A Modified Surface on Titanium Deposited by a Blasting Process

Abstract : Hydroxyapatite (HA) coating of hard tissue implants is widely employed for its biocompatible and osteoconductive properties as well as its improved mechanical properties. Plasma technology is the principal deposition process for coating HA on bioactive metals for this application. However, thermal decomposition of HA can occur during the plasma deposition process, resulting in coating variability in terms of purity, uniformity and crystallinity, which can lead to implant failure caused by aseptic loosening. In this study, CoBlast™, a novel blasting process has been used to successfully modify a titanium (V) substrate with a HA treatment using a dopant/abrasive regime. The impact of a series of apatitic abrasives under the trade name MCD, was investigated to determine the effect of abrasive particle size on the surface properties of both microblast (abrasive only) and CoBlast (HA/abrasive) treatments. The resultant HA treated substrates were compared to substrates treated with abrasive only (microblasted) and an untreated Ti. The HA powder, apatitic abrasives and the treated substrates were characterized for chemical composition, coating coverage, crystallinity and topography including surface roughness. The results show that the surface roughness of the HA blasted modification was affected by the particle size of the apatitic abrasives used. The CoBlast process did not alter the chemistry of the crystalline HA during deposition. Cell proliferation on the HA surface was also assessed, which demonstrated enhanced osteo-viability compared to the microblast and blank Ti. This study demonstrates the ability of the CoBlast process to deposit HA coatings with a range of surface properties onto Ti substrates. The ability of the CoBlast technology to offer diversity in modifying surface topography offers exciting new prospects in tailoring the properties of medical devices for applications ranging from dental to orthopedic settings

Rapid development and implementation of a behaviour change strategy to improve COVID-19 personal protective equipment use in a regional Australian emergency department

Objective: To identify barriers to, describe the development of and evaluate the implementation of a behavioural theory informed strategy to improve staff personal protective equipment (PPE) compliance during COVID-19 in a regional Australian Emergency Department. Methods: Barriers to PPE use were identified through staff consultation then categorised using the Theoretical Domains Framework. The Behaviour Change Wheel was used to develop a strategy to address the barriers to PPE compliance. The strategy was refined and endorsed by the site COVID taskforce. Data were collected through direct observation. Descriptive statistics were used to summarise PPE compliance and inductive content analysis for free text data of staff behaviours. Results: 73 barriers were identified, mapped to 9 intervention functions and 42 behaviour change techniques. The predominant mechanisms were: (1) Executive communication reinforcing policy and consequences; (2) implementation of a PPE Marshal; (3) face to face reinforcement / modeling; (4) environmental restructuring including electronic medical record modifications. The PPE Marshal observed 281 PPE activities. PPE compliance varied between 47.9% (Buddy check) and 91.8% (Bare below elbow). The PPE Marshal intervened on 121 occasions, predominantly through buddying, explaining and demonstrating correct PPE use, most frequently with medical staff (72%). Conclusion: We describe an evidence-based process to overcome barriers to PPE compliance that maximize safe work practice in a time critical situation. Staff require enabling, access to equipment and reinforcement to use PPE correctly

Impact of renal insufficiency on short-term morbidity and mortality after lower extremity revascularization: Data from the Department of Veterans Affairs\u27 National Surgical Quality Improvement Program

Few data are available on the impact of renal insufficiency on short-term operative outcomes after lower extremity surgical revascularization. We used prospectively collected data from the Department of Veterans Affairs\u27 National Surgical Quality Improvement Program (NSQIP) to explore the association with renal dysfunction of adverse outcomes occurring within 30 d of lower extremity surgical revascularization in a cohort of all patients undergoing at least one lower extremity surgical revascularization from 1/1/94 to 9/30/01 (n = 18,217). Even moderate renal insufficiency (estimated GFR 30-59cc/min/1.73m2) was associated with an increased incidence of postoperative death (adjusted odds ratio (OR) 1.44, 95% confidence interval (CI), 1.17 to 1.77, P = 0.001), cardiac arrest (OR 1.43, CI 1.09 to 1.88, P = 0.011), myocardial infarction (OR 1.68, 1.39 to 2.16, P \u3c 0.001), unplanned intubation (OR 1.69, CI 1.39 to 2.07, P \u3c 0.001) and prolonged intubation (OR 1.57, CI 1.28 to 1.94, P \u3c 0.001) within 30 d of lower extremity revascularization. However, the incidence of wound infection and graft failure requiring return to the operating room did not appear to be substantially higher in this group. Our data also show that patients with renal insufficiency undergoing revascularization were more likely to require distal procedures and to present with limb-threatening infection compared to those with normal renal function. Efforts to improve pre-and post-operative care in patients with renal insufficiency undergoing lower extremity revascularization should take into account the increased incidence of postoperative death and cardiopulmonary complications in this group in addition to more traditional concerns about operative site complications. Further studies are needed to explore reasons for the higher rate of limb-threatening infection in patients with renal insufficiency undergoing revascularization

Suez, wond\u27rous Suez, where I was captured with your love [first line of chorus]

Performers: "Husk" O\u27Hare and His Super-OrchestraPiano, Voice and Chord

Sequence recognition in the minor groove of DNA by covalently linked formamido imidazole-pyrrole-imidazole polyamides: effect of H-pin linkage and linker length on selectivity and affinity

The polyamide N-formamido imidazole-pyrrole-imidazole (f-ImPyIm) binds with an exceptionally high affinity for its cognate site 5\u27-ACGCGT-3\u27 as a stacked, staggered, and noncovalent cooperative dimer. Investigations are presented into its sequence specificity and binding affinity when linked covalently as an H-pin dimer . Five f-ImPyIm cross-linked analogues with six to nine methylene linkers and an eight-linked ethylene glycol linker were examined to investigate the effect of linkage and linker length on DNA binding. Thermal denaturation studies on short DNA hairpins showed preferential binding by both f-ImPyIm (DeltaTm = 7.8 degrees C) and its cross-linked derivatives (DeltaTm \u3e 30 degrees C) at 5\u27-ACGCGT-3\u27, indicating sequence specificity was retained on linkage. DNase I footprinting confirmed strict cognate site selectivity and demonstrated that affinity increased with linker length (f-ImPyIm-9 = f-ImPyIm-8 = f-ImPyIm-EG-8 \u3e f-ImPyIm-7 \u3e f-ImPyIm-6). The eight- and nine-linked derivatives bound at 100-fold lower concentrations at the cognate site relative to f-ImPyIm-6, and with 10-fold higher affinity than unlinked f-ImPyIm. Use of an ethylene glycol linkage in f-ImPyIm-EG-8 to improve solubility slightly increased the cognate site affinity relative to those of f-ImPyIm-8 and f-ImPyIm-9, although some selectivity was lost at high ligand concentration. CD demonstrated that cognate site binding by eight and nine-linked compounds occurred in the minor groove. SPR analysis gave a binding affinity (K) for f-ImPyIm-EG-8 at the cognate site of 2 x 10(10) M-1, representing a 100-fold increase relative to that of f-ImPyIm. This study demonstrates that the high-affinity cooperative binding of f-ImPyIm can be enhanced significantly by suitable covalent linkage, while maintaining its strict cognate site selectivity

Evasion of innate cytosolic DNA sensing by a gammaherpesvirus facilitates establishment of latent infection

Herpesviruses are DNA viruses harboring the capacity to establish lifelong latent-recurrent infections. There is limited knowledge about viruses targeting the innate DNA-sensing pathway, as well as how the innate system impacts on the latent reservoir of herpesvirus infections. In this article, we report that murine gammaherpesvirus 68 (MHV68), in contrast to alpha- and beta-herpesviruses, induces very limited innate immune responses through DNA-stimulated pathways, which correspondingly played only a minor role in the control of MHV68 infections in vivo. Similarly, Kaposi\u27s sarcoma-associated herpesvirus also did not stimulate immune signaling through the DNA-sensing pathways. Interestingly, an MHV68 mutant lacking deubiquitinase (DUB) activity, embedded within the large tegument protein open reading frame (ORF)64, gained the capacity to stimulate the DNA-activated stimulator of IFN genes (STING) pathway. We found that ORF64 targeted a step in the DNA-activated pathways upstream of the bifurcation into the STING and absent in melanoma 2 pathways, and lack of the ORF64 DUB was associated with impaired delivery of viral DNA to the nucleus, which, instead, localized to the cytoplasm. Correspondingly, the ORF64 DUB active site mutant virus exhibited impaired ability to establish latent infection in wild-type, but not STING-deficient, mice. Thus, gammaherpesviruses evade immune activation by the cytosolic DNA-sensing pathway, which, in the MHV68 model, facilitates establishment of infections