Search

Abstract: We have established a mobile phone-assisted microarray decoding platform for signal-enhanced mutation detection. A large amount of single-stranded DNA (ssDNA) was obtained by combining symmetric PCR and magnetic isolation, and ssDNA prepared with magnetic bead as label was further allowed to hybridize against the tag-array for decoding purpose. High sensitivity and specificity was achieved with the detection of genomic DNA. When simultaneously genotyping nine common mutations associated with hereditary hearing loss, the detection limit of 1ng genomic DNA was achieved. Significantly, a mobile phone was also used to record and decode the genotyping results through a custom-designed imaging adaptor and a dedicated mobile phone software. A total of 51 buccal swabs from patients probably with deafness-related mutations were collected and analyzed. The genotyping results were all confirmed by fluorescence-based laser confocal scanning and direct DNA sequencing. This mobile phone-assisted decoding platform provides an effective but economic mutation detection alternative for the future quicker and sensitive detection of virtually any mutation-related diseases in developing and underdeveloped countries. [Copyright &y& Elsevier]

The lasing wavelength shift characteristics of amplified spontaneous emission (ASE)-injected wavelength-locked Fabry-Perot laser-diodes used in the wavelength division multiplexed passive optical network are studied. The lasing wavelength shift at different injected-ASE powers and different bias currents are experimentally evaluated. The saturation effect has been found as the bias current increases. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26088 [ABSTRACT FROM AUTHOR]

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has swept the world and poses a serious threat to human health. In the post-pandemic-era, we must remain vigilant against the co-infection of SARS-CoV-2 and other respiratory viruses. More accurate and convenient detection methods are required for the diagnosis of SARS-CoV-2 due to its prolonged existence. In this study, the application value of a novel lyophilized-pellet-based 2019-nCoV nucleic acid diagnostic kit (PCoV-Kit) was evaluated by comparing it with a conventional liquid diagnostic kit (LCoV-Kit). We assessed the sensitivity, precision, accuracy, specificity, and amplification efficiency of PCoV-Kit and LCoV-Kit using diluted SARS-CoV-2 RNA reference materials. The results showed that both kits had high sensitivity, precision, accuracy, and specificity. A total of 2,033 oropharyngeal swab specimens collected during mass screening in Fuzhou in December 2022 were applied for the consistency analysis of the two reagents. In the detection of clinical oropharyngeal swab specimens, although the positive rate of PCoV-Kit (19.28%) was slightly lower than that of LCoV-Kit (20.86%), statistical analysis demonstrated a high degree of consistency between the test results obtained using both kit (χ2 = 1.57, P>0.05; Kappa coefficient = 0.90, 95%CI: 0.88–0.93). In conclusion, the use of lyophilized PCoV-Kit provides a non-inferior assay for the diagnosis of COVID-19. [ABSTRACT FROM AUTHOR]

Cancer cells evolve various mechanisms to overcome cellular stresses and maintain progression. Protein kinase R (PKR) and its protein activator (PACT) are the initial responders in monitoring diverse stress signals and lead to inhibition of cell proliferation and cell apoptosis in consequence. However, the regulation of PACT-PKR pathway in cancer cells remains largely unknown. Herein, we identify that the long non-coding RNA (lncRNA) aspartyl-tRNA synthetase antisense RNA 1 (DARS-AS1) is directly involved in the inhibition of the PACT-PKR pathway and promotes the proliferation of cancer cells. Using large-scale CRISPRi functional screening of 971 cancer-associated lncRNAs, we find that DARS-AS1 is associated with significantly enhanced proliferation of cancer cells. Accordingly, knocking down DARS-AS1 inhibits cell proliferation of multiple cancer cell lines and promotes cancer cell apoptosis in vitro and significantly reduces tumor growth in vivo. Mechanistically, DARS-AS1 directly binds to the activator domain of PACT and prevents PACT-PKR interaction, thereby decreasing PKR activation, eIF2α phosphorylation and inhibiting apoptotic cell death. Clinically, DARS-AS1 is broadly expressed across multiple cancers and the increased expression of this lncRNA indicates poor prognosis. This study elucidates the lncRNA DARS-AS1 directed cancer-specific modulation of the PACT-PKR pathway and provides another target for cancer prognosis and therapeutic treatment. A loss-of-function screen reveals a role for lncRNA DARS-AS1 in promoting cancer cell proliferation and further experiments shows DARS-AS1 regulates the PACT-PKR pathway, overall suggesting it as a potential target for cancer therapy and prognosis. [ABSTRACT FROM AUTHOR]

Abstract: A fiber-optic sensor for liquid refractive index measurement based on a Michelson interferometer is described. The interferometer is achieved between the Fresnel reflections from the fiber ends of the coupler. The fiber ends are then in contact with the solvent and solution samples to provide reference and refractive index measurement, respectively. The refractive index of the solution is determined according to the fringe contrast of the interference fringes in the reflective spectrum of the sensor. Its ease of fabrication and low-cost offer the attractive applications in chemical and biological sensing. [Copyright &y& Elsevier]

Abstract: A simple sensor for simultaneous measurement of refractive index and temperature in solutions based on fiber Bragg grating (FBG) is proposed. The sensor contains only a normal FBG with a pigtail fiber. When the FBG is immersed in different liquids of refractive index, the side mode suppression ratio of the FBG varies due to the Fresnel reflection of the pigtail fiber. The sensor is also capable of simultaneous measurement refractive index and temperature combining the thermo-optic effect of the FBG. Its ease of fabrication and low-cost offer the attractive applications in chemical and biological sensing. [Copyright &y& Elsevier]

Abstract A smartphone-assisted microfluidic chemistry analyzer using an image-based colorimetric detection method was successfully developed for the simultaneous analysis of three diabetes- and hyperlipidemia-related indexes, glucose (GLU), triglyceride (TG), and total cholesterol (TC). A fan-shaped microfluidic chip was designed and optimized to reliably allocate a premixed serum sample into four reaction chambers by a simple pipetting. The color changes of the peroxidase-H 2 O 2 enzymatic reactions in the chambers were captured and analyzed using a smartphone-controlled analyzer with a LED light source and a CCD camera. The highly quantitative relationships between the analyte concentrations and the color characteristic values of the green channel of the captured images were successfully established, enabling accurate and reproducible detections of GLU, TG, and TC simultaneously at a low cost. The parallel analyses of 111 serum samples using our system and a conventional chemistry analyzer were conducted, yielding an excellent correlation and consistency between these two systems. This study proved the feasibility of performing the multi-index monitoring of diabetes, hyperlipidemia, and other chronic diseases on a point-of-care platform at a high fidelity, but a low cost. Graphical abstract Image 1 Highlights • A smartphone-assisted microfluidic analyzer was developed for measuring diabetes- and hyperlipidemia-related indexes. • A fan-shaped microchip was designed to reliably allocate a sample into four reaction chambers with a simple pipetting. • An image-based colorimetric detection was established for analyzing glucose, triglyceride, and total cholesterol. • A large-scale comparative study proved the system had an excellent consistency with conventional chemistry analyzers. [ABSTRACT FROM AUTHOR]

A relative humidity (RH) sensor based on a seven-core fiber (SCF) coated with graphene oxide (GO) is proposed. The sensing structure consists of a part of the SCF sandwiched between two parts of no-core fibers (NCFs). The SCF was corroded by hydrofluoric acid until the six outer cores were exposed to air and then coated with a layer of GO. The two NCFs play splitting and coupling roles because of the core diameter mismatch. The center core of the SCF acts as the reference arm, and the outer six cores of the SCF act as the sensing arm to construct a Mach–Zehnder interferometer. When GO absorbs water molecules, its refractive index changes. Consequently, the phase difference between the center core and outer core modes varies, and the resonant dip moves. The experimental results indicate that the RH sensitivity can reach 0.165 nm/%RH in the range of 30% to 100%, and the corresponding linear fitting coefficient is 99.9%. [ABSTRACT FROM AUTHOR]

A simple fiber-optic displacement sensor based on reflective intensity modulated technology is demonstrated using a fiber collimator. The sensing range is over 30 cm, which is over 100 times that of the conventional fiber-optic displacement sensor based on the normal single-mode fiber. The measured data are fitted into linear equation very well and the values of R-square are more than 0.995. The sensitivity of the device achieves 0.426 dB/cm over the range of 5-30 cm. By applying the relative technique, the errors resulted from the fluctuation of light source and influences of environment are effectively eliminated, and the stability for wide range measurement can be improved. The simplicity of the design, high dynamic range, stability and the ease of the fabrication make it suitable for applications in industries. [ABSTRACT FROM AUTHOR]