Dual-channel in-fiber SPR sensor for simultaneous and highly sensitive measurement of salinity and temperature.

In this Letter, an in-fiber dual-channel surface plasmon resonance (SPR) sensor is reported that uses polydimethylsiloxane (PDMS)-filled C-type microstructured optical fiber (COF). The COF is made of HF-acid-etched single-sided hole optical fiber (SSHF), and its inner and outer sides are coated with gold film to stimulate SPR. The inner channel is filled with PDMS and acts as the temperature measurement channel, and the outer channel is directly in contact with the salt solution and acts as the salinity measurement channel. Experiments show that the sensor is qualified to detect salinity and temperature simultaneously, and it exhibits a salinity sensitivity of 0.296 nm/‰ in the salinity range of 0-153.32‰ and a high temperature sensitivity of -2.4 nm/°C in the temperature range of 22-44°C. Furthermore, the sensor also enjoys good hysteresis, repeatability, and reversibility in salinity detection. In a word, the high sensitivity, simple preparation, and good integration of the proposed sensor endow it with the potential for deep-sea exploration.

Comprehensive analysis of the differences between left- and right-side colorectal cancer and respective prognostic prediction.

BACKGROUND: Previous studies have reported that the tumor heterogeneity and complex oncogenic mechanisms of proximal and distal colon cancer (CRC) are divergent. Therefore, we aim to analyze the differences between left-sided CRC (L_cancer) and right-sided CRC (R_cancer), as well as constructing respective nomograms. METHODS: We enrolled 335 colon cancer patients (146 L_cancer patients and 189 R_cancer patients) from The Cancer Genome Atlas (TCGA) data sets, and 102 pairs of color cancer tissue and adjacent normal tissue (51 L_cancer patients and 51 R_cancer patients) from our hospital. Firstly, we analyzed the differences between the L_cancer patients and R_cancer patients, and then established the L_cancer and R_cancer prognostic models using LASSO Cox. RESULTS: R_cancer patients had lower survival than L_cancer patients. R_cancer patients had higher ESTIMATE and immune scores and lower tumor purity. These patterns of expression of immune checkpoint-related genes and TMB level were higher in R_cancer than in L_cancer patients. Finally, we using Lasso Cox regression analyses established a prognostic model for L_cancer patients and a prognostic model for R_cancer patients. The AUC values of the risk score for OS in L_cancer were 0.862 in the training set and 0.914 in the testing set, while those in R_cancer were 0.835 in the training set and 0.857 in the testing set. The AUC values in fivefold cross-validation were between 0.727 and 0.978, proving that the two prognostic models have great stability. The nomogram of L_cancer included prognostic genes, age, pathological M, pathological stage, and gender, the AUC values of which were 0.800 in the training set and 0.905 in the testing set. Meanwhile, the nomogram of R_cancer comprised prognostic genes, pathological N, pathological T, and age, the AUC values of which were 0.836 in the training set and 0.850 in the testing set. In the R_cancer patients, high-risk patients had a lower proportion of 'B cells memory', 'Dendritic cells resting', immune score, ESTIMATE score, immune checkpoint-related genes, and HLA-family genes, and a higher proportion of 'T cells follicular helper', 'Dendritic cells activated', and 'Mast cells activated'. CONCLUSIONS: We found significant differences between L_cancer and R_cancer patients and established a clinical predictive nomogram for L_cancer patients and a nomogram for R_cancer patients. Additionally, R_cancer patients in low-risk groups may be more beneficial from immunotherapy.

In-situ and label-free measurement of cytochrome C concentration with a Ti2C-MXene sensitized fiber-optic MZI sensor.

BACKGROUND: The concentration of cytochrome C is demonstrated to be an effective indicator of the microbial corrosion strength of metals. Traditional cytochrome C sensor can detect cytochrome C with a low detection limit, but their use is limited by their high cost, cumbersome operation, and susceptibility to malignant environments. In addition, studies on the monitoring of cytochrome C in the field of microbial corrosion has still not been carried out. Therefore, there is a need for a highly sensitive, selective, low-cost, anti-interference, and stable cytochrome C sensor with online monitoring and remote sensing capabilities for in-situ measurement of microbial corrosion strength. RESULTS: This paper proposed a highly sensitive label-free fiber-optic sensor based on Mach-Zehnder interferometer (MZI) for in-situ measurement of the microbial corrosion marker cytochrome C. Two-dimensional Ti2C-MXene material is uniformly immobilized onto the surface of the sensing area to improve the sensitivity, hydrophilicity, and specific surface area of the sensing area, as well as to facilitate the immobilization of specific sensitive materials. The cytochrome C antibody is modified on the surface of Ti2C-MXene to specifically recognize cytochrome C, whose concentration variation can be measured by monitoring the spectral shift of MZI sensor. Results demonstrate a measurement sensitivity of 1.428 nm/µM for cytochrome C concentrations ranging from 0 to 7.04 µM. The detection limit of the sensor is calculated to be 0.392 µM with remarkable performance, including selectivity, stability, and reliability. Besides, the measurement result of the proposed sensor in real microbial corrosive environment is consistent with that of the ideal environment. SIGNIFICANCE AND NOVELTY: This is the first instance of achieving in-situ and label-free measurement of cytochrome C by using a fiber-optic MZI sensor, which undoubtedly provides a feasible solution for the effective monitoring of microbial metal corrosion in the environment.

Optofluidic lasers and their applications in biochemical sensing.

Optofluidic laser (OFL) technology, as an emerging technology combining microfluidics and laser technology, offers many unique advantages in sensing applications and has become a research hotspot for highly-sensitive intracavity biochemical analysis. Biochemical sensors based on OFLs can detect changes in biochemical parameters by using significant changes in laser output characteristics, so as to achieve high detection sensitivity. Here, we provide an overview of OFLs with a focus on their constructions, the design of OFL-based biochemical sensors, and their applications in biochemical analysis. Firstly, the three elements of an OFL, including the optical microcavity, gain medium, and pump source, are described systematically. After explaining the basic principles and characterization of OFLs for biochemical sensing, the current research progress of OFL-based biochemical sensors is summarized and analyzed according to the combination of OFLs with different assay techniques. This is followed by a discussion of the research on OFLs at the level of biological macromolecules, cells, and tissues. Finally, in view of the applications of OFLs in the field of biochemical sensing, the current challenges and future development directions are briefly discussed.

Highly sensitive salinity sensor based on Mach-Zehnder interferometer with double-C fiber.

This paper proposes a highly sensitive, compact, and low-cost optical fiber salinity sensor based on the Mach-Zehnder interferometer. The sensor is constructed using a single mode fiber (SMF) - no-core fiber - double-C fiber (DCF) - NCF-SMF structure, with the DCF prepared by etching the dual side-hole fiber with HF acid. The DCF's large-size exposed microfluidic channels solve the previous microstructured optical fiber's challenging liquid filling and replacement problems. Theoretical simulations and experiments demonstrate that the sensor is suitable for high-sensitivity salinity measurement. The sensor exhibits a high salinity sensitivity of -2.26 nm/‰ in the salinity range of 10‰-50‰, as demonstrated by the experimental results. Additionally, the sensor exhibits some fascinating characteristics, including high repeatability, hysteresis, reversibility, and stability.

Optical fiber SPR biosensor based on gold nanoparticle amplification for DNA hybridization detection.

An optical fiber SPR biosensor based on multimode fiber (MMF)- hollow core fiber (HCF)-MMF is proposed and experimentally confirmed for in situ DNA hybridization analysis. In order to improve the sensitivity of DNA hybridization detection, a sandwich model based on gold nanoparticles (AuNPs) amplification is proposed. In this model, the probe DNA (pDNA) is first modified on the optical fiber sensing area by covalent bonding, and then the biotinylated target DNA (tDNA) is modified on the AuNPs by the high affinity between biotin and streptavidin. Finally, the tDNA on the surface of the AuNPs specifically hybridizes with the pDNA on the optical fiber to form a sandwich model. The near field coupling enhancement between AuNPs and gold film and the high mass ratio of AuNPs give high sensitivity to DNA hybridization detection. Experimental results show that the sandwich-type fiber SPR sensor has a log-linear response in the DNA concentration range of 1 pM-10 nM, and the sensitivity and detection limit are 4.04 nm/log(µM) and 1pM, respectively. This is 1.44 times more sensitive than that without sandwich assay. In addition, the DNA sensor has good specificity and stability, which foreshadows its great application potential in the fields of disease diagnosis, microbial detection and environmental science.

A plug-and-play optical fiber SPR sensor for simultaneous measurement of glucose and cholesterol concentrations.

A plug-and-play surface plasmon resonance (SPR) dual-parameter optical fiber biosensor is reported, in which Au film was firstly coated on the fiber surface for exciting SPR and the end half of the Au film was modified with Au nanoparticles to generate double SPR resonance valleys. For simultaneous detecting of glucose and cholesterol concentrations, modified P-mercaptophenylboronic acid (PMBA) and ß-cyclodextrin (ß-CD) were subsequently coated on the surface of sensor probe. Due to the cis-diol structure of glucose, it can interact with PMBA, leading to a red shift of one SPR resonant valley, whose maximum wavelength shift is 11.228 nm in the range of 0-1.7 mM glucose concentration. On the same time, the cholesterol molecules can realize the host-guest combination with ß-CD, leading to a red shift of another SPR resonant valley, and the maximum wavelength shift is 18.893 nm in the cholesterol concentration range of 0-300 nM. The detection limits of the sensor to glucose and cholesterol are 0.00078 mM and 0.012 nM, respectively. The enhances the practical value of the dual-parameter sensor. Both theory and experiment results verify the feasibility of the "plug-and-play" sensor to measure the dual biomass of glucose and cholesterol with ultra-low detection limit and good selectivity. The proposed method provides a huge research value for the optical fiber sensor in multi-parameter measurement.

Lattice Boltzmann model for conjugate heat transfer across thin walls.

A lattice Boltzmann (LB) model with an efficient and accurate interface treatment for conjugate heat transfer across a thin wall between two different media is developed. The proposed interface treatment avoids fine meshing and computation within the thin layer; instead, the energy balance within the thin layer and the conjugate conditions on each interface are utilized to construct explicit updating schemes for the microscopic distribution functions of the LB model at the interior lattice nodes of the two media next to the thin layer. The proposed interface schemes reduce to the standard interface scheme for conjugate conditions in the literature in the limit of zero thickness of the thin layer, and thus it can be considered a more general interface treatment. A simplified version of the interface treatment is also proposed when the heat flux variation along the tangential direction of the thin layer is negligible. Three representative numerical tests are conducted to verify the applicability and accuracy of the proposed interface schemes. The results demonstrate that the intrinsic second-order accuracy of the LB model is preserved with the proposed interface schemes for thin layers with constant tangential fluxes, while for general situations with varying tangential fluxes, first-order accuracy is obtained. This interface treatment within the LB framework is attractive in conjugate heat transfer modeling involving thin layers for its simplicity, accuracy, and significant reduction in computational resources.

Anomalous sub-diffusion of water in biosystems: From hydrated protein powders to concentrated protein solution to living cells.

Water is essential to life and its translational motion in living systems mediates various biological processes, including transportation of function-required ingredients and facilitating the interaction between biomacromolecules. By combining neutron scattering and isotopic labeling, the present work characterizes translational motion of water on a biomolecular surface, in a range of systems: a hydrated protein powder, a concentrated protein solution, and in living Escherichia coli (E. coli) cells. Anomalous sub-diffusion of water is observed in all samples, which is alleviated upon increasing the water content. Complementary molecular dynamics simulations and coarse-grained numerical modeling demonstrated that the sub-diffusive behavior results from the heterogeneous distribution of microscopic translational mobility of interfacial water. Moreover, by comparing the experimental results measured on E. coli cells with those from a concentrated protein solution with the same amount of water, we show that water in the two samples has a similar average mobility, however the underlying distribution of motion is more heterogeneous in the living cell.

In vitro protective effects of pyrroloquinoline quinone on methylmercury-induced neurotoxicity.

Methylmercury (MeHg), as a well-known neurotoxicant, has been implicated to induce massive neurodegeneration. Pyrroloquinoline quinone (PQQ) is a novel redox cofactor and also exists in various plants and animal tissues. In vivo as well as in vitro experimental studies have shown that PQQ functions as an essential nutrient or antioxidant. In this study, we demonstrated the protective effects of PQQ on MeHg-induced neurotoxicity in PC12 cells. The results showed that after pretreatment of PC12 cells with PQQ prior to MeHg exposure, the MeHg-induced cytotoxicity was significantly attenuated, and then DNA fragmentation was correspondingly reduced. PQQ prevented the disruption of mitochondrial membrane potential, up-regulated the level of Bcl-2, and consequently inhibited the activation of caspase-3. Moreover, PQQ also decreased the production of ROS and maintained the GSH levels in PC12 cells exposed to MeHg. Thus, these data indicate that PQQ can protect neurons against MeHg-induced apoptosis and oxidative stress via ameliorating the mitochondrial dysfunction. Data from this study provide a new useful strategy for the treatment of neuronal toxicity induced by mercury toxins.

Multiple-time-scaling lattice Boltzmann method for the convection diffusion equation.

A multiple-time-scaling (MTS) strategy that decouples the time discretization in different domains and enables flexible time-step coarsening, refinement, and stretching in the lattice Boltzmann method (LBM) for the convection diffusion equation is developed. The key in the multiple-time scaling is the satisfaction of physical interface conditions without nested iterations in each time step by implementing appropriate interface schemes for the distribution functions in the LBM. The applicability and second-order accuracy of the MTS-LBM approach is demonstrated with two numerical tests. Our approach greatly expands the avenue and expedites the progress of applying the LBM for modeling complex flows and transport phenomena involving multiphases and multicomponents with large property ratios.

Optimizing Micromixer Surfaces To Deter Biofouling.

Using computational modeling, we show that the dynamic interplay between a flowing fluid and the appropriately designed surface relief pattern can inhibit the fouling of the substrate. We specifically focus on surfaces that are decorated with three-dimensional (3D) chevron or sawtooth "micromixer" patterns and model the fouling agents (e.g., cells) as spherical microcapsules. The interaction between the imposed shear flow and the chevrons on the surface generates 3D vortices in the system. We pinpoint a range of shear rates where the forces from these vortices can rupture the bonds between the two mobile microcapsules near the surface. Notably, the patterned surface offers fewer points of attachment than a flat substrate, and the shear flows readily transport the separated capsules away from the layer. We contrast the performance of surfaces that encompass rectangular posts, chevrons, and asymmetric sawtooth patterns and thereby identify the geometric factors that cause the sawtooth structure to be most effective at disrupting the bonding between the capsules. By breaking up nascent clusters of contaminant cells, these 3D relief patterns can play a vital role in disrupting the biofouling of surfaces immersed in flowing fluids.

Pathogenesis of non-alcoholic fatty liver disease mediated by YAP.

OBJECTIVE: This study aimed to investigate the mechanism of the interaction between Yes-associated protein (YAP) and transforming growth factor-ß (TGF-ß)/Smad signaling pathways in the development of non-alcoholic fatty liver disease (NAFLD). METHODS: Serum samples of monkeys with biopsy-proven NAFLD and healthy normal monkeys were used to measure fasting plasma glucose (FPG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG) and albumin (ALB) with the BECKMAN CX5 PRO. Hematoxylin-eosin staining (H&E) was used for pathologic analysis, Masson trichrome staining was used to assess for fibrosis staging, and Oil Red O staining was used to detect lipid droplet deposition. According to an NAFLD activity score of < 4 points and > 4 points, the samples were divided into groups: the steatosis group and fibrosing NASH group. Furthermore, monkeys with a fibrosis stage < 2 were assigned to the mild fibrosis group, while monkeys with fibrosis stage ≥ 2 were assigned to the significant fibrosis group. Moreover, the fibrosis stage was subdivided as follows: stages 1a, 1c and 2-3. Immunohistochemistry and real-time quantitative PCR were used to quantify protein and gene expression, respectively. RESULTS: In the present study, 54 monkeys with NAFLD and 23 normal monkeys were recruited. Serum FPG and TG levels were higher in fibrosing NASH monkeys compared with simple steatosis and normal monkeys, and differences between simple steatosis and normal monkeys were not statistically significant (p > 0.05). YAP increased in NAFLD, which mainly localized in the nuclei of hepatocytes, perivascular cells and bile duct cells; the accumulation of YAP correlated with the severity of hepatocyte injury. Compared with normal monkeys, the expression of TGF-ß, α-smooth muscle actin (α-SMA), Drosophila mothers against decapentaplegic protein 3 (Smad3) and connective tissue growth factor (CTGF) in the liver of simple steatosis monkeys significantly increased (p < 0.01). Compared with simple steatosis monkeys, the expression of TGF-ß, α-SMA, Smad3 and CTGF in fibrosing NASH significantly increased (p < 0.01). However, the expression of Drosophila mothers against decapentaplegic protein 7 (Smad7) in the liver of fibrosing NASH monkeys significantly decreased (p < 0.01). With the severity of liver fibrosis, the expression of TGF-ß, α-SMA, Smad3 and CTGF gradually increased, and the difference was statistically significant (p < 0.01). However, there was no significant difference in the expression of Smad3 between fibrosis stage 1a and 1c. Compared with normal monkeys, the expression of Smad7 in the liver of monkeys with fibrosis significantly decreased (p < 0.01), but was significantly higher at fibrosis stage 1c than at fibrosis stage 1a and 2. CONCLUSION: The YAP and TGF-ß signaling pathways and the interaction between them promote the development and progression of NAFLD.

Effects of soy isoflavones on testosterone synthetase in diet-induced obesity male rats.

Obesity is a complex metabolic disease, which causes serious impairment to the health of people. This study aimed to determine the influence of different-doses of soy isoflavones (SIF) on testicular morphology, testosterone levels and the expression of genes and proteins related to testosterone synthesis in diet-induced obesity (DIO) male rats. We used high-fat diet (HFD) to establish a DIO male rat model, then obese rats orally received SIF at doses of 0, 50, 250 and 500 mg/kg per day for four weeks. Results revealed that the body weight was obviously increased, and seminiferous tubules were significantly deformed in obese rats compared with that in normal diet fed controls. After SIF treatment, DIO male rats exhibited decreased body weight in a dose-dependent manner, accompanied with significantly alleviated testicular damages, as well as increased testosterone levels and steroidogenic acute regulatory (StAR), cytochrome P450 11A1 (CYP11A1), cytochrome P450 17A1 (CYP17), hydroxysteroid dehydrogenase-3ß (HSD3ß), and hydroxysteroid dehydrogenase-17ß (HSD17ß) protein and mRNA levels. In conclusion, SIF could alleviate testicular damages, increase testosterone levels, and upregulate the expression of proteins and genes related to testosterone synthesis in DIO male rats, which would be important for obesity male reproduction treatment.

Changes in blood anti-oxidation enzyme levels in MPTP-treated monkeys.

Oxidative stress has been implicated in a range of neurodegenerative diseases, in particular, Parkinson's disease (PD). However, the pathogenic mechanism of its influence on PD progression remains unclear. In order to clarify this, PD models are generated by 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intramuscular injection in eight rhesus monkeys. During the of progress PD pathogenesis, the activities of some major antioxidant enzymes, such as serum superoxide dismutase (SOD), glutathione peroxidase (GPX), and glutathione-s-transferase (GST), were measured, which show continuously decrease. While, the GSH and MDA content, as well as the expression of gamma-glutamylcysteine synthetase (GCS) and glutathione-s-transferase pi (GST-pi) exhibit robust increase. Taken together, this study shows the dynamic changes of antioxidant enzymes and lipid peroxidation in blood of PD monkeys during its progress, which will be important for the diagnosis and treatment of PD.

Pilot study: molecular risk factors for diagnosing sporadic Parkinson's disease based on gene expression in blood in MPTP-induced rhesus monkeys.

Clinical diagnosis of Parkinson's disease (PD) is characterized by the classical features of tremor, bradykinesia and rigidity, which are present only when more than 70%-80% degeneration of dopaminergic (DA) neurons in the substantia nigra. The lack of means for early diagnosis of PD has elicited interest in searching for its risk factors, which, by now, are almost obtained at a single time point in PD process, and little developing risk factors, obtained from completely normal situation to the onset or even advanced stage of PD in individual person which could monitor the progress of PD, are present. Here we have detected some potential factors in the blood of MPTP induced PD monkeys along with the progress of the disease. All the PD monkeys showed mild PD symptoms since the 9th week and gradually reached a classic and stable parkinsonism stage at the 18th week. Our results have found that the expression of Parkin, USP30, MUL1, PINK1, and LRRK2 significantly increased at 1st, 3th, 3th, 5th, and 8th week respectively and remained high till the end; The expression of UCHL1 and TRIM24 significantly increased at the 1st and 18th week, respectively, then gradually decreased and significantly lower than normal value; DJ-1 showed significantly decreased since the 12th week, while SNCA showed no significantly changed excepted at the 5th week. And, the terminal results of whole blood were highly consistent with those of in SN. These results support that these genes change may as biomarkers to monitor the progress of PD, and may facilitate the development of biomarkers for early diagnosis.

Effects of tangential-type boundary condition discontinuities on the accuracy of the lattice Boltzmann method for heat and mass transfer.

We present a systematic study on the effects of tangential-type boundary condition discontinuities on the accuracy of the lattice Boltzmann equation (LBE) method for Dirichlet and Neumann problems in heat and mass transfer modeling. The second-order accurate boundary condition treatments for continuous Dirichlet and Neumann problems are directly implemented for the corresponding discontinuous boundary conditions. Results from three numerical tests, including both straight and curved boundaries, are presented to show the accuracy and order of convergence of the LBE computations. Detailed error assessments are conducted for the interior temperature or concentration (denoted as a scalar ϕ) and the interior derivatives of ϕ for both types of boundary conditions, for the boundary flux in the Dirichlet problem and for the boundary ϕ values in the Neumann problem. When the discontinuity point on the straight boundary is placed at the center of the unit lattice in the Dirichlet problem, it yields only first-order accuracy for the interior distribution of ϕ, first-order accuracy for the boundary flux, and zeroth-order accuracy for the interior derivatives compared with the second-order accuracy of all quantities of interest for continuous boundary conditions. On the lattice scale, the LBE solution for the interior derivatives near the singularity is largely independent of the resolution and correspondingly the local distribution of the absolute errors is almost invariant with the changing resolution. For Neumann problems, when the discontinuity is placed at the lattice center, second-order accuracy is preserved for the interior distribution of ϕ; and a "superlinear" convergence order of 1.5 for the boundary ϕ values and first-order accuracy for the interior derivatives are obtained. For straight boundaries with the discontinuity point arbitrarily placed within the lattice and curved boundaries, the boundary flux becomes zeroth-order accurate for Dirichlet problems; and all three quantities, including the interior and boundary ϕ values and the interior derivatives, are only first-order accurate for Neumann problems.

Solar Thermochemical Energy Storage Through Carbonation Cycles of SrCO3/SrO Supported on SrZrO3.

Solar thermochemical energy storage has enormous potential for enabling cost-effective concentrated solar power (CSP). A thermochemical storage system based on a SrO/SrCO3 carbonation cycle offers the ability to store and release high temperature (≈1200 °C) heat. The energy density of SrCO3/SrO systems supported by zirconia-based sintering inhibitors was investigated for 15 cycles of exothermic carbonation at 1150 °C followed by decomposition at 1235 °C. A sample with 40 wt % of SrO supported by yttria-stabilized zirconia (YSZ) shows good energy storage stability at 1450 MJ m(-3) over fifteen cycles at the same cycling temperatures. After further testing over 45 cycles, a decrease in energy storage capacity to 1260 MJ m(-3) is observed during the final cycle. The decrease is due to slowing carbonation kinetics, and the original value of energy density may be obtained by lengthening the carbonation steps.

Conjugate heat and mass transfer in the lattice Boltzmann equation method.

An interface treatment for conjugate heat and mass transfer in the lattice Boltzmann equation method is proposed based on our previously proposed second-order accurate Dirichlet and Neumann boundary schemes. The continuity of temperature (concentration) and its flux at the interface for heat (mass) transfer is intrinsically satisfied without iterative computations, and the interfacial temperature (concentration) and their fluxes are conveniently obtained from the microscopic distribution functions without finite-difference calculations. The present treatment takes into account the local geometry of the interface so that it can be directly applied to curved interface problems such as conjugate heat and mass transfer in porous media. For straight interfaces or curved interfaces with no tangential gradient, the coupling between the interfacial fluxes along the discrete lattice velocity directions is eliminated and thus the proposed interface schemes can be greatly simplified. Several numerical tests are conducted to verify the applicability and accuracy of the proposed conjugate interface treatment, including (i) steady convection-diffusion in a channel containing two different fluids, (ii) unsteady convection-diffusion in the channel, (iii) steady heat conduction inside a circular domain with two different solid materials, and (iv) unsteady mass transfer from a spherical droplet in an extensional creeping flow. The accuracy and order of convergence of the simulated interior temperature (concentration) field, the interfacial temperature (concentration), and heat (mass) flux are examined in detail and compared with those obtained from the "half-lattice division" treatment in the literature. The present analysis and numerical results show that the half-lattice division scheme is second-order accurate only when the interface is fixed at the center of the lattice links, while the present treatment preserves second-order accuracy for arbitrary link fractions. For curved interfaces, the present treatment yields second-order accurate interior and interfacial temperatures (concentrations) and first-order accurate interfacial heat (mass) flux. An increase of order of convergence by one degree is obtained for each of these three quantities compared with the half-lattice division scheme. The surface-averaged Sherwood numbers computed in test (iv) agree well with published results.