Increase In Initial Rate Research Articles

Optimization of laser osteotomy at 1064 nm using a graphite topical absorber and a nitrogen assist gas jet.

Laser ablation of bone for the purposes of osteotomy is not as well understood as ablation of homogeneous, non-biological materials such as metals and plastics. Ignition times and etch rate can vary during ablation of cortical bone. In this study, we propose the use of two techniques to optimize bone ablation at 1064nm using a coaxial nitrogen jet as an assist gas and topical application of graphite as a highly absorbing chromophore. We show a two order of magnitude reduction in mean time to ignition and variance by using the graphite topical chromophore. We also show that an increase in volumetric flow rate of the assist gas jet does show an initial increase in etch rate, but increased pressure beyond a certain point shows decreased return. This study also demonstrates a 2 nd order relationship between exposure time, volumetric flow rate of nitrogen, and etch rate of cortical bone. The results of this study can be used to optimize the performance of laser ablation systems for osteotomy. This is a companion study to an earlier one carried out by Wong et al. [Biomedical Opt. Express6, 1 (2015)].

Mediatorless, Reversible Optical Nanosensor Enabled through Enzymatic Pocket Doping

Single-walled carbon nanotubes (SWCNTs) exhibit intrinsic near-infrared fluorescence that benefits from indefinite photostability and tissue transparency, offering a promising basis for in vivo biosensing. Existing SWCNT optical sensors that rely on charge transfer for signal transduction often require exogenous mediators that compromise the stability and biocompatibility of the sensors. This study presents a reversible, mediatorless, near-infrared glucose sensor based on glucose oxidase-wrapped SWCNTs (GOx-SWCNTs). GOx-SWCNTs undergo a selective fluorescence increase in the presence of aldohexoses, with the strongest response toward glucose. When incorporated into a custom-built membrane device, the sensor demonstrates a monotonic increase in initial response rates with increasing glucose concentrations between 3 × 10−3 and 30 × 10−3 M and an apparent Michaelis–Menten constant of KM(app) ≈ 13.9 × 10−3 M. A combination of fluorescence, absorption, and Raman spectroscopy measurements suggests a fluorescence enhancement mechanism based on localized enzymatic doping of SWCNT defect sites that does not rely on added mediators. Removal of glucose reverses the doping effects, resulting in full recovery of the fluorescence intensity. The cyclic addition and removal of glucose is shown to successively enhance and recover fluorescence, demonstrating reversibility that serves as a prerequisite for continuous glucose monitoring.

The effect of pre-activation and milling on improving natural clinoptilolite for ion exchange of cesium and strontium

Natural clinoptilolite, of relatively low-grade, was investigated for its capability to remove cesium and strontium ions from water and simulated seawater. To improve its capacity, the material was pre-activated with concentrated NaCl and HCl solutions. Additionally, it was milled to a number of <300 μm size fractions, to expose exchange sites. Electron microscopy was used to characterise the naturally occurring impurities, where regions of high iron and potassium content was shown to correlate to lower levels of cesium adsorption. Adsorption kinetics for natural and activated resins with 5, 300 and 1500 ppm salt solutions were fitted with the Pseudo-Second Order (PSO) rate model. Activation led to clear increases in initial adsorption rate for both Cs+ and Sr2+, but only enhanced the overall rate constant for Cs+, due to the weaker interaction of the Sr2+. Equilibrium isotherms were compared with Langmuir and Freundlich monolayer models, where the adsorption capacity (Qc) for Cs+ was 67 mg/g which increased by over 100% with NaCl activation to 140 mg/g. Values for Sr2+ were significantly lower at 35 mg/g, with a considerably smaller enhancement with activation to 52 mg/g. Milling of the natural clinoptilolite was found to increase Cs+ uptake to similar levels as activation, in a linear correlation with specific surface area; although, improvements for Sr2+ were again lower, due to its weaker interaction with surface sites. In simulated seawater solutions, all materials gave considerably reduced performance due to K+ ion competition, with Sr2+ uptake decreased more extensively compared to Cs+. Overall, this work highlights that pre-activation and milling of clinoptilolite can be used to significantly enhance the grade of the ore for nuclear effluent treatment in low-salinity conditions.

Promotion of CO2 capture performance using piperazine (PZ) and diethylenetriamine (DETA) bi‐solvent blends

AbstractThe carbon dioxide post‐combustion capture process using amine solutions is considered the most appropriate method for CO2 capture from flue gas in power plants. This paper focuses on the CO2 capture performance of six common organic amines. Two amines, piperazine (PZ) and diethylenetriamine (DETA), which showed better performance, were then filtered out to form amine blends to improve performance further. The absorption heat from the CO2 absorbing process was measured directly using an advanced C80 micro calorimeter for more accurate calculation of regenerative energy consumption. Experimental results confirmed the optimal amine blend to be 10% PZ plus 20% DETA, with a 42% increase in absorption capacity and a 9% increase in initial absorption rate compared to traditional 30% monoethanolamine (MEA). The regeneration energy consumption of this chosen PZ‐DETA blend was calculated to be 3.979 GJ/ton CO2, a decrease of 9% compared with MEA. Moreover, it led to an improvement of about 55% in stable cyclic absorption capacity in comparison with 30% MEA. It was confirmed that this PZ‐DETA blend can bring practical economic benefits to industrial applications when replacing the current 30% MEA solution. © 2019 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Characterization of surface modified glycerol/silk fibroin film for application to corneal endothelial cell regeneration

Corneal endothelial cells (CEnCs) play a fundamental role in maintaining the transparency of the cornea. CEnCs lose their full proliferating capacity when tissue damages occur. The loss in proliferation rate is associated with corneal edema and decrease in visual acuity, leading in severe cases, to blindness. In these situations, a corneal transplant is usually needed to restore the original tissue functions. Tissue engineering is an efficient alternative for the production of implantable films, which can regenerate the tissue functions regulating at the same time the immune-response.In this study, we proposed a stable and transparent film, composed of silk fibroin modified with glycerol (G/SF), as a potential substrate for corneal endothelial cells regeneration. Our results confirmed that G/SF films have a uniform structure, rougher surface and lower thickness respect to the SF film. In vitro tests show that G/SF films can induce a slight increase in CEnCs initial adhesion and proliferation rate if compared with the SF film. Morphology and gene expression evaluations demonstrated that the bioactive effects of silk fibroin were not affected by the presence of glycerol. For this reason, the G/SF films are suitable as CEnCs carrier and promising for the corneal damages treatments.

Corrosion Inhibition Study of Mg-Nd-Y High Strength Magnesium Alloy Using Organic Inhibitor

A study on corrosion inhibition mechanism has been performed on rare earth containing WE43 magnesium alloy in 3.5 wt.% NaCl containing 8-hydroxyquinoline (HQ). After an initial increase in corrosion rate due to the formation of sparingly soluble MgQ2 complex, it was found to decrease owing to inhibition effect of the complex. Scanning electrochemical microscopic analysis showed a decrease in corrosion currents and enhanced resistance to pitting corrosion was observed for WE43 samples in the presence of HQ after an exposure of 48 h. With time, the MgQ2 thus generated formed a protective layer on the Mg alloy surface to prevent further corrosion. The corrosion rate of WE43 samples decreased by ~ 50% in HQ containing medium after a constant exposure of 28 days (from ~ 0.22 mg/cm2 day in no HQ to ~ 0.11 mg/cm2 day in HQ). For the WE43 samples in the presence of HQ, formation of MgO and MgQ2 was detected by x-ray photoelectron spectroscopy and x-ray diffraction. Shallower and smaller pits appeared on the magnesium alloy with HQ in the solution as compared to deeper and larger pits on the samples with no HQ in the solution. The significance of metal-complexing organic agent, hydroxyquinoline, in initial acceleration and subsequent prevention of Mg corrosion via protective MgQ2 complex layer formation is demonstrated.

Wheat bran and oat hulls have dose-dependent effects on ad-libitum feed intake in pigs related to digesta hydration and colonic fermentation.

Undigested nutrients and fermentable fibre in the distal ileum and colon stimulate intestinal brakes, which reduce gastric-emptying and digesta-passage-rate, and subsequently limit feed/food-intake. Fibre can also stimulate passage rate potentially increasing feed intake (FI). In order to experimentally determine the relationships between these two hypothesised actions of fibre, five levels of wheat-bran (WB) or oat-hulls (OH) were added to a highly digestible starch-based diet fed to pigs ad-libitum for three weeks. Average-daily-feed-intake (ADFI), faecal short-chain-fatty-acids (SCFA) and related parameters were determined at 7, 14 and 21d. A linear mixed model was fitted to FI and fermentation parameters. Overall, WB diets showed 8-11% lower ADFI (7-14d: p < 0.05; 7-21 & 0-21d: p = 0.053) than OH diets. WB diets produced over 20% more (21d: p < 0.01) SCFA than OH or Control diets. WB at 25% produced 22% more (7d: p < 0.05) SCFA than any other diet. Diets with WB at 25 and 35%, showed higher hydration capacity than any other diet (p < 0.001). OH at 10% had an unusually low FI and a markedly higher hydration capacity. With increasing levels of OH, intake of base diet was 7% more than control at 5% OH, but 8% less than control at 20% OH. With increasing WB content, intake of base diet decreased. From these results, we propose that three mechanisms control the effects of fibre on FI: initial increase in passage rate and feed intake at low concentrations of non-swelling fibres; a depression in FI from high fibre bulk; and reduced feed intake from stimulation of ileal and colonic brakes.

Timing of breeding and female fecundity of the greater bilby (Macrotis lagotis) in the temperate zone of South Australia: implications for translocations of a previously widespread species

Context Many of Australia’s threatened mammals were once widespread across the continent and present in both arid, semiarid and temperate habitats. However, data on breeding biology can be lacking for some climatic regions due to local extinctions of populations. The breeding biology of the greater bilby (Macrotis lagotis) has previously only been studied in captive colonies or free-ranging arid zone populations. Between 1997 and 2005, captive-bred bilbies were released at two sites in temperate South Australia. These populations provided an opportunity to determine whether bilbies adopt a seasonal reproductive strategy in the temperate zone, where this species has not been present since the early 1900s. Aims To determine the season of births, litter size and female reproductive potential in two free-ranging populations of the bilby in the temperate zone of South Australia. Methods Bilbies were regularly cage-trapped at Venus Bay Conservation Park and Thistle Island between August 2007 and April 2010 to obtain data on reproductive activity in both populations. Key results Births of pouch young in both populations occurred in winter (June–August), spring and early summer, but not between February and mid-May. Males had a significantly smaller mean testes size relative to head length in late summer, when breeding activity ceased. Average litter size at pouch emergence was between 1.00 and 1.47 pouch young, with females producing up to three litters per annum. The mean head length of females that successfully raised twins was significantly larger than that of females who raised a single pouch young. Conclusions The seasonal breeding pattern observed in the present study differs from that of year-round reproductive activity in captivity and the arid zone. The present study suggests that female body size influences fecundity, and that releasing large females at the start of the breeding season in temperate areas may maximise the initial rate of increase of a translocated bilby population. Implications The present study suggests previously widespread species such as the bilby can adapt their reproductive strategy to suit local conditions. Cessation of breeding in autumn, as observed in this study, has also been observed in other bandicoot species in southern Australia.

Demographic parameters of the predaceous ladybird, Hippodamia variegata (Goeze), on the aphid species, Aphis craccivora (Koch), reared on four host plants

The reproductive and demographic attributes of the aphidophagous ladybird, Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae), when fed on the aphid species, Aphis craccivora (Koch), reared on four host plants, viz. Dolichos lablab L., Vigna unguiculata L. Walp, Cajanus cajan (L.) Millsp., and Ranunculus sceleratus L., were investigated in the laboratory to find host suitability for the production of the ladybird. Results indicated that there was a significant effect of host plant on both reproductive and demographic parameters of the predator. The host plant suitability was in the rank order D. lablab = V. unguiculata > C. cajan > R. sceleratus. This ladybird started reproducing very early and laid a high number of eggs for a longer period of time when the adults were fed on aphids raised on D. lablab and V. unguiculata. Both the fecundity and percent egg hatching increased significantly in the case of the abovementioned two host plants. Similar host plant effects were found on demographic parameters of H. variegata, with significantly high values of net reproductive rate (rm), short generation (Tc), and doubling times (D.T.) on D. lablab and V. unguiculata. Age-specific fecundity of H. variegata at all host plant treatments was triangular in function with an initial increase in ovipositional rate with age, followed by attainment of peak and gradual decline till egg laying ceases. These peaks were higher on the host plant treatments, D. lablab and V. unguiculata. Sub-optimal values of both reproductive and demographic parameters were found on the host plant, R. sceleratus. Thus, it could be concluded that both D. lablab and V. unguiculata were the suitable host plants to raise aphid, A. craccivora, for the augmentative rearing of the ladybird, H. variegata.

DETERMINATION OF ADSORPTION KINETICS OF COCONUT HUSK ADSORBENT FOR HEAVY METALS REMOVAL USING LANGMUIR AND FREUNDLICH ISOTHERM EXPRESSIONS

Adsorption of heavy metal cationic ions (Cr, Pb, and Cu) onto coconut husk carbon (CHC) adsorbent has been studied using batch-adsorption method. The study was carried out to investigate the adsorption kinetic and adsorption isotherm of the coconut husk adsorbent for the removal of heavy metals in waste liquid effluent. The influence of pH, contact time, adsorbent dose, and adsorbent concentration, and temperature on the adsorption process was also studied. Results indicated an initial increase in adsorption rate, and optimal removal of heavy metal was reached within 70 minutes, further increase in contact time and temperature show significant change in equilibrium concentration. Also, further increase in adsorbent dosage revealed significant change in the sorption capacity of the CHC. The adsorption isotherms could be fitted well by both Langmuir and Freundlich models. The RI (equilibrium parameter) value in the present investigation was less than 1 (one) which indicates that the adsorption of the heavy metals ions on the CHC is favorable. The value of n for this study which indicates the degree of non-linearity between solution concentration and adsorption were 0.31–0.39, this result indicated that the adsorption of heavy metals onto the CHC is a chemical sorption. After treatment of synthetic heavy metal solution with the CHC, the adsorption isotherm model analysis revealed that the adsorption capacity (b) of CHC for the heavy metal were 89 mg/L (Cr), 125.5 mg/L (Pb), and 129.7 mg/L (Cu). Conclusively, the results indicate that the freely abundant agricultural waste-coconut husk can be treated for heavy metal adsorption but it’s not economically viable because it’s not renewable due to the chemisorption nature of the adsorption process.

Human Papillomavirus Vaccine Initiation for Adolescents Following Rhode Island's School-Entry Requirement, 2010-2016.

To assess changes in human papillomavirus (HPV) vaccine initiation for adolescent girls and boys in Rhode Island compared with all other states. We estimated the gender-specific effects of Rhode Island's school-entry HPV vaccination policy on self-reported HPV vaccination initiation by using a difference-in-differences design with the National Immunization Survey-Teen from 2010 through 2016. Compared with boys in other states, boys in Rhode Island increased their HPV vaccine initiation rate by 11% (b = 0.11; 95% confidence interval [CI] = 0.05, 0.18) after enactment of the requirement. No difference was seen in the probability of HPV vaccine initiation among girls in Rhode Island compared with girls in the multistate control (b = -0.01; 95% CI = -0.08, 0.05). Our analysis identified an 11% increase in HPV vaccine initiation rate among boys in Rhode Island after the school-entry requirement was enacted, whereas no significant change was observed for girls. Public Health Implications. Given suboptimal vaccine uptake rates in the United States, continued pursuit of state-level public policy to improve HPV vaccination is needed. School-entry requirements for HPV vaccination may be a strategy for closing the gap in HPV vaccine uptake for boys and girls.

Modulation of Mg2+ influx and cytoplasmic free Mg2+ concentration in rat ventricular myocytes.

To examine whether TRPM7, a member of the melastatin family of transient receptor potential channels, is a physiological pathway for Mg2+ entry in mammalian cells, we studied the effect of TRPM7 regulators on cytoplasmic free Mg2+ concentration ([Mg2+]i) of rat ventricular myocytes. Acutely isolated single cells were AM-loaded with the fluorescent indicator furaptra, and [Mg2+]i was estimated at 25°C. After [Mg2+]i was lowered by soaking the cells with a high-K+ and Mg2+-Ca2+-free solution, [Mg2+]i was recovered by extracellular perfusion of Ca2+-free Tyrode's solution that contained 1mMMg2+. The initial rate of increase in [Mg2+]i was analyzed as the Mg2+ influx rate. The Mg2+ influx rate was increased by the TRPM7 activator, naltriben (2-50μM), in a concentration-dependent manner with a half maximal effective concentration (EC50) of 24μM. This EC50 value is similar to that reported for the activation of recombinant TRPM7 overexpressed in HEK293 cells. Naltriben (50μM) caused little change in basal [Mg2+]i (~ 0.9mM) in Ca2+-free Tyrode's solution, but significantly raised [Mg2+]i to 1.31 ± 0.03mM in 94min after the removal of extracellular Na+. Re-introduction of extracellular Na+ lowered [Mg2+]i back to the basal level even in the presence of naltriben. Application of 10μM NS8593, an inhibitor of TRPM7, significantly lowered [Mg2+]i to 0.72 ± 0.03mM in 50-60min independent of extracellular Na+. The results suggest that Mg2+ entry through TRPM7 significantly contributes to physiological Mg2+ homeostasis in mammalian heart cells.

Experimental investigation of flow patterns and external performance of a centrifugal pump that transports gas-liquid two-phase mixtures

In order to reveal the mechanism of two-phase flow inside a centrifugal pump, visualization experiments were performed to investigate the gas-liquid two-phase flow patterns by using high-speed photography. Meanwhile, the external performance of the pump was measured under different conditions. The flow patterns in the suction pipe can be classified into plug flow and stratified flow distinguished by the critical inlet gas volume fraction (IGVF) of 6.2%. The critical IGVF of the pump is not obviously influenced by the rotational speed and initial liquid volume flow rate. The flow patterns in the impeller and volute can be classified into four categories with the increasing IGVF. The liquid volume flow rate has a small change in the condition of isolated bubbles flow, an obvious decrease in the condition of bubbly flow, a sharp decrease in the condition of gas pocket flow, and a gentle reduction in the condition of gas-liquid separation flow. Once the IGVF reaches the critical value, some bubbles in the volute begin to flow back into the impeller near the volute tongue. When the flow pattern transfers from gas pocket flow to gas-liquid separation flow, some bubbles in the discharge pipe flow back into the impeller. When the height of gas in the suction pipe reaches a critical value about 70 mm, bubbles sometimes flow into the volute and sometimes flow back into impeller, and the liquid volume flow rate is nearly to be zero. The differential pressure of the pump decreases with the increase of IGVF, and it decreases with the increase of initial liquid volume flow rate at the same IGVF.

Velocity and attenuation of elastic wave in a developed layer with the initial inner percolation in the pores

An improved model based on Biot poroelastic theory is presented incorporating the initial seepage flow in the matrix. The proposed model quantifies wave propagation in the oil field development process as VSP, transient well tests, and seismic production technology. Porosity variation, fluid–solid compressibility, and pseudo-threshold pressure gradient in low permeability reservoir are simultaneously considered, resulting in a modified form of continuity and motion equations. Integrating the equations and decomposition for the fluid–solid displacements helps to derive the analytical wave vectors of the fast P, slow P, and S waves in porous media. The sensitivity of affecting factors, such as petrophysical parameter, fluid property, and vibration frequency, on the wave velocity and attenuation is subsequently evaluated. Furthermore, the Biot model can be considered a special situation when the initial flow rate in this model tends to zero. The increase in initial percolating rate, expressed by the ratio of initial flow rate and solid scalar potential, causes an obvious decrease in the fast P wave velocity and an increase in its quality factor. Propagation of the slow P wave and the S wave is scarcely influenced. Low vibration frequency and low permeability also contribute to a large difference between the wave propagation parameters of the improved and Biot models. Cognition of the proportion in the inertia and viscosity effects is helpful in analyzing the complicated multiple mechanisms in wave propagation in the actual developed layer.

Recovery of ovulation rate in ewes following their removal from an oestrogenic lucerne forage

Grazing ewes on lucerne crops that contain elevated coumestrol concentrations before and during their mating period can decrease ovulation rate, which results in fewer multiple birth lambs. In this experiment, the ovulation rate of ewes grazing a moderately oestrogenic (29.1 ± 2.88 mg coumestrol/kg DM) lucerne crop for 6 weeks was compared with those transferred to grass pasture for 1 or 3 weeks, and a Control group on grass throughout. Ordinal regression predicted an exponential relationship with a sharp initial increase in ovulation rate from 0 to 14 days on grass that levelled off when ewes were on grass for durations greater than 3 weeks. Of importance, moderate coumestrol levels in lucerne remained throughout the experiment, and liveweight was unaffected by grazing treatment. This experiment quantified the decrease in risk of impaired lambing performance due to moderately oestrogenic lucerne consumption in relation to time on grass before ovulation. Specifically, removal of ewes from lucerne 2 weeks before ovulation mitigated the risk of decreased lambing performance.

Temperature-Dependent Surface Charge and Flashover Behaviors of Oil-Paper Insulation Under Impulse With Superimposed DC Voltage

Oil-paper insulation will inevitably endure impulse voltage with a superimposed dc voltage (superimposed voltage) because of introduced lightning or switching, which can induce charge accumulation and trigger flashover during the operation of a converter transformer. Temperature rise is also a nonnegligible factor that can significantly influence the performances of oil-paper insulation. This paper aims to reveal the effects of ambient temperature and superimposed voltage on surface charge and flashover behaviors in an oil-paper insulation system. Surface potential decay (SPD) experiments were performed under superimposed voltage with various polarity and amplitude combinations and at the temperature ranging from 20 °C to 80 °C. The results show that the initial surface potential and decay rate increase as the amplitude of the impulse voltage increases at 20 °C. The initial surface potential declines, and the process of SPD is accelerated at higher temperatures because of the increased concentration of shallow traps. Subsequently, flashover tests were conducted under superimposed voltage. It is found that flashover occurs after applying superimposed voltages even with a rather low dc voltage. In addition, the dc voltage component is primarily responsible for flashover. Weibull results also indicate that it is prone to trigger flashover at higher temperatures, because thermal excitation helps more carriers to escape from deep traps and participate in the process of flashover. Accordingly, the insulation characteristics of oil-paper system can be significantly influenced by superimposed voltage and temperature, which should draw great concern among the power grid.

The History and Impact of Molecular Coding Changes on Coverage and Reimbursement of Molecular Diagnostic Tests: Transition from Stacking Codes to the Current Molecular Code Set Including Genomic Sequencing Procedures

Changes in coding and coverage generate an uncertain reimbursement environment for molecular pathology laboratories. We analyzed our experience with two representative molecular oncology tests: a T-cell receptor (TCR) β rearrangement test and a large (467-gene) cancer next-generation sequencing panel, the Columbia Combined Cancer Panel (CCCP). Before 2013, the TCR β test was coded using stacked current procedural terminology codes and subsequently transitioned to a tier 1 code. CCCP was coded using a combination of tier 1 and 2 codes until 2015, when a new Genomic Sequencing Procedure code was adopted. A decrease in reimbursement of 61% was observed for the TCR β test on moving from stacking to tier 1 codes. No initial increase in total rejection rate was observed, but a subsequent increase in rejection rates in 2015 and 2016 was noted. The CCCP test showed a similar decrease (48%) in reimbursement after adoption of the new Genomic Sequencing Procedure code and was accompanied by a sharp increase in rejection rates both on implementation of the new code and over time. Changes in coding can result in substantial decreases in reimbursement. This may be a barrier to patient access because of the high cost of molecular diagnostics. Revisions to the molecular code set will continue. These findings help laboratories and manufacturers prepare for the financial impact and advocate appropriately.

Is obesity actually non-communicable?

ObjectivesObesity, broadly speaking, is characterised by having a body-mass index above 30 kg.m2, and described as a non-communicable risk factor. Obesity levels in the UK (and worldwide) are consistently acknowledged as, and accepted to be an epidemic. Moreover, when defining an epidemic, its' severity and initial rate of increase depend upon the value of the Basic Reproduction Number (R 0), and given the consistent rise in weight status over recent decades, obesity could be considered to be highly communicable. The objective was therefore to question the non-communicability of obesity. MethodsA review of literature was conducted using online databases; Web of Science, PubMed and Google Scholar. A narrative short-communication was subsequently prepared on the topic of obesity and its potential communicability. ResultsBoth familial and social transmission of obesity is apparent, and network phenomena are evidently relevant to the physiological and behavioural tenets of obesity. ConclusionA reclassification of obesity to being socially-communicable should be considered and adopted by clinicians, scientists and key-stakeholders, further considering this communicability during treatment and intervention.

Mediatorless, Reversible Optical Nanosensor Enabled through Enzymatic Pocket Doping.

Single-walled carbon nanotubes (SWCNTs) exhibit intrinsic near-infrared fluorescence that benefits from indefinite photostability and tissue transparency, offering a promising basis for in vivo biosensing. Existing SWCNT optical sensors that rely on charge transfer for signal transduction often require exogenous mediators that compromise the stability and biocompatibility of the sensors. This study presents a reversible, mediatorless, near-infrared glucose sensor based on glucose oxidase-wrapped SWCNTs (GOx-SWCNTs). GOx-SWCNTs undergo a selective fluorescence increase in the presence of aldohexoses, with the strongest response toward glucose. When incorporated into a custom-built membrane device, the sensor demonstrates a monotonic increase in initial response rates with increasing glucose concentrations between 3 × 10-3 and 30 × 10-3 m and an apparent Michaelis-Menten constant of KM (app) ≈ 13.9 × 10-3 m. A combination of fluorescence, absorption, and Raman spectroscopy measurements suggests a fluorescence enhancement mechanism based on localized enzymatic doping of SWCNT defect sites that does not rely on added mediators. Removal of glucose reverses the doping effects, resulting in full recovery of the fluorescence intensity. The cyclic addition and removal of glucose is shown to successively enhance and recover fluorescence, demonstrating reversibility that serves as a prerequisite for continuous glucose monitoring.

High Strength-High Ductility Combination Ultrafine-Grained Dual-Phase Steels Through Introduction of High Degree of Strain at Room Temperature Followed by Ultrarapid Heating During Continuous Annealing of a Nb-Microalloyed Steel

Ultrafine-grained dual-phase (UFG-DP) steel consisting of ferrite (1.2 μm) and martensite (1 μm) was uniquely processed via combination of hot rolling, cold rolling and continuous annealing of a low-carbon Nb-microalloyed steel. Room temperature tensile properties were evaluated and fracture mechanisms studied and compared to the coarse-grained (CG) counterpart. In contrast to the CG-DP steel, UFG-DP had 12.7% higher ultimate tensile strength and 10.7% greater uniform elongation. This is partly attributed to the increase in the initial strain-hardening rate, decrease in nanohardness ratio of martensite and ferrite. Moreover, a decreasing number of ferrite grains with {001} orientation increased the cleavage fracture stress and increased the crack initiation threshold stress with consequent improvement in ductility UFG-DP steel.