Modelling of pressure ulcer (PU) risk prediction system

Human skin deformation occurs due to external loading. As a result, blood flow in soft tissue becomes low and also the oxygenation decreases. Tissue under continuous loading results in tissue necrosis and leads to pressure ulcer (PU), also known as bedsore, decubitus ulcer, and ischemia. The amount of external load applied to the body support surface is associated with a subject's BMI (body mass index). Therefore interface pressure (IP) at the skin and the surface is the result of a subject's physical and support surface properties. Interface pressure increases, the blood flow decreases and a subject starts developing stage-1 pressure ulcer. Previous research suggests that interface pressure of 32 mmHg (4.26 kPa) can cause PU, but there is no strong evidence to show at what time that pressure is reached. Also interface pressure changes from subject to subject due to their body compositions. Three risk assessment scales are available to predict overall risk of PU formation. But none of these scales take interaction of body support surface materials into account. Also these do not provide any information at which area a subject is at risk of PU formation. In this work a study is presented where external load at different bony areas are measured using 11 volunteers. By measuring the external load for 11 subjects (age:33 ± 7 yrs and BMI:25.04 ± 3.01 kg/m2) at different bony areas, the relationship with the total body weight was identified. A mathematical model is proposed to predict the risk of PU formation combining the Waterlow risk assessment scales for bony areas and a graphic user interface to predict this is discussed

Airborne anaphylaxis: highlighting an invisible enemy

Purpose of review Airborne anaphylaxis is a rare disorder defined by the occurrence of anaphylactic reactions to inhaled allergens, which may arise not only in occupational exposure but also in common settings. Foods are the most common cause of airborne anaphylaxis, even organic mixtures scents. The other important cause is represented by drugs, while in the wide range of other causes, there are often reports on unique cases. This review aims to make an overview about the potential causes of airborne anaphylaxis, by analysing what is described in literature on this topic. Recent findings Concerning epidemiology, no data on specific prevalence of airborne allergy in adults are available. To date, only one study evaluated the specific prevalence of airborne allergy with anaphylaxis to foods in children, resulting in 5.9% of reactions due to exposure to aerosolized foods, compared with 78% of reactions caused by food ingestion. In addition to anaphylaxis, airborne-related reactions may also present with symptoms such as rhino-conjunctivitis, wheezing, dyspnoea and asthma. A detailed anamnesis facilitates a correct diagnosis, which allows appropriate therapeutic and preventive interventions, but, similarly to rare diseases in general, only specialized doctors are able to implement it. The assumption of the approach used in emergency medicine for other causes of anaphylaxis, that is referring the patient at discharge to an allergist who will teach the basic notions to recognize symptoms and access the appropriate therapy, would allow the patient to avoid situations of serious danger

Creating tactile feedback with intelligent electrical stimulation to compensate for sensory impairment.

Performing daily life activities can be more challenging as a result of peripheral neuropathy in the feet and can lead to an increased risk of falls and injuries. Biofeedback, in the form of electrocutaneous stimulation, can be used as a means to transmit information about the force and pressure applied to the feet, and this can help people determine their body position in relation to the ground and the amount of sway movements. The motivation for the present work was to explore whether a wearable electrotactile feedback system (EFS) could improve life quality by supporting people with balance instability as a result of this condition. In this study a wearable EFS was designed to estimate the magnitude of pressure applied to the feet during standing and walking. The study also aimed to determine whether the EFS had an effect on posture control in standing and confidence in walking among individuals suffering from peripheral neuropathy. A wearable EFS has been developed in this work including the hardware design for an electrocutaneous stimulation and a processing unit to compute the sensor data. The EFS uses a sensor system with piezoresitive force sensors that has been developed and tested beforehand. The proposed system considers aspects of safety and portability, as well as meeting individual parameters. The latter one was assured by implementing and testing a novel calibration method for the detection of sensory thresholds and device parameters. A software for magnitude estimation and force and pressure feedback based on the centre of pressure (COP) movement was programmed and a psychophysical transfer function involving sensory thresholds and sensor system variables was implemented. A pilot study with 11 participants was carried out to evaluate the suitability of the EFS for magnitude estimation. Magnitude estimation with the EFS showed high accuracy and sensitivity and it was found that the design proposed in this work is beneficial over other solutions. The upper leg was identified as a suitable location for electrotactile feedback. A proof of concept study was undertaken among 14 individuals suffering with peripheral neuropathy and five controls in a clinical environment, testing the effects of the EFS on balancing and walking in different scenarios. It was shown that, when used by patients with neuropathy, the EFS helped improving posture control in certain scenarios and did not hinder patients during walking. A longer learning period might be necessary so that users can fully benefit from the EFS. The findings of the study contribute to the understanding of electrotactile feedback and are valuable for further developments of wearable EFS to compensate for sensory impairment and improve activities of daily life for people with sensation loss in their feet

Cryogenic analysis of frozen hydrated biological tissue at the Hard X-ray Micro-Probe Beamline at PETRA III

C

Ultrastructural Observations on Bacterial Invasion in Cementum and Radicular Dentin of Periodontally Diseased Human Teeth

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141124/1/jper0493.pd

The First Data Release of the Sloan Digital Sky Survey

The Sloan Digital Sky Survey has validated and made publicly available its First Data Release. This consists of 2099 square degrees of five-band (u, g, r, i, z) imaging data, 186,240 spectra of galaxies, quasars, stars and calibrating blank sky patches selected over 1360 square degrees of this area, and tables of measured parameters from these data. The imaging data go to a depth of r ~ 22.6 and are photometrically and astrometrically calibrated to 2% rms and 100 milli-arcsec rms per coordinate, respectively. The spectra cover the range 3800--9200 A, with a resolution of 1800--2100. Further characteristics of the data are described, as are the data products themselves.Comment: Submitted to The Astronomical Journal. 16 pages. For associated documentation, see http://www.sdss.org/dr