The fractional shortening-velocity ratio: Validation of a new echocardiographic doppler method for identifying patients with significant aortic stenosis

AbstractPrevious studies have shown that Doppler echographic methods based on the continuity equation can accurately determine aortic valve area in patients with clinically significant aortic stenosis; nonetheless, methods based on the continuity equation are time-consuming and may not be technically possible in all subsets of patients. Thee purpose of this study was to develop and prospectively evaluate a simpler new noninvasive method for determining aortic valve area. With this new method, aortic valve area is obtained by dividing the percent fractional anteroposterior shortening at the midventriclevel by 4V2, where V is the peak instantaneous Doppler-derived How velocity across the aortic valve.In the fast part of the study, the fractional shortening-velocity ratio was used to examine a group of 25 patients evaluated retrospectively. There was a highly significant linear relation between the fractional shortening-velocity ratio (FSVR) and the aortic valve area (AVA) determined by the Gorlin formula at cardiac catheterization: FSVR = 1.1(AVA) − 0.1 (r = 0.88; significance of slope p < 0.001). Furthermore, a fractional shortening-velocity ratio <1.1 reliably identified all patients with clinically significant aortic stenosis (aortic valve area <1 cm2), whereas a fractional shortening-velocity ratio <0.8 reliably identified all patients with critical aortic stenosis (aortic valve area <0.7 cm2).This new method was then validated by prospectively applying the fractignal shortening-velocity ratio to a group of 44 patients from two separate institutions. This prospective study showed that a fractional shortening-velocity ratio <l.l had a seRR-Jitivity of 90% to 96% and a positive predictive accuracy of 90% to 92% for identifying patients with significant aortic stenosis, whereas a fractional shortening-velocity ratio <0.8 had a sensitivity of 100% and a predictive accuracy of 74% to % for identifying patients with critical aortic stenosis.In summary, the fractional shortening-velocity ratio is a new Doppler echocardiographic method that reliably identifies patients with clinically significant aortic stenosis. The simplicity of this new noninvasive method readily lends itself to routine clinical use

Lifshitz transition and van Hove singularity in a Topological Dirac Semimetal

A topological Dirac semimetal is a novel state of quantum matter which has recently attracted much attention as an apparent 3D version of graphene. In this paper, we report critically important results on the electronic structure of the 3D Dirac semimetal Na3Bi at a surface that reveals its nontrivial groundstate. Our studies, for the first time, reveal that the two 3D Dirac cones go through a topological change in the constant energy contour as a function of the binding energy, featuring a Lifshitz point, which is missing in a strict 3D analog of graphene (in other words Na3Bi is not a true 3D analog of graphene). Our results identify the first example of a band saddle point singularity in 3D Dirac materials. This is in contrast to its 2D analogs such as graphene and the helical Dirac surface states of a topological insulator. The observation of multiple Dirac nodes in Na3Bi connecting via a Lifshitz point along its crystalline rotational axis away from the Kramers point serves as a decisive signature for the symmetry-protected nature of the Dirac semimetal's topological groundstate.Comment: 5 pages, 4 Figures, Related papers on topological Fermi arcs and Weyl Semimetals (WSMs) are at http://physics.princeton.edu/zahidhasangroup/index.htm

Molecular impact of launch related dynamic vibrations and static hypergravity in planarians

Although many examples of simulated and real microgravity demonstrating their profound effect on biological systems are described in literature, few reports deal with hypergravity and vibration effects, the levels of which are severely increased during the launch preceding the desired microgravity period. Here, we used planarians, flatworms that can regenerate any body part in a few days. Planarians are an ideal model to study the impact of launch-related hypergravity and vibration during a regenerative process in a “whole animal” context. Therefore, planarians were subjected to 8.5 minutes of 4 g hypergravity (i.e. a human-rated launch level) in the Large Diameter Centrifuge (LDC) and/or to vibrations (20–2000 Hz, 11.3 Grms) simulating the conditions of a standard rocket launch. The transcriptional levels of genes (erg-1, runt-1, fos, jnk, and yki) related with the early stress response were quantified through qPCR. The results show that early response genes are severely deregulated after static and dynamic loads but more so after a combined exposure of dynamic (vibration) and static (hypergravity) loads, more closely simulating real launch exposure profiles. Importantly, at least four days after the exposure, the transcriptional levels of those genes are still deregulated. Our results highlight the deep impact that short exposures to hypergravity and vibration have in organisms, and thus the implications that space flight launch could have. These phenomena should be taken into account when planning for well-controlled microgravity studies

Spatio-temporal gait analysis based on human-smart rollator interaction

The ability to walk is typically related to several biomechanical components that are involved in the gait cycle (or stride), including free mobility of joints, particularly in the legs; coordination of muscle activity in terms of timing and intensity; and normal sensory input, such as vision and vestibular system. As people age, they tend to slow their gait speed, and their balance is also affected. Also, the retirement from the working life and the consequent reduction of physical and social activity contribute to the increased incidence of falls in older adults. Moreover, older adults suffer different kinds of cognitive decline, such as dementia or attention problems, which also accentuate gait disorders and its consequences. In this paper we present a methodology for gait identification using the on-board sensors of a smart rollator: the i-Walker. This technique provides the number of steps performed in walking exercises, as well as the time and distance travelled for each stride. It also allows to extract spatio-temporal metrics used in medical gait analysis from the interpretation of the interaction between the individual and the i-Walker. In addition, two metrics to assess users’ driving skills, laterality and directivity, are proposed.Peer ReviewedPostprint (author's final draft

Motivational interviewing for screening and feedback and encouraging lifestyle changes to reduce relative weight in 4-8 year old children: design of the MInT study

<p>Abstract</p> <p>Background</p> <p>Because parental recognition of overweight in young children is poor, we need to determine how best to inform parents that their child is overweight in a way that enhances their acceptance and supports motivation for positive change. This study will assess 1) whether weight feedback delivered using motivational interviewing increases parental acceptance of their child's weight status and enhances motivation for behaviour change, and 2) whether a family-based individualised lifestyle intervention, delivered primarily by a MInT mentor with limited support from "expert" consultants in psychology, nutrition and physical activity, can improve weight outcomes after 12 and 24 months in young overweight children, compared with usual care.</p> <p>Methods/Design</p> <p>1500 children aged 4-8 years will be screened for overweight (height, weight, waist, blood pressure, body composition). Parents will complete questionnaires on feeding practices, physical activity, diet, parenting, motivation for healthy lifestyles, and demographics. Parents of children classified as overweight (BMI ≥ CDC 85^th) will receive feedback about the results using Motivational interviewing or Usual care. Parental responses to feedback will be assessed two weeks later and participants will be invited into the intervention. Additional baseline measurements (accelerometry, diet, quality of life, child behaviour) will be collected and families will be randomised to Tailored package or Usual care. Parents in the Usual care condition will meet once with an advisor who will offer general advice regarding healthy eating and activity. Parents in the Tailored package condition will attend a single session with an "expert team" (MInT mentor, dietitian, physical activity advisor, clinical psychologist) to identify current challenges for the family, develop tailored goals for change, and plan behavioural strategies that best suit each family. The mentor will continue to provide support to the family via telephone and in-person consultations, decreasing in frequency over the two-year intervention. Outcome measures will be obtained at baseline, 12 and 24 months.</p> <p>Discussion</p> <p>This trial offers a unique opportunity to identify effective ways of providing feedback to parents about their child's weight status and to assess the efficacy of a supportive, individualised early intervention to improve weight outcomes in young children.</p> <p>Trial registration</p> <p>Australian New Zealand Clinical Trials Registry ACTRN12609000749202</p

PINCH is an independent prognostic factor in rectal cancer patients without preoperative radiotherapy - a study in a Swedish rectal cancer trial of preoperative radiotherapy

<p>Abstract</p> <p>Background</p> <p>The clinical significance between particularly interesting new cysteine-histidine rich protein (PINCH) expression and radiotherapy (RT) in tumours is not known. In this study, the expression of PINCH and its relationship to RT, clinical, pathological and biological factors were studied in rectal cancer patients.</p> <p>Methods</p> <p>PINCH expression determined by immunohistochemistry was analysed at the invasive margin and inner tumour area in 137 primary rectal adenocarcinomas (72 cases without RT and 65 cases with RT). PINCH expression in colon fibroblast cell line (CCD-18 Co) was determined by western blot.</p> <p>Results</p> <p>In patients without RT, strong PINCH expression at the invasive margin of primary tumours was related to worse survival, compared to patients with weak expression, independent of TNM stage and differentiation (<it>P </it>= 0.03). No survival relationship in patients with RT was observed (<it>P </it>= 0.64). Comparing the non-RT with RT subgroup, there was no difference in PINCH expression in primary tumours (invasive margin (<it>P </it>= 0.68)/inner tumour area (<it>P </it>= 0.49). In patients with RT, strong PINCH expression was related to a higher grade of LVD (lymphatic vessel density) (<it>P </it>= 0.01)</p> <p>Conclusions</p> <p>PINCH expression at the invasive margin was an independent prognostic factor in patients without RT. RT does not seem to directly affect the PINCH expression.</p

Finding Water Scarcity Amid Abundance Using Human–Natural System Models

Water scarcity afflicts societies worldwide. Anticipating water shortages is vital because of water’s indispensable role in social-ecological systems. But the challenge is daunting due to heterogeneity, feedbacks, and water’s spatial-temporal sequencing throughout such systems. Regional system models with sufficient detail can help address this challenge. In our study, a detailed coupled human–natural system model of one such region identifies how climate change and socioeconomic growth will alter the availability and use of water in coming decades. Results demonstrate how water scarcity varies greatly across small distances and brief time periods, even in basins where water may be relatively abundant overall. Some of these results were unexpected and may appear counterintuitive to some observers. Key determinants of water scarcity are found to be the cost of transporting and storing water, society’s institutions that circumscribe human choices, and the opportunity cost of water when alternative uses compete

Surface Charge Induced Dirac Band Splitting in a Charge Density Wave Material (TaSe4)2I

(TaSe4)2I, a quasi-one-dimensional (1D) crystal, shows a characteristic temperature-driven metal-insulator phase transition. Above the charge density wave (CDW) temperature Tc, (TaSe4)2I has been predicted to harbor a Weyl semimetal phase. Below Tc, it becomes an axion insulator. Here, we performed angle-resolved photoemission spectroscopy (ARPES) measurements on the (110) surface of (TaSe4)2I and observed two sets of Dirac-like energy bands in the first Brillion zone, which agree well with our first-principles calculations. Moreover, we found that each Dirac band exhibits an energy splitting of hundreds of meV under certain circumstances. In combination with core level measurements, our theoretical analysis showed that this Dirac band splitting is a result of surface charge polarization due to the loss of surface iodine atoms. Our findings here shed new light on the interplay between band topology and CDW order in Peierls compounds and will motivate more studies on topological properties of strongly correlated quasi-1D materials.Comment: 18 pages, 4 figures. Comments are welcom