A Random Shuffle Method to Expand a Narrow Dataset and Overcome the Associated Challenges in a Clinical Study: A Heart Failure Cohort Example

Heart failure (HF) affects at least 26 million people worldwide, so predicting adverse events in HF patients represents a major target of clinical data science. However, achieving large sample sizes sometimes represents a challenge due to difficulties in patient recruiting and long follow-up times, increasing the problem of missing data. To overcome the issue of a narrow dataset cardinality (in a clinical dataset, the cardinality is the number of patients in that dataset), population-enhancing algorithms are therefore crucial. The aim of this study was to design a random shuffle method to enhance the cardinality of an HF dataset while it is statistically legitimate, without the need of specific hypotheses and regression models. The cardinality enhancement was validated against an established random repeated-measures method with regard to the correctness in predicting clinical conditions and endpoints. In particular, machine learning and regression models were employed to highlight the benefits of the enhanced datasets. The proposed random shuffle method was able to enhance the HF dataset cardinality (711 patients before dataset preprocessing) circa 10 times and circa 21 times when followed by a random repeated-measures approach. We believe that the random shuffle method could be used in the cardiovascular field and in other data science problems when missing data and the narrow dataset cardinality represent an issue

On the Electrical and Optical Features of the Plasma Coagulation Controller Low Temperature Atmospheric Plasma Jet

We report on the electrical and optical characterization of the Plasma Coagulation Controller (PCC) device, a low temperature atmospheric plasma source for biomedical applications. This device, designed for the study of plasma-induced blood coagulation, has been developed to operate flexibly in several operational conditions, since it is possible to vary the applied voltage V p and the pulse repetition rate f in a quite wide range ( V p range: 2–12 kV, f range: 1–40 kHz). Emission spectroscopy measurements were conducted by varying the line of sight along the axis of helium and neon plasma plumes. The increase of the Reactive Oxygen and Nitrogen Species (RONS) has been observed, as one moves from inside the gas pipe to the outside, as a consequence of the gas mixture with the surrounding air. Furthermore, high-speed photographs of the plasma jet were taken, showing that the plasma is not uniformly distributed in a continuous volumetric region, the plasma being concentrated in localized structures called Pulsed Atmospheric-pressure Plasma Streams (PAPS). The propagation velocities of these objects have been examined, noting that they are not related to the propagation of ion sound waves. Rather, we provide indications that the streamer propagation speed is proportional to the electron drift velocity

Thermal and transport characterization of rfp plasmas from electron temperature data

The work deals with electron tempearature and transport analysis in RFP plasams; in particular the following topics are discussed: - the commissioning of the edge Thomson Scattering in RFX-mod for temperature evaluation; - the commissioning of the laser blow-off system in RFX-mod for impurity transport characterization -the analysis of RFP helical states in term of electron temperature, diffusivity and confinement on the experiments RFX-mod (Padua) and MST (madison, WI).Il presente lavoro sviluppa una caratterizzazione dei plasmi RFP dal punto di vista termico e di trasporto; in particolare vengonodiscussi i seguenti punti: -lo sviluppo della diagnostica di Thomson Scattering di bordo per la misura della temperaturea elettronica; -lo sviluppo del sistema di laser blow off per l'iniezione di impurezze e lo studio del loro trasporto -l'analisi degli stati elicoidali negli RFP, in termini di caratteristiche termiche e di confinamento, negli esperimenti RFX-mod(Padova) e MST(Madison-WI

Overview of photo-neutralization techniques for negative ion-based neutral beam injectors in future fusion reactors

Photo-neutralization of negative ions ($$H^-/D^-$$) is now regarded as a promising technique to increase the efficiency of neutral beam heating systems in future fusions reactors. In a gas or plasma neutralizer, the extra electron in the negative ion is detached by stripping, while in photo-neutralizers it detaches by absorbing a visible or near-infrared photon. The main technological challenge is the level of optical power required (several MW), which forbids the use of direct illumination and requires some form of light trapping: the research focuses on the development of suitable coherent sources and enhancement cavities. This overview discusses the different concepts so far developed, describing their working principles, advantages and critical points as well as new possible methodologies to realize photo-neutralization for nuclear fusion reactor applications

Dual-angle, self-calibrating Thomson scattering measurements in RFX-MOD

In the multipoint Thomson scattering (TS) system of the RFX-MOD experiment the signals from a few spatial positions can be observed simultaneously under two different scattering angles. In addition the detection system uses optical multiplexing by signal delays in fiber optic cables of different length so that the two sets of TS signals can be observed by the same polychromator. Owing to the dependence of the TS spectrum on the scattering angle, it was then possible to implement self-calibrating TS measurements in which the electron temperature Te, the electron density ne and the relative calibration coefficients of spectral channels sensitivity Ci were simultaneously determined by a suitable analysis of the two sets of TS data collected at the two angles. The analysis has shown that, in spite of the small difference in the spectra obtained at the two angles, reliable values of the relative calibration coefficients can be determined by the analysis of good S/N dual\u2011angle spectra recorded in a few tens of plasma shots. This analysis suggests that in RFX-MOD the calibration of the entire set of TS polychromators by means of the similar, dual-laser (Nd:YAG/Nd:YLF) TS technique, should be feasible

Dual-laser, self-calibrating Thomson scattering measurements in RFX-mod

A self-calibrating Thomson scattering technique, based on using two lasers of different wavelength and never implemented before in a fusion experiment, is tested for the first time in RFX-mod. The method employs two laser systems, Nd:YAG (\u3bb = 1064 nm) and Nd:YLF (\u3bb = 1053 nm), fired in sync through the same plasma volume. The combination of the two scattered spectra, individually recorded, is used to simultaneously obtain the measurements of the electron temperature Te and the relative calibration coefficients of the polychromator spectral channels sensitivities Ci. This work is a continuation of the dual-angle technique, a similar alternative method. Due to the small difference in the wavelengths of the two lasers, the sensitivity of this method is low in RFX-mod and reliable measurements of the calibration coefficients could not be obtained on a shot-to-shot basis, but only with a statistical analysis of a reasonable number of pairs of laser shots with good signal-to-noise ratio. The dual-laser method can be applied to most fusion devices and could provide continuous online monitoring of the spectral transmission of the detection system. This may prove essential in larger devices (ITER), where access for traditional calibration is difficult

A feasibility study of a NBI photoneutralizer based on nonlinear gating laser recirculation

The neutralization efficiency of negative ion neutral beam injectors is a major issue for future fusion reactors. Photon neutralization might be a valid alternative to present gas neutralizers, but still with several challenges for a valid implementation. Some concepts have been presented so far but none has been validated yet. A novel photoneutralization concept is discussed here, based on an annular cavity and a duplicated frequency laser beam (recirculation injection by nonlinear gating). The choice of lithium triborate as the material for the second harmonic extractor is discussed and a possible cooling method via crystal slicing is presented; laser intensity enhancement within the cavity is evaluated in order to quantify the achievable neutralization rate. Mockups of the critical components are proposed as intermediate steps toward system realization

Design of JT-60SA core Thomson scattering diagnostic system

An incoherent Thomson scattering diagnostic will be installed in the JT-60SA tokamak to measure electron temperature and electron density profiles. The target radial spatial resolution is 25 mm with 46 spatial channels. The accuracy in electron temperature and density is a few percent at ne = 7.5 × 10^19 m^−3 , which is the expected value in the plasma core. This paper presents the designs of collection optics, fibers with their alignment system, and polychromators. The collection optics overcomes unique issues for superconducting fusion devices, i.e., limited design space, high-temperature measurements, and harsh radiation condition. When in several years the more performing plasma will generate intense nuclear radiation, the lens materials of the optics can be replaced by radiation resistant glasses without major changes in the lens holder. It will prevent transmission degradation and keep stable measurement accuracy

Design of JT-60SA core Thomson scattering diagnostic system

JT-60SAでは電子温度と電子密度の分布を計測するためにトムソン散乱計測システムを設置する。本発表では、ポートプラグ内の限られた空間に設置可能な集光光学系、レーザー伝送系、分光器、制御システムの概念設計を示す。集光光学系はポートプラグからは独立した片持ち張り構造とし、ディスラプション等が原因となる変位の影響を抑制する。電子温度の計測誤差は、10%以下であると評価され、プラズマ研究に十分な精度で計測できる見込みを得た。第23回高温プラズマ計測に関するトピカル会議(HTPD