Potentiating Hemorrhage in a Periadolescent Rat Model of Closed-Head Traumatic Brain Injury Worsens Hyperexcitability but Not Behavioral Deficits

Post-traumatic epilepsy (PTE) and neurocognitive deficits are devastating sequelae of head injuries that are common in adolescents. Investigating desperately needed treatments is hindered by the difficulties in inducing PTE in rodents and the lack of established immature rat models of pediatric PTE. Hemorrhage is a significant risk factor for PTE, but compared to humans, rats are less prone to bleeding because of their rapid blood coagulation system. In this study, we promoted bleeding in the controlled cortical impact (CCI) closed-head injury model with a 20 min pre-impact 600 IU/kg intraperitoneal heparin injection in postnatal day 35 (P35) periadolescent rats, given the preponderance of such injuries in this age group. Temporo-parietal CCI was performed post-heparin (HTBI group) or post-saline (TBI group). Controls were subjected to sham procedures following heparin or saline administration. Continuous long-term EEG monitoring was performed for 3 months post-CCI. Sensorimotor testing, the Morris water maze, and a modified active avoidance test were conducted between P80 and P100. Glial fibrillary acidic protein (GFAP) levels and neuronal damage were also assessed. Compared to TBI rats, HTBI rats had persistently higher EEG spiking and increased hippocampal GFAP levels (p < 0.05). No sensorimotor deficits were detected in any group. Compared to controls, both HTBI and TBI groups had a long-term hippocampal neuronal loss (p < 0.05), as well as contextual and visuospatial learning deficits (p < 0.05). The hippocampal astrogliosis and EEG spiking detected in all rats subjected to our hemorrhage-promoting procedure suggest the emergence of hyperexcitable networks and pave the way to a periadolescent PTE rat model.     

Auxetic Polymeric Bone Stent for Tubular Fractures: Design,Fabrication and Structural Analysis

Fracture fixation techniques, fracture management, and orthopedic trauma care have evolved, and various advancements have been made in the last 50 years. Minimally invasive biological osteosynthetic devices have the potential of transforming the prospects of orthopedic treatment. Internal fixation techniques offer tremendous advantages in the management of bone fractures. The main objective of this study was to fabricate a novel auxetic polymeric bone stent with potential applications in internal fixation procedures. A new “connected stars” geometry has been used for the fabrication of this device. After fabrication, the mechanical characterization of the auxetic bone stent was also carried out to study its properties and deformation behavior. The research work undertaken also assesses the potential for auxetic behavior of these tubular structures.     

Effective enhancement of electric and magnetic properties of PMMA/LiFe5O8 nanocomposites via magnetic treatment

Journal of Materials Science: Materials in Electronics - The present study presents a facile effective method to enhance the electric as well as the magnetic properties of polymer/ferrite...     

Lithium ferrite (LiFe5O8)/polymethyl methacrylate (PMMA) nano-composite used in high dielectric constant capacitor and electromagnetic applications

Poly methyl methacrylate/ Lithium ferrite nano-composites have been prepared by solution mixing process. The electrical conductivity and dielectric properties of these prepared nano-composite have been investigated in the frequency range 10²–10⁶ Hz at different LiFe₅O₈ concentrations from 0 vol% to 25 vol%. The prepared samples are studied by thermal gravimetric analysis (TGA) and X-ray diffraction (XRD). Moreover, the magnetic properties of these nano-composites are investigated through vibrating sample magnetometer studies. XRD spectral investigation revealed that the structural of PMMA and its chemical characterization are appreciably affected by mixed lithium ferrite filler. The thermal stability of the PMMA matrix was found to increase appreciably by LiFe₅O₈ loading. The (I-V) characteristic of these nano-composites are in very good agreement with the non-linearity predicted by Kaiser et al. model. The effective dielectric constant is studied through different proposed models. Saturation magnetization of 10.05 emu/g is achieved for PMMA sample loaded with 25 vol% of LiFe₅O₈ particles.     

Effect of selection for growth rate on the ageing of myofibrils, meat texture properties and the muscle proteolytic potential of m. longissimus in rabbits

The effect of selection for growth rate on the degradation of the myofibrillar proteins and on meat texture properties of rabbit longissimus muscle at two ageing times (1 and 7 days) was studied as well as its effect on the proteolytic potential of the muscle. Two groups of contemporary animals (20 rabbits per group), one selected for growth rate (S) for 14 generations and the other unselected control group (C) were compared. The control group was formed from the offspring of the embryos belonging to the 7th generation and was compared with selected animals belonging to 21st generation. Myofibrillar protein degradation was studied by SDS-PAGE electrophoresis (12.5% and 4-15% polyacrylamide gels) followed by densitometric analysis of the pherograms. Texture properties were evaluated by Warner-Bratzler (WB) test and Texture profile analysis (TPA). The activities of proteolytic enzymes calpains and cathepsins and of their inhibitors were determined in the muscle at 24h. Densitometric analysis of the pherograms of samples aged 7 days showed an extra 30kDa band and the disappearance of a band with higher molecular weight than the myosin heavy chain with respect to samples aged 24h in both groups of rabbits. TPA results showed that cohesiveness was significantly lower in meat at 7 days than at 24h (P<0.0001), whereas springiness and chewiness presented a clear tendency to be lower at 7 days than at 24h (P=0.0646 and P=0.0764, respectively). Regarding the genetic type, S animals presented higher hardness and chewiness than C rabbits. Shear firmness (WB test) was significantly (P<0.0001) higher for S group, whereas no significant differences in shear force and area were found. No significant effect (P>0.05) of ageing time was detected using WB test. Selection for growth rate did not affect the activities of proteolytic enzymes or their inhibitors.     

Rep-PCR characterization and biochemical selection of lactic acid bacteria isolated from the Delta area of Egypt

Samples of raw milk and traditional dairy products were collected from different rural areas in the Delta region. 170 isolates from these products were identified using repetitive genomic element-PCR (Rep-PCR) fingerprinting. The identified isolates were tested for efficiency of biomass production and separation, acidifying activity, autolytic and aminopeptidase properties, antagonistic activities and exopolysaccharide production. The obtained results revealed that the Lactobacillus delbrueckii subsp. lactis, Lactobacillus fermentum, Enterococcus faecium Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum and Lactococcus lactis subsp. lactis were the predominant species in Egyptian dairy products. Two percent of Lactococcus, 10% of Lactobacillus and 1% of Enterococcus isolates showed fast acidifying activity. Aminopeptidase and autolytic properties were generally higher for most Lactobacillus strains when compared to other strains. Among these species, lactobacillus paracasei subsp. paracasei was the highest in Aminopeptidase activity and autolytic properties. Antagonistic activity was detected in 40% of Lactococcus, 70% of Lactobacillus and 50% of Enterococcus isolates. Some isolates produced exopolysaccharides in milk and dairy products.     

Trust calibration of automated security IT artifacts: A multi-domain study of phishing-website detection tools

Phishing websites become a critical cybersecurity threat affecting individuals and organizations. Phishing-website detection tools are designed to protect users against such sites. Nevertheless, detection tools face serious user trust and suboptimal performance issues which require trust calibration to align trust with the tool’s capabilities. We employ the theoretical framework of automation trust and reliance as a kernel theory to develop the trust calibration model for phishing-website detection tools. We test the model using a controlled lab experiment. The results of our analysis show that users’ trust in detection tools can be calibrated by trust calibrators. Moreover, users’ calibrated trust has significant consequences, including users’ tool reliance, use, and performance against phishing websites.     

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.