Impact of Seasonal Conditions on Quality and Pathogens Content of Milk in Friesian Cows

Heat stress negatively affects milk quality altering its nutritive value and cheese making properties. This study aimed at assessing the impact of seasonal microclimatic conditions on milk quality of Friesian cows. The study was carried out in a dairy farm from June 2013 to May 2014 at Beni-Suef province, Egypt. Inside the barn daily ambient temperature and relative humidity were recorded and used to calculate the daily maximum temperature-humidity index (mxTHI), which was used as indicator of the degree of heat stress. The study was carried out in three periods according to the temperature-humidity index (THI) recorded: from June 2013 to September 2013 (mxTHI>78), from October 2013 to November 2013 (mxTHI 72–78) and from December 2013 to April 2014 (mxTHI78 was observed. In addition, the isolation rate of both S. aureus and E. coli increased when the mxTHI increased. The results of this study show the seriousness of the negative effects of hot conditions on milk composition and mammary gland pathogens. These facts warrant the importance of adopting mitigation strategies to alleviate negative consequences of heat stress in dairy cows and for limiting related economic losses

Subclinical Mastitis in Selected Bovine Dairy Herds in North Upper Egypt: Assessment of Prevalence, Causative Bacterial Pathogens, Antimicrobial Resistance and Virulence-Associated Genes

Mastitis is a significant disease affecting dairy cattle farms in Egypt. The current study aimed to investigate the prevalence and major bacterial pathogens causing subclinical mastitis (SCM) in three bovine dairy herds, with a history of SCM, at three Governorates in North Upper Egypt. The antimicrobial resistance profiles and specific virulence-associated genes causing bovine SCM were investigated. One thousand sixty-quarter milk samples (QMS) were collected aseptically from 270 apparently healthy cows in three farms and examined. The total prevalence of SCM was 46% and 44.8% based on California Mastitis Test (CMT) and Somatic Cell Count (SCC), respectively. Bacteriological examination of CMT positive quarters revealed that the prevalence of bacterial isolation in subclinically mastitic quarters was 90.4% (26 and 64.3% had single and mixed isolates, respectively). The most frequent bacterial isolates were E. coli (49.8%), Staphylococcus aureus (44.9%), streptococci (44.1%) and non-aureus staphylococci (NAS) (37.1%). Antimicrobial susceptibility testing of isolates revealed a high degree of resistance to the most commonly used antimicrobial compound in human and veterinary medicine. Implementation of PCR revealed the presence of mecA and blaZ genes in 60% and 46.7% of S. aureus isolates and in 26.7% and 53.3% of NAS, respectively. Meanwhile 73.3% of streptococci isolates harbored aph(3’)-IIIa gene conferring resistance to aminoglycosides and cfb gene. All E. coli isolates harbored tetA gene conferring resistance to tetracycline and sul1 gene conferring resistance to sulfonamides. The fimH and tsh genes were found in 80% and 60%, respectively. A significant association between the phenotypes and genotypes of AMR in different bacteria was recorded. The presence of a high prevalence of SCM in dairy animals impacts milk production and milk quality. The coexistence of pathogenic bacteria in milk is alarming, threatens human health and has a public health significance. Herd health improvement interventions are required to protect human health and society

Ti3C2Tx-Au hybrid composites-based electrochemical biosensors for calreticulin biomarker detection

A sensitive biosensor is critical for early breast cancer treatment and prognosis. Herein, a label-free electrochemical immunosensor is proposed for the sensitive detection of calreticulin (CALR), a new breast cancer biomarker. The biosensor relied upon an electroactive hybrid of ultra-thin Ti3C2Tx nanosheets preadsorbed with Au NPs and methylene blue (MB)(MB–Ti3C2Tx–Au), which served as redox-active centers and an electroactive probe to detect CALR biomarkers respectively. The detection mechanism followed a simple inhibition strategy, where the optimal differential pulse voltammetry (DPV) response of preadsorbed MB over the Ti3C2Tx–Au electrode decreased in proportion to the concentration of CALR biomarkers owing to the formation of the antibody-antigen immunocomplex. The biosensor could detect CALR-biomarker in the concentration range of 0.0015 to 0.94 ng mL−1 with a limit of detection (LOD) of 0.28 pg mL−1 and showed excellent antifouling properties against commonly encountered biomolecules such as hemoglobin (Ig), immunoglobulin G (IgG), neuron-specific enolase (NSE), and tumor necrosis factor-alpha (TNF). The proposed strategy provides an efficient method for utilizing MXene nanosheets to construct advanced biosensors with promising clinical applications

Viscoelastic and Properties of Amphiphilic Chitin in Plasticised Polylactic Acid/Starch Biocomposite

The enhancement of the PLA thermomechanical properties is significant due to its suitability as a replacement for primary synthetic polymer use in diverse industrial production. The amphiphilic chitin was used as a compatibilizer in PLA/starch biocomposite. The properties of plasticised polylactic acid blended with starch, and amphiphilic chitin was studied for enhanced thermomechanical and viscoelastic properties. Chitin was modified using acetylated substitution reaction and blended with plasticised PLA/starch biocomposite. The biocomposite was prepared with combined compression and melt extrusion techniques. The biocomposite’s thermomechanical, thermal, mechanical, and morphological properties were studied using dynamic mechanical analysis, TGA-DSC, tensile test, and scanning electron microscopy. The storage and loss modulus were significantly enhanced with increased amphiphilic chitin content. Similarly, the single peak of tan delta showed good miscibility of the polymeric blend. Additionally, the modulus increases with frequency change from 1 Hz to 10 Hz. The thermal stability of the biocomposite was observed to be lower than the neat PLA. The tensile properties of the biocomposite increased significantly more than the neat PLA, with P4S4C having the highest tensile strength and modulus of 87 MPa and 7600 MPa. The SEM images show good miscibility with no significant void in the fractured surface. The viscoelastic properties of PLA were enhanced considerably with plasticizer and amphiphilic chitin with improved biodegradability. The properties of the biocomposite can be adapted for various industrial applications

Progress and current challenges for CO2 capture materials from ambient air

As a major component of greenhouse gases, excessive carbon dioxide (CO2) in the atmosphere can affect human health and ecosystems. Therefore, the capture and transformation of CO2 has attracted extensive attention in academic circles in recent years. Direct air capture (DAC) of CO2 is a technology developed in recent years that can capture and collect CO2 directly from the ambient air, which is a potential negative CO2 emission technology. Currently, DAC technology is being promoted worldwide. Therefore, given the lack of a timely review of the latest developments in DAC technology, an appropriate and timely summary of this technology and a comprehensive understanding of it is necessary. In this paper, we review the research progress of adsorbent materials for directly capturing CO2 from ambient air in recent years, including liquid-based absorbent, solid adsorbent, and moisture-swing adsorbent. How their chemical composition, structure, morphology, modification method affects their performance and long-term use is thoroughly discussed. In addition to efficient CO2 adsorption properties, designing low-cost sustainable materials is critical, especially for practical applications. Therefore, the technical and economic evaluation of CO2 adsorbents directly capturing from ambient air is reviewed. This review is of great significance for researchers to fully understand the development status and future trends of direct capture of CO2 from ambient air

Waterborne acrylic resin co-modified by itaconic acid and γ-methacryloxypropyl triisopropoxidesilane for improved mechanical properties, thermal stability, and corrosion resistance

The waterborne acrylic resin modified by both itaconic acid (IA) and γ-methacryloxypropyl triisopropoxidesilane (KH571) was successfully synthesized by the seeded emulsion polymerization. The effects of IA and KH571 on the properties of waterborne acrylic resin, including mechanical properties, water resistance, thermal stability, storage stability and corrosion resistance, were studied. Fourier transform infrared spectroscopy analysis showed that IA and KH571 were successfully copolymerized with acrylic monomers. Compared with the unmodified resin, the introduction of IA and KH571 greatly improved the water resistance of the resin coating. When 2 wt% IA and 4 wt% KH571 were added, the contact angle of the resin coating increased from 78.91° to 90.49°. The water resistance time of the resin coating was improved from one day to 17 days. Additionally, the modified resin showed better mechanical properties, thermal stability, storage stability and corrosion resistance. The waterborne acrylic resin modified with IA and KH571 has a potential application prospect in the fields of waterproof and anticorrosive coating

Improving water resistance and mechanical properties of waterborne acrylic resin modified by 3,3',5,5'-tetramethyl-4,4'-biphenyl diglycidyl ether

3,3',5,5'-tetramethyl-4,4'-biphenyl diglycidyl ether (TMBPDGE) modified waterborne acrylic resin with excellent water resistance and mechanical properties was synthesized by a homogeneous solution polymerization. Infrared analysis revealed that TMBPDGE could successfully participate in the synthesis. On this basis, the experimental conditions such as polymerization method, solid content, monomer addition method and curing temperature are optimized by using the results of immersion test, contact angle, tensile strength, elongation at break and hardness determination. The optimal amount of TMBPDGE is investigated and the resin is further characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The experimental results show that when the amount of TMBPDGE is 10 wt, the water resistance and mechanical properties of the resin are greatly enhanced, and the cured resin film modified by TMBPDGE can withstand the soaking in water for more than 35 days, while that of film without modification is only one day. The tensile strength can reach 9.12 MPa, which is 2.2 times than that of the film without modification. Based on the enhanced properties, the modified resin provides a great potential in the fields of wood coatings, which require good water resistance and mechanical properties