Electrodeposited nickel–graphene nanocomposite coating: effect of graphene nanoplatelet size on its microstructure and hardness

In this study, the effect of graphene nanoplatelet (GNP) size on the microstructure and hardness of the electrodeposited nickel–graphene nanocomposite coatings were investigated. GNPs with different sizes were prepared by using a high energy ball milling technique. The experimental result revealed the high energy ball milling technique could reduce the size, increase the surface area, and improve the dispersion ability of GNPs. The microstructure, hardness, and components of the nanocomposite coatings were greatly affected by GNP sizes. The highest microhardness was measured to be 273 HV for the nanocomposite coatings containing 5 h-milled GNPs, which is increased up to ∼47% compared to pristine Ni coating. The enhancement in the hardness is attributed to the uniform dispersion of the small GNP sizes inside the Ni matrix and the Ni grain size reduction when using milled GNPs.

The effect of graphene nanoplatelet size on the microstructure and hardness of electrodeposited nickel–graphene nanocomposite coatings was investigated.     

Association between granzyme B and perforin I polymorphisms and allograft outcomes in Hispanic kidney transplant recipients

Granzyme B (GZMB) and perforin 1 gene (PRF1) are key effector molecules of cytotoxic T lymphocytes, in causing acute and chronic solid organ transplant rejection. In this study, we analyzed the impact of GZMB and PRF1 polymorphism on kidney allograft outcomes. In all, 527 de novo kidney Hispanic allograft recipients were genotyped for PRF1 (rs10999426, rs35947132) and GZMB (rs8192917, rs7144366). PRF1 (rs10999426, rs35947132) G alleles and GG genotypes were negatively associated with allograft rejection, demonstrating protection against allograft rejection (OR = 0.61, p = 0.005 for rs1099946; OR = 0.4, p = 0.01 for rs 35947132). On the other hand, the GA heterozygosity of PRF1 was found marginally associated with the rejection group (OR = 1.53, p = 0.05 for rs10999426; OR = 2.24, p = 0.07 for rs35947132). There was a significant increase in allograft survival in time period studied for the PRF1 (rs10999426) GG genotype, while the GA heterozygosity was associated with graft failure. We found no association for polymorphic markers in GZMB gene with allograft rejection. Survival was significantly improved for patients who were homozygous TT for the GZMB (rs8192917) (TT vs. CC/TT, p = 0.041). The result suggests that PRF1 and GZMB gene polymorphisms may determine the incidence of acute rejection or graft survival among Hispanic allograft recipients.     

The comparison of two negative‐pressure wound therapy systems in a porcine model of wound healing

The purpose of this study was to compare two negative‐pressure wound healing systems (NPWT), ?75 mmHg with a silicone‐coated (SC) dressing and ?125 mmHg with polyurethane foam dressing (standard of care). In addition, this study compared the effects of two different dressing interfaces, SC dressing and gauze, with ?75 mmHg pressure. For both comparisons, two groups of five pigs were evaluated over a 21‐day time course. Two excisional wounds were made on each animal and NPWT dressings were applied. A canvas saddle was constructed to hold the NPWT device so the animal had free range of the pen. Dressings were changed twice a week and wound measurements were taken. Specimens for histology and gene expression analyses were taken on day 7 and 21. These data show that there is increased expression in a few genes associated with remodeling and inflammatory processes in the NPWT‐125 with polyurethane foam as compared with the NPWT‐75 with SC dressing. These two systems, however, are equivalent with respect to wound healing, histology, and gene expression over 21 days of healing. Further, we demonstrate that there is no difference in measure of healing between the SC dressing and a basic gauze dressing.     

The Effect of Court Location and Available Time on the Tactical Shot Selection of Elite Squash Players

No previous research in squash has considered the time between shots or the proximity of the ball to a wall, which are two important variables that influence shot outcomes. The aim of this paper was to analyse shot types to determine the extent to which they are played in different court areas and a more detailed analysis to determine whether the time available had an influence on the shot selected. Ten elite matches, contested by fifteen of the world’s top right handed squash players (age 27 ± 3.2, height 1.81 ± 0.06 m, weight 76.3 ± 3.7 kg), at the men’s World Team Championships were processed using the SAGIT/Squash tracking system with shot information manually added to the system. Results suggested that shot responses were dependent upon court location and the time between shots. When these factors were considered repeatable performance existed to the extent that one of two shots was typically played when there was limited time to play the shot (< 1.20s). For example, it was clear that when players did not have a lot of time to hit the ball (low time i.e. < 1.06s, and mid time i.e. 1.06 - 1.20s) in the front left corner close to the side wall, the crosscourt lob was used frequently (44.30% and 36.31% respectively) whereas when there was more time this shot was seldom used (13.64%). Consequently variant and invariant behaviour were shown to exist in elite squash although for the first time it was suggested that the availability of time to play a shot contributed to which of these behaviours was evident. This analysis could be extended by adopting a case study approach to see how individual differences in strategy and tactics affect shot selections.

Key points

• Previous research has suggested that a playing strategy, elements decided in advance of the match, may be evident for elite players by examining court location and preceding shot type, however these parameters alone are unlikely to be sufficient predictors.
• At present there is no known analysis in squash, or indeed in any of the racket sports, that has quantified the time available to respond to different shot types. An understanding of the time interval between shots and the movement characteristics of the player responding to different shots according to the court positions might facilitate a better understanding of the dynamics that determine shot selection.
• Some elements of a general playing strategy were evident e.g. predominately hitting to the back left of the court, but tactical differences in shot selection were also evident on the basis of court location and time available to play a shot.

Key words: Strategy, tactics, SAGIT, invariant behaviour.     

Enhanced thrombin generation in women with a history of oral contraception-related venous thrombosis

Introduction

In women who suffer venous thrombosis (VT) during oral contraceptive (OC) use, a transient risk factor (OC) is removed during the acute event, while most co-existing forms of thrombophilia persist and presumably continue to maintain hypercoagulability. The aim of this study was to establish if hypercoagulability persists long after OC-related VT and if it could be attributed to thrombophilia.

Materials and Methods

60 women (age 33.0 ± 8.5 years) were investigated 5 – 64 (median 33) months after OC-related VT (patients) and compared to 63 apparently healthy women (controls). All women were tested for thrombophilia, activated partial thromboplastin time (APTT), fibrinogen, D-dimer, P-selectin and C-reactive protein. Thrombin generation was measured by Technothrombin® TGA assay. Overall haemostasis potential (OHP) assay with overall coagulation potential (OCP) and overall fibrinolytic potential (OFP) as supplementary parameters were measured by repeated fibrin formation and degradation registration.

Results

In patients increased endogenous thrombin potential (4205 ± 440 nM x min vs 4015 ± 421 nM x min, p = 0.017), increased OCP (22.6 ± 4.6 Abs-sum vs 20.8 ± 4.1 Abs-sum, p = 0.025), shorter APTT (30.9 ± 3.8 s vs 33.4 ± 3.6 s, p < 0.001) and lower antithrombin activity (99, 93-105% vs 104, 100-109%, p < 0.05) were observed. Thrombophilia was observed in 22/60 (36%) patients and in 5/63 (7.9%, p < 0.001) controls. The only significant difference between thrombophilic and non-thrombophilic patients was higher soluble P-selectin in the former subgroup (22, 20-33 μg/L vs 17, 12-22 μg/L, p = 0.012).

Conclusions

In women with a history of OC-related VT persistent hypercoagulability was observed, which, however was not augmented by the presence of thrombophilia.     

Phase 3 evaluation of HP802‐247 in the treatment of chronic venous leg ulcers

In 2012 we reported promising results from a phase 2 clinical trial of HP802‐247, a novel spray‐applied investigational treatment for chronic venous leg ulcers consisting of human, allogeneic fibroblasts and keratinocytes. We now describe phase 3 clinical testing of HP802‐247, its failure to detect efficacy, and subsequent investigation into the root causes of the failure. Two randomized, controlled trials enrolled a total of 673 adult outpatients at 96 centers in North America and Europe. The primary endpoint was the proportion of ulcers with confirmed closure at the end of 12 weeks of treatment. An investigation into the root cause for the failure of HP802‐247 to show efficacy in these two phase 3 trials was initiated immediately following the initial review of the North American trial results. Four hundred twenty‐one patients were enrolled in the North American (HP802‐247, 211; Vehicle 210) and 252 in the European (HP802‐247, 131; Vehicle 121) trials. No difference in proportion of closed ulcers at week 12 was observed between treatment groups for either the North American (HP802‐247, 61.1%; Vehicle 60.0%; p = 0.5896) or the European (HP802‐247, 47.0%; Vehicle 50.0%; p = 0.5348) trials. Thorough investigation found no likelihood that design or execution of the trials contributed to the failure. Variability over time during the trials in the clinical response implicated the quality of the cells comprising HP802‐247. Concordance between the two separate, randomized, controlled trials with distinct, nonoverlapping investigative sites and independent monitoring teams renders the possibility of a Type II error vanishingly small and provides strong credibility for the unexpected lack of efficacy observed. The most likely causative factors for the efficacy failure in phase 3 was phenotypic change in the cells (primarily keratinocytes) leading to batch to batch variability due to the age of the cell banks.     

Defining a new diagnostic assessment parameter for wound care: Elevated protease activity,an indicator of nonhealing,for targeted protease‐modulating treatment

It is widely accepted that elevated protease activity (EPA) in chronic wounds impedes healing. However, little progress has occurred in quantifying the level of protease activity that is detrimental for healing. The aim of this study was to determine the relationship between inflammatory protease activity and wound healing status, and to establish the level of EPA above which human neutrophil‐derived elastase (HNE) and matrix metalloproteases (MMP) activities correlate with nonhealing wounds. Chronic wound swab samples (n = 290) were collected from four wound centers across the USA to measure HNE and MMP activity. Healing status was determined according to percentage reduction in wound area over the previous 2–4 weeks; this was available for 211 wounds. Association between protease activity and nonhealing wounds was determined by receiver operating characteristic analysis (ROC), a statistical technique used for visualizing and analyzing the performance of diagnostic tests. ROC analysis showed that area under the curve (AUC) for HNE were 0.69 for all wounds and 0.78 for wounds with the most reliable wound trajectory information, respectively. For MMP, the corresponding AUC values were 0.70 and 0.82. Analysis suggested that chronic wounds having values of HNE >5 and/or MMP ≥13, should be considered wound healing impaired. EPA is indicative of nonhealing wounds. Use of a diagnostic test to detect EPA in clinical practice could enable clinicians to identify wounds that are nonhealing, thus enabling targeted treatment with protease modulating therapies.