While numerous types of gas sensors have been developed for various industries and applications such as the automotive industry, environmental monitoring, and personal safety, nanoscale ...chemiresistive gas sensors have gained significant research interest due to several advantages such as high sensitivity, low power consumption, and portability. An essential component of these gas sensors is the sensing material where metal oxide semiconductor (MOS) materials are the most prevalent sensing material. Since the adoption of nanoscale synthesis methods for sensing materials development, such as electrospinning and hydrothermal synthesis, many novel 1D MOS‐based nanostructured sensing materials have been demonstrated to enhance gas sensing performance. Overall, nanoengineering approaches and mechanisms for enhancement of gas sensing performance of 1D metal oxide‐based sensing materials are systematically discussed and categorized into several overarching strategies, such as tuning of materials dimension, morphology, and composition. Furthermore, integration of 1D sensing nanomaterials into sensor devices are discussed from the perspective of different chemiresistive sensor architectures and device fabrication methods. Finally, this review also discusses use of 1D MOS materials for emerging and novel electronic nose applications.
This is a systematic review of recent works demonstrating strategies to modulate and enhance sensing properties of chemiresistive gas sensors and sensor arrays (i.e., electronic nose) via nanoengineering compositions and morphologies of 1D metal oxide semiconducting sensing materials, such as, introduction of dopants and heterojunctions, complex hierarchical structures (e.g., core‐shell and branched structures), and manipulation of diameter and grain size/crystallinity.
•Graphene/carbon nanotubes (CNM) synthesis and properties are discussed.•Discussion of CNM nano-field effect transistor (nFET) biosensing mechanisms.•Fabrication of nFET biosensors from C.NM is ...presented.•Examples of label-free sensing applications using CNM nFET biosensors are reviewed.
Graphene and carbon nanotubes (CNTs) have gained major research interests as signal transducing elements in electrical biosensors for applications in biosensing of a wide range of analytes. This is mostly due to the unique physical, chemical, and electrical properties of the carbon nanomaterials. This review discusses the integration and applications of these carbon allotropes into field-effect transistor-type (FET-type) nanobiosensors. We first discuss the various properties of CNTs and graphene that make them useful and attractive for FET-type sensing, followed by methods for synthesis of CNTs and graphene nanomaterials. Additionally, the underlying sensing mechanisms of CNT- and graphene-based FET-type biosensors and the methods for fabrication of these devices are discussed. Finally, recent reports on CNT- and graphene-based FET biosensors that employed a variety of novel device configurations, fabrication techniques, and assay strategies to achieve sensitive detection of small molecules, metal ions, proteins, and nucleic acids are examined.
Citrus greening, or Huanglongbing (HLB), is currently the most devasting disease of citrus, creating unprecedented crisis for the multibillion-dollar global citrus industry. To-date, there is no ...effective cure and disease management relies on early detection and removal of infected trees. Thus, it is imperative that accurate, timely, and robust disease detection and diagnosis technologies are available to minimize the spread of disease. This study reports a sensitive and selective label-free biosensor that combines the physical and chemical advantages of carbon nanomaterials like single-walled carbon nanotubes (SWNTs) in a field-effect transistor (FET)/chemiresistor architecture with selective antibodies against Sec-delivered effector 1 (SDE1), a secreted protein biomarker, for the detection of HLB. The biosensor detected SDE1 biomarkers for citrus greening in plant tissue extracts with the dynamic range over three orders of magnitude in the low nanomolar to micromolar concentration range and limit of detection of 5 nM. The study also demonstrated the use of the standard additions assay method with the biosensor to attain a 90-percent signal recovery in concentrated plant tissue extract, allowing for quantitative detection without an external calibration. Adopting the novel detection strategy targeting the secreted protein biomarker, SDE1, addresses some of the challenges faced by current methods of nucleic acid-based assays and symptom-based diagnosis, which have been found prone to false negatives and misdiagnoses, respectively.
•Label-free biosensor for secretory biomarker of citrus greening was developed.•Single-walled carbon nanotubes (SWNTs) were used as chemiresistive transducer.•Polyclonal antibodies were used as the biorecognition element.•The sensor was sensitive and specific, with 5-nM detection limit in plant extract.•Quantitative detection in plant extract was attained with standard addition method.
PurposeThe rapid evolution in artificial intelligence (AI) has redefined the customer experience and created huge opportunities for companies to interact with customers using chatbots. This study ...explores the role of AI chatbots in influencing the online customer experience and customer satisfaction in e-retailing.Design/methodology/approachA research model based on the technology acceptance model and information system success model is proposed to describe the interrelationships among chatbot adoption, online customer experience and customer satisfaction. Personality is a moderator in the model. The authors used a quantitative approach to collect 425 useable online questionnaires and Statistical Product and Service Solutions (SPSS) and SmartPLS to analyze the measurement model and proposed hypotheses.FindingsThe usability of the chatbot had a positive influence on extrinsic values of customer experience, whereas the responsiveness of the chatbot had a positive impact on intrinsic values of customer experience. Furthermore, online customer experience had a positive relationship with customer satisfaction, and personality influenced the relationship between the usability of the chatbot and extrinsic values of customer experience.Originality/valueThis research extends understanding of the online customer experience with chatbots in e-retailing and provides empirical evidence by showing that extrinsic and intrinsic values of online customer experience are enhanced by chatbot adoption.
A BCMO-ANN algorithm for vibration and buckling optimization of functionally graded porous (FGP) microplates is proposed in this paper. The theory is based on a unified framework of higher-order ...shear deformation theory and modified couple stress theory. A combination of artificial neural network (ANN) and balancing composite motion optimization (BCMO) is developed to solve the optimization problems and predict stochastic vibration and buckling behaviors of functionally graded porous microplates with uncertainties of material properties. The characteristic equations are derived from Hamilton’s principle and approximation of field variables under Ritz-type exponential series. Numerical results are obtained to investigate the effects of the material distribution, material length scale, porosity density and boundary conditions on natural frequencies and critical buckling loads of functionally graded porous microplates. The novel results derived from this paper can be used as future references.
•A BCMO-ANN algorithm for stochastic vibration and buckling analysis of functionally graded porous microplates is presented.•A unified framework of higher-order shear deformation theory and modified couple stress theory is presented.•Ritz method with hybrid shape functions yields fast convergence and accurate results.•Effects of materials and geometry on stochastic behaviors of functionally graded porous microplates are investigated.
Membrane technology has emerged as an attractive approach for water purification, while mitigation of fouling is key to lower membrane operating costs. This article reviews various materials with ...antifouling properties that can be coated or grafted onto the membrane surface to improve the antifouling properties of the membranes and thus, retain high water permeance. These materials can be separated into three categories, hydrophilic materials, such as poly(ethylene glycol), polydopamine and zwitterions, hydrophobic materials, such as fluoropolymers, and amphiphilic materials. The states of water in these materials and the mechanisms for the antifouling properties are discussed. The corresponding approaches to coat or graft these materials on the membrane surface are reviewed, and the materials with promising performance are highlighted.
Paper-based biosensors are promising for low-cost diagnostics. However, its widespread use has been hampered due to a lack of sensitive detection methods that can be easily implemented on paper ...substrates. On the other hand, single-walled carbon nanotubes (SWNTs) -based chemiresistive biosensors are gaining popularity as label-free, highly sensitive biosensors. However, traditional SWNT-based chemiresistors need to be more affordable for use in resource-limited settings. In this study, we report fabrication, optimization and analytical characterization of a chemiresistive biosensor on paper for label-free immunosensing. We synthesized a water-based ink using pyrene carboxylic acid (PCA) through non-covalent π-π stacking interaction between PCA and SWNTs. The PCA/SWNTs ink concentration can reach ~4 mg mL−1 and was stable at room temperature for one month. We introduced a combination of wax printing and vacuum filtration to fabricate the hydrophilic channels and the well-defined PCA/SWNTs ink deposition on paper in a facile manner requiring no additional masks or stencils. Specific antibodies were then functionalized on the PCA/SWNTs. Quantitative and selective detection of human serum albumin (HSA) is demonstrated with a limit of detection (LOD) of 1 pM. This low LOD is attributed to the porous structure of the paper surface, which can accommodate more SWNTs. Furthermore, the hydroxyl group-containing cellulose fibers help connect the SWNTs into an electrical network. The paper-based chemiresistive biosensor proposed here is easy to fabricate, and designed for rapid, sensitive and selective detection of HSA. This work provides a potential platform for automated, disposable paper-based biosensors with multiplexed detection capability and microfluidic controls.
•Low-cost, label-free SWNTs-based chemiresistive biosensor on paper is reported.•Simple, fast, stencil-free wax printing and vacuum filtration used for fabrication.•High concentration, stable, water-based SWNTs ink defines sensing channel.•Bioreceptor immobilized covalently on SWNTs by zero-length crosslinking chemistry.•Highly sensitive, selective, label-free human serum albumin detection demonstrated.
Electrochemical processes have been known as a very efficient method for the industrial wastewaters treatment, especially for the removal of heavy metal ions. In this work, we would like to provide a ...method that not only effectively treats heavy metal ions but also carries out the process with a notable selectivity rate. An electrochemical cell with conductive carbon fibers cloth cathode and Platinum coated titanium panel anode (5 × 5 cm), low voltage supply energy of 10 V, and pH value of 6.8 is designed to remove Coppers, and Nickels out of the solutions contains Nickel Sulfate and Copper Sulfate (0.06 M).
There are modifications applied to the electrode to improve its conductivity and durability, the two factors that may effect directly on the efficiency of the whole process. The result we obtained shows a good and promising data with high removal efficiency (up to 97%) during the 20 h working time. Together with the removal process, the properties of electrode materials are also well investigated. With the conductive carbon cloth shows its superiority, the electrochemical cell in this work become a very versatile system. In that manner, we provide a system which is not only can treat the wastewater, but also creating energies such as hydrogen and oxygen, collecting of heavy metals in hydroxide form, and can be easily improved to a continuous process with higher efficiency and larger application.
Furthermore, the affection of electrode arrangement is carefully studied and revealed its properties, providing a chance applying the method to actual industrial purpose. With a close, medium and far distance of the two electrodes we arrange, the result of removal heavy metal ions is differently achieved (97, 96.5 and 71%). Technical problems appear during the process seems to be minor and could be solved quickly by a simple solution which will be described in the later part. However, a single effective process to treat the wastewater we introduced here is just the beginning. A continuous system which can be operated for a longer time, more effective and creating a decent amount of energies would be welcome to investigate.
•There are no additives required.•A pair of excellent electrodes was provided.•The arrangement of electrodes directly effects to the efficiency of the work.•A promising versatile electrochemical system was introduced.•There are plenty of spaces for the method to be improved.
Biomass, one of the renewable resources, is expected to play an important role in the world's energy future. In Asia, rice straw is an abundant agricultural surplus because rice is one of the leading ...staple food crops in the region. Often, rice straw is burned directly in the field via uncontrolled combustion methods that emit large amounts of short-lived air pollutants, greenhouse gases, and other pollutants. In Vietnam, the energy and environment protection sectors are facing great challenges because of rapid urbanisation and industrialisation. A national strategic choice is to exploit renewable energy, including biomass-derived energy, to achieve energy security and CO
emission reduction. This study investigates the potential of rice straw as an energy source for power plants at a local scale in Vietnam using data derived from satellite Sentinel-1 images. The results show that Vietnam can produce 2,565 MW from rice straw, for which 24 out of 63 provinces have a potential capacity higher than 30 MW, and the Kien Giang province has the highest capacity (245 MW). The study also analyses limitations and obstacles overcoming which can promote the biomass energy sector in the country.
Subcutaneous (SC) and visceral (VIS) obesity are associated with different risks of diabetes and the metabolic syndrome. To elucidate whether these differences are due to anatomic location or ...intrinsic differences in adipose depots, we characterized mice after transplantation of SC or VIS fat from donor mice into either SC or VIS regions of recipient mice. The group with SC fat transplanted into the VIS cavity exhibited decreased body weight, total fat mass, and glucose and insulin levels. These mice also exhibited improved insulin sensitivity during hyperinsulinemic-euglycemic clamps with increased whole-body glucose uptake, glucose uptake into endogenous fat, and insulin suppression of hepatic glucose production. These effects were observed to a lesser extent with SC fat transplanted to the SC area, whereas VIS fat transplanted to the VIS area was without effect. These data suggest that SC fat is intrinsically different from VIS fat and produces substances that can act systemically to improve glucose metabolism.
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