Analytical modeling of light transport in scattering materials with strong absorption

We have investigated the transport of light through slabs that both scatter and strongly absorb, a situation that occurs in diverse application fields ranging from biomedical optics, powder technology, to solid-state lighting. In particular, we study the transport of light in the visible wavelength range between $420$ and $700$ nm through silicone plates filled with YAG:Ce$^{3+}$ phosphor particles, that even re-emit absorbed light at different wavelengths. We measure the total transmission, the total reflection, and the ballistic transmission of light through these plates. We obtain average single particle properties namely the scattering cross-section $\sigma_s$, the absorption cross-section $\sigma_a$, and the anisotropy factor $\mu$ using an analytical approach, namely the P3 approximation to the radiative transfer equation. We verify the extracted transport parameters using Monte-Carlo simulations of the light transport. Our approach fully describes the light propagation in phosphor diffuser plates that are used in white LEDs and that reveal a strong absorption ($L/\ell_{\mathrm{a}} > 1$) up to $L/\ell_{\mathrm{a}} = 4$, where $L$ is the slab thickness, $\ell_{\mathrm{a}}$ is the absorption mean free path. In contrast, the widely used diffusion theory fails to describe this parameter range. Our approach is a suitable analytical tool for industry, since it provides a fast yet accurate determination of key transport parameters, and since it introduces predictive power into the design process of white light emitting diodes

The association between birth weight and plasma fibrinogen is abolished after the elimination of genetic influences

Low birth weight is associated with an increased risk of atherothrombosis, which may be related in part to the association between low birth weight and high plasma fibrinogen. The association between birth weight and fibrinogen may be explained by intrauterine, socio-economic or genetic factors. We examined birth weight and fibrinogen in 52 dizygotic and 56 adolescent monozygotic (genetically identical) twin pairs. The dizygotic but not the monozygotic twins with the lowest birth weight from each pair had a fibrinogen level that was higher compared with their co-twins with the highest birth weight [dizygotic twins: 2.62±0.46 g

Relation between stimulation characteristics and clinical outcome in studies using electrical stimulation to improve motor control of the upper extremity in stroke

Objective: Electrical stimulation can be applied in a variety of ways to the hemiparetic upper extremity following stroke. The aim of this review is to explore the relationship between characteristics of stimulation and the effect of electrical stimulation on the recovery of upper limb motor control following stroke. Methods: A systematic literature search was performed to identify clinical trials evaluating the effect of electrical stimulation on motor control. The reported outcomes were examined to identify a possible relationship between the reported effect and the following characteristics: duration of stimulation, method of stimulation, setting of stimulation parameters, target muscles and stage after stroke. Results: Nineteen clinical trials were included, and the results of 22 patient groups were evaluated. A positive effect of electrical stimulation was reported for 13 patient groups. Positive results were more common when electrical stimulation was triggered by voluntary movement rather than when non-triggered electrical stimulation was used. There was no relation between the effect of electrical stimulation and the other characteristics examined. Conclusion: Triggered electrical stimulation may be more effective than non-triggered electrical stimulation in facilitating upper extremity motor recovery following stroke. It appears that the specific stimulus parameters may not be crucial in determining the effect of electrical stimulation

Decision for reconstructive interventions of the upper limb in individuals with tetraplegia: the effect of treatment characteristics

Objective: To determine the effect of treatment characteristics on the\ud decision for reconstructive interventions for the upper extremities (UE) in\ud subjects with tetraplegia. - \ud Setting: Seven specialized spinal cord injury centres in the Netherlands. - \ud Method: Treatment characteristics for UE reconstructive interventions were\ud determined. Conjoint analysis (CA) was used to determine the contribution\ud and the relative importance of the treatment characteristics on the decision\ud for therapy. Therefore, a number of different treatment scenarios using these\ud characteristics were established. Different pairs of scenarios were presented\ud to subjects who were asked to choose the preferred scenario of each set. - \ud Results: forty nine subjects with tetraplegia with a stable C5, C6 or C7\ud lesion were selected. All treatment characteristics significantly influenced\ud the choice for treatment. Relative importance of treatment characteristics\ud were: intervention type (surgery or surgery with FES implant) 13%, number\ud of operations 15%, in patient rehabilitation period 22%, ambulant\ud rehabilitation period 9%, complication rate 15%, improvement of elbow\ud function 10%, improvement of hand function 15%. In deciding for therapy\ud 40% of the subjects focused on one characteristic. - \ud Conclusion: CA is applicable in Spinal Cord Injury medicine to study the\ud effect of health outcomes and non-health outcomes on the decision for\ud treatment. Non-health outcomes which relate to the intensity of treatment\ud are equally important or even more important than functional outcome in the\ud decision for reconstructive UE surgery in subjects with tetraplegia

Impact of COVID-19 on cancer service delivery: results from an international survey of oncology clinicians.

To report clinician-perceived changes to cancer service delivery in response to COVID-19. Multidisciplinary Australasian cancer clinician survey in collaboration with the European Society of Medical Oncology. Between May and June 2020 clinicians from 70 countries were surveyed; majority from Europe (n=196; 39%) with 1846 COVID-19 cases per million people, Australia (AUS)/New Zealand (NZ) (n=188; 38%) with 267/236 per million and Asia (n=75; 15%) with 121 per million at time of survey distribution. Medical oncologists (n=372; 74%), radiation oncologists (n=91; 18%) and surgical oncologists (n=38; 8%). Eighty-nine per cent of clinicians reported altering clinical practices; more commonly among those with versus without patients diagnosed with COVID-19 (n=142; 93% vs n=225; 86%, p=0.03) but regardless of community transmission levels (p=0.26). More European clinicians (n=111; 66.1%) had treated patients diagnosed with COVID-19 compared with Asia (n=20; 27.8%) and AUS/NZ (n=8; 4.8%), p<0.001. Many clinicians (n=307; 71.4%) reported concerns that reduced access to standard treatments during the pandemic would negatively impact patient survival. The reported proportion of consultations using telehealth increased by 7.7-fold, with 25.1% (n=108) of clinicians concerned that patient survival would be worse due to this increase. Clinicians reviewed a median of 10 fewer outpatients/week (including non-face to face) compared with prior to the pandemic, translating to 5010 fewer specialist oncology visits per week among the surveyed group. Mental health was negatively impacted for 52.6% (n=190) of clinicians. Clinicians reported widespread changes to oncology services, in regions of both high and low COVID-19 case numbers. Clinician concerns of potential negative impacts on patient outcomes warrant objective assessment, with system and policy implications for healthcare delivery at large

User needs elicitation via analytic hierarchy process (AHP). A case study on a Computed Tomography (CT) scanner

Background: The rigorous elicitation of user needs is a crucial step for both medical device design and purchasing. However, user needs elicitation is often based on qualitative methods whose findings can be difficult to integrate into medical decision-making. This paper describes the application of AHP to elicit user needs for a new CT scanner for use in a public hospital. Methods: AHP was used to design a hierarchy of 12 needs for a new CT scanner, grouped into 4 homogenous categories, and to prepare a paper questionnaire to investigate the relative priorities of these. The questionnaire was completed by 5 senior clinicians working in a variety of clinical specialisations and departments in the same Italian public hospital. Results: Although safety and performance were considered the most important issues, user needs changed according to clinical scenario. For elective surgery, the five most important needs were: spatial resolution, processing software, radiation dose, patient monitoring, and contrast medium. For emergency, the top five most important needs were: patient monitoring, radiation dose, contrast medium control, speed run, spatial resolution. Conclusions: AHP effectively supported user need elicitation, helping to develop an analytic and intelligible framework of decision-making. User needs varied according to working scenario (elective versus emergency medicine) more than clinical specialization. This method should be considered by practitioners involved in decisions about new medical technology, whether that be during device design or before deciding whether to allocate budgets for new medical devices according to clinical functions or according to hospital department

Impedance-based phenotypic readout of transporter function: a case for glutamate transporters

Excitatory amino acid transporters (EAAT/SLC1) mediate Na+-dependent uptake of extracellular glutamate and are potential drug targets for neurological disorders. Conventional methods to assess glutamate transport in vitro are based on radiolabels, fluorescent dyes or electrophysiology, which potentially compromise the cell's physiology and are generally less suited for primary drug screens. Here, we describe a novel label-free method to assess human EAAT function in living cells, i.e., without the use of chemical modifications to the substrate or cellular environment. In adherent HEK293 cells overexpressing EAAT1, stimulation with glutamate or aspartate induced cell spreading, which was detected in real-time using an impedance-based biosensor. This change in cell morphology was prevented in the presence of the Na+/K+-ATPase inhibitor ouabain and EAAT inhibitors, which suggests the substrate-induced response was ion-dependent and transporter-specific. A mechanistic explanation for the phenotypic response was substantiated by actin cytoskeleton remodeling and changes in the intracellular levels of the osmolyte taurine, which suggests that the response involves cell swelling. In addition, substrate-induced cellular responses were observed for cells expressing other EAAT subtypes, as well as in a breast cancer cell line (MDA-MB-468) with endogenous EAAT1 expression. These findings allowed the development of a label-free high-throughput screening assay, which could be beneficial in early drug discovery for EAATs and holds potential for the study of other transport proteins that modulate cell shape.Medicinal Chemistr

TCT-588 2-Year Clinical Outcome of the Randomized, Multicenter DUTCH PEERS (TWENTE II) Trial, Comparing Cobalt-Chromium Zotarolimus-Eluting Resolute Integrity Stents and Platinum-Chromium Everolimus-Eluting Promus Element Stents in “All-Comer” Patients

Background: The multicenter, prospective, randomized, single-blinded, investigator-initiated DUTCH PEERS (TWENTE II) “All Comers” Trial demonstrated at 1-year follow-up the non-inferiority of third-generation Resolute Integrity zotarolimus-eluting stents (Medtronic Vascular, Santa Rosa, CA) versus Promus Element everolimus-eluting stents (Boston Scientific, Natick, MA), based on a similar incidence of the primary endpoint target vessel failure (TVF), a composite of cardiac death, target vessel revascularization (TVR), or myocardial infarction (MI). No other follow-up data beyond 12 months have been published from a randomized head-to-head comparison of both stents. Methods: In 4 study centers in the Netherlands, 1,811 patients were 1:1 randomly assigned to treatment with one of both stents. Patients with any clinical syndrome, any lesion type, and any number of lesions or vessels to be treated were included. Study monitoring and clinical event adjudication were performed by two independent Dutch contract research organizations (Diagram, Zwolle, and Cardialysis, Rotterdam, respectively). Results: DUTCH PEERS examines an all-comer patient population that included 59% of patients with acute coronary syndromes (20% of all patients presented with an acute STEMI) and 66% of patients with complex target lesions. We will compare for both stent groups the 2-year incidence of TVF (primary endpoint) and various secondary endpoints, including individual components of the primary endpoint, the incidence of stent thrombosis, and other composite endpoints, such as target lesion failure, major adverse cardiac events, and the patient-oriented composite endpoint. In addition, we will report the outcome of patients with longitudinal stent deformation after discontinuation of dual anti-platelet therapy. Conclusions: Clinical outcome of the DUTCH PEERS trial at 2-year follow-up will be presented