Measurement of the interfacial temperature jump during steady-state evaporation of a droplet

Evaporation is an important phenomena that occurs in a wide range of natural and industrial processes. Although this phenomena has been a subject of research for many years, it is still not fully understood.Experimental results of the last few decades seem to contradict with each other, and with the theory which describes this process, e.g. the kinetic theory of gasses (KTG) and non-equilibrium thermodynamics (NET). Temperature jumps of about 3.2-8.1oC at the interface of a steady state evaporating water dropletat a pressure of about 245 Pa were measured . In order to determine whether this temperature jump exists and what influences this temperature jump, an experimental setup has been developed and the results are compared to theory

Development of a micro-optofluidic temperature sensor

A fluorescent micro-optofluidic temperature sensor is developed using a temperature sensitive dye. The sensor can measure temperatures in microregions up to 70 ºC and is applicable in lab-on-a chip devices. It is fabricated using soft lithography method and uses Rhodamine B dissolved in water as a temperature indicator

Development of a micro-optofluidic temperature sensor

A fluorescent micro-optofluidic temperature sensor is developed using a temperature sensitive dye. The sensor can measure temperatures in microregions up to 70 ºC and is applicable in lab-on-a chip devices. It is fabricated using soft lithography method and uses Rhodamine B dissolved in water as a temperature indicator

SoftVoice improves speech recognition and reduces listening effort in cochlear implant users

Objectives:The ability to perceive soft speech by cochlear implant (CI) users is restricted in part by the inherent system noise produced by the speech processor, and in particular by the microphone(s). The algorithm "SoftVoice" (SV) was developed by Advanced Bionics to enhance the perception of soft speech by reducing the system noise in speech processors. The aim of this study was to examine the effects of SV on speech recognition and listening effort.Design:Seventeen adult Advanced Bionics CI recipients were recruited and tested in two sessions. The effect of SV on speech recognition was tested by determining the SRT in quiet using the Matrix test. Based on the individual subjects' SRTs, we investigated speech-recognition scores at fixed speech levels, namely SRT -5 dB, SRT +0 dB, SRT +5 dB, and SRT +10 dB, again in quiet and using the Matrix test. Listening effort was measured at each of these speech levels subjectively by using a rating scale, and objectively by determining pupil dilation with pupillometry. To verify whether SoftVoice had any negative effects on speech perception in noise, we determined the SRT in steady state, speech-weighted noise of 60 dBA.Results:Our results revealed a significant improvement of 2.0 dB on the SRT in quiet with SoftVoice. The average SRT in quiet without SoftVoice was 38 dBA. SoftVoice did not affect the SRT in steady state, speech-weighted noise of 60 dB. At an average speech level of 33 dBA (SRT -5 dB) and 38 dBA (SRT +0 dB) in quiet, significant improvements of 17% and 9% on speech-recognition scores were found with SoftVoice, respectively. At higher speech levels, SoftVoice did not significantly affect speech recognition. Pupillometry did not show significant effects of SoftVoice at any speech level. However, subjective ratings of listening effort indicated a decrease of listening effort with SoftVoice at a speech level of 33 dBA.Conclusions:We conclude that SoftVoice substantially improves recognition of soft speech and lowers subjective listening effort at low speech levels in quiet. However, no significant effect of SoftVoice was found on pupil dilation. As SRTs in noise were not statistically significantly affected by SoftVoice, we conclude that SoftVoice can be used in noisy listening conditions with little negative impact on speech recognition, if any. The increased power demands of the algorithm are considered to be negligible. It is expected that SoftVoice will reduce power consumption at low ambient sound levels. These results support the use of SoftVoice as a standard feature of Advanced Bionics CI fittings for everyday use.Disorders of the head and nec

Mathematical modeling of thermal and circulatory effects during hemodialysis.

Intradialytic hypotension (IDH) is one of the most common complications of hemodialysis (HD) treatment. The initiating factor of IDH is a decrease in blood volume which is related to an imbalance between ultrafiltration (UF) and refilling rate. Impaired reactivity of resistance and capacitance vessels in reaction to hypovolemia plays possibly a major role in the occurrence of IDH. These vessels also fulfill an important function in body temperature regulation. UF induced cutaneous vasoconstriction would result in a reduced surface heat loss and an increase in core temperature. To release body heat, skin blood flow (SBF) is increased at a later stage of the HD treatment, whereby possibly IDH can occur. Aim of the study is to develop a mathematical model which can provide insight into the impact of thermoregulatory processes on the cardiovascular system during HD treatment. The mathematical procedure has been created by coupling a thermo-physiological (TP) model with a cardiovascular (CV) model to study regulation mechanisms in the human body during HD+UF. Model simulations for isothermal vs. thermoneutral HD+UF were compared to measurement data of patients on chronic intermittent HD (n=13). Core temperature during simulated HD+UF sessions increased within the range of measurement data (0.23ºC vs. 0.32±0.41ºC). The model showed a decline in mean arterial pressure (MAP) of -7% for thermoneutral HD+UF versus -4% for isothermal HD+UF after 200 minutes during which relative blood volume (RBV) changed by -13%. In conclusion, simulation results of the combined model show possibilities for predicting circulatory and thermal responses during HD+UF

Sneddon syndrome: a comprehensive clinical review of 53 patients

BACKGROUND: The presence of livedo reticularis in patients with ischaemic stroke is associated with Sneddon syndrome (SS). Our objective was to present the clinical features of SS patients and to assess the role of antiphospholipid antibodies (APL). METHODS: Consecutive patients, diagnosed with SS between 1996 and 2017, were retrospectively reviewed for their demographic, neurological, dermatological, cardiac and extracerebral vascular features. Diagnosis of SS was made only if other causes of stroke were excluded. Patients with and without APL were included and compared for their clinical features. RESULTS: Fifty-three patients (79% female) were included, of whom 14 patients were APL-positive. Median age at diagnosis was 40 years. Approximately 60% of the patients had ≥ 3 cardiovascular risk factors. There were 129 previous vascular events (66 ischaemic strokes, 62 TIAs and 1 amaurosis fugax) during a median period of 2 years between the first event and diagnosis of SS. Skin biopsy was positive for SS in 29 patients (67%), mostly showing a thickened vessel wall with neovascularization in the deep dermis. After a median follow-up of 28 months, 4 patients, either on antiplatelet or oral anticoagulation therapy, had a recurrent stroke. There were few statistically significant differences between APL-negative and APL-positive patients, including the number of vascular events before diagnosis. CONCLUSIONS: SS predominantly affects young women with a relatively large number of cardiovascular risk factors. Clinical features of SS are comparable across different studies. We found no differences in the main clinical features between APL-positive and APL-negative patients

The diagnostic value of skin biopsies in Sneddon syndrome

Background Sneddon syndrome (SS) is defined by widespread livedo reticularis (LR) and stroke. There is no single diagnostic test for SS and diagnosis can be solely based on clinical features. This cross-sectional case-control study aimed to determine the diagnostic value of skin biopsies in SS patients. Materials and methods We studied skin biopsies from patients with a clinical diagnosis of SS or isolated LR. We also studied controls with vitiligo or normal skin. Biopsies were considered standardized if 3 biopsies were taken from the white centre of the livedo and reached until the dermis-subcutis border. Biopsies were scored for features of an occlusive microangiopathy without knowledge of the clinical features. Sensitivity and specificity of the biopsy findings were calculated with the clinical criteria as the reference standard. Results We included 34 SS patients, 14 isolated LR patients and 41 control patients. Biopsies of 17 patients with SS (50%), 4 with isolated LR (31%) and 10 control patients (24%) showed at least one artery in the deep dermis with a thickened vessel wall combined with recanalization or neovascularization (sensitivity 50% and specificity 69% with LR as reference). Standardized biopsies increased the sensitivity to 70%. In a post hoc analysis the combination of an occlusive microangiopathy and the presence of a livedo pattern in the superficial dermis increased the specificity to 92%. Conclusions Standardized skin biopsies can support the clinical diagnosis of SS. An occlusive microangiopathy as the only positive criterion for the diagnosis of SS had insufficient specificity for a definite diagnosis