on both buccal and lingual surfaces of 30 premolars by Er:YAG laser or bur and divided into six groups. The occlusal margins were in enamel, and the cervical margins were in cementum. Group-1: bur preparation(bp)+Adper Single Bond 2 (ASB)+Filtek Z550 (FZ); Group-2: laser preparation(lp)+(ASB)+(FZ); Group-3: bp + Clearfil S3 Bond Plus (CSBP)+(FZ); Group-4: lp+(CSBP) (FZ); Group-5: bp + acid etching+(CSBP)+(FZ); Group-6: lp + acid etching+(CSBP)+(FZ). All teeth were stored in distilled water at 37°C for 24 hr, and then thermocycled 1000 times (5–55°C). Five teeth from each group were chosen for the microleakage investigation, and two teeth for the scanning electron microscope evaluation. Teeth which were prepared for the microleakage test were immersed in .5% methylene blue dye for 24 hr. After immersion, the teeth were sectioned and observed under a stereomicroscope for dye penetration. Data were analyzed using Kruskal–Wallis and Mann–Whitney U tests ( p  〈 .05). More microleakage was observed in the cervical regions compared to the occlusal regions in Groups 3, 5, and 6, respectively ( p  〈 .05). There is no statistically significant difference in Groups 1, 2, and 4, in terms of cervical regions versus occlusal regions ( p  〉 .05). No significant differences were observed among any groups in terms of occlusal and cervical surfaces, separately ( p  〉 .05). Different etching techniques did not influence microleakage of Class V restorations prepared by Er:YAG laser and bur.

Beschreibung: Protein–membrane interactions are still an important topic of investigation. One of the suitable experimental techniques used by the scientific community to address such question is atomic force microscopy. In a previous work, we have reported that the binding mechanism between the cytolytic and antimicrobial protein (Cyt2Aa2) and lipid/cholesterol bilayers was concentration-dependent, leading to either the formation of holes in the bilayer or aggregates. Here we study such binding mechanism as a function of time at low protein concentrations (10 µg/mL). We demonstrate that although holes are formed during the first stages of the protein–lipid interaction, a reparation process due to molecular mobility in the bilayer leads to a homogenous and isotropic protein–lipid/cholesterol layer within 3 hr. The combination of imaging, force spectroscopy, and phase contrast delivered information about topography dynamics (molecular mobility), layer thickness, and mechanical properties of the protein–lipid/cholesterol system. These results highlight the importance of the observation time in (such type of) protein–lipid interactions (at low protein concentrations).

Beschreibung: Atomic force microscopy (AFM) is an enormous tool to observe nature in highest resolution and understand fundamental processes like friction and tribology on the nanoscale. Atomic resolution in highest quality was possible only in well-controlled environments like ultrahigh vacuum (UHV) or controlled buffer environments (liquid conditions) and more specified for long-term high-resolution analysis at low temperatures (∼4 K) in UHV where drift is nearly completely absent. Atomic resolution in these environments is possible and is widely used. However, in uncontrolled environments like air, with all its pollutants and aerosols, unspecified thin liquid films as thin as a single molecular water-layer of 200 pm or thicker condensation films with thicknesses up to hundred nanometer, have been a problem for highest resolution since the invention of the AFM. The goal of true atomic resolution on hydrophilic as well as hydrophobic samples was reached recently. In this manuscript we want to review the concept of ambient AFM with atomic resolution. The reader will be introduced to the phenomenology in ambient conditions and the problems will be explained and analyzed while a method for scan parameter optimization will be explained. Recently developed concepts and techniques how to reach atomic resolution in air and ultra-thin liquid films will be shown and explained in detail, using several examples.

Beschreibung: The visualization of taxonomically diagnostic features of individual pollen grains can be a challenge for many ecologically and phylogenetically important pollen types. The resolution of traditional optical microscopy is limited by the diffraction of light (250 nm), while high resolution tools such as electron microscopy are limited by laborious preparation and imaging workflows. Airyscan confocal superresolution and structured illumination superresolution (SR-SIM) microscopy are powerful new tools for the study of nanoscale pollen morphology and three-dimensional structure that can overcome these basic limitations. This study demonstrates their utility in capturing morphological details below the diffraction limit of light. Using three distinct pollen morphotypes ( Croton hirtus, Dactylis glomerata , and Helianthus sp.) and contrast-enhancing fluorescent staining, we were able to assess the effectiveness of the Airyscan and SR-SIM. We further demonstrate that these new superresolution methods can be easily applied to the study of fossil pollen material.

Beschreibung: Segmentation of objects from a noisy and complex image is still a challenging task that needs to be addressed. This article proposed a new method to detect and segment nuclei to determine whether they are malignant or not (determination of the region of interest, noise removal, enhance the image, candidate detection is employed on the centroid transform to evaluate the centroid of each object, the level set [LS] is applied to segment the nuclei). The proposed method consists of three main stages: preprocessing, seed detection, and segmentation. Preprocessing stage involves the preparation of the image conditions to ensure that they meet the segmentation requirements. Seed detection detects the seed point to be used in the segmentation stage, which refers to the process of segmenting the nuclei using the LS method. In this research work, 58 H&E breast cancer images from the UCSB Bio-Segmentation Benchmark dataset are evaluated. The proposed method reveals the high performance and accuracy in comparison to the techniques reported in literature. The experimental results are also harmonized with the ground truth images.

Beschreibung: In this paper, by applying the differential quadrature (DQ) method, a semi analytical model has been developed for atomic force microscope cantilever, and then by using the interfacial forces between the cantilever tip and imaged surfaces, a 2D model has been extracted for imaging nano-sized fine samples. By employing the present model, several simple and standard samples have been imaged, and finally the effects of the microcantilever's structural damping and its stiffness on the imaging results have been investigated. It has been observed that, through the control of damping, the quality of the acquired images is considerably improved. It has also been shown that the self-softening and self-hardening properties of cantilever have serious effects on the obtained images. The present model can be used to study the effects of different parameters on the process of imaging small-scale samples. Also, as one of its most important applications, this model can be used in common multiscale models for simulating and predicting the effects of large and small fields on each other.

Beschreibung: Three-dimensional optical super-resolution imaging is capable of providing 3D visualization of cellular structures in nanoscale detail. The past decade has witnessed the blossoming of 3D super-resolution imaging technologies. In this review, we comprehensively discuss and compare the imaging depth, resolution enhancement, and imaging speed of the existing 3D super-resolution imaging techniques.

Beschreibung: The electrochemical reduction of CO 2 is a promising method for its conversion which still suffers from important challenges that have to be solved before industrial realization becomes attractive. This study describes the optimization of gas diffusion electrodes with respect to catalyst dispersion and mass transport limitations allowing solubility issues to be circumvented and current densities to be increased to industrially relevant values. Consequently, the transfer of the promising results from semi-batch experiments into continuous mode of operation is demonstrated, and it is shown how the energetic efficiency can be significantly improved by the choice of electrolyte, in terms of concentration and type. Thereby ohmic losses can be decreased and the intrinsic activity improved.

Beschreibung: In a future energy system, flexible reactor operation may be needed if renewable electricity is converted to chemical energy carriers (synfuels). Limiting factors for the flexibility in a synfuel process can occur on different scales (catalyst, reactor, process). The present study addresses transient catalyst and reactor effects in 3-phase catalytic synthesis reactors with low-temperature Fischer-Tropsch synthesis as example reaction. A method was developed based on lab-scale experiments with step-changes and periodic-changes of inlet variables and mathematical models for experimental design and data analysis. Changes of feed gas flow, syngas H 2 /CO-ratio and temperature as inlet variables led, in some cases, to transient effects caused by catalyst changes or by reactor characteristics (e.g. residence times of gas components affected by their solubility in liquid hydrocarbon products). Catalyst changes include the reversible storage of carbon species during CO-rich intervals and hydrogenation of these carbon species during H 2 -rich intervals. The approach will help to scale-up for industrial applications and can be applied to other synthesis reactions.

Beschreibung: Profile measurements in a catalytic gauze reactor are conducted for catalytically assisted methane combustion over platinum. The reactor combines a capillary sampling technique with a novel fiber-optic Laser-Induced Fluorescence (LIF) Spectroscopy method for detection and quantification of gas phase OH[[[Wingdings;F09E]]] radicals serving as indicator species for gas phase reactions. The steep spatial gradients in the vicinity of the gauze are resolved at submillimeter scale. Experimental profiles are compared with three dimensional numerical reactor simulations including flow, mass transport, heat transport and microkinetic models for both surface and gas phase chemistry. The results provide insight into the interaction of chemistry and transport upstream, at and downstream the catalytic gauze and the interaction of surface and gas phase reactions by exchange of heat and radicals released from the catalyst surface.

Beschreibung: A packed bed algae biofilm reactor was developed using porous and non-porous dual packings. The biofilm was cultivated on reticulated polyurethane foam cubes of 0.01 m dimension. The non-porous glass raschigs were used as bed support that helps the removal of generated gas from the system. The effect of variables such as column L/D ratio, catalyst cube dimension and feed flow rate on the treatment of sewage water was studied. The reaction kinetics indicates that the nutrients uptake rate is dependent on both pore and film diffusion. The kinetics of uptake of nutrients follows a pseudo-first order reaction. From the pseudo reaction rate constant, Thiele Modulus and effectiveness factor were calculated and a kinetic model equation for fractional nutrients uptake was developed in terms of operating variables. It was observed that the model can predict the reaction rate with ±5% deviation. The packed bed column was operated continuously for 90 days with 76-83% of TN and 70-76% TP removal in 24 h of residence time and the results obtained may be useful for large-scale treatment of sewage water.

Beschreibung: With the high interest in renewable resources, the field of biosorption has undergone a huge leap in importance in recent years. The arsenic contamination in water causes many diseases. Various biosorbent materials have been tested for their ability to remove the two inorganic arsenic species commonly found in water; arsenite As (III) and arsenate As (V). The review evaluates source and various biosorbent used for arsenic removal from wastewater. The arsenic biosorption is influenced by the pH of aqueous phase, the concentration of arsenic, the presence of competing ions and arsenic speciation. The biosorption kinetic of As (III) and As (V) by biosorbents has been reported to be rapid, with greater than 80 % biosorption occurring between 30- 60 min, followed by second step which may take up several hours. The pseudo-second order model showed the best fit for kinetics of arsenic, which corresponds to a chemisorption process. Langmuir equation is widely used in a large number of equilibrium studies; this finding indicates that most arsenic ions are adsorbed in monolayer form and removal is better for As (III) than for As (V).

Beschreibung: Reversible photoswitching has been proposed as a way to identify molecules that are present in small numbers over a large, non-switching, background. This approach, called optical-lock-in-detection (OLID) requires the deterministic control of the fluorescence of a photochromic emitter through optical modulation between a bright (on) and a dark state (off). OLID yields a high-contrast map where the switching molecules are pinpointed, but the fractional intensities of the emitters are not returned. The present work presents a modified OLID approach (quantitative OLID or qOLID) that yields quantitative information of the switching (f SW ) and non-switching (f NS ) components. After the validation of the method with a sample dataset and image sequence, we apply qOLID to measurements in cells that transiently express the photochromic protein EYQ1. We show that qOLID is efficient in separating the modulated from the non-modulated signal, the latter deriving from background/autofluorescence or fluorophores emitting in the same spectral region. Finally, we apply qOLID to Förster (Fluorescence) Resonance Energy Transfer (FRET) imaging. We here demonstrate that qOLID is able to highlight the distribution of FRET intensity in a sample by using a photochromic donor and a non-photochromic acceptor.

Beschreibung: Introduction Pregnancy-related deep vein thrombosis (DVT) is most common during the late phase of pregnancy and the first 6-weeks postpartum. Pregnancy-related DVT can have long-term complications, specifically post-thrombotic syndrome (PTS). Fibrin network ultrastructure is altered during pregnancy and post-partum. It is therefore essential to evaluate fibrin fiber diameter during and after pregnancy as this may provide insight into pregnancy-related DVT and subsequent PTS. Materials and methods The fibrin network ultrastructure of females during different phases of pregnancy was compared to that of non-pregnant females to assess possible changes to the fibrin network morphology and fibrin fiber diameter using scanning electron microscopy micrographs. Results The fibrin network arrangement was more densely packed during different phases of pregnancy, corresponding to earlier findings. Fibrin diameter decreased significantly during pregnancy, with the greatest decrease occurring during the late phase of pregnancy. The fractal dimensions of fibrin micrographs increased significantly during pregnancy compared to nonpregnant females. These changes are indicative of a simultaneous hypercoagulable and hypofibrinolytic state and correspond to the increased risk of DVT and subsequent development of PTS. Conclusion It is critical to identify “vulnerable” females with an inflammatory predisposition to prevent possible DVT and subsequent PTS. Modifiable risk factors like obesity and smoking should be addressed to alleviate the burden on the coagulation system. Morphological and viscoelastic techniques are crucial in assessing the coagulatory health of females during pregnancy.

Beschreibung: Objectives Chemotherapy targets rapidly dividing tissues in the body. It destroys the progenitor cells in gonads resulting in premature ovarian failure. Studies have suggested that bone marrow-derived stem cells can generate oocytes in chemotherapy treated female rats after transplantation. The present study aimed to assess mechanism of homing, the action of injected BM-MSCs on ovarian function after ovarian damage. Experimental design : Seventy two female albino rats were randomly allocated into Control and CTX group, The Experimental protocol was lasted for 12 weeks during which serum FSH and E2 were monitored twice at the end of the 2nd week (12 rats) and 8th week (6 rats). Stem cells identification and homing were evaluated by Flowcytometry and tagging of stem cells with iron oxide particles respectively. Also, histopathological examination was done to evaluate both degeneration (6 rats at 4th week) and regeneration (6 rats at 12th week) of ovarian tissue together with assessment of the levels of TNF-α in ovarian homogenate and IGF-I as a growth factor in ovarian tissue. Principal observations : Partial improvement of E2 and FSH levels as well as ovarian architecture. Elevation of ovarian TNF- α levels and of IGF-I immunohistochemical expressions in ovarian tissues of BM-MSCs injected rats were noticed following homing of BM- MSCs in the ovarian stroma in both control and chemotherapy groups. Conclusion : Injected BM- MSCs can home in the stroma of the injured ovaries. IGF-I and TNF- α may have a role in the attraction of stem cells in vivo.

Beschreibung: Lasers and photodynamic therapy have been considered a convergence treatment for onychomycosis, which is a fungal infection on the nail bed and nail plate. Laser therapies have shown satisfactory results without significant complications for onychomycosis; however, the mechanism of clearing remains unknown. In this work, we investigated changes in the chemical structure of nail keratin induced by Nd:YAG laser using Raman spectroscopy. Toe nails with onychomycosis were treated with 1064 nm Nd:YAG laser. After laser treatment, the disulfide band (490–590 cm −1 ) of nail keratin was rarely observed or was reduced in intensity. The amide I band (1500–1700 cm −1 ) also showed changes induced by the laser. The α-helical (1652 cm −1 ) structures dominated the β-sheet (1673 cm −1 ) in nontreated nail, but the opposite phenomenon was observed after laser treatment.

Beschreibung: Ionotropic alginate microgels are commonly used for bioencapsulation applications and the air extrusion system is one of the common methods employed to produce these microgels. Although there have been many individual studies, no single report to date has comprehensively summarized the findings and results of the use of this system. Our review gives insight into the air extrusion methods, covering the setup, type and characteristics of the system, focussing on their innovative aspects. Characterization techniques for the resulting microgels are presented, along with the influence of process variables on their product size, and the development of empirical models for size prediction.