Development of a Mortality Prediction Model in Hospitalised SARS-CoV-2 Positive Patients Based on Routine Kidney Biomarkers

Acute kidney injury (AKI) is a prevalent complication in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive inpatients, which is linked to an increased mortality rate compared to patients without AKI. Here we analysed the difference in kidney blood biomarkers in SARS-CoV-2 positive patients with non-fatal or fatal outcome, in order to develop a mortality prediction model for hospitalised SARS-CoV-2 positive patients. A retrospective cohort study including data from suspected SARS-CoV-2 positive patients admitted to a large National Health Service (NHS) Foundation Trust hospital in the Yorkshire and Humber regions, United Kingdom, between 1 March 2020 and 30 August 2020. Hospitalised adult patients (aged ≥ 18 years) with at least one confirmed positive RT-PCR test for SARS-CoV-2 and blood tests of kidney biomarkers within 36 h of the RT-PCR test were included. The main outcome measure was 90-day in-hospital mortality in SARS-CoV-2 infected patients. The logistic regression and random forest (RF) models incorporated six predictors including three routine kidney function tests (sodium, urea; creatinine only in RF), along with age, sex, and ethnicity. The mortality prediction performance of the logistic regression model achieved an area under receiver operating characteristic (AUROC) curve of 0.772 in the test dataset (95% CI: 0.694–0.823), while the RF model attained the AUROC of 0.820 in the same test cohort (95% CI: 0.740–0.870). The resulting validated prediction model is the first to focus on kidney biomarkers specifically on in-hospital mortality over a 90-day period.     

正弦发生器使用双输出电流控制传输器

第二代电流传输器具有信号带宽高、线性，动态范围大、电路简单以及低功耗的特性。因此，设计者在这些设备中采用几种电流模式，以便实现多种功能。以前的一个设计实例介绍了一种创建振荡器的第二代双输出电流控制传输器（参考文献1）。遗憾的是，这些电路不像集成电路那样广泛可用，但是可以用分离元件构建它们。     

x-index: Identifying core competency and thematic research strengths of institutions using an NLP and network based ranking framework

Scientometrics - The currently prevailing international ranking systems for institutions are limited in their assessment as they only provide assessments either at an overall level or at very broad...     

Novel voltage/current-mode quadrature oscillator using current differencing transconductance amplifier

This letter proposes a new realization of voltage/current-mode (CM) quadrature oscillator (QO) using Current Differencing Transconductance Amplifier (CDTA) as the active element. The proposed circuit employs canonic number of components, namely two CDTAs, one resistor and two grounded capacitors. The oscillator is capable of providing two explicit quadrature current outputs and two quadrature voltage outputs. Moreover, the circuit enjoys the advantage of independent control of condition of oscillation (CO) and frequency of oscillation (FO). The non-ideal analysis and sensitivity study of the circuit has been carried out and the circuit exhibits a good sensitivity performance. B2SPICE simulation results are included that validate the working of the circuit.     

An electronically tunable current-mode quadrature oscillator using PCAs

This article presents a new realisation of active RC sinusoidal oscillator with electronically tunable condition and frequency of oscillation (FO). As compared to the class of three resistors, two capacitors (3R-2C)-based canonic oscillators, the circuit proposed here uses only two resistors and two capacitors as the passive components and still provides non-interactive tuning laws for the condition of oscillation and the FO. The proposed circuit employs new bipolar programmable current amplifier as the active building block and is capable of simultaneously providing two explicit quadrature current outputs. SPICE simulation results have been included to verify the workability of the circuit as an oscillator and the tuning range of the FO.     

Realization of electronically tunable voltage-mode/current-mode quadrature sinusoidal oscillator using ZC-CG-CDBA

This paper presents a first of its kind canonic realization of active RC (ARC) sinusoidal oscillator with non-interactive/independent tuning laws, which simultaneously provides buffered quadrature voltage outputs and explicit quadrature current outputs. The proposed circuit is created using a new active building block, namely the Z-copy controlled-gain current differencing buffered amplifier (ZC-CG-CDBA). The circuit uses three resistors and two grounded capacitors, and provides independent/non-interactive control of the condition of oscillation (CO) and the frequency of oscillation (FO) by means of different resistors. Other advantageous features of the circuit are the inherent electronic tunability of the FO via controlling current gains of the active elements and the suitability to be employed as a low-frequency oscillator. A non-ideal analysis of the circuit is carried out and experimental results verifying the workability of the proposed circuit are included.     

基于MOSFET的平方根计算模拟电路

在仪表和测量系统中广泛使用了平方根计算电路，例如：用于计算任意波形rms（均方根）等。因此，设计师需要有一种高效的模拟平方根计算装置。由于制造商常采用MOS技术制造IC，采用基于MOSFET的模拟平方根计算装置应该是很合适的。此设计实例就描述了一个这样的电路。该电路只采用MoSFET提供平方根功能（图1）。它设计简单，     

Voltage-mode quadrature sinusoidal oscillator with current tunable properties

This letter presents a realization of voltage-mode quadrature sinusoidal oscillator with independent current tunable frequency of oscillation. The circuit uses a single differential voltage current conveyor transconductance amplifier (DVCCTA) as the active building block and four all grounded passive elements. PSPICE simulation results have been included to verify the theoretical results.     

Realizations of Grounded Negative Capacitance Using CFOAs

The paper presents new realizations of grounded negative capacitance, using current feedback operational amplifiers (CFOAs), two resistors and one capacitor. All the proposed realizations are canonic in the number of passive components and do not require any critical component matching condition. Application examples in capacitive cancellation schemes and resistance-controlled low-frequency quadrature sinusoidal oscillator design are provided. The workability of the circuits has been verified by PSPICE simulations.     

Current-mode variable frequency quadrature sinusoidal oscillators using two CCs and four passive components including grounded capacitors: a supplement

This letter comments on the recently published paper in [1] which provides realizations of minimum component quadrature sinusoidal oscillators. On re-examination of the ‘Type 3’ oscillator circuits in [1], it has been found that the circuits actually suffer from ‘latch up’ problem due to use of incorrect polarity of the CCII based negative-impedance convertor. This problem has been corrected (without altering the characteristic equation) by swapping the impedances at y and x terminals. Explicit quadrature current outputs are derived similarly as done in [1].