Factors Associated with Worsening Oxygenation in Patients with Non-severe COVID-19 Pneumonia.

BACKGROUND: This study aimed to determine the parameters for worsening oxygenation in non-severe coronavirus disease 2019 (COVID-19) pneumonia. METHODS: This retrospective cohort study included cases of confirmed COVID-19 pneumonia in a public hospital in South Korea. The worsening oxygenation group was defined as that with SpO2 ≤94% or received oxygen or mechanical ventilation (MV) throughout the clinical course versus the non-worsening oxygenation group that did not experience any respiratory event. Parameters were compared, and the extent of viral pneumonia from an initial chest computed tomography (CT) was calculated using artificial intelligence (AI) and measured visually by a radiologist. RESULTS: We included 136 patients, with 32 (23.5%) patients in the worsening oxygenation group; of whom, two needed MV and one died. Initial vital signs and duration of symptoms showed no difference between the two groups; however, univariate logistic regression analysis revealed that a variety of parameters on admission were associated with an increased risk of a desaturation event. A subset of patients was studied to eliminate potential bias, that ferritin ≥280 µg/L (p=0.029), lactate dehydrogenase ≥240 U/L (p=0.029), pneumonia volume (p=0.021), and extent (p=0.030) by AI, and visual severity scores (p=0.042) were the predictive parameters for worsening oxygenation in a sex-, age-, and comorbid illness-matched case-control study using propensity score (n=52). CONCLUSION: Our study suggests that initial CT evaluated by AI or visual severity scoring as well as serum markers of inflammation on admission are significantly associated with worsening oxygenation in this COVID-19 pneumonia cohort.

Clinical Experience with Use of Remdesivir in the Treatment of Severe Acute Respiratory Syndrome Coronavirus 2: a Case Series.

BACKGROUND: A novel antiviral agent, remdesivir (RDV), is a promising candidate treatment for coronavirus disease 2019 (COVID-19) in the absence of any proven therapy. MATERIALS AND METHODS: This retrospective case series included 10 patients with a clinically and laboratory confirmed diagnosis of severe COVID-19 pneumonia who had received RDV for 5 days (n = 5) or 10 days (n = 5) in the Phase III clinical trial of RDV (GS-US-540-5773) conducted by Gilead Sciences. The clinical and laboratory data for these patients were extracted. RESULTS: One patient in the 10-day group received RDV for only 5 days because of nausea and elevated liver transaminases. No patient had respiratory comorbidity. Seven patients had bilateral lesions and three had unilateral lesions on imaging. All patients had received other medications for COVID-19, including lopinavir/ritonavir and hydroxychloroquine, before administration of RDV. Five patients required supplemental oxygen and one required mechanical ventilation. All patients showed clinical and laboratory evidence of improvement. Half of the patients developed elevated liver transaminases and three had nausea. There were no adverse events exceeding grade 2. CONCLUSION: Our experience indicates that RDV could be a therapeutic option for COVID-19. A well-designed randomized controlled clinical trial is now needed to confirm the efficacy of RDV in patients with COVID-19.

Ruthenium Decorated Polypyrrole Nanoparticles for Highly Sensitive Hydrogen Gas Sensors Using Component Ratio and Protonation Control.

Despite being highly flammable at lower concentrations and causing suffocation at higher concentrations, hydrogen gas continues to play an important role in various industrial processes. Therefore, an appropriate monitoring system is crucial for processes that use hydrogen. In this study, we found a nanocomposite comprising of ruthenium nanoclusters decorated on carboxyl polypyrrole nanoparticles (Ru_CPPy) to be successful in detecting hydrogen gas through a simple sonochemistry method. We found that the morphology and density control of the ruthenium component increased the active surface area to the target analyte (hydrogen molecule). Carboxyl polypyrrole (CPPy) in the nanocomposite was protonated to increase the charge transfer rate during gas detection. This material-based sensor electrode was highly sensitive (down to 0.5 ppm) toward hydrogen gas and had a fast response and recovery time under ambient conditions. The sensing ability of the electrode was maintained up to 15 days without structure deformations.

Ultrasensitive, Selective, and Highly Stable Bioelectronic Nose That Detects the Liquid and Gaseous Cadaverine.

Field-effect transistor (FET) devices based on conductive nanomaterials have been used to develop biosensors. However, development of FET-based biosensors that allow efficient stability, especially in the gas phase, for obtaining reliable and reproducible responses remains a challenge. In this study, we developed a nanodisc (ND)-functionalized bioelectronic nose (NBN) based on a nickel (Ni)-decorated carboxylated polypyrrole nanoparticle (cPPyNP)-FET that offers the detection of liquid and gaseous cadaverine (CV). The TAAR13c, specifically binding to CV, which is an indicator of food spoilage, was successfully constructed in NDs. The NBN was fabricated by the oriented assembly of TAAR13c-embedded NDs (T13NDs) onto the transistor with Ni/cPPyNPs. The NBN showed high performance in selectivity and sensitivity for the detection of CV, with excellent stability in both aqueous and gas phases. Moreover, the NBN allowed efficient measurement of corrupted real-food samples. It demonstrates the ND-based device can allow the practical biosensor that provides high stability in the gas phase.

Highly porous structured polyaniline nanocomposites for scalable and flexible high-performance supercapacitors.

Recently, flexible energy devices have been used to power up portable electronics such as E-skins, smart clothes, and bendable displays. However, the usage of rigid and inactive components in electrode materials limits the application in flexible energy devices. Here, we report a novel method to fabricate porous polyaniline composites (Pt_CPPy/PANI:CSA) using Pt decorated carboxyl polypyrrole nanoparticles (Pt_CPPyNPs) as a nucleating agent for electrodes of supercapacitors. The specific capacitance and electrical conductivity of the Pt_CPPy/PANI:CSA film are 325.0 F g-1 and 814 S cm-1, respectively, which are much higher than those of the pristine PANI:CSA film. Furthermore, the porous PANI:CSA composites exhibit excellent rate capability and cycling stability as the pores in the PANI structure enhance the active surface area between PANI and the ions of the electrolytes. This unique fabrication technique is an effective approach for preparing large scale highly porous polyaniline nanomaterials for diverse electrochemical applications.

Fabrication of N-doped multidimensional carbon nanofibers for high-performance cortisol biosensors.

Cortisol is an hormone that regulates blood pressure, glucose levels and carbohydrate metabolism in humans. Abnormal secretion of cortisol can cause various symptoms closely linked to psychological and physical health. In this study, high-performance field-effect transistor (FET)-based biosensors for cortisol detection were fabricated from N-doped multidimensional carbon nanofibers. Nanofiber morphology was controlled by tailoring the pressure conditions during vapor deposition polymerization (VDP). Thereafter, conductive channels of FET were completed by thermal annealing, acid treatment, and antibody attachment. Changes associated with chemical processes were characterized by various instruments. The resulting transducers exhibited a rapid response toward cortisol molecules with accurate selectivity, stable reusability, and high sensitivity. Minimum detection level were as low as 100 aM with a wide linear detection range of 100 aM to 10 nM due to the large surface area of the transducer and a correspondingly high number of antibody labels. The response and applicability of these cortisol biosensors were also assessed using saliva as a test matrix.

Multidimensional Conductive Nanofilm-Based Flexible Aptasensor for Ultrasensitive and Selective HBsAg Detection.

Hepatitis B virus (HBV) infection is a major worldwide health issue causing serious liver diseases, including liver cirrhosis and hepatocellular carcinoma. Monitoring the serum hepatitis B surface antigen (HBsAg) level is pivotal to the diagnosis of HBV infection. In this study, we describe multidimensional conductive nanofilm (MCNF)-based field-effect transistor (FET) aptasensor for HBsAg detection. The MCNF, composed of vertically oriented carboxylic polypyrrole nanowires (CPPyNW) and graphene layer, is formed using electropolymerization of pyrrole on the graphene surface and following acid treatment. The amine-functionalized HBsAg-binding aptamers are then immobilized on the CPPyNW surface through covalent bonding formation (i.e., amide group). The prepared aptasensor presents highly sensitive to HBsAg as low as 10 aM among interfering biomolecules with various deformations. Moreover, the MCNF-based aptasensor has great potential for practical application in the noninvasive real-time diagnosis because of its improved sensing ability to the human serum and artificial saliva.

Ultrasensitive and Selective Organic FET-type Nonenzymatic Dopamine Sensor Based on Platinum Nanoparticles-Decorated Reduced Graphene Oxide.

Dopamine (DA), a catecholamine hormone, is an important neurotransmitter that controls renal and cardiovascular organizations and regulates physiological activities. Abnormal concentrations of DA cause unfavorable neuronal illnesses such as Parkinson's disease, schizophrenia, and attention deficit hyperactivity disorder/attention deficit disorder. However, the DA concentration is exceedingly low in patients and difficult to detect with existing biosensors. In this study, we developed an organic field-effect-transistor-type (OFET) nonenzyme biosensor using platinum nanoparticle-decorated reduced graphene oxide (Pt_rGO) for ultrasensitive and selective DA detection. The Pt_rGOs were fabricated by reducing GO aqueous solution-containing Pt precursors (PtCl4) with a chemical reducing agent. The Pt_rGOs were immobilized on a graphene substrate by π-π interactions and a conducting-polymer source-drain electrode was patterned on the substrate to form the DA sensor. The resulting OFET sensor showed a high sensitivity to remarkably low DA concentrations (100 × 10-18 M) and selectivity among interfering molecules. Good stability was expected for the OFET sensor because it was fabricated without an enzymatic receptor, and π-π conjugation is a part of the immobilization process. Furthermore, the OFET sensors are flexible and offer the possibility of wide application as wearable and portable sensors.

Wireless, Room Temperature Volatile Organic Compound Sensor Based on Polypyrrole Nanoparticle Immobilized Ultrahigh Frequency Radio Frequency Identification Tag.

Due to rapid advances in technology which have contributed to the development of portable equipment, highly sensitive and selective sensor technology is in demand. In particular, many approaches to the modification of wireless sensor systems have been studied. Wireless systems have many advantages, including unobtrusive installation, high nodal densities, low cost, and potential commercial applications. In this study, we fabricated radio frequency identification (RFID)-based wireless sensor systems using carboxyl group functionalized polypyrrole (C-PPy) nanoparticles (NPs). The C-PPy NPs were synthesized via chemical oxidation copolymerization, and then their electrical and chemical properties were characterized by a variety of methods. The sensor system was composed of an RFID reader antenna and a sensor tag made from a commercially available ultrahigh frequency RFID tag coated with C-PPy NPs. The C-PPy NPs were covalently bonded to the tag to form a passive sensor. This type of sensor can be produced at a very low cost and exhibits ultrahigh sensitivity to ammonia, detecting concentrations as low as 0.1 ppm. These sensors operated wirelessly and maintained their sensing performance as they were deformed by bending and twisting. Due to their flexibility, these sensors may be used in wearable technologies for sensing gases.

Wireless Hydrogen Smart Sensor Based on Pt/Graphene-Immobilized Radio-Frequency Identification Tag.

Hydrogen, a clean-burning fuel, is of key importance to various industrial applications, including fuel cells and the aerospace and automotive industries. However, hydrogen gas is odorless, colorless, and highly flammable; thus, appropriate safety protocol implementation and monitoring are essential. Highly sensitive hydrogen-gas leak detection and surveillance systems are needed; additionally, the ability to monitor large areas (e.g., cities) via wireless networks is becoming increasingly important. In this report, we introduce a radio frequency identification (RFID)-based wireless smart-sensor system, composed of a Pt-decorated reduced graphene oxide (Pt_rGO)-immobilized RFID sensor tag and an RFID-reader antenna-connected network analyzer to detect hydrogen gas. The Pt_rGOs, produced using a simple chemical reduction process, were immobilized on an antenna pattern in the sensor tag through spin coating. The resulting Pt_rGO-based RFID sensor tag exhibited a high sensitivity to hydrogen gas at unprecedentedly low concentrations (1 ppm), with wireless communication between the sensor tag and RFID-reader antenna. The wireless sensor tag demonstrated flexibility and a long lifetime due to the strong immobilization of Pt_rGOs on the substrate and battery-independent operation during hydrogen sensing, respectively.

Platinum-decorated reduced graphene oxide/polyaniline:poly(4-styrenesulfonate) hybrid paste for flexible dipole tag-antenna applications.

With recent developments in technology, tremendous effort has been devoted to producing materials for flexible device systems. As a promising approach, solution-processed conducting polymers (CPs) have been extensively studied owing to their facile synthesis, high electrical conductivity, and various morphologies with diverse substrates. Here, we report the demonstration of platinum decorated reduced graphene oxide intercalated polyanililne:poly(4-styrenesulfonate) (Pt_rGO/PANI:PSS) hybrid paste for flexible electric devices. First, platinum decorated reduced graphene oxide (Pt_rGO) was fabricated through the chemical reduction of platinum cations and subsequent heat reduction of GO sheets. Then, the Pt_rGO was mixed with PANI:PSS solution dispersed in diethylene glycol (DEG) using sonication to form a hybrid PANI-based paste (Pt_rGO/PANI:PSS). The Pt_rGO/PANI:PSS was printed as a micropattern and exhibited high electrical conductivity (245.3 S cm(-1)) with flexible stability. Moreover, it was used in a dipole tag antenna application, where it displayed 0.15 GHz bandwidth and high transmitted power efficiency (99.6%).

Highly Sensitive and Selective Field-Effect-Transistor NonEnzyme Dopamine Sensors Based on Pt/Conducting Polymer Hybrid Nanoparticles.

Dopamine (DA), as one of catecholamine family of neurotransmitters, is crucially important in humans owing to various critical effects on biometric system such as brine circuitry, neuronal plasticity, organization of stress responses, and control of cardiovascular and renal organizations. Abnormal level of dopamine in the central nervous system causes several neurological diseases, e.g., schizophrenia, Parkinson's disease, and attention deficit hybperactivity disorder (ADHD)/attention deficit disorder (ADD). In this report, we suggest the fabrication of nonenzyme field effect transistor (FET) sensor composed of immobilized Pt particle decorated conducting-polymer (3-carboxylate polypyrrole) nanoparticles (Pt_CPPy) to detect dopamine. The hybrid nanoparticles (NPs) are produced by means of facile chemical reduction of pristine CPPyNP-contained Pt precursor (PtCl4 ) solution. The Pt_CPPys are then immobilized on an amine-functionalized (-NH2 ) interdigitated-array electrode substrate, through the formation of covalent bonds with amine groups (-CONH). The resulting Pt_CPPy-based FET sensors exhibit high sensitivity and selectivity toward DA at unprecedentedly low concentrations (100 × 10(-15) m) and among interfering biomolecules, respectively. Additionally, due to the covalent bonding involved in the immobilization process, a longer lifetime is expected for the FET sensor.