X-ray CT analysis after blast of composite sandwich panels

Four composite sandwich panels with either single density or graded density foam cores and different face-sheet materials were subjected to full-scale underwater blast testing. The panels were subjected to 1kg PE4 charge at a stand-off distance of 1 m. The panel with graded density core and carbon fiber face-sheets had the lowest deflection. Post-blast damage assessment was carried out using X-ray CT scanning. The damage assessment revealed that there is a trade-off between reduced panel deflection and panel damage. This research has been performed as part of a program sponsored by the Office of Naval Research (ONR)

Geographic variation and evolutionary history of Dipodomys nitratoides (Rodentia: Heteromyidae), a species in severe decline

We examined geographic patterns of diversification in the highly impacted San Joaquin kangaroo rat, Dipodomys nitratoides, throughout its range in the San Joaquin Valley and adjacent basins in central California. The currently recognized subspecies were distinct by the original set of mensural and color variables used in their formal diagnoses, although the Fresno kangaroo rat (D. n. exilis) is the most strongly differentiated with sharp steps in character clines relative to the adjacent Tipton (D. n. nitratoides) and short-nosed (D. n. brevinasus) races. The latter two grade more smoothly into one another but still exhibit independent, and different, character clines within themselves. At the molecular level, as delineated by mtDNA cytochrome b sequences, most population samples retain high levels of diversity despite significant retraction in the species range and severe fragmentation of local populations in recent decades due primarily to landscape conversion for agriculture and secondarily to increased urbanization. Haplotype apportionment bears no relationship to morphologically defined subspecies boundaries. Rather, a haplotype network is shallow, most haplotypes are single-step variants, and the time to coalescence is substantially more recent than the time of species split between D. nitratoides and its sister taxon, D. merriami. The biogeographic history of the species within the San Joaquin Valley appears tied to mid-late Pleistocene expansion following significant drying of the valley resulting from the rain shadow produced by uplift of the Central Coastal Ranges

An investigation into the impact of childhood maltreatment on brain structure

Childhood maltreatment remains a major public health concern and has been shown to significantly elevate the risk of developing a psychiatric disorder. However, there is limited understanding of the underlying mechanisms by which maltreatment heightens risk of psychiatric outcomes. By investigating cortical structural abnormalities associated with maltreatment in childhood we hope to learn more about the possible pathways that lead from abuse to psychopathology. This thesis sets out to systematically investigate two main questions within one of the largest community samples of maltreated adolescents studied to date. First, the way in which maltreatment experience impacts on brain structure. In Chapter 2, novel surface-based neuroimaging analysis techniques are used to investigate the impact of maltreatment on discrete structural indices, including cortical thickness, surface area and local gyrification. Chapter 3 explores how dimensions of maltreatment, comprising severity, subtype and duration of abuse, influence the impact of childhood maltreatment on cortical volume. Chapter 4 extends this investigation into the impact of maltreatment characteristics on cortical structure using surface-based methods of structural analysis. Second, this thesis aims to investigate sex differences in how maltreatment experience impacts brain structure, given that males and females are observed to exhibit differing behavioural and psychopathological outcomes associated with the experience of childhood maltreatment. Chapter 5 explores the sexually dimorphic impact of maltreatment on cortical volume, and this investigation is replicated in Chapter 6 in relation to distinct cortical indices using surface-based methods. Finally, Chapter 7 summarises the implications of these empirical studies, and considers the hypothesis that such cortical differences may constitute biological markers of vulnerability, increasing risk for psychiatric disorders across the lifespan

Advanced Practice Providers Recognized as Valuable Healthcare Resources: Increasing the Illinois PA’s Scope of Practice to Match Their NP Cohort

Abstract: Nurse practitioners (NPs) and physician assistants (PAs) represent a group of non-physician, advanced-practice providers (APPs) within our healthcare system. Non-physician providers are part of an inter-disciplinary team, working alongside physicians and a variety of allied healthcare providers. The purpose of this paper is to take a closer look at these two professions (NP and PA), with a focus on Illinois providers and the legislative strategies that guide their roles and abilities to practice. Illinois is a region where APP practices are inequitably regulated. Their Nurse Practice Act outlines a broad scope of practice for Advanced Practice Registered Nurses (APRNs). However, the Illinois PA Practice Act barely addresses the PA’s scope of practice, and also delineates certain restrictions, which limit practice in ways not paralleled for the NP. The goal of this paper was to construct an objective comparison between these two APP groups, in order to dispel the misconceptions that have led to these disparate Practice Acts. Specifically, the Master of Science in Nursing - Family Nurse Practitioner (MSN-FNP) training was compared to the Master of Science in Physician Assistant Studies (MSPA or MPAS) degree. Using these criteria, fifteen MSN-FNP programs were compared to nine MSPA programs among Illinois universities. Results revealed that NP and PA programs have similar educational objectives, all with demanding medical curricula, guided by strict accreditation standards. The data further revealed that Illinois PA educational training requires completion of more clinical practicum hours than does NP training: 704 (mean) hours for FNP students; compared to 2,108 (mean) hours for PA students. Furthermore, PA program accreditation requires that students complete practicum hours within seven medical fields, as well as elder care in long-term residential facilities, plus procedural skills training and proof of procedural skills competencies. Most NP programs are online and encourage concurrent nursing employment, thus supporting a part-time course load. NP programs are therefore designed to allow a flexible timeline for completion, some permitting five to six years. In comparison, all PA programs are full-time, in-person curricula, and discourage concurrent employment due to extensive course hours, and stringent requirements for advancement. The bottom line here is, NP and PA programs both have sound delivery methods and rigorous requirements, but longer chronological length should not be misinterpreted as greater in substance. Conclusion: This paper evaluated the highly advanced training programs of NPs and PAs in Illinois and found no data to support the differences in the Illinois Practice Acts governing these two groups. Despite the rigorous, highly advanced, and closely monitored training protocols of PA education, legislative bodies in Illinois do not fully recognize the PA provider’s significant potential. It is therefore, fair and reasonable to request these limitations be re-evaluated, in order to allow Illinois PAs to practice to the full potential of their professional training. In Illinois, NPs have achieved full provider status. Equal designation should be delegated to Illinois PAs

Clinical experience with the novel histone deacetylase inhibitor vorinostat (suberoylanilide hydroxamic acid) in patients with relapsed lymphoma

Preclinical studies indicate that vorinostat (suberoylanilide hydroxamic acid or SAHA) inhibits histone deacetylase (HDAC) activity, increases acetylated histones H2a, H2b, H3, and H4, and thereby induces differentiation and apoptosis in a variety of tumour cell lines, including murine erythroleukaemia, human bladder transitional cell carcinoma, and human breast adenocarcinoma. On the basis of these favourable preclinical findings, vorinostat has been selected as a candidate for clinical development with the potential to treat patients with selected malignances, including Hodgkin's disease and non-Hodgkin's lymphomas. Phase I clinical trials in patients with haematological malignances and solid tumours showed that both intravenous (i.v.) and oral formulations of vorinostat are well tolerated, can inhibit HDAC activity in peripheral blood mononuclear cells and tumour tissue biopsies, and produce objective tumour regression and symptomatic improvement with little clinical toxicity. The dose-limiting toxicities (DLT) of i.v. vorinostat were primarily haematologic and were rapidly reversible within 4–5 days of therapy cessation. In contrast, the DLT for oral vorinostat were primarily non-haematologic (including dehydration, anorexia, diarrhoea, fatigue) and were also rapidly reversible, usually within 3 days. Further research is warranted to optimise the dosing schedule for vorinostat, particularly with respect to dose, timing of administration, and duration of therapy, and to fully delineate the mechanism(s) of antitumour effect of vorinostat in various types of malignances. Several phase II studies are currently ongoing in patients with haematological malignances and solid tumours

Compressive strength after blast of sandwich composite materials

Composite sandwich materials have yet to be widely adopted in the construction of naval vessels despite their excellent strength-to-weight ratio and low radar return. One barrier to their wider use is our limited understanding of their performance when subjected to air blast. This paper focuses on this problem and specifically the strength remaining after damage caused during an explosion. Carbon-fibre-reinforced polymer (CFRP) composite skins on a styrene–acrylonitrile (SAN) polymer closed-cell foam core are the primary composite system evaluated. Glass-fibre-reinforced polymer (GFRP) composite skins were also included for comparison in a comparable sandwich configuration. Full-scale blast experiments were conducted, where 1.6×1.3 m sized panels were subjected to blast of a Hopkinson–Cranz scaled distance of 3.02 m kg−1/3, 100 kg TNT equivalent at a stand-off distance of 14 m. This explosive blast represents a surface blast threat, where the shockwave propagates in air towards the naval vessel. Hopkinson was the first to investigate the characteristics of this explosive air-blast pulse (Hopkinson 1948 Proc. R. Soc. Lond. A 89, 411–413 (doi:10.1098/rspa.1914.0008)). Further analysis is provided on the performance of the CFRP sandwich panel relative to the GFRP sandwich panel when subjected to blast loading through use of high-speed speckle strain mapping. After the blast events, the residual compressive load-bearing capacity is investigated experimentally, using appropriate loading conditions that an in-service vessel may have to sustain. Residual strength testing is well established for post-impact ballistic assessment, but there has been less research performed on the residual strength of sandwich composites after blast

Incidence of Lead System Malfunction Detected During Implantable Defibrillator Generator Replacement

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71565/1/j.1540-8159.1996.tb04183.x.pd

Modelling isotropic and kinematic hardening of granular materials with a thermodynamical approach

The thermodynamic framework for continuum mechanics can be applied to model granular and porous materials. Broadly speaking, there exists two approaches: the French school approach and Ziegler’s approach. Despite the fact that they both have the same foundations, differences between them emerge regarding the way in which stored energy is accounted for. This is illustrated here by applying the two approaches to the classical Von Mises kinematic and isotropic hardening models. In Ziegler’s approach, the stored energy is solely used for the kinematic hardening, as opposed to the French school approach in which the stored energy is allowed in both cases of hardening. In spite of which modelling approach is taken, we will show how certain modifications to these theories have to be made in order to develop the classical modified Cam Clay model, which emphasises the difference between the classical and the thermodynamic formulations

Impact of proctoring on success rates for percutaneous revascularisation of coronary chronic total occlusions.

OBJECTIVE: To assess the impact of proctoring for chronic total occlusion (CTO) percutaneous coronary intervention (PCI) in six UK centres. METHODS: We retrospectively analysed 587 CTO procedures from six UK centres and compared success rates of operators who had received proctorship with success rates of the same operators before proctorship (pre-proctored) and operators in the same institutions who had not been proctored (non-proctored). There were 232 patients in the pre-proctored/non-proctored group and 355 patients in the post-proctored group. Complexity was assessed by calculating the Japanese CTO (JCTO) score for each case. RESULTS: CTO PCI success was greater in the post-proctored compared with the pre-proctored/non-proctored group (77.5% vs 62.1%, p<0.0001). In more complex cases where JCTO≥2, the difference in success was greater (70.7% vs 49.5%, p=0.0003). After proctoring, there was an increase in CTO PCI activity in centres from 2.5% to 3.5%, p<0.0001 (as a proportion of total PCI), and the proportion of very difficult cases with JCTO score ≥3 increased from 15.3% (35/229) to 29.7% (105/354), p<0.0001. CONCLUSIONS: Proctoring resulted in an increase in procedural success for CTO PCI, an increase in complex CTO PCI and an increase in total CTO PCI activity. Proctoring may be a valuable way to improve access to CTO PCI and the likelihood of procedural success

Microstructural characterization of AISI 431 martensitic stainless steel laser-deposited coatings

High cooling rates during laser cladding of stainless steels may alter the microstructure and phase constitution of the claddings and consequently change their functional properties. In this research, solidification structures and solid state phase transformation products in single and multi layer AISI 431 martensitic stainless steel coatings deposited by laser cladding at different processing speeds are investigated by optical microscopy, Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), orientation imaging microscopy (OIM), ternary phase diagram, Schaeffler and TTT diagrams. The results of this study show how partitionless solidification and higher solidification rates alter the microstructure and phase constitution of martensitic stainless steel laser deposited coatings. In addition, it is shown that while different cladding speeds have no effect on austenite–martensite orientation relationship in the coatings, increasing the cladding speed has resulted in a reduction of hardness in deposited coatings which is in contrast to the common idea about obtaining higher hardness values at higher cladding speeds.