Vibration energy harvesting is being pursued as a means to power wireless sensors and ultra-low power autonomous devices. From a design standpoint, matching the electrical damping induced by the ...energy harvesting mechanism to the mechanical damping in the system is necessary for maximum efficiency. In this work two independent energy harvesting techniques are coupled to provide higher electrical damping within the system. Here the coupled energy harvesting device consists of a primary piezoelectric energy harvesting device to which an electromagnetic component is added to better match the total electrical damping to the mechanical damping in the system. The first coupled device has a resonance frequency of 21.6 Hz and generates a peak power output of ~332 muW, compared to 257 and 244 muW obtained from the optimized, stand-alone piezoelectric and electromagnetic energy harvesting devices, respectively, resulting in a 30% increase in power output. A theoretical model has been developed which closely agrees with the experimental results. A second coupled device, which utilizes the d33 piezoelectric mode, shows a 65% increase in power output in comparison to the corresponding stand-alone, single harvesting mode devices. This work illustrates the design considerations and limitations that one must consider to enhance device performance through the coupling of multiple harvesting mechanisms within a single energy harvesting device.
The effects of nonionic polymers on human red blood cell (RBC) aggregation were investigated. The hydrodynamic radius (
R
h) of individual samples of dextran, polyvinylpyrrolidone, and ...polyoxyethylene over a range of molecular weights (1500–2,000,000) were calculated from their intrinsic viscosities using the Einstein viscosity relation and directly measured by quasi-elastic light scattering, and the effect of each polymer sample on RBC aggregation was studied by nephelometry and low-shear viscometry. For all three polymers, despite their different structures, samples with
R
h <4
nm were found to inhibit aggregation, whereas those with
R
h >4
nm enhanced aggregation. Inhibition increased with
R
h and was maximal at ∼3
nm; above 4
nm the pro-aggregant effect increased with
R
h. For comparison, the
R
h of 12 plasma proteins were calculated from literature values of intrinsic viscosity or diffusion coefficient. Each protein known to promote RBC aggregation had
R
h >4
nm, whereas those with
R
h <4
nm either inhibited or had no effect on aggregation. These results suggest that the influence of a nonionic polymer or plasma protein on RBC aggregation is simply a consequence of its size in an aqueous environment, and that the specific type of macromolecule is of minor importance.
Chloride concentrations are increasing at a rate that threatens the availability of fresh water in the northeastern United States. Increases in roadways and deicer use are now salinizing fresh ...waters, degrading habitat for aquatic organisms, and impacting large supplies of drinking water for humans throughout the region. We observed chloride concentrations of up to 25% of the concentration of seawater in streams of Maryland, New York, and New Hampshire during winters, and chloride concentrations remaining up to 100 times greater than unimpacted forest streams during summers. Mean annual chloride concentration increased as a function of impervious surface and exceeded tolerance for freshwater life in suburban and urban watersheds. Our analysis shows that if salinity were to continue to increase at its present rate due to changes in impervious surface coverage and current management practices, many surface waters in the northeastern United States would not be potable for human consumption and would become toxic to freshwater life within the next century.
This article examines the reach of Black Internationalism, a dialogue on race, politics, and modernity nurtured by Black nationalists in the United States, between 1971 and 1974. It focuses on ...Israel’s encounter with the topic and how Israeli political leaders neutralize its effects. Israel, one of America’s closes Cold War allies, faced three explosive movements with ties to the discourse and politics of Black Internationalism—the Israeli Black Panthers, the Black Hebrews, and the Jewish Defense League. Each group challenged the narrative of inclusion the nation cultivated since its inception. Israel’s ability to manage the crisis of Black Internationalism demonstrates the topic’s global reach in the final stages of the Cold War, but also its limitations.
Rural landscapes in South Africa experience high conversion rates due to intense land use; however, the changes are site specific and depend on the socio-economic and political history of the area. ...Land cover change (LCC) was assessed in response to socio-economic and political factors in uThukela Municipal District, KwaZulu-Natal, using Landsat imagery from 1984 to 2014, while making comparisons to other studies in South Africa. Socio-economic/political data were used to gain insights into the observed LCC patterns. Land cover was classified using a random forest classifier, and accuracies ranging from 87% to 92% were achieved. Systematic and intensity analysis methods were used to describe patterns, rates, and transitions of LCC in Imbabazane (ILM) and Okhahlamba (OLM) local municipalities. The results showed a reduced rate of change intensity from 3.4% to 0.9% in ILM and from 3.1% to 1.1% in OLM between 1984 and 2014. Grassland was persistent, covering over 70% in both local municipalities between 1984 and 2014. Although persistent, grassland experienced respective losses of 3.7% and 14.3% in both observation periods in ILM and of 10.2% and 13.3% in OLM. During the analysis period, settlements and cropland gained actively in both local municipalities. The changes represent a degree of population, local authority, and people’s perception as influencers of land use and LCC. It is therefore argued that socio-economic and political changes can potentially influence land use and LCC; however, natural ecosystems can persist under those conditions, and this requires more research efforts.
Significance:
This study contributes towards a growing knowledge and understanding of land cover change studies in marginalised landscapes in South Africa. The findings enforce the notion that natural vegetation systems can be altered by human-induced land use such as expansion of settlement and commercial agricultural. We show that in recent times there has been a decline in the overall rate of land cover conversion, and a high persistence of grassland amid global change, although the quality of the vegetation needs further research. We argue that the changes observed in marginalised landscapes are potentially driven by socio-economic and political dynamics.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Tumour vessels have been studied extensively as they are critical sites for drug delivery, anti-angiogenic therapies and immunotherapy. As a preclinical tool, intravital microscopy (IVM) allows for ...in vivo real-time direct observation of vessels at the cellular level. However, to date there are no reports of intravital high-resolution imaging of human tumours in the clinical setting. Here we report the feasibility of IVM examinations of human malignant disease with an emphasis on tumour vasculature as the major site of tumour-host interactions. Consistent with preclinical observations, we show that patient tumour vessels are disorganized, tortuous and ∼50% do not support blood flow. Human tumour vessel diameters are larger than predicted from immunohistochemistry or preclinical IVM, and thereby have lower wall shear stress, which influences delivery of drugs and cellular immunotherapies. Thus, real-time clinical imaging of living human tumours is feasible and allows for detection of characteristics within the tumour microenvironment.
This paper explores the relationship between people's feelings about dirt, and an apparent reduction in the lifetime of vacuum cleaners. The short life-spans of vacuum cleaners is a significant ...environmental issue. In addition to the waste generated, they have an impact on climate change: vacuum cleaners account for the second largest embodied greenhouse gas emissions of electrical goods in the UK after televisions, largely because of their high sales volumes.
Drawing from qualitative and quantitative research undertaken for the UK Department for Environment, Food & Rural Affairs (Defra), the paper demonstrates that one motivation for vacuum cleaner replacement is the increased enjoyment from dirt removal that a new vacuum cleaner may provide. The paper also shows that premature disposal can occur once a product becomes dirty and visually damaged, and whilst functional, is perceived to be less effective. Solutions to premature disposal were explored through the co-creation of design concepts and design features were tested via an online survey.
Vacuum cleaner users were clustered into four cleaner types; Spartan, Minimal, Caring and Manic. Overall, respondents reported that improving the ease of maintaining vacuum cleaners would be the most effective way to help them to increase their vacuum cleaner's longevity. Across all cleaner types maintenance levels were low, although Caring and Manic cleaners were significantly more likely to undertake such tasks. Motivations for disposal were similar across cleaner types and we found no evidence that Caring and Manic cleaners disposed of their machines earlier because they were ‘worn out.’
We discovered that Caring and Manic cleaners spend the most on their vacuum cleaners, vacuum more often and are the most likely to replace their machine after the shortest period. Those willing to do ‘a lot more’ to help the environment were significantly more likely to want to ‘keep the floors in my home spotlessly clean’ and significantly more likely to indicate that they preferred their vacuum cleaner to look new. Consequently, the paper proposes that design interventions to increase vacuum longevity should be targeted toward Caring and Manic cleaners and concludes with key design recommendations for these two cleaner types.
Landscape change is a key driver of biodiversity declines due to habitat loss and fragmentation, but spatially shifting resources can also facilitate range expansion and invasion. Invasive ...populations are reproductively successful, and landscape change may buoy this success.
We show how modeling the spatial structure of reproductive success can elucidate the mechanisms of range shifts and sustained invasions for mammalian species with attendant young. We use an example of white‐tailed deer (deer; Odocoileus virginianus) expansion in the Nearctic boreal forest, a North American phenomenon implicated in severe declines of threatened woodland caribou (Rangifer tarandus).
We hypothesized that deer reproductive success is linked to forage subsidies provided by extensive landscape change via resource extraction. We measured deer occurrence using data from 62 camera traps in northern Alberta, Canada, over three years. We weighed support for multiple competing hypotheses about deer reproductive success using multistate occupancy models and generalized linear models in an AIC‐based model selection framework.
Spatial patterns of reproductive success were best explained by features associated with petroleum exploration and extraction, which offer early‐seral vegetation resource subsidies. Effect sizes of anthropogenic features eclipsed natural heterogeneity by two orders of magnitude. We conclude that anthropogenic early‐seral forage subsidies support high springtime reproductive success, mitigating or exceeding winter losses, maintaining populations.
Synthesis and Applications. Modeling spatial structuring in reproductive success can become a key goal of remote camera‐based global networks, yielding ecological insights into mechanisms of invasion and range shifts to inform effective decision‐making for global biodiversity conservation.
White‐tailed deer are expanding into the boreal with detrimental effects on the mammal community. Landscape change via resource extraction best explains successful deer reproduction in this boreal landscape.
Background
Adverse events (AEs) on Children's Oncology Group (COG) trials are reported manually by clinical research assistants (CRAs). The Common Terminology Criteria for Adverse Events (CTCAE) was ...developed to provide standardized definitions for identifying and grading AEs. The CTCAE has expanded significantly over its five versions, but the impact of CTCAE definitional changes has not been examined.
Procedure
This study compared AE number and ascertainment among the first four CTCAE versions using a case vignette. Each CTCAE version was used to create a list of AEs and grades by two separate CRAs.
Results
The CTCAE expanded from 9 categories and 49 AEs in v1.0 to 26 categories and 790 AEs in v4.0. CRAs independently selected different approaches to AE ascertainment—comprehensive and parsimonious. The number of AEs identified in the parsimonious approach was stable with 10–14 in each CTC version. The comprehensive approach identified 9, 20, 29, and 37 AEs in CTC versions 1.0, 2.0, 3.0, and 4.0, respectively. Only approximately 65% of AEs were conclusively graded in versions 2.0 to 4.0 using the comprehensive approach.
Conclusions
CTCAE has increased in complexity. Although this increased complexity allows for more granular AE reporting, these data demonstrate potential unintended negative consequences of increasing CTC AE complexity, including the risk of varying approaches to AE capture. A comprehensive evaluation of CTC AE definitions and CRA reporting practices across COG institutions and AEs are needed to improve the accuracy and efficiency of AE reporting.
T-cell trafficking at vascular sites has emerged as a key step in antitumour immunity. Chemokines are credited with guiding the multistep recruitment of CD8(+) T cells across tumour vessels. However, ...the multiplicity of chemokines within tumours has obscured the contributions of individual chemokine receptor/chemokine pairs to this process. Moreover, recent studies have challenged whether T cells require chemokine receptor signalling at effector sites. Here we investigate the hierarchy of chemokine receptor requirements during T-cell trafficking to murine and human melanoma. These studies reveal a non-redundant role for Gαi-coupled CXCR3 in stabilizing intravascular adhesion and extravasation of adoptively transferred CD8(+) effectors that is indispensable for therapeutic efficacy. In contrast, functional CCR2 and CCR5 on CD8(+) effectors fail to support trafficking despite the presence of intratumoral cognate chemokines. Taken together, these studies identify CXCR3-mediated trafficking at the tumour vascular interface as a critical checkpoint to effective T-cell-based cancer immunotherapy.
PDF
