Machine learning for emerging infectious disease field responses.

Emerging infectious diseases (EIDs), including the latest COVID-19 pandemic, have emerged and raised global public health crises in recent decades. Without existing protective immunity, an EID may spread rapidly and cause mass casualties in a very short time. Therefore, it is imperative to identify cases with risk of disease progression for the optimized allocation of medical resources in case medical facilities are overwhelmed with a flood of patients. This study has aimed to cope with this challenge from the aspect of preventive medicine by exploiting machine learning technologies. The study has been based on 83,227 hospital admissions with influenza-like illness and we analysed the risk effects of 19 comorbidities along with age and gender for severe illness or mortality risk. The experimental results revealed that the decision rules derived from the machine learning based prediction models can provide valuable guidelines for the healthcare policy makers to develop an effective vaccination strategy. Furthermore, in case the healthcare facilities are overwhelmed by patients with EID, which frequently occurred in the recent COVID-19 pandemic, the frontline physicians can incorporate the proposed prediction models to triage patients suffering minor symptoms without laboratory tests, which may become scarce during an EID disaster. In conclusion, our study has demonstrated an effective approach to exploit machine learning technologies to cope with the challenges faced during the outbreak of an EID.

Comparing machine learning with case-control models to identify confirmed dengue cases.

In recent decades, the global incidence of dengue has increased. Affected countries have responded with more effective surveillance strategies to detect outbreaks early, monitor the trends, and implement prevention and control measures. We have applied newly developed machine learning approaches to identify laboratory-confirmed dengue cases from 4,894 emergency department patients with dengue-like illness (DLI) who received laboratory tests. Among them, 60.11% (2942 cases) were confirmed to have dengue. Using just four input variables [age, body temperature, white blood cells counts (WBCs) and platelets], not only the state-of-the-art deep neural network (DNN) prediction models but also the conventional decision tree (DT) and logistic regression (LR) models delivered performances with receiver operating characteristic (ROC) curves areas under curves (AUCs) of the ranging from 83.75% to 85.87% [for DT, DNN and LR: 84.60% ± 0.03%, 85.87% ± 0.54%, 83.75% ± 0.17%, respectively]. Subgroup analyses found all the models were very sensitive particularly in the pre-epidemic period. Pre-peak sensitivities (<35 weeks) were 92.6%, 92.9%, and 93.1% in DT, DNN, and LR respectively. Adjusted odds ratios examined with LR for low WBCs [≤ 3.2 (x103/µL)], fever (≥38°C), low platelet counts [< 100 (x103/µL)], and elderly (≥ 65 years) were 5.17 [95% confidence interval (CI): 3.96-6.76], 3.17 [95%CI: 2.74-3.66], 3.10 [95%CI: 2.44-3.94], and 1.77 [95%CI: 1.50-2.10], respectively. Our prediction models can readily be used in resource-poor countries where viral/serologic tests are inconvenient and can also be applied for real-time syndromic surveillance to monitor trends of dengue cases and even be integrated with mosquito/environment surveillance for early warning and immediate prevention/control measures. In other words, a local community hospital/clinic with an instrument of complete blood counts (including platelets) can provide a sentinel screening during outbreaks. In conclusion, the machine learning approach can facilitate medical and public health efforts to minimize the health threat of dengue epidemics. However, laboratory confirmation remains the primary goal of surveillance and outbreak investigation.

Ultrathin (Bi1-xSbx)2Se3 Field Effect Transistor with Large ON/OFF Ratio.

Ultrathin three-dimensional topological insulator films are promising for use in field effect devices. (Bi1-xSbx)2Se3 ultrathin films were fabricated on SrTiO3 substrate, where large resistance changes of ∼25 000% could be achieved using the back gate voltage. We suggest that the large ON/OFF ratio was caused by the combined effect of Sb-doping and the reduction of film thickness down to the ultrathin regime. The crossover of different quantum transport under an electric field may form the basis for topological insulators (TI)-based spin transistors with large ON/OFF ratios in the future.

The Relationship of Diabetes and Smoking Status to Hepatocellular Carcinoma Mortality.

The relationship of diabetes and smoking status to hepatocellular carcinoma (HCC) mortality is not clear. We aimed to investigate the association of smoking cessation relative to diabetes status with subsequent deaths from HCC.We followed up 51,164 participants (aged 44-94 years) without chronic hepatitis B or C from 1 January 1998 to 31 December 2008 enrolled from nationwide health screening units in a prospective cohort study. The primary outcomes were deaths from HCC.During the study period, there were 253 deaths from HCC. History of diabetes was associated with deaths from HCC for both total participants (adjusted hazard ratio [HR], 2.97; 95% confidence interval [CI], 2.08-4.23) and ever smokers with current or past smoking habits (HR, 1.92; 95% CI, 1.10-3.34). Both never smokers (HR, 0.46; 95% CI, 0.32-0.65) and quitters (HR, 0.62; 95% CI, 0.39-0.97) had a lower adjusted risk of HCC deaths compared with current smokers. Among all ever smokers with current or past smoking habits, as compared with diabetic smokers, only quitters without diabetes had a lower adjusted risk of HCC deaths (HR, 0.37; 95% CI, 0.18-0.78). However, quitters with diabetes were observed to have a similar risk of deaths from HCC when compared with smokers with diabetes. Regarding the interaction between diabetes and smoking status on adjusted HCC-related deaths, with the exception of quitters without history of diabetes, all groups had significantly higher HRs than nondiabetic never smokers. There was also a significant multiplicative interaction between diabetes and smoking status on risk of dying from HCC (P = 0.033). We suggest clinicians should promote diabetes prevention and never smoking to associate with reduced subsequent HCC mortality even in adults without chronic viral hepatitis.

The effects of fluorine-contained molecules on improving the polymer solar cell by curing the anomalous S-shaped I-V curve.

In this study, we investigate the effects of fluorinated poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) buffer layer on the performance of polymer photovoltaic cells. We demonstrate for the first time, the deterioration of the device performance can be effectively mended by modifying the interface between the active layer and buffer layer with heptadecafluoro-1,1,2,2-tetra-hydro-decyl trimethoxysilane (PFDS) and perfluorononane. Device performance shows a substantial enhancement of short-circuit current from 7.90 to 9.39 mA/cm(2) and fill factor from 27% to 53%. The overall device efficiency was improved from 0.98% to 3.12% for PFDS modified device. The mechanism of S-shape curing is also discussed. In addition, the stability of modified devices shows significant improvement than those without modification. The efficiency of the modified devices retains about half (1.88%) of its initial efficiency (4.1%) after 30 d compared to the unmodified ones (0.61%), under air atmosphere.

Nano-textured fluidic biochip as biological filter for selective survival of neuronal cells.

This is an innovative study to engineer biological filter to evaluate the effect of template surface structure and physiochemical properties that can be used for wide variety of applications in biological, health care as well as environmental protection. Specifically, planar silicon (Si) wafer and arrayed Si nano-tips (SiNT) templates were fabricated and coated with gold for various lengths of time to study the effect of surface charge, surface roughness, and hydrophilicity on biological activity of rat pheochromocytoma cell lines PC12. The initial growth and proliferation of PC12 cells on Si and SiNT templates showed an antipathy for the ultra-sharp SiNTs templates. In contrast, the same cells demonstrated a preferable adherence to and proliferation on planar Si templates, resulting in higher cell densities by three orders of magnitude than those on SiNT templates. It is hypothesized that SiNTs array does generate nano-fluidic effect such that the effective contact region for aqueous solution on SiNTs is lower than that on planar Si templates, thus decreasing adsorbable area for cell viability and survival. Moreover, the effect of the gold coating on cell number density was analyzed in terms of the surface roughness, zeta potential and wetting properties of the templates. It was determined that surface charge, as measured by the zeta potential, strongly correlated with the trend observed in the surface cell density, whereas no such correlation was observed for surface roughness or wetting properties in the ranges of our experiment conditions.

Surface plasmon resonance-induced color-selective Au-peapodded silica nanowire photodetectors with high photoconductive gain.

We report the optoelectronic device properties of individual Au-silica hybrid nanowires prepared by microwave plasma enhanced chemical vapor deposition. Due to the surface plasmon resonance (SPR) effect the photo-responsivity peak strongly depends on the shape of the embedded gold nanostructures in the silica nanowire in which the shape can be modified by controlling the growth time of Au-silica nanowires. Finite difference time domain (FDTD) simulation shows that the electric field distribution profiles of Au-silica hybrid nanowires support the photo-responsivity spectrum results. The photodetector performance of the Au-NPs@silica nanowire is investigated. The single Au-NPs@silica nanowire exhibits unique photo-responsivity in the visible range (500 nm), high selectivity, high photoconductive gain, and very fast rise (141 µs) and decay (298 µs) time constants. Furthermore, the mechanism for the high photoconductive gain is also discussed. This result implies that the Au-NPs@silica nanowire can be applied for future nanoscale optoelectronic devices.

High k nanophase zinc oxide on biomimetic silicon nanotip array as supercapacitors.

A 3D trenched-structure metal-insulator-metal (MIM) nanocapacitor array with an ultrahigh equivalent planar capacitance (EPC) of ~300 µF cm(-2) is demonstrated. Zinc oxide (ZnO) and aluminum oxide (Al2O3) bilayer dielectric is deposited on 1 µm high biomimetic silicon nanotip (SiNT) substrate using the atomic layer deposition method. The large EPC is achieved by utilizing the large surface area of the densely packed SiNT (!5 × 10(10) cm(-2)) coated conformally with an ultrahigh dielectric constant of ZnO. The EPC value is 30 times higher than those previously reported in metal-insulator-metal or metal-insulator-semiconductor nanocapacitors using similar porosity dimensions of the support materials.

Eco-friendly plasmonic sensors: using the photothermal effect to prepare metal nanoparticle-containing test papers for highly sensitive colorimetric detection.

Convenient, rapid, and accurate detection of chemical and biomolecules would be a great benefit to medical, pharmaceutical, and environmental sciences. Many chemical and biosensors based on metal nanoparticles (NPs) have been developed. However, as a result of the inconvenience and complexity of most of the current preparation techniques, surface plasmon-based test papers are not as common as, for example, litmus paper, which finds daily use. In this paper, we propose a convenient and practical technique, based on the photothermal effect, to fabricate the plasmonic test paper. This technique is superior to other reported methods for its rapid fabrication time (a few seconds), large-area throughput, selectivity in the positioning of the NPs, and the capability of preparing NP arrays in high density on various paper substrates. In addition to their low cost, portability, flexibility, and biodegradability, plasmonic test paper can be burned after detecting contagious biomolecules, making them safe and eco-friendly.

Gold nanoparticle-modulated conductivity in gold peapodded silica nanowires.

We report the enhanced electrical conductivity properties of single gold-peapodded amorphous silica nanowires synthesized using microwave plasma enhanced chemical vapor deposition. Dark conductivity of the gold-peapodded silica nanowires can be adjusted by controlling the number of incorporated metal nanoparticles. The temperature-dependent conductivity measurement reveals that the band tail hopping mechanism dominates the electron transport in the gold-peapodded silica nanowires. The high conductivity in the nano-peapodded nanowires with more embedded gold-nanoparticles can be explained by the higher density of hopping states and shorter hopping distance. These Au-embedded amorphous silica nanowires have provided a new approach to enhance not only the electron conduction, but also the chemical-sensor response/sensitivity.

Giant room temperature electric-field-assisted magnetoresistance in La0.7Sr0.3MnO3/n-Si nanotip heterojunctions.

An on-chip approach for fabricating ferromagnetic/semiconductor-nanotip heterojunctions is demonstrated. The high-density array of Si nanotips (SiNTs) is employed as a template for depositing La(0.7)Sr(0.3)MnO(3) (LSMO) rods with a pulsed-laser deposition method. Compared with the planar LSMO/Si thin film, the heterojunction shows a large enhancement of room temperature magnetoresistance (MR) ratio up to 20% under 0.5 T and a bias current of 20 µA. The MR ratio is found to be tunable, which increases with increasing external bias and the aspect ratios of the nanotips. Electric-field-induced metallization, in conjunction with nanotip geometry, is proposed to be the origin for the giant MR ratio.

Label free sub-picomole level DNA detection with Ag nanoparticle decorated Au nanotip arrays as surface enhanced Raman spectroscopy platform.

Label free optical sensing of adenine and thymine oligonucleotides has been achieved at the sub-picomole level using self assembled silver nanoparticles (AgNPs) decorated gold nanotip (AuNT) arrays. The platform consisting of the AuNTs not only aids in efficient bio-immobilization, but also packs AgNPs in a three dimensional high surface area workspace, assisting in surface enhanced Raman scattering (SERS). The use of sub-10 nm AgNPs with optimum inter-particle distance ensures amplification of the chemically specific Raman signals of the adsorbed adenine, thymine, cytosine and guanine molecules in SERS experiments. High temporal stability of the Raman signals ensured reliable and repeatable DNA detection even after three weeks of ambient desk-top conservation. This facile architecture, being three dimensional and non-lithographic, differs from conventional SERS platforms.

Application of parylene-coated quartz crystal microbalance for on-line real-time detection of microbial populations.

A novel technique of applying a quartz crystal microbalance (QCM) sensor to the on-line real-time detection of microbial populations is described. The pQCM sensor was fabricated by depositing di-para-xylene (parylene) over the entire surface of a QCM sensor through a chemical vapor deposition (CVD) process. An electrically insulated film of parylene on the QCM sensor enabled the operation of the sensor in the liquid environment, and the resonance frequency of the pQCM sensor set in the medium of a cultivation flask shifted in response to the microbial population. The effects of pH, conductivity, and viscosity of the medium on the frequency shift of the pQCM sensor were investigated. Ignorable responses (less than 1% at 10(3)cells) were obtained during an incubation cycle. The detection limit of the pQCM sensor was identified as 10(2) cells ml(-1) with a frequency shift of around 2 x 10(3)Hz. The cell numbers of Escherichia coli cultivated in both the YEM medium and whole milk were detected. A satisfactory correlation (r(2)=0.95) was obtained between the cell number and the response of the pQCM sensor. Experimental results suggest that the pQCM described here is applicable to the continuous long-term detection of microbial populations during a fermentation process.