Higher Tool Productivity due to New Generation of PVD Coatings

PVD coating technology has seen many new developments in the past few years. HIPIMS⁺ is an example of these developments with excellent results on tool productivity and lifespan. The technology combines the advantages of arc evaporation with those of magnetron sputtering and results in a dense and defect‐free coating with tuneable residual stress. The coatings have been tested successfully by international tool manufacturers. Additional developments can be seen in DLC coatings and the hydrogen‐free variety ta‐C. These coatings are suitable for low temperature deposition and machining of special materials.     

The effect of lignin on the structure and characteristics of composite coatings electrodeposited on titanium

Composite coatings based on lignin, obtained by electrophoretic deposition (EPD) on titanium, were investigated. The aim of this work was to produce hydroxyapatite/lignin (HAP/Lig) coatings on titanium and to investigate the effect of the lignin concentration on microstructure, morphology, phase composition, thermal behavior and cytotoxicity of the HAP/Lig coatings. An organosolv lignin was used for the production of the composite coatings studied in this research. The properties of HAP/Lig coatings were characterized using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT-IR) and X-ray photoelectron spectroscopy (XPS), as well as the MTT test of cytotoxicity. The results showed that higher lignin concentrations protected the HAP lattice during sintering, thereby improving the stability of the HAP/Lig coatings. The cell survival of peripheral blood mononuclear cells (PBMC) after proliferation indicates that the HAP/Lig coating with 1 wt% Lig electrodeposited on titanium was non-toxic with significant promise as a potential bone-repair material.     

Sensory and physicochemical evolution of tropical cooked peeled shrimp inoculated by Brochothrix thermosphacta and Lactococcus piscium CNCM I-4031 during storage at 8°C

This study investigated the sensory quality and physicochemical evolution (pH, glucose, l-lactic acid, biogenic amine, free amino-acids and volatile compounds) during storage at 8 °C of cooked peeled shrimp inoculated with the specific spoilage bacteria Brochothrix thermosphacta alone or mixed with the protective strain Lactococcus piscium CNCM I-4031. Growth of both bacteria was monitored at regular intervals during storage by microbial counts and the thermal temperature gradient gel electrophoresis (TTGE) technique. Bacterial counts showed that L. piscium and B. thermosphacta inoculated at 7 log CFU/g and 3 log CFU/g were well adapted to shrimp, reaching a maximum level of 9 log CFU/g after 4 days and 10 days respectively. In mixed culture, the growth of B. thermosphacta was reduced by 3.2 ± 0.1 log CFU/g. The TTGE technique allowed monitoring the colonisation of the strains on the shrimp matrix and confirming the dominance of L. piscium in mixed culture throughout the experiment. Sensory analysis confirmed that B. thermosphacta spoiled the product after 11 days, when its cell number attained 8 log CFU/g with the emission of strong butter/caramel off-odours. This sensory profile could be linked to the production of 2,3 butanedione, cyclopentanol, 3-methylbutanol, 3-methylbutanal, 2-methylbutanal, 4-methyl-3-chloro-3-pentanol and ethanol, which were produced in more significant quantities in the B. thermosphacta batch than in the batches in which the protective strain was present. On the contrary, TVBN and TMA were not suitable as quality indicators for B. thermosphacta spoilage activity. In the products where the protective L. piscium strain was present, no adverse effect on sensory quality was noted by the sensory panels. Moreover, biogenic amine assessment did not show any histamine or tyramine production by this strain, underlining its safety profile. Both strains produced lactic acid (1850 mg/kg in L. piscium and B. thermosphacta batch on days 3 and 10 respectively; 3830 mg/kg on day 7 in mixed culture) and the pH decrease from 6.6 ± 0.0 to 5.9 ± 0.1 was similar in all batches. Lactic acid production or competition for free amino-acid was not involved in the inhibition mechanism; however rapid glucose consumption by L. piscium could partially explain the growth limitation of the spoilage micro-organism. This study demonstrated the spoilage characteristic of B. thermosphacta and the usefulness of L. piscium as a bioprotective culture for tropical cooked peeled shrimp without any adverse effect on the sensory quality of the product.     

Development of ultra-fine grained dual phase microalloyed steels through severe cold rolling and intercritical annealing

A Nb-microalloyed structural steel with ferrite-pearlite microstructure was subjected to cold rolling and intercritical annealing to produce ultra-fine grained dual phase microstructure. Optical and transmission electron microscopy techniques were employed to characterise the microstructure. Initial results showed that the intercritical annealing (at 790°C for 90s) of samples rolled to a true strain of 2.4 resulted in a significant grain refinement from the average initial grain size of 20 μm to 1–2 microns. The microstructure primarily consisted of UFG ferrite matrix with homogeneously distributed islands of plate martensite with volume fraction of 27%.     

NK Cells in Chronic Lymphocytic Leukemia and Their Therapeutic Implications

Key features of chronic lymphocytic leukemia (CLL) are defects in the immune system and the ability of leukemic cells to evade immune defenses and induce immunosuppression, resulting in increased susceptibility to infections and disease progression. Several immune effectors are impaired in CLL, including T and natural killer (NK) cells. The role of T cells in defense against CLL and in CLL progression and immunotherapy has been extensively studied. Less is known about the role of NK cells in this leukemia, and data on NK cell alterations in CLL are contrasting. Besides studies showing that NK cells have intrinsic defects in CLL, there is a large body of evidence indicating that NK cell dysfunctions in CLL mainly depend on the escape mechanisms employed by leukemic cells. In keeping, it has been shown that NK cell functions, including antibody-dependent cellular cytotoxicity (ADCC), can be retained and/or restored after adequate stimulation. Therefore, due to their preserved ADCC function and the reversibility of CLL-related dysfunctions, NK cells are an attractive source for novel immunotherapeutic strategies in this disease, including chimeric antigen receptor (CAR) therapy. Recently, satisfying clinical responses have been obtained in CLL patients using cord blood-derived CAR-NK cells, opening new possibilities for further exploring NK cells in the immunotherapy of CLL. However, notwithstanding the promising results of this clinical trial, more evidence is needed to fully understand whether and in which CLL cases NK cell-based immunotherapy may represent a valid, alternative/additional therapeutic option for this leukemia. In this review, we provide an overview of the current knowledge about phenotypic and functional alterations of NK cells in CLL and the mechanisms by which CLL cells circumvent NK cell-mediated immunosurveillance. Additionally, we discuss the potential relevance of using NK cells in CLL immunotherapy.     

Determination of viability of Aeromonas hydrophila in increasing concentrations of sodium chloride at different temperatures by flow cytometry and plate count technique

Aeromonads in waters and foods can represent a risk to human health. Factors such as sodium chloride concentration and temperature can affect growth and viability of several food and water-borne pathogens. The behaviour of an Aeromonas hydrophila strain in the presence of 1.7%, 3.4% and 6% NaCl concentrations at 24 degrees C and 4 degrees C was studied over a 188 day period. Viability and membrane potential were assessed by flow cytometry; growth was evaluated by plate count technique. Flow cytometry evidenced that A. hydrophila retained viability over the period although varying according to temperature and salt concentrations. Colony Forming Units were generally lower in number than viable cells especially in the presence of 6% NaCl, indicating the occurrence of stressed cells which maintain metabolic activity yet are not able to grow on agar plates. In conclusion, A. hydrophila showed a long-term halotolerance even at elevated (6%) NaCl concentrations and a lesser sensitivity to salt at low temperature; therefore, low temperature and salt, which are two important factors limiting bacterial growth, do not assure safety in the case of high initial contamination. Finally, cytometry appears a valid tool for the rapid detection of the viability of pathogenic bacteria in food and environmental matrices to control and prevent health risks.     

Serratiopeptidase Affects the Physiology of Pseudomonas aeruginosa Isolates from Cystic Fibrosis Patients

Pseudomonas aeruginosa is frequently involved in cystic fibrosis (CF) airway infections. Biofilm, motility, production of toxins and the invasion of host cells are different factors that increase P. aeruginosa’s virulence. The sessile phenotype offers protection to bacterial cells and resistance to antimicrobials and host immune attacks. Motility also contributes to bacterial colonization of surfaces and, consequently, to biofilm formation. Furthermore, the ability to adhere is the prelude for the internalization into lung cells, a common immune evasion mechanism used by most intracellular bacteria, such as P. aeruginosa. In previous studies we evaluated the activity of metalloprotease serratiopeptidase (SPEP) in impairing virulence-related properties in Gram-positive bacteria. This work aimed to investigate SPEP’s effects on different physiological aspects related to the virulence of P. aeruginosa isolated from CF patients, such as biofilm production, pyoverdine and pyocyanin production and invasion in alveolar epithelial cells. Obtained results showed that SPEP was able to impair the attachment to inert surfaces as well as adhesion/invasion of eukaryotic cells. Conversely, SPEP’s effect on pyocyanin and pyoverdine production was strongly strain-dependent, with an increase and/or a decrease of their production. Moreover, SPEP seemed to increase swarming motility and staphylolytic protease production. Our results suggest that a large number of clinical strains should be studied in-depth before drawing definitive conclusions. Why different strains sometimes react in opposing ways to a specific treatment is of great interest and will be the object of future studies. Therefore, SPEP affects P. aeruginosa’s physiology by differently acting on several bacterial factors related to its virulence.     

Microbiota Composition in Diverticular Disease: Implications for Therapy

Gut microbiota (GM) composition and its imbalance are crucial in the pathogenesis of several diseases, mainly those affecting the gastrointestinal tract. Colon diverticulosis and its clinical manifestations (diverticular disease, DD) are among the most common digestive disorders in developed countries. In recent literature, the role of GM imbalance in the onset of the different manifestations within the clinical spectrum of DD has been highlighted. This narrative review aims to summarize and critically analyze the current knowledge on GM dysbiosis in diverticulosis and DD by comparing the available data with those found in inflammatory bowel disease (IBD). The rationale for using probiotics to rebalance dysbiosis in DD is also discussed.