Search

We studied the impact of socioeconomic status (SES) on mortality in hepatocellular carcinoma patients and analyzed the effect of SES on initial treatment allocation.A cohort study was conducted using data from the National Health Insurance Service- National Sample Cohort of Korea. A total of 3,032 hepatocellular carcinoma patients who were newly diagnosed between January 2003 and December 2013 were included. Income level was categorized as Medical Aid and ≤30th, 31st-70th, or70th percentile as an SES indicator.The proportion of Medical Aid was 4.3%. The highest risks of all-cause mortality associated with Medical Aid were evident in the transcatheter arterial chemoembolization group (fully adjusted hazard ratio [HR], 2.40; 95% confidence interval [CI], 1.25 to 4.58), the other treatments group (fully adjusted HR, 2.86; 95% CI, 1.85 to 4.41), and the no treatment group (fully adjusted HR, 2.69; 95% CI, 1.79 to 4.04) but not in the curative treatment group. An association between the lower-income percentile and higher liver cancer-specific mortality was also observed, except in the curative treatment group. The association between income percentile and all-cause mortality was nonlinear, with a stronger association in the lower-income percentiles than in the higher income percentiles (p-value for nonlinear spline terms0.05).Patients in the lower SES group, especially patients not eligible for curative treatment, had an increased risk of mortality. In addition, the association between SES and the risk for mortality was stronger in the lower-income percentile than in the moderate to higher income percentiles.

Background and Objectives: The coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to be a pandemic even in 2022. As the initial symptoms of COVID-19 overlap with those of infections from other respiratory viruses, an accurate and rapid diagnosis of COVID-19 is essential for administering appropriate treatment to patients. Currently, the most widely used method for detecting respiratory viruses is based on real-time polymerase chain reaction (PCR) and includes reverse-transcription real-time quantitative PCR (RT-qPCR). However, RT-qPCR assays require sophisticated facilities and are time-consuming. This study aimed to develop a real-time quantitative loop-mediated isothermal amplification (RT-qLAMP) assay and compare its analytical performance with RT-qPCR. Materials and Methods: A total of 315 nasopharyngeal swabs from patients with symptoms of respiratory infections were included in this study. A primary screening of the specimens was performed using RT-qPCR. RNA/DNA from standard strains for respiratory viruses and heat-inactivated preparations of standard strains for SARS-CoV-2 were used to evaluate the accuracy and target specificity of the RT-qLAMP assay. Results: We successfully developed an RT-qLAMP assay for seven respiratory viruses: respiratory syncytial virus (RSV) A, RSV B, adenovirus, influenza (Flu) A (H1N1 and H3N2), Flu B, and SARS-CoV-2. RT-qLAMP was performed in a final reaction volume of 9.6 µL. No cross-reactivity was observed. Compared with the RT-PCR results, the sensitivity and specificity of the RT-qLAMP assay were 95.1% and 100%, respectively. The agreement between the two methods was 97.1%. The median amplification time to RT-qLAMP positivity was 22:34 min (range: 6:80–47:98 min). Conclusions: The RT-qLAMP assay requires a small number of reagents and samples and is performed with an isothermal reaction. This study established a fast, simple, and sensitive test that can be applied to point-of-care testing devices to facilitate the detection of respiratory viruses, including SARS-CoV-2.

The use of the smartphone is an ideal platform to realize the future point-of-care (POC) diagnostic system. Herein, we propose an integrated smartphone-based genetic analyzer. It consists of a smartphone and an integrated genetic analysis unit (i-Gene), in which the power of the smartphone was utilized for heating the gene amplification reaction, and the camera function was used for imaging the colorimetric change of the reaction for quantitative and multiplex foodborne pathogens. The housing of i-Gene was fabricated by using a 3D printer, which was equipped with a macro lens, white LEDs, a disposable microfluidic chip for loop-mediated isothermal amplification (LAMP), a thin-film heater, and a power booster. The i-Gene was installed on the iPhone in alignment with a camera. The LAMP mixture for Eriochrome Black T (EBT) colorimetric detection was injected into the LAMP chip to identify Escherichia coli O157:H7, Salmonella typhimurium, and Vibrio parahaemolyticus. The proportional–integral–derivative controller-embedded film heater was powered by a 5.0 V power bank to maintain 63 °C for the LAMP reaction. When the LAMP proceeded, the color was changed from violet to blue, which was real-time monitored by the smartphone complementary metal oxide semiconductor camera. The images were transported to the desktop computer via Wi-Fi. The quantitative LAMP profiles were obtained by plotting the ratio of green/red intensity versus the reaction time. We could identify E. coli O157:H7 with a limit of detection of 101 copies/μL within 60 min. Our proposed smartphone-based genetic analyzer offers a portable, simple, rapid, and cost-effective POC platform for future diagnostic markets.

In this study, we proposed an advanced point-of-care molecular diagnostic technology to evaluate the acute rejection (AR) in kidney transplanted patients. On the contrary to the conventional PCR method, we developed a colorimetric loop mediated isothermal amplification (LAMP) for quantitative analysis of the six biomarkers related to AR (CD3ϵ, IP-10, Tim-3-HAVCR2, CXCL9, PSMB9, C1QB) with a reference gene (18S rRNA). Using urinary cDNA samples of transplanted patients, it turned out that three biomarkers among six, namely IP-10, Tim-3-HAVCR2 and C1QB, have significant discrepancy in quantity between the stable graft (STA) patient and the AR patient. The AR prediction model using these three biomarkers was established, which could estimate the immune-rejection in the patients with 93.3% of accuracy. For the point-of-care (POC) molecular diagnostics for the AR evaluation, we constructed a centrifugal microfluidic platform, in which the RNA extraction from the clinical urinary samples, the quantitative reverse-transcription (RT)-LAMP reaction, and the data analysis based on the AR prediction model could be performed in a serial order. Ten blind clinical samples were analyzed on the POC genetic analyzer, showing 100% match with the validated qPCR data. Thus, the proposed advanced molecular diagnostic platform enables us to perform the timely treatment for the transplanted patients who are suffering from the allograft failure and side effects such as infection and malignancy.

An integrated microfluidic device, consisting of a solid-phase extraction (SPE) unit for metal ion pretreatment, a micropump, a micromixer, and a detachable graphene oxide quantum dot (GOQD) array chip was constructed for selective and sensitive detection of As3+, Cd2+, and Pb2+. The entire process could be sequentially and automatically completed by actuating a pneumatic micropump. Effect of the pH for metal ion capture and pumping scheme for recovery efficiency were investigated on a chip. The ion As3+, Cd2+, and Pb2+ whose concentrations ranged from 10−2 µM to 102 µM were successfully recovered with high efficiency over 80%. Monoplex and multiplex detection of As3+, Cd2+, and Pb2+ were then executed on a GOQD array chip. The target metal ions were specifically captured on the DNA aptamer linked GOQD array, which results in the fluorescence quenching of GOQD due to the electron transfer from the GOQD to metal ions under the laser irradiation. The proposed integrated SPE-GOQD array based microdevice could perform As3+, Cd2+, and Pb2+ detection with detection limits of 5.03 nM, 41.1 nM, and 4.44 nM, respectively. Simultaneous multiplex detection for binary or ternary mixture of As3+, Cd2+, and Pb2+ was performed, and the proposed integrated microdevice also showed high recovery values ranging from 83.52% to 128.3% from the environmental samples.

We aimed to evaluate the feasibility and safety of long-term balloon indwelling technique for the treatment of single benign biliary stricture. Five patients with single benign biliary stricture were included from December 2014 to November 2016. The patients were three men and two women with a mean age of 50 years (range, 30–65 years). A balloon catheter was inserted into the drainage catheter and emerged through the side hole of the catheter so that the balloon and drainage catheters could be placed together at the stricture site. Follow-up fluoroscopic examination was performed at least once every 2 weeks to evaluate the adequacy of expansion and location of the balloon. The balloon was reinflated at each session, and then removed after an approximately two-month indwelling period. The catheters used were 10–16 French and the diameter of indwelling balloons were 4–8 mm. The primary technical and clinical success rates were 100%. Maintenance of the balloon location was achieved in 25 of 26 follow-up fluoroscopic examinations (mean, 5.2 times per patient) with a rate of 96.1%. The mean follow-up period after successful removal of the balloon was 542.2 days (range, 93–1042 days), and there were no recurrences in the five cases. The long-term balloon indwelling technique is a good way to induce maximal dilatation at the stricture site without large diameter skin and subcutaneous tract dilatation and can be successfully used for single benign biliary stricture.

In this study, we report the highest mobility in the reduced graphene oxide- (rGO-) based TFTs embedded with Au NPs. In addition, we fabricated a reduced graphene oxide memory device (rGO-capacitor), a reduced graphene oxide thin film transistor (rGO-TFT), and a reduced graphene oxide memory thin film transistor (rGO-MTFT) and characterized their electrical performances. While the rGO-TFT device was investigated for nonambipolar channel performance, the rGO-capacitor and rGO-MTFT were examined for nonvolatile memory capabilities in a metal-graphene-insulator-silicon (MGIS) structure. The incorporation of the gold nanoparticles (Au NPs) between the rGO and an insulator silicon dioxide (SiO2) layer served as a charging element. The rGO-capacitor revealed the memory effect of hysteretic capacitance-voltage (C-V) loops, and the flat-band voltage shift ( Δ V FB ) was measured as 0.1375 V after 100 s retention time. The rGO-TFT shows the p-channel characteristics with high hole mobility of 16.479 cm2/V⋅s. The threshold voltage shift ( Δ V th ) of the rGO-MTFT was detected as 5.74 V from 10 V to -30 V sweep, demonstrating high mobility of 22.887 cm2/V⋅s.

We introduce a novel centrifugal disc for purifying nucleic acid (NA) in a high-throughput manner to perform the human sex-typing of forensic samples. The centrifugal disc was designed with double-sided etched channels to fabricate 30 extraction units, which was capable of purifying 30 forensic samples in a single run. In order to introduce the washing solution (70% ethanol) and the elution buffer for the 30 extraction units in an automatic manner, we designed the aliquoting chambers that were connected with a zigzag delivery channel. The super-hydrophobic zigzag-shaped aliquot structure plays a crucial role in automatically dividing the washing solution and the elution buffer into 30 aliquots with one injection shot. The Whatman glass filter paper was used as an NA extraction matrix and sophisticated passive valves were equipped to avoid the overflowing of these buffers to the neighboring chamber during the injection. To operate the disc, we developed a portable workstation that consists of a buffer storage system, a buffer injection system, and a spinning unit. The entire process was automatically operated by the in-house portable workstation. Genomic DNA extraction using thirty forensic samples was completed in 10 min. Using the purified genomic DNA, we performed a loop-mediated isothermal amplification (LAMP) reaction for sex-typing by targeting the human alphoid repeat sequence of the Y-chromosome and the human 18S rRNA. The combination of the high-throughput centrifugal disc for NA extraction and the LAMP reaction enables us to complete the genetic sex-typing in 30 min.

Recent advances in the development of hybrid organic–inorganic halide perovskite quantum dots (HP-QDs) have proven their versatility and potential applications in photovoltaics and light sources through compositional tuning. However, the compositional complexity for mixed-cation and/or mixed-halide HP-QDs would require repetitive optimization processes to obtain the desired perovskite crystals via traditional batch-scale chemistry, causing prolonged time, labor, and cost. To address this issue, we herein report a dynamic flow chemistry synthetic system operated with the on-and-off feedback control with hysteresis algorithm to produce methylammonium lead trihalide perovskite quantum dots (MAPbBrXI3-X QDs with 0 ≤ X ≤ 3), automatically showing a target emission wavelength. We set up the target photoluminescent (PL) emission wavelength of the MAPbBrXI3-X QDs and started with an arbitrary flow rate of the bromide and iodide precursor solution. The PL emission wavelength of the synthesized perovskites was in-situ monitored in the flow cell equipped with a miniaturized optical detector. By comparing the measured wavelength with the target one, the controlling algorithm recalculated to adjust the flow rates of the bromide and iodide precursor solution accordingly. Then, the PL emission wavelength of the newly synthesized MAPbBrXI3-X QDs was detected again in real-time, and the iterative feedback control process was repeated until the observed wavelength was matched with the user-defined emission target. Thus, the desired MAPbBrXI3-X QDs could be obtained eventually through the feedback control in an automatic manner, suggesting an advanced flow chemistry synthetic platform to produce on-demanded nanomaterials with high efficiency.

Background: The incidence of venous thrombosis based on access route after implantation of the totally implanted venous access port (TIVAP) is controversial. Symptomatic TIVAP-related venous thrombosis remains relatively rare. However, characteristics of symptomatic axillary vein thrombosis after TIVAP implantation via access of the axillary vein has not been reported. Objectives: In this historical cohort study, the incidence and characteristics of venous thrombosis associated with TIVAP via the axillary vein in cancer patients were evaluated. Patients and Methods: A total of 4,773 TIVAPs were placed via the axillary vein in patients with various types of cancer between May 2012 and July 2018. Eighteen patients experienced symptomatic venous thrombosis associated with TIVAPs. Radiologic findings for venous thrombosis were evaluated using computed tomography (CT) including scans of the axillary vein. Medical records were retrospectively reviewed. Results: The prevalence of symptomatic thrombosis was 0.38% (18/4,773). The patients with symptomatic venous thrombosis included 14 males and four females. Among the 18 patients, the most common types of cancer were lung cancer (n = 7) and pancreatic cancer (n = 4), with the incidence rates of 0.79% (lung cancer, 7/882) and 1.58% (pancreatic cancer, 4/253), respectively. The median time between placement of the TIVAP and diagnosis of thrombosis was 35.5 days (range: 6 - 292 days). All symptomatic patients had thrombosis in the axillary vein on CT images. Symptoms were improved in all patients with treatment including removal of TIVAP at the time of diagnosis and following anticoagulation therapy. From the multiple binary logistic regression, pancreatic cancer and lung cancer were statistically significant risk factors of symptomatic axillary vein thrombosis. Conclusion: After insertion of TIVAPs through the axillary vein, symptomatic axillary vein thrombosis rarely developed. Pancreatic cancer and lung cancer were associated with the risk of symptomatic axillary vein thrombosis.

A micro-capillary electrophoresis (μCE) system is one of the widely adopted techniques in the molecular diagnostics and DNA sequencing due to the benefits of high resolution, rapid analysis, and low reagent consumption, but due to the requirements of bulky high-power suppliers and an expensive laser-induced fluorescence detector module, the conventional set-up of μCE system is not adequate for point-of-care (POC) molecular diagnostics. In this study, we constructed a miniaturized and integrated μCE system which can be manipulated by a smartphone. The smartphone not only powers two boost converters and an excited laser, but also controls the relay for the power switch. Moreover, the complementary metal-oxide-semiconductor (CMOS) camera of the smartphone was used for detecting the fluorescence signal of amplicons amplified with reverse transcription-polymerase chain reaction (RT-PCR). We also developed a web-based application so that the raw data of the recorded fluorescence intensity versus the running time can display typical capillary electropherograms on the smartphone. The total size of the hand-held μCE system was 9.6 cm [Width] × 22 cm [Length] × 15.5 cm [Height], and the weight was ∼1 kg, which is suitable for POC DNA testing. In the integrated smartphone-associated μCE system, we could accurately analyze two genes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), namely N gene and S gene along with two bracket ladders in 6 min to identify SARS-CoV-2. Such an advanced μCE platform can be applied for a variety of on-site molecular diagnostics fields with user-friendliness.

We present a portable genetic analyzer with an integrated centrifugal disc which is equipped with a glass-filter extraction column for purifying nucleic acid (NA) and multiple reaction chambers for analyzing major feline upper respiratory tract disease (FURTD) pathogens. We targeted four kinds of FURTD including Feline herpesvirus 1 (FHV), Mycoplasma felis (MPF), Bordetella bronchiseptica (BDB), and Chlamydophila felis (CDF). The portable genetic analyzer consists of a spinning motor, two pairs of Peltier heaters, two Minco heater, fluorescent optics, a touchscreen, and software for data analysis, so loop-mediated isothermal amplification (LAMP) or polymerase chain reaction (PCR) can be performed. The overall size of the genetic analyzer was 28 cm × 28 cm × 26 cm and the weight was 10 kg, which was deliverable for point-of-care testing (POCT). Owing to the sophisticated microchannel design and spinning program, the serial injection of the sample solution, the washing solution, and the elution solution was executed through a glass filter membrane for nucleic acid (NA) extraction, and then the cocktail with the purified genome was aliquoted into 9 reaction chambers for LAMP or PCR. The whole process for the LAMP reaction or the PCR was completed within 1.5 h. The fluorescence profiles by a scanning mode showed the matched results between the LAMP and the PCR.

Rapid and accurate testing tools for SARS-CoV-2 detection are urgently needed to prevent the spreading of the virus and to take timely governmental actions. Internet of things (IoT)-based diagnostic devices would be an ideal platform for point-of-care (POC) screening of COVID-19 and ubiquitous healthcare monitoring for patients. Herein, we present an advanced IoT-based POC device for real-time direct reverse-transcription-loop mediated isothermal amplification assay to detect SARS-CoV-2. The diagnostic system is miniaturized (10 cm [height] × 9 cm [width] × 5.5 cm [length]) and lightweight (320 g), which can be operated with a portable battery and a smartphone. Once a liquid sample was loaded into an integrated microfluidic chip, a series of sample lysis, nucleic amplification, and real-time monitoring of the fluorescent signals of amplicons were automatically performed. Four reaction chambers were patterned on the chip, targeting As1e, N, E genes and a negative control, so multiple genes of SARS-CoV-2 could be simultaneously analyzed. The fluorescence intensities in each chamber were measured by a CMOS camera upon excitation with a 488 nm LED light source. The recorded data were processed by a microprocessor inside the IoT-based POC device and transferred and displayed on the wirelessly connected smartphone in real-time. The positive results could be obtained using three primer sets of SARS-CoV-2 with a limit of detection of 2 × 101 genome copies/μL, and the clinical sample of SARS-CoV-2 was successfully analyzed with high sensitivity and accuracy. Our platform could provide an advanced molecular diagnostic tool to test SARS-CoV-2 anytime and anywhere.

Point-of-care (POC) molecular diagnostics plays a pivotal role for the prevention and treatment of infectious diseases. In spite of recent advancement in microfluidic based POC devices, there are still rooms for development to realize rapid, automatic and cost-effective sample-to-result genetic analysis. In this study, we propose an integrated rotary microfluidic system that is capable of performing glass microbead based DNA extraction, loop mediated isothermal amplification (LAMP), and colorimetric lateral flow strip based detection in a sequential manner with an optimized microfluidic design and a rotational speed control. Rotation direction-dependent coriolis force and siphon valving structures enable us to perform the fluidic control and metering, and the use of the lateral flow strip as a detection method renders all the analytical processes for nucleic acid test simplified and integrated without the need of expensive instruments or human intervention. As a proof of concept for point-of-care DNA diagnostics, we identified the food-borne bacterial pathogen which was contaminated in water or milk. Not only monoplex Salmonella Typhimurium but also multiplex Salmonella Typhimurium and Vibrio parahaemolyticus were analysed on the integrated rotary genetic analysis microsystem with a limit of detection of 50 CFU in 80min. In addition, three multiple samples were simultaneously analysed on a single device. The sample-to-result capability of the proposed microdevice provides great usefulness in the fields of clinical diagnostics, food safety and environment monitoring.

Placement of an implantable venous access port (IVAP) is a popular procedure for repeated and intermittent chemotherapy in patients with malignancy. In this article, we present various IVAP related complications. In addition, we review the technical tips to prevent and manage the complications. It is important that the operator should keep the mechanism of the complications in mind, perform a careful procedure for prevention, and manage the complication properly and immediately in case of its development for safety and satisfaction of the patients.

It is essential to identify the causative artery in case of active intra-abdominal or gastrointestinal bleeding. A thorough understanding of the basic arterial anatomy is required to identify the causative artery on contrast-enhanced CT angiography and conventional catheter angiography. If one is familiar with the basic arterial anatomy, obtaining access to the bleeding artery will be easier, despite the variations in the origin and course of the vessels. We describe the basic arterial anatomy that will help beginners in diagnostic radiology to identify the blood vessels that can cause active intra-abdominal or gastrointestinal bleeding.

Since the emergence of the lab-on-a-chip technology in 1979, a variety of microfluidic devices have been developed and utilized for chemical and biological applications. Among the microfluidic devices, the centrifugal microfluidic device or lab-on-a-disc (LOAD) has advanced remarkably due to simple operation by the rotation, total integration, and high-throughput capability. Moreover, the centrifugal microdevices do not need complex tubing and pumping systems, which render them ideal for point-of-care testing (POCT) system. Owing to these characteristics, the centrifugal microdevices have been extensively used for bio-diagnostics. In particular, molecular diagnostics, which are regarded as an essential method for definite determination of the targets related with diseases, have been widely applied on the LOAD. In this review paper, we focus on the molecular diagnostics on the LOAD. The steps for the molecular diagnostics such as cell lysis, genome purification, gene amplification, amplicon detection, and data analysis can be performed individually or totally on the LOAD. Future directions of the LOAD in the fields of bio-diagnostics is to realize POCT for U-healthcare monitoring. In this context, the latest LOAD strategies for molecular diagnostics are summarized in this review paper, which would provide an insight for future POCT platform.

Background: Postpartum hemorrhage (PPH) remains a major cause of maternal morbidity and mortality worldwide. Delayed PPH has received less attention compared to early PPH because the incidence rate of delayed PPH is relatively lower than that of early PPH. Objectives: The aim of this study was to evaluate the clinical manifestations, angiographic findings, and effectiveness of selective transcatheter arterial embolization (TAE) for delayed PPH. Patients and Methods: Selective TAE was performed on 37 women (mean age: 32.1 years, range: 24 - 40) with delayed PPH between March 2006 and October 2016. Delayed PPH was defined as continuous hemorrhage from the female genital tract 24 hours to 6 weeks after delivery. Medical records were retrospectively reviewed for patient characteristics, the time interval between delivery and TAE, angiographic findings, embolized artery, embolic materials, technical and clinical success rate, and complications. Results: Delayed bleeding developed at a median 11.6 days (range: 2 - 34 days) after cesarean section (n = 19) and vaginal delivery (n = 18). On angiography, diffuse hypervascularity was detected in 24 patients, pseudoaneurysm in 11, active extravasation in 1, and arteriovenous malformation in 1. Arteries subjected to TAE included bilateral uterine arteries (UAs) (n = 29), bilateral UAs and unilateral ovarian artery (OA) (n = 4), bilateral UAs and bilateral OAs (n = 1), bilateral UAs and cervicovaginal branch (n = 1), unilateral OA (n = 1), and internal pudendal artery (n = 1). Embolic materials were Gelfoam (n = 30), Gelfoam and coil (n = 3), polyvinyl alcohol (PVA) (n = 2), and PVA and coil (n = 2). There were no procedure-related major complications. Technical success was obtained in all patients (100%), and clinical success was obtained in 34 patients (91.9%) Conclusion: Selective TAE in patients with delayed PPH is a useful treatment with high technical and clinical success.

We present a fully integrated portable centrifugal microsystem for multiplex detection of food poisoning bacteria with a large volume of sample up to 1 mL. The microsystem consists of a portable genetic analyzer and a fully integrated centrifugal microdevice. The centrifugal microdevice is designed with two units: a 3D printed solution-loading cartridge and a centrifugal microfluidic disc. All the essential solutions for loop-mediated isothermal amplification (LAMP) reaction are stored inside the cartridge, and orderly released into centrifugal microdevice by a rotation program. Each unit of the device is designed with 20 reaction chambers for simultaneous detection of food-borne bacteria in one test. To increase the amount of a sample to 1 mL, we incorporated the super absorbent polymer (SAP) in the waste chamber to absorb the sample and the washing solution during the device operation. The whole process was automatically conducted including designated solution release, bead-based DNA extraction, isothermal gene amplification by Eriochrome Black (EBT)-mediated LAMP reaction, and colorimetric and UV–visible detection of amplicons. The ratio between Abs640nm and Abs570nm was used as a criterion to confirm the positive result, and the result was positive upon the condition of Abs640/Abs570 ≥ 1.0. To demonstrate the pathogenic bacteria detection on our proposed microsystem, we targeted three kinds of bacteria (Escherichia coli O157:H7, Salmonella typhimurium, and Vibrio parahaemolyticus) for monoplex and multiplex detection. The whole process from sample to result was completed within 1 h with a low limit of detection (LOD) of 102 cells/mL.

Herein, we present a fully integrated portable centrifugal microsystem for multiplex detection of food poisoning bacteria with a large volume of sample up to 1 mL. The microsystem consists of a portable rotary genetic analyzer and a fully integrated lab-on-a-disc device. The portable rotary genetic analyzer is equipped with a couple of heating blocks, a motor and a UV-Vis optical detector. The device was designed with two units: a 3D printed solution-loading cartridge and a centrifugal microfluidic disc. All the essential solutions for the LAMP reaction (a sample, a washing, an elution and a LAMP cocktail solution) are stored inside the cartridge, and orderly released into centrifugal microdevice by a rotation program. Each unit of the device was designed with 20 reaction chambers for simultaneously detecting 19 kinds of food poisoning bacteria in one test. To increase the amount of a sample to 1 mL, we incorporated the super absorbent polymer (SAP) in the waste chamber to absorb the sample and washing solution during the device operation. The whole process was automatically conducted from bead-based DNA extraction to isothermal DNA amplification by LAMP reaction to colorimetric and UV-vis detection of amplicons in 60 min to identify three kinds of bacteria (Escherichia coli O157:H7, Salmonella Typhimurium, and Vibrio parahaemolyticus).

Sophisticated cell pattern provides unique cellular assay platform for studying cell to cell interaction, cellular differentiation and signaling, high-throughput cell response to chemicals. In this study, we demonstrated reactive oxygen species (ROS) mediated endothelial cell micropatterning on a polydimethylsiloxane (PDMS) substrate. The exposure of UV/O radiation led to the formation of ROS on the surface of PDMS, which could selectively prevent adhesion of endothelial cells. The degree of ROS amount was monitored according to the UV/O irradiation time, and at least 36 μM of ROS resulted in the precise cellular micropattern on the PDMS. The presence of ROS affected not only cellular detachment from the substrate, but also endothelial cell morphology such as cell spreading area, confluence, nuclear area and nuclear inverse aspect ratio. In addition, we could observe that the actin cytoskeleton of cells was also constricted due to ROS, thereby minimizing the focal adhesion area of vinculin. Compared with previously reported methods which use chemical treatment or nano/microstructure on the substrate, the proposed methodology is quite simple, accurate, and harmless to the patterned endothelial cells.

We present a centrifugal microfluidic device which enables multiplex foodborne pathogen identification by loop-mediated isothermal amplification (LAMP) and colorimetric detection using Eriochrome Black T (EBT). Five identical structures were designed in the centrifugal microfluidic system to perform the genetic analysis of 25 pathogen samples in a high-throughput manner. The sequential loading and aliquoting of the LAMP cocktail, the primer mixtures, and the DNA sample solutions were accomplished by the optimized zigzag-shaped microchannels and RPM control. We targeted three kinds of pathogenic bacteria (Escherichia coli O157:H7, Salmonella typhimurium and Vibrio parahaemolyticus) and detected the amplicons of the LAMP reaction by the EBT-mediated colorimetric method. For the limit-of-detection (LOD) test, we carried out the LAMP reaction on a chip with serially diluted DNA templates of E. coli O157:H7, and could observe the color change with 380 copies. The used primer sets in the LAMP reaction were specific only to the genomic DNA of E. coli O157:H7, enabling the on-chip selective, sensitive, and high-throughput pathogen identification with the naked eyes. The entire process was completed in 60min. Since the proposed microsystem does not require any bulky and expensive instrumentation for end-point detection, our microdevice would be adequate for point-of-care (POC) testing with high simplicity and high speed, providing an advanced genetic analysis microsystem for foodborne pathogen detection.

Development of a three-dimensional (3D) vascular co-cultivation system is one of the major challenges to provide an advanced analytical platform for studying blood vessel related diseases. To date, however, the in vivo-like vessel system has not been fully realized due to the difficulty of co-cultivation of the cells with orthogonal alignment. In this study, we report the utilization of microfabrication technology to construct biomimetic 3D co-cultured vasculature. First, microwrinkle patterns whose direction was perpendicular to the axis of a circular microfluidic channel were fabricated, and vascular smooth muscle cells (VSMCs) were cultured inside the microchannel, leading to an in vivo-like circumferential VSMC layer. Then, human umbilical vein endothelial cells (HUVECs) were co-cultured on the circumferentially aligned VSMC, and the success of double layer formation of HUVEC-VSMC in the circular microchannel could be monitored. After HUVEC cultivation, we applied shear flow in order to induce the orientation of HUVEC parallel to the axis, and the analysis of orientation angle and spreading area of HUVECs indicated that they were changed by shear stress to be aligned to the direction of flow. Thus, the HUVEC and VSMC layer could be aligned with a distinct direction. The expression level of VE-Cadherin located at the boundary of HUVECs implies in vivo-like vascular behavior. The proposed in vitro microfluidic vascular assay platform would be valuable for studying vascular diseases with high reliability due to in vivo-likeness.

Previous studies have shown that the drying shrinkage of recycled aggregate concrete (RAC) is greater than that of natural aggregate concrete (NAC). Drying shrinkage is the fundamental reason for the cracking of concrete, and tensile creep caused by the restraint of drying shrinkage plays a significant role in the cracking because it can relieve the tensile stress and results in the delay of cracking occurrence. However, up till now, all research has been focusing on the compressive creep of RAC. Therefore, in this study, a uniaxial restrained shrinkage cracking test was executed to investigate the tensile creep properties caused by the restraint of drying shrinkage of RAC. The mechanical properties, such as compressive strength, tensile splitting strength, and Young’s modulus of RAC were also investigated in this study. The results confirmed that the tensile creep of RAC caused by the restraint of shrinkage was about 20–30 % larger than that of NAC.

Thermal cracking of slender mass concrete in attached walls, retaining walls and bridge towers, is controlled by mainly using low heat cement and the control joint. However, it is impossible to con...

The graphene oxide (GO) and graphene oxide quantum dots (GOQDs), which have gained research interest as new types of light-emitting materials, were synthesized by the modified Hummers method for oxidation of graphite flake and graphite nanoparticle. The optical properties of GO and GOQDs have been compared by mean of photoluminescence (PL), PL excitation (PLE), UV-vis absorbance, and time-resolved PL. The GO have an absorption peak at 229 nm and shoulder part at 310 nm, whereas the GOQDs show broad absorption with a gradual change up without any absorption peaks. The PL emission of GOQDs and GO showed the green color at 520 nm and the red color at 690 nm, respectively. The red emission of GO showed faster PL decay time than the green emission of GOQDs. In particular, the temporal PL profile of the GO showed redshift from 560 nm to 660 nm after the pump event.

Droplet generating microfluidic systems can provide miniaturized bioanalytical tools by using the homogenous and high-throughput droplets as nanoreactors. In this study, we demonstrated a sensitive and in-situ glucose monitoring system using water-in-air droplets in an enzyme incorporated microfluidic device. A thin film structure of a glucose oxidase (GOx) enzyme immobilized hydrogel was constructed in the middle of the microfluidic channel, and nanoliter scaled water-in-air droplets which contain a glucose sample, horseradish peroxidase (HRP), and an Amplex Red substrate were generated by flow focusing of water phase with air. Once the droplets passed through the enzyme trapped hydrogel, the droplets temporarily halted and a GOx mediated catalytic reaction with glucose proceeded, resulting in producing fluorescent resorufin products in the droplets. With optimized conditions such as the thickness of a hydrogel film and the size and flowing rate of droplets, fluorescence intensities of the released droplets linearly increased in proportional to the glucose concentration up to 3 mM, and the limit of detection was calculated as 6.64 µM. A spiked glucose in a real urine sample was also successfully analyzed, and the functionality of the proposed enzyme immobilized microfluidic chip was maintained for at least two weeks without loss of enzymatic activity and detection sensitivity. Thus, our methodology suggests a novel droplet based glucose sensing chip which can monitor glucose in a real-time and high-throughput manner.

We have proposed a novel rotary microdevice in which multiplex anisotropic metallic nanoparticles (NPs) can be synthesized under diverse conditions in a high-throughput manner. In this study, by tuning the concentration of ascorbic acid (AA) as a control solution, the shape evolution from hexagon to tripod of gold nanoparticles (Au NPs) was achieved.

In case of the slender mass concrete like attached wall, retaining wall and bridge tower, the low heat cement and the control joint are mainly used for thermal cracking control. However, even if these cracking control methods are considered, it is impossible to control thermal cracks perfectly, because the external restraint is largely in these mass concrete. Because these cracks occurring in slender mass concrete members almost penetrate concrete member, the special cracking control is demanded in these mass concretes. The vertical pipe cooling method improving existing pipe cooling method was developed for the active thermal cracking control of slender mass concrete, and applied at the field attached wall. In results, the maximum temperature dropped more than by vertical pipe cooling method, and the cracks decreased about more than 50%.

In this study, the vertical pipe cooling method was developed to propose the pipe cooling method suited for the vertically long mass concrete structures. FEM (finite element method) analysis was carried out to investigate the validity of the vertical pipe cooling method, and the temperature, the behavior of tensile stress of concrete and the crack index were investigated. In result, it was confirmed that the vertical pipe cooling method was effective in the thermal cracking control of mass concrete member.

A perforated hemispherical microwell structure is shown to efficiently capture single Chlamydomonas reinhardtii (C. reinhardtii) cells, culture them to form colonies, and retrieve these colonies to serve as seeds for large-scale cultivation. This solution-phase formation and recovery of colonies could overcome the tedious and time-consuming process of selecting colonies from a solid-phase agar plate. The fabricated microdevice was composed of three layers: a top layer consisting of a cell solution for injection and recovery of a microalgal solution, a hemispherical perforated microwell array in the middle, and a bottom layer in which the solution is manipulated by controlling the hydrodynamic force. The microalgal (wild type and hygromycin B-resistant mutant) cells loaded in the top layer rapidly diffused into the microwell holes, and individual such cells were captured with high efficiency (>90%) and within 1 min by applying a withdraw mode in the bottom layer. Single-cell-based cultivation in a medium containing hygromycin B was then performed to generate colonies in the hemispherical microwell. While the wild type cells died, mutant cells resistant to hygromycin B survived well and grew into a colony within 2 days. The produced colonies in the microwells were recovered by applying a release mode in the bottom layer, so that a hydrodynamic force was exerted vertically to push out the colonies through the outlet in 10 s. The recovered cells were cultured on a large scale in medium by using a flask. The recovered C. reinhardtii was confirmed as a hygromycin B-resistant mutant by identifying the hygromycin gene in the polymerase chain reaction (PCR). The microdevice described here could in solution perform single-cell capture, colony formation, and retrieval of colonies for further large-scale cultivation, which could replace tedious and time-consuming solid-phase agar plate processes with a 7-fold reduction in the duration of the process.

The circumferential alignment of human aortic smooth muscle cells (HASMCs) in an orthogonally micropatterned circular microfluidic channel is reported to form an in vivo-like smooth muscle cell layer. To construct a biomimetic smooth muscle cell layer which is aligned perpendicular to the axis of blood vessel, a half-circular polydimethylsiloxane (PDMS) microchannel is first fabricated by soft lithography using a convex PDMS mold. Then, the orthogonally microwrinkle patterns are generated inside the half-circular microchannel by a strain responsive wrinkling method. During the UV treatment on a PDMS substrate with uniaxial 40% stretch and a subsequent strain releasing step, the microwrinkle patterns perpendicular to the axial direction of the circular microchannel are generated, which can guide the circumferential alignment of HASMCs during cultivation. The analysis of orientation angle, shape index, and contractile protein marker expression indicates that the cultured HASMCs reveal the in vivo-like cell phenotype. Finally, a fully circular microchannel is produced by bonding two half-circular microchannels, and the HASMCs are cultured circumferentially inside the channels with high alignment and viability for 5 days. These results demonstrated the creation of an in vivo-like 3D smooth muscle cell layer in the circular microfluidic channel which can provide a bioassay platforms for in-depth study of HASMC biology and vascular function.

Development of a three-dimensional (3D) vascular co-cultivation system is one of the major challenges to provide an advanced analytical platform for studying blood vessel related diseases. To date, however, the in vivo-like vessel system has not been fully realized due to the difficulty of co-cultivation of the cells with orthogonal alignment. In this study, we report the utilization of microfabrication technology to construct biomimetic 3D co-cultured vasculature. First, microwrinkle patterns whose direction was perpendicular to the axis of a circular microfluidic channel were fabricated, and vascular smooth muscle cells (VSMCs) were cultured inside the microchannel, leading to an in vivo-like circumferential VSMC layer. Then, human umbilical vein endothelial cells (HUVECs) were co-cultured on the circumferentially aligned VSMC, and the success of double layer formation of HUVEC-VSMC in the circular microchannel could be monitored. After HUVEC cultivation, we applied shear flow in order to induce the orientation of HUVEC parallel to the axis, and the analysis of orientation angle and spreading area of HUVECs indicated that they were changed by shear stress to be aligned to the direction of flow. Thus, the HUVEC and VSMC layer could be aligned with a distinct direction. The expression level of VE-Cadherin located at the boundary of HUVECs implies in vivo-like vascular behavior. The proposed in vitro microfluidic vascular assay platform would be valuable for studying vascular diseases with high reliability due to in vivo-likeness.

New thermal crack control system for mass concrete was developed to increase quality and to save construction period and cost. The principle of this system is that the curing water having proper temperature is supplied automatically to the surface of mass concrete member to keep the temperature difference between center and surface of concrete less than generally recommended temperature difference (20℃). Mock-up test was conducted to investigate the validity of newly developed curing system. As a result, no crack was founded in the specimen using automated curing system developed in this study, while many cracks occurred in another specimen without automated curing system. It was also confirmed that the strength and the durability of the concrete cured by automated curing system were improved.

This paper describes the development of a novel paper-based capillary electrophoresis (pCE) microdevice using mineral paper, which is durable, oil and tear resistant, and waterproof. The pCE device is inexpensive (~$1.6 per device for materials), simple to fabricate, lightweight, and disposable, so it is more adequate for point-of-care (POC) pathogen diagnostics than a conventional CE device made of glass, quartz, silicon or polymer. In addition, the entire fabrication process can be completed within 1h without using expensive clean room facilities and cumbersome photolithography procedures. A simple cross-designed pCE device was patterned on the mineral paper by using a plotter, and assembled with an OHP film via a double-sided adhesive film. After filling the microchannel with polyacrylamide gel, the injection, backbiasing, and separation steps were sequentially operated to differentiate single-stranded DNA (ssDNA) with 4 bp resolution in a 2.9cm-long CE separation channel. Furthermore, we successfully demonstrated the identification of the PCR amplicons of two target genes of Escherichia coli O157:H7 (rrsH gene, 121 bp) and Staphylococcus aureus (glnA gene, 225 bp). For accurate assignment of the peaks in the electropherogram, two bracket ladders (80 bp for the shortest and 326 bp for the longest) were employed, so the two amplicons of the pathogens were precisely identified on a pCE chip within 3min using the relative migration time ratio without effect of the CE environments. Thus, we believe that the pCE microdevice could be very useful for the separation of nucleic acids, amino acids, and ions as an analytical tool for use in the medical applications in the resource-limited environments as well as fundamental research fields.

Background: Superselective transarterial embolization (TAE) is the most commonly used treatment for lower gastrointestinal (LGI) bleeding when endoscopic management is impossible or fails. Its effectiveness and safety are increased using advanced techniques, instruments, and embolic materials. Objectives: To evaluate the outcome and safety of TAE for LGI bleeding and to analyze various influencing factors, including embolic material, embolization site, and anticoagulant or antiplatelet medication. Patients and Methods: Fifty-two patients who underwent superselective TAE for LGI bleeding between 2003 and 2011 were included, and their clinical and imaging information were retrospectively reviewed. Outcome and safety measures, including technical and clinical success, early and delayed rebleeding, and complications, were evaluated. Logistic regression analysis was used to determine whether the clinical success rate was associated with specific variables. Results: Technical and clinical success was achieved in 52 (100%) and 43 (83%) patients, respectively. The prior embolization site was the point of rebleeding in five of the nine patients with early rebleeding. Delayed rebleeding was documented in four patients, including two patients with angiodysplasia. Logistic regression analysis showed that embolization site, embolic material, and anticoagulant or antiplatelet medication were not statistically significant factors affecting the clinical success rate of TAE for LGI bleeding. A major complication, ischemic colitis, occurred in one patient. Conclusion: Superselective TAE for LGI bleeding has a high success and low complication rate. There are no statistical correlations between the clinical success rate and several variables, including embolic material, embolization site, and anticoagulant or antiplatelet medication.