High frequency travelling surface acoustic waves for microparticle separation

In this study, we have demonstrated a particle separation device taking advantage of the high frequency sound waves. The sound waves, in the form of surface acoustic waves, are produced by an acoustofluidic platform built on top of a piezoelectric substrate bonded to a microfluidic channel. The particles’ mixture, pumped through the microchannel, is focused using a sheath fluid. A Travelling surface acoustic wave (TSAW), propagating normal to the flow, interacts with the particles and deflects them from their original path to induce size-based separation in a continuous flow. We initially started the experiment with 40 MHz TSAWs for deflecting 10 µm diameter polystyrene particles but failed. However, larger diameter particles (~ 30 µm) were successfully deflected from their streamlines and separated from the smaller particles (~ 10 µm) using TSAWs with 40 MHz frequency. The separation of smaller diameter particles (3, 5 and 7 µm) was also achieved using an order of magnitude higher-frequency (~ 133 MHz) TSAWs.     

Impact of heat processing on the detection of the major shellfish allergen tropomyosin in crustaceans and molluscs using specific monoclonal antibodies

The major heat-stable shellfish allergen, tropomyosin, demonstrates immunological cross-reactivity, making specific differentiation of crustaceans and molluscs for food labelling very difficult. The aim of this study was to evaluate the application of allergen-specific monoclonal antibodies in differential detection of shellfish-derived tropomyosin in 11 crustacean and 7 mollusc species, and to study the impact of heating on its detection. Cross-reactive tropomyosin was detected in all crustacean species, with partial detection in molluscs: mussels, scallops and snails but none in oyster, octopus and squid. Furthermore, we have demonstrated that heating of shellfish has a profound effect on tropomyosin detection. This was evident by the enhanced recognition of multiple tropomyosin variants in the analysed shellfish species. Specific monoclonal antibodies, targetting the N-terminal region of tropomyosin, must therefore be developed to differentiate tropomyosins in crustaceans and molluscs. This can help in correct food labelling practices and thus protection of consumers.     

Occurrence and Antimicrobial Susceptibility of Listeria monocytogenes Isolated from Brined White Cheese in Jordan

Listeria monocytogenes is a serious foodborne pathogen that has been isolated from different dairy food products. Several foodborne outbreaks of listeriosis have been associated with consumption of cheese. The aims of this study were to determine the occurrence of L. monocytogenes and Listeria spp. in brined white cheese (BWC) sold in Jordan, and to determine the susceptibility of isolated L. monocytogenes to antimicrobials. Three hundred and fifty samples of 5 different types of BWC (akkawi, boiled, halloumi, pasteurized, and shellal) were collected from a local market in Jordan. The ISO (11290-1) procedure was followed for isolation and identification of Listeria spp. from cheese samples and a polymerase chain reaction (PCR) technique was used for confirmation of L. monocytogenes isolates. The VITEK2 automated system was used for testing antimicrobial susceptibility of L. monocytogenes isolates. The overall prevalence of Listeria spp. in cheese sample was 27.1%. L. monocytogenes was isolated from 39 (11.1%) samples. Other isolated species were L. grayi (6.9%), L. innocua (2%), L. ivanovii (4%), L. seeligeri (2%), and L. welshimeri (0.3%). The pH values and salt concentrations of L. monocytogenes positive cheese samples ranged from 5.10 to 6.32 and 5.64 to 13.16, respectively. L. monocytogenes isolates were sensitive or intermediate susceptible to imipenem, gentamicin, linezolid, teicoplanin, vancomycin, fusidic acid, trimethoprim/sulfamethoxazole, benzylpenicillin, ciprofloxacin, erythromycin, tetracycline, and rifampicin, but resistant to fosfomycin, oxacillin, and clindamycin.     

Time Effects on Total Suction of Bentonites

This paper presents a study on time effects on total suction of bentonite-based materials under constant water content conditions. Three different types of bentonite (i.e., MX80, Calcigel I, and Calcigel II) and a natural expansive clay (i.e., London Clay) were used. Total suction was measured using chilled-mirror hygrometer technique. The measurements were performed on specimens aged 1 hour, 6 hours, 1 day, 2 days, 1 week, 2 weeks, 1 month, and 2 months. The results show that the true equilibrium state for two types of bentonite (i.e., MX80 and Calcigel I) used is time dependent. Total suction increases with time and this behaviour is controlled by the characteristics of the bentonites. Total suction of the other specimens (i.e., Calcigel II and London Clay) is not affected by curing time. The changes in total suction with time as the specimen's age are attributed to non homogeneity of the water content distribution in the micro- and macropores of the bentonites and inaccuracy of the device used.     

Dissecting Breast Cancer Circulating Tumor Cells Competence via Modelling Metastasis in Zebrafish

Background: Cancer metastasis is a deathly process, and a better understanding of the different steps is needed. The shedding of circulating tumor cells (CTCs) and CTC-cluster from the primary tumor, its survival in circulation, and homing are key events of the metastasis cascade. In vitro models of CTCs and in vivo models of metastasis represent an excellent opportunity to delve into the behavior of metastatic cells, to gain understanding on how secondary tumors appear. Methods: Using the zebrafish embryo, in combination with the mouse and in vitro assays, as an in vivo model of the spatiotemporal development of metastases, we study the metastatic competency of breast cancer CTCs and CTC-clusters and the molecular mechanisms. Results: CTC-clusters disseminated at a lower frequency than single CTCs in the zebrafish and showed a reduced capacity to invade. A temporal follow-up of the behavior of disseminated CTCs showed a higher survival and proliferation capacity of CTC-clusters, supported by their increased resistance to fluid shear stress. These data were corroborated in mouse studies. In addition, a differential gene signature was observed, with CTC-clusters upregulating cell cycle and stemness related genes. Conclusions: The zebrafish embryo is a valuable model system to understand the biology of breast cancer CTCs and CTC-clusters.     

PV‐betriebene Umkehrosmoseanlage zur Meerwasserentsalzung – Modellierung und Analyse verschiedener Energieversorgungsvarianten

Reverse osmosis is a very energy‐efficient approach for seawater desalination. Since it requires only electrical energy, a combination of reverse osmosis and photovoltaic (PV) plants seems to be a promising solution. Therefore, a PV‐based reverse osmosis plant for seawater desalination for a location in Saudi Arabia is designed and modeled. On this basis, different options of a PV‐powered seawater desalination plant are investigated and conclusions for the construction of such plants are derived.     

Survival of Cronobacter Species in Reconstituted Herbal Infant Teas and their Sensitivity to Bovine Lactoferrin

ABSTRACT:  Cronobacter  is a new genus containing 5 species previously known as  Enterobacter sakazakii . The popularity of "natural" substances and alternative medicine has extended the use of natural antimicrobials and herbs to foods, and some herbs are claimed to relieve gastric disturbances in infants. The present study investigated the antimicrobial activity of bovine lactoferrin (LF) and  Cronobacter  survival in commercial herbal infant teas (HITs) reconstituted with water at different temperatures.  Cronobacter  cells were able to grow in all reconstituted HITs at 37 or 21 °C after 6 h. A 4-log reduction in  Cronobacter  was achieved by reconstituting herbal infant tea at ≥ 60 °C. LF was able to reduce  Cronobacter  species viability in herbal infant tea. No viable cells were recovered after 4 h at 37 °C in the presence of ≥5mg LF/mL. The bactericidal activity of LF was reduced at lower concentrations and lower temperatures. This study demonstrates that if present in reconstituted herbal infant tea,  Cronobacter  can grow and this may compromise the safety of these products. Therefore, addition of LF to reconstituted HIT may be a promising approach for the effective control of this organism.
Practical Application:  Cronobacter  species can be isolated from herbal teas, and these products are claimed to relieve gastric disturbances in infants. This study demonstrates that  Cronobacter  cells present in reconstituted herbal infant teas (HITs) can grow if not held at acceptable temperatures. It was shown that reconstitution of these tea formulas with ≥ 60 °C water reduced the potential risk from  Cronobacter . Furthermore, use of lactoferrin (LF) may be a promising approach for effective control of these organisms in HIT held at nonrefrigeration temperatures (10 to 37 °C) for short periods.     

On the correlation between T<Subscript>2</Subscript> and tissue diffusion coefficients in exercised muscle: quantitative measurements at 3T within the tibialis anterior

PURPOSE: To assess the transverse relaxation time T(2) and diffusion coefficient D before and following exercise in the tibialis anterior muscle and determine whether T(2) and D values were correlated. METHODS: Measurements of T(2) and D were performed at 3 T within axial slices through the calf muscles of six healthy volunteers at 95 s intervals before and for 10-12 min after a dorsiflexion exercise to exhaustion. RESULTS: The mean +/- standard deviation (SD) of T(2) and D before exercise were 32 +/- 1.55 ms and 1.52 +/- 0.15 mum(2)/ms, and after exercise were 43 +/- 2.5 ms and 1.72 +/- 0.13 mum(2)/ms, respectively. The mean +/- SD inter-individual recovery times of the % change in T(2) and D after exercise were 7.9 +/- 4.2 and 10.9 +/- 7.0 min, respectively. The T(2) and D values showed a significant correlation throughout the experiments (r (2) = 0.45). CONCLUSIONS: The increase in T(2) of skeletal muscle after exercise is correlated with the increase of the diffusion coefficient D and the recovery times appear similar, indicating that any model used to explain T(2) increases with exercise must also account for increased diffusion coefficients.     

An Optimized CNN Model Architecture for Detecting Coronavirus (COVID-19) with X-Ray Images

This paper demonstrates empirical research on using convolutional neural networks (CNN) of deep learning techniques to classify X-rays of COVID-19 patients versus normal patients by feature extraction. Feature extraction is one of the most significant phases for classifying medical X-rays radiography that requires inclusive domain knowledge. In this study, CNN architectures such as VGG-16, VGG-19, RestNet50, RestNet18 are compared, and an optimized model for feature extraction in X-ray images from various domains involving several classes is proposed. An X-ray radiography classifier with TensorFlow GPU is created executing CNN architectures and our proposed optimized model for classifying COVID-19 (Negative or Positive). Then, 2,134 X-rays of normal patients and COVID-19 patients generated by an existing open-source online dataset were labeled to train the optimized models. Among those, the optimized model architecture classifier technique achieves higher accuracy (0.97) than four other models, specifically VGG-16, VGG-19, RestNet18, and RestNet50 (0.96, 0.72, 0.91, and 0.93, respectively). Therefore, this study will enable radiologists to more efficiently and effectively classify a patient’s coronavirus disease.     

If it looks like a spammer and behaves like a spammer,it must be a spammer: analysis and detection of microblogging spam accounts

Spam in online social networks (OSNs) is a systemic problem that imposes a threat to these services in terms of undermining their value to advertisers and potential investors, as well as negatively affecting users’ engagement. As spammers continuously keep creating newer accounts and evasive techniques upon being caught, a deeper understanding of their spamming strategies is vital to the design of future social media defense mechanisms. In this work, we present a unique analysis of spam accounts in OSNs viewed through the lens of their behavioral characteristics. Our analysis includes over 100 million messages collected from Twitter over the course of 1 month. We show that there exist two behaviorally distinct categories of spammers and that they employ different spamming strategies. Then, we illustrate how users in these two categories demonstrate different individual properties as well as social interaction patterns. Finally, we analyze the detectability of spam accounts with respect to three categories of features, namely content attributes, social interactions, and profile properties.