Efficacy and safety of osimertinib for patients with EGFR-mutated NSCLC: a systematic review and meta-analysis of randomized controlled studies.

BACKGROUND: Osimertinib is a recently approved third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that selectively inhibits both EGFR-TKI-sensitizing and EGFR-T790M resistance mutations. The aim of the present meta-analysis was to investigate the efficacy and safety of osimertinib for patients with EGFR-mutated non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS: Databases were searched for randomized controlled studies that reported the efficacy and safety of osimertinib versus other treatments (chemotherapy, other EGFR-TKIs, etc.) in treating EGFR-mutated NSCLC. The measured effects included objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), central nervous system progression-free survival (CNS-PFS), and overall survival (OS). Additional outcome was the incidence of adverse event. Relative risk (RR) for incidence and hazard ratio (HR) for survival outcomes were pooled. RESULTS: Seven studies containing 3335 participants were finally included. Osimertinib tended to improve ORR and DCR (RRs >1) as compared with other treatments. Osimertinib was also a significant protective factor for PFS, CNS-PFS, and OS (HRs <1 and p < .05). Osimertinib showed similar advantages in improving tumor response and patient survival when used as first-line, second-line, and third-line/adjuvant therapy, respectively, as compared with other treatments (RRs >1 for ORR and DCR; HRs <1 for PFS, CNS-PFS, and OS). Osimertinib also had better therapeutic effects as compared with chemotherapy, other EGFR TKIs, docetaxel + bevacizumab, and placebo, respectively. The five most common adverse events with pooled incidence > 20% were diarrhea, rash, nail effects, dry skin, and stomatitis, yet the pooled incidence of serious adverse events was less than 2%. CONCLUSIONS: This meta-analysis suggests that osimertinib has a positive effect in disease control and survival for patients with EGFR-mutated NSCLC with acceptable toxicities.

Hesperidin delays cell cycle progression into the G0/G1 phase via suspension of MAPK signaling pathway in intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (iCCA) derived from epithelial cells of bile ducts is highly aggressive tumor. Hesperidin extracted from citrus fruits is a promising antitumor compound. The purpose of this study is to explore molecular mechanism by which hesperidin affects cholangiocarcinoma progression. Cellular functional experiments were performed and subcutaneous transplant xenograft model was established. Our findings indicated that hesperidin suppressed iCCA cell proliferation in time- and concentration-dependent manners. Hesperidin treatment induced cell cycle arrest at G0/G1 phase, whereas it has no effect on cell apoptosis. Further, data revealed that hesperidin attenuated MEK5 and ERK5 phosphorylation and inhibited ERK5 nuclear localization by reducing MEKK2 activity in MAPK signaling pathway. It could cause alterations in expression of the downstream genes, including CDK4, CDK6 (cell cycle protein kinases), Cyclin D1 (a G1/S checkpoint), P21, and P27 (two G1-checkpoint CDK inhibitors), thereby arresting cell cycle distribution of iCCA cells in the G0/G1 phase. BIX02189 treatment, a specific inhibitor of MEK5, in combination with hesperidin displayed synergistic inhibitory effects on cell cycle arrest and gene expressions. Furthermore, hesperidin administration alone or in combination with MEK5 inhibitor BIX02189 restrained iCCA tumor growth in vivo. Taken together, these results confirmed that hesperidin regulated the expression of cell cycle-related genes by inhibiting the activation of MEKK2/MEK5/ERK5 signaling pathway, inducing iCCA cell cycle arrest at the G0/G1 phase. Our study provides a theoretical foundation and experimental basis for further development of hesperidin as a therapeutic agent for iCCA treatment.

Long intergenic non-coding RNA Linc00485 promotes lung cancer progression by modulating miR-298/c-Myc axis.

Long non-coding RNAs (lncRNAs), which are non-protein-coding transcripts, are emerging as novel biomarkers for cancer diagnosis. Their dysregulation is increasingly recognized to contribute to the development and progression of human cancers, including lung cancer. Linc00485 is a newly discovered cancer-related lncRNA; however, little is known about its role in lung cancer progression. In this study, we found that the expression of Linc00485 was significantly increased in human lung cancer tissue and associated with malignant phenotypes, including tumour-node-metastasis (TNM) stage, metastasis and relapse. Furthermore, the proliferative, migratory and invasive abilities of lung cancer cells in vitro were significantly enhanced by overexpression of Linc00485 but inhibited by its silencing. Mechanistically, Linc00485 regulated the expression of c-Myc by directly binding to miR-298; the effects of Linc00485 overexpression could be significantly reversed by a c-Myc inhibitor or small interfering RNA. Xenotransplantation experiments showed that Linc00485 silencing significantly weakened the proliferation potential of A549 cells in vivo. Overall, these findings indicate that Linc00485 overexpression down-regulates miR-298, resulting in the up-regulation of c-Myc and thereby promoting the development of lung cancer.

Long Noncoding RNA HOXD-AS1 Promotes the Proliferation, Migration, and Invasion of Colorectal Cancer via the miR-526b-3p/CCND1 Axis.

BACKGROUND: Colorectal cancer (CRC) is one of the most common malignancies in the world. It has been reported that the abnormal expression of long noncoding RNA HOXD-AS1 promotes the development of CRC, while the mechanism is still unclear. The aim of this study is to investigate the effects of HOXD-AS1 on proliferation, migration, and invasion in CRC and explore the underlying mechanism. METHODS: Quantitative real-time polymerase chain reaction was used to detect the expression levels of HOXD-AS1, miR-526b-3p, and cyclin D1 (CCND1) in CRC tissues and cells. Dual-luciferase reporter assay was applied to examine the interaction between miR-526b-3p and HOXD-AS1 or CCND1. In addition, cell proliferation ability was assessed by Cell Counting Kit-8 assay. Cell migration and invasion abilities were determined using transwell assay. Furthermore, Western blot assay was conducted to measure the protein expression of CCND1. RESULTS: HOXD-AS1 was highly expressed in CRC, and high expression of HOXD-AS1 was related to the poor prognosis of patients with CRC. MiR-526b-3p could be targeted by HOXD-AS1. Function experiment results revealed that miR-526b-3p inhibitor could reverse the suppressive effect of HOXD-AS1 knockdown on the proliferation, migration, and invasion of CRC cells. Moreover, CCND1 was a target of miR-526b-3p, and its overexpression could reverse the inhibitory effect of miR-526b-3p overexpression on the proliferation, migration, and invasion of CRC cells. In addition, CCND1 overexpression reversed the suppressive effect of HOXD-AS1 knockdown on the proliferation, migration, and invasion of CRC. CONCLUSIONS: HOXD-AS1 upregulated the expression of CCND1 to promote the proliferation, migration, and invasion of CRC through targeting miR-526b-3p. This provided a new theoretical basis for clinical anticancer research of CRC.

Fabrication of Thermal Conductivity Detector Based on MEMS for Monitoring Dissolved Gases in Power Transformer.

In this work, a high sensitivity micro-thermal conductivity detector (µTCD) with four thermal conductivity cells was proposed. Compared with conventional TCD sensors, the thermal conductivity cell in this work was designed as a streamlined structure; the thermistors were supported by a strong cantilever beam and suspended in the center of the thermal conductivity cell, which was able to greatly reduce the dead volume of the thermal conductivity cell and the heat loss of the substrate, improving the detection sensitivity. The experimental results demonstrated that the µTCD shows good stability and high sensitivity, which could rapidly detect light gases with a detection limit of 10 ppm and a quantitative repeatability of less than 1.1%.

Highly Integrated MEMS-ASIC Sensing System for Intracorporeal Physiological Condition Monitoring.

In this paper, a highly monolithic-integrated multi-modality sensor is proposed for intracorporeal monitoring. The single-chip sensor consists of a solid-state based temperature sensor, a capacitive based pressure sensor, and an electrochemical oxygen sensor with their respective interface application-specific integrated circuits (ASICs). The solid-state-based temperature sensor and the interface ASICs were first designed and fabricated based on a 0.18-µm 1.8-V CMOS (complementary metal-oxide-semiconductor) process. The oxygen sensor and pressure sensor were fabricated by the standard CMOS process and subsequent CMOS-compatible MEMS (micro-electromechanical systems) post-processing. The multi-sensor single chip was completely sealed by the nafion, parylene, and PDMS (polydimethylsiloxane) layers for biocompatibility study. The size of the compact sensor chip is only 3.65 mm × 1.65 mm × 0.72 mm. The functionality, stability, and sensitivity of the multi-functional sensor was tested ex vivo. Cytotoxicity assessment was performed to verify that the bio-compatibility of the device is conforming to the ISO 10993-5:2009 standards. The measured sensitivities of the sensors for the temperature, pressure, and oxygen concentration are 10.2 mV/°C, 5.58 mV/kPa, and 20 mV·L/mg, respectively. The measurement results show that the proposed multi-sensor single chip is suitable to sense the temperature, pressure, and oxygen concentration of human tissues for intracorporeal physiological condition monitoring.

Enhanced expression of long non-coding RNA NEAT1 is associated with the progression of gastric adenocarcinomas.

BACKGROUND: Long non-coding RNAs (lncRNAs) are emerging as new players in the cancer. The aim of this study was to examine the abnormalities of NEAT1 (nuclear paraspeckle assembly transcript 1, also known as MENε/ß) in gastric adenocarcinomas (GACs). METHODS: One hundred thirty-one GAC tissues and matched adjacent normal tissues (ANTs) were collected from patients who undergone surgery. Differences in of NEAT1 expression were examined via quantitative reverse transcriptase PCR (qRT-PCR). WST-1 assay and transwell assay were carried out in vitro to investigate the proliferation and migration of GAC cells with alteration in NEAT1 long non-coding RNA (lncRNA) expression. RESULTS: The expression levels of lncRNA NEAT1 were significantly elevated in GAC tissues (P<0.001) compared with ANTs. There was also a statistical difference in NEAT1 expression between early and advanced GACs (P=0.0111). GACs with lymph node metastasis (LNM) expressed higher levels of NEAT1 lncRNA compared with those without LNM (P=0.004). In the in vitro experiments, the proliferation but not migration of GAC cells was attenuated after NEAT1 knockdown by RNA interference. CONCLUSIONS: Expression of NEAT1 lncRNA was enhanced in GACs; and NEAT1 may influence GAC progression by promoting tumor growth.

Deletion and down-regulation of SMAD4 gene in colorectal cancers in a Chinese population.

OBJECTIVE: Colorectal cancer (CRC) is one of the most common types of human cancers. As a tumor suppressor, SMAD4 plays a key role in colorectal carcinogenesis and invasiveness. Copy number variations (CNVs) of the SMAD4 gene have been reported to be associated with cancer pathogenesis in array-based studies in different populations. Here we aimed to investigate the CNVs of the SMAD4 gene in a relatively large number of CRC patients from China. METHODS: In the present study, we collected 147 Chinese CRC tumors as well as self-paired normal control tissues. Quantitative PCR was carried out to examine the copy number as well as the mRNA expression of the SMAD4 gene. RESULTS: Our results showed that the copy number deletions of SMAD4 were frequent in a relatively high percentage of CRC samples (34.7%, 51 out of 147). There was a positive correlation between the copy number decrease of SMAD4 and tumor progression in CRCs. Furthermore, copy number loss of SMAD4 was correlated with decreased mRNA expression. CONCLUSIONS: These findings suggested that the copy number deletions of SMAD4 were frequent in CRC patients from China and had the potential to serve as a diagnostic indicator, alone or in combination with other markers, for CRC.

FPGA-based Lightweight QDS-CNN System for sEMG Gesture and Force Level Recognition.

Deep learning (DL) has been used for electromyographic (EMG) signal recognition and achieved high accuracy for multiple classification tasks. However, implementation in resource-constrained prostheses and human-computer interaction devices remains challenging. To overcome these problems, this paper implemented a low-power system for EMG gesture and force level recognition using Zynq architecture. Firstly, a lightweight network model structure was proposed by Ultra-lightweight depth separable convolution (UL-DSC) and channel attention-global average pooling (CA-GAP) to reduce the computational complexity while maintaining accuracy. A wearable EMG acquisition device for real-time data acquisition was subsequently developed with size of 36mm×28mm×4mm. Finally, a highly parallelized dedicated hardware accelerator architecture was designed for inference computation. 18 gestures were tested, including force levels from 22 healthy subjects. The results indicate that the average accuracy rate was 94.92% for a model with 5.0k parameters and a size of 0.026MB. Specifically, the average recognition accuracy for static and force-level gestures was 98.47% and 89.92%, respectively. The proposed hardware accelerator architecture was deployed with 8-bit precision, a single-frame signal inference time of 41.9µs, a power consumption of 0.317W, and a data throughput of 78.6 GOP/s.

Study of cell and drug interactions based on dual-mode detection using SPR and fluorescence imaging.

The investigation of the interactions between cells and drugs forms a crucial aspect of biological and clinical medical studies. Generally, single-cell or local-cellular studies require a microscopic imaging system with high magnifications, which suffers from low detection throughputs and poor time responses. The study presented in this paper combined SPR and fluorescence to achieve cell localization, real-time monitoring of cell images and quantitative analysis of drugs. In order to obtain more comprehensive, accurate and real-time data, a dual-mode system based on surface plasmon resonance (SPR) and fluorescence was constructed based on a 4× magnification lens. This enables simultaneous studies of an entire cell and a specific region of the cell membrane. An adaptive adjustment algorithm was established for distorted SPR images, achieving temporal and spatial matching of the dual-mode detection. The combination of SPR and fluorescence not only achieved micro-detection but also complemented the qualitative or quantitative limitations of SPR or fluorescence method alone. In system characterization, the response signal of SPR was noticed to increase with the increasing concentration of EGF in stimulated cells. It indicated that this platform could be employed for quantitative detection of the cell membrane region. Upon addition of EGF, a peak in the SPR curve was observed, and the cells in the corresponding SPR image turned whiter. This indicated that the platform can simultaneously monitor the SPR response signal and image changes. The response time of fluorescence in EGF testing was several seconds earlier than SPR, revealing that signal transduction first occurred in the whole cell and then propagated to the cell membrane region. The inhibitory ability of Gefitinib on cells was verified in a fast and real-time manner within 20 min. The results indicated that the detection limit of this method was 20 IU/mL for EGF and 10 µg/mL for Gefitinib. In conclusion, this study demonstrates the advantages of SPR and fluorescence dual-mode techniques in the analysis of cell-drug interactions, as well as their strong potential in drug screening.

Patient-Controlled Subcutaneous Analgesia with Hydromorphone versus Oral Oxycontin for Opioid Titration of Cancer Pain: A Prospective Multicenter Randomized Trial.

Background: Studies have shown that oral oxycontin tablets can be used for opioid titration. The European Society for Medical Oncology (ESMO) guidelines for adult cancer pain recommend opioid titration through the parenteral route, usually the intravenous or subcutaneous route. Patient-controlled subcutaneous analgesia (PCSA) with hydromorphone needs further evaluation for opioid titration. This prospective multicenter study was designed to compare the efficacy and safety of hydromorphone PCSA with oral oxycontin tablets for opioid titration of cancer pain. Patients and Methods: Eligible patients with cancer pain were randomly assigned in a 1:1 ratio to the PCSA group or the oxycontin group for dose titration. Different titration methods were given in both groups depending on whether the patient had an opioid tolerance. The primary endpoint of this study was time to successful titration (TST). Results: A total of 256 patients completed this study. The PCSA group had a significantly lower TST compared with the oxycontin group (median [95% confidence interval (CI)], 5.5[95% CI:2.5-11.5] hours vs.16.0 [95% CI:11.5-22.5] hours; p<0.001). The frequency (median; interquartile) of breakthrough pain (Btp) over 24 hours was significantly lower in the PCSA group (2.5;2.0-3.5) than in the oxycontin group.(3.0; 2.5-4.5) (p=0.04). The pain was evaluated by numeric rating scale (NRS) score at 12 hours after the start of titration. The pain score (median; interquartile) was significantly lower in the PCSA versus the oxycontin group (2.5;1.5-3.0) vs 4.5;3.0-6.0) (p=0.02). The equivalent dose of oral morphine (EDOM) for a successful titration was similar in both groups (p=0.29), but there was a significant improvement in quality of life (QoL) in both groups (p=0.03). No between-group difference in the incidence of opioid-related adverse effects was observed (p=0.32). Conclusion: Compared with oral oxycontin tablet, the use of PCSA with hydromorphone achieved a shorter titration duration for patients with cancer pain (p<0.001), without significantly increasing adverse events (p=0.32).

Pd/Pt-Bimetallic-Nanoparticle-Doped In2O3 Hollow Microspheres for Rapid and Sensitive H2S Sensing at Low Temperature.

H2S is a poisonous gas that is widespread in nature and human activities. Its rapid and sensitive detection is essential to prevent it from damaging health. Herein, we report Pd- and Pt-bimetallic-nanoparticle-doped In2O3 hollow microspheres that are synthesized using solvothermal and in situ reduction methods for H2S detection. The structure of as-synthesized 1 at% Pd/Pt-In2O3 comprises porous hollow microspheres assembled from In2O3 nanosheets with Pd and Pt bimetallic nanoparticles loaded on its surface. The response of 1 at% Pd/Pt-In2O3 to 5 ppm H2S is 140 (70 times that of pure In2O3), and the response time is 3 s at a low temperature of 50 °C. In addition, it can detect trace H2S (as low as 50 ppb) and has superior selectivity and an excellent anti-interference ability. These outstanding gas-sensing performances of 1 at% Pd/Pt-In2O3 are attributed to the chemical sensitization of Pt, the electronic sensitization of Pd, and the synergistic effect between them. This work supplements the research of In2O3-based H2S sensors and proves that Pd- and Pt-bimetallic-doped In2O3 can be applied in the detection of H2S.

Efficacy of hyperthermic intrathoracic chemotherapy for initially diagnosed lung cancer with symptomatic malignant pleural effusion.

Initially diagnosed malignant pleural effusion (MPE) has different systematic treatments, and defining the best drainage regimen according to the responsiveness of MPE to different systematic treatments is important. This study compared the efficacy of hyperthermic intrathoracic chemotherapy (HITHOC) and pleural catheter drainage (IPCD) for initially diagnosed lung cancer with symptomatic MPE. We retrospectively reviewed the medical records of initially diagnosed lung cancer patients with symptomatic MPE between January 2018 and May 2022. The patients were treated with IPCD or HITHOC for local control of MPE after diagnosis. Systematic regimens were conducted during 1 month according to guidelines after local treatment. Intrathoracic MPE progression-free survival (iPFS) and overall survival (OS) were calculated, Univariate and multivariable Cox-regression were used to identify factors associated with iPFS and OS. A total of 33 patients were evaluated; 10 (30.3%) patients received IPCD, and 23 (69.7%) patients received HITHOC. No difference in the MPE control rate at 1 month was found between the IPCD group (90%) and HITHOC group (95.7%). However, this control rate was significantly higher in the HITHOC group (69.6%) than in the IPCD group (30%) at 3 months (P = 0.035). Multivariate analysis showed that receiving tyrosine kinase inhibitors (TKIs) or chemotherapy was a significant protective factor for iPFS (HR = 0.376, 95% CI 0.214-0.659, P = 0.007) and OS (HR = 0.321, 95% CI 0.174-0.594, P < 0.001). According to subgroup analysis, among patients treated with TKIs, those who received HITHOC had longer iPFS and OS than those who received IPCD (P = 0.011 and P = 0.002, respectively), but this difference was not found in the palliative care subgroup. Moreover, no patients treated with chemotherapy showed reaccumulation of MPE. Systematic TKIs or chemotherapy prolonged iPFS and OS for those initially diagnosed with lung cancer with symptomatic MPE. HITHOC prolonged iPFS and OS for those treated with systematic TKIs.

Cu-doped SnO2/rGO nanocomposites for ultrasensitive H2S detection at low temperature.

Hydrogen sulfide (H2S) detection remains a significant concern and the sensitivity, selectivity, and detection limit must be balanced at low temperatures. Herein, we utilized a facile solvothermal method to prepare Cu-doped SnO2/rGO nanocomposites that have emerged as promising candidate materials for H2S sensors. Characterization of the Cu-SnO2/rGO was carried out to determine its surface morphology, chemical composition, and crystal defects. The optimal sensor response for 10 ppm H2S was ~1415.7 at 120 °C, which was over 320 times higher than that seen for pristine SnO2 CQDs (Ra/Rg = 4.4) at 280 °C. Moreover, the sensor material exhibited excellent selectivity, a superior linear working range (R2 = 0.991, 1-150 ppm), a fast response time (31 s to 2 ppm), and ppb-level H2S detection (Ra/Rg = 1.26 to 50 ppb) at 120 °C. In addition, the sensor maintained a high performance even at extremely high humidity (90%) and showed outstanding long-term stability. These superb H2S sensing properties were attributed to catalytic sensitization by the Cu dopant and a synergistic effect of the Cu-SnO2 and rGO, which offered abundant active sites for O2 and H2S absorption and accelerated the transfer of electrons/holes.

Recent Advancements in Physiological, Biochemical, and Multimodal Sensors Based on Flexible Substrates: Strategies, Technologies, and Integrations.

Flexible wearable devices have been widely used in biomedical applications, the Internet of Things, and other fields, attracting the attention of many researchers. The physiological and biochemical information on the human body reflects various health states, providing essential data for human health examination and personalized medical treatment. Meanwhile, physiological and biochemical information reveals the moving state and position of the human body, and it is the data basis for realizing human-computer interactions. Flexible wearable physiological and biochemical sensors provide real-time, human-friendly monitoring because of their light weight, wearability, and high flexibility. This paper reviews the latest advancements, strategies, and technologies of flexibly wearable physiological and biochemical sensors (pressure, strain, humidity, saliva, sweat, and tears). Next, we systematically summarize the integration principles of flexible physiological and biochemical sensors with the current research progress. Finally, important directions and challenges of physiological, biochemical, and multimodal sensors are proposed to realize their potential applications for human movement, health monitoring, and personalized medicine.

Multichannel Flexible Pulse Perception Array for Intelligent Disease Diagnosis System.

Pressure sensors with high sensitivity, a wide linear range, and a quick response time are critical for building an intelligent disease diagnosis system that directly detects and recognizes pulse signals for medical and health applications. However, conventional pressure sensors have limited sensitivity and nonideal response ranges. We proposed a multichannel flexible pulse perception array based on polyimide/multiwalled carbon nanotube-polydimethylsiloxane nanocomposite/polyimide (PI/MPN/PI) sandwich-structure pressure sensor that can be applied for remote disease diagnosis. Furthermore, we established a mechanical model at the molecular level and guided the preparation of MPN. At the structural level, we achieved high sensitivity (35.02 kPa-1) and a broad response range (0-18 kPa) based on a pyramid-like bilayer microstructure with different upper and lower surfaces. A 27-channel (3 × 9) high-density sensor array was integrated at the device level, which can extract the spatial and temporal distribution information on a pulse. Furthermore, two intelligent algorithms were developed for extracting six-dimensional pulse information and automatic pulse recognition (the recognition rate reaches 97.8%). The results indicate that intelligent disease diagnosis systems have great potential applications in wearable healthcare devices.

Effectiveness and safety of chemotherapy combined with immunomodulatory therapies for multiple myeloma: A protocol for systematic review and meta-analysis.

BACKGROUND: Multiple myeloma (MM) is considered one of the prevalent malignant plasma cell diseases affecting people. In essence, maintenance treatment is valuable for prolonging the survival time of patients experiencing MM. The majority of the currently used treatment protocols for MM are founded on a combination of chemotherapy and immunomodulatory drugs, of which immunomodulatory drugs seems to be one of the most active drugs. However, in the literature, chemotherapy combined with immunomodulatory therapies have not been unambiguously proven. To systematically appraise and synthesize these results, the present investigation will evaluate whether combining chemotherapy with immunomodulatory therapies an effective and safe approach to treating patients with MM. METHODS: Two authors relied in 7 different databases: PubMed, EMBASE, Cochrane Library, Web of Science, WanFang Database, Chinese Biomedical Literature Database, China National Knowledge Infrastructure and for studies on chemotherapy's effectiveness when combined with immunomodulatory therapies. The authors only considered studies published up to December 16, 2021 and only those written in English or Chinese. They will also carry out selection of studies, extraction of data, along with assessing risk of bias. Besides, they will also use RevMan V.5.3 to conduct data synthesis. They will establish heterogeneity using the I2 test. At the same time, the authors will evaluate publication bias by making a funnel plot and conducting the Begg as well as Egger tests. ETHICS AND DISSEMINATION: The present study will not necessitate ethics approval since it will be funded on already published works. OSF REGISTRATION NUMBER: 10.17605/OSF.IO/X7DE4.

Evaluation of Typical Volatile Organic Compounds Levels in New Vehicles under Static and Driving Conditions.

In modern societies, the air quality in vehicles has received extensive attention because a lot of time is spent within the indoor air compartment of vehicles. In order to further understand the level of air quality under different conditions in new vehicles, the vehicle interior air quality (VIAQ) in new vehicles with three different brands was investigated under static and driving conditions, respectively. Air sampling and analysis are conducted under the requirement of HJ/T 400-2007. Static vehicle tests demonstrate that with the increasing of vehicle interior air temperature in sunshine conditions, a higher concentration and different types of volatile organic compounds (VOCs) release from the interior materials than that in the environment test chamber, including alkanes, alcohols, ketones, benzenes, alkenes, aldehydes, esters and naphthalene. Driving vehicle tests demonstrate that the concentration of VOCs and total VOCs (TVOC) inside vehicles exposed to high temperatures will be reduced to the same level as that in the environment test chamber after a period of driving. The air pollutants mainly include alkanes and aromatic hydrocarbons. However, the change trends of VOCs and TVOC vary under different conditions according to various kinds of factors, such as vehicle model, driving speed, air exchange rate, temperature, and types of substance with different boiling points inside the vehicles.

A compact gas chromatography platform for detection of multicomponent volatile organic compounds biomarkers.

Some human exhaled volatile organic compounds (VOCs) can be employed to diagnose related human endogenous diseases as characteristic biomarkers, which is expected to be applied to rapid screening and grading because of their non-invasive and cost-effective advantages. In this study, we developed a compact gas chromatography (GC) platform mainly composed of an integrated silicon-based micro-column chip using micro-electromechanical system techniques and a miniaturized metal oxide semiconductor gas detector. In addition, the sampling/switching valve with related components and embedded microcontrollers was used for airflow control. The fabricated system selectively detected the five VOCs (pentane, acetone, toluene, octane, and decane) considered the typical endogenous disease biomarkers. In the experiments, the functional parameters of the system were investigated, and the optimum temperature conditions of the system for separation were determined. The results show that the system can successfully test the studied five VOCs as low as 1 ppm. In addition, the influence of interfering gas (carbon dioxide and ammonia) on the system for the VOC mixture is also investigated. Moreover, to prove the possibility of breath analysis of the fabricated system, the detection performance of isoprene and acetone at the ppb level is studied. Then, the concentration changes of the isoprene at the ppb concentration for human breath are successfully detected in the system. Therefore, we believe that the prepared compact GC system has potential applications in the human endogenous disease diagnosis for the VOC biomarkers.

Design and Characterization of a Microfluidic Circuit for Air Particulate Matter Separation.

Air microfluidic circuits have been widely concerned in the separation of atmospheric particulate matter, especially for portable particulate matter separation detection devices. Currently, no systematic approach for the design and optimization of an air-microfluidic system for PM separation has been reported in the literature. In this paper, a two-stage air microfluidic circuit is designed. The design process is divided into two stages: first, the preliminary design of the structure is completed according to aerodynamic theory. Then, the influences of various factors (such as flow channel width, tilt angle, flow rate, etc.) on the collection efficiency and particle wall loss are explored through numerical analysis to complete the optimization design of the structure. Finally, the air microfluidic circuit is prepared by MEMS processing technology and the particulate matter separation experiments are carried out. The developed two-stage air microfluidic circuit can realize the efficient separation of PM10 and PM2.5. Thus, the important factors affecting the collection efficiency and particle wall loss of air microfluidic circuit are clarified, and a systematic design theory method is formed.