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The electrical stimulation of meridian points in rats inhibits the withdrawal reflex of the nociceptive tail. Its pain mechanisms are well-documented. Moreover, electroacupuncture (EA) at special abdominal acupoints has been shown to induce a short-term hypoglycemia effect in streptozotocin diabetic rats. The Zusanli and Zhongwan acupoints have been widely used in traditional Chinese medicine to relieve symptoms of diabetes mellitus. It is still unclear whether they can affect extracellular glucose and lactate metabolites at the cellular level. The aim of this study is to evaluate these effects using a rat model for the analysis of extracellular neurochemicals. First, electrical stimulus of 2 ms 2 Hz square pulses (30 minutes) was applied to anesthetized intact rats (n = 7) at the Zusanli points. One and a half hours later, a second electrical stimulus (2 Hz pulses, 30 minutes) was delivered to two of the rats at the same spot. Another two rats received a different stimulation (100 Hz pulses, 30 minutes) at the same location. In the final three rats, a second electrical stimulus of 2 Hz pulses was delivered to non-acupoints. An automated micro-blood sample collector was used to examine the glucose, pyruvate and lactate concentrations. The EA signal has an influence on the biologic process of energy metabolism by mediating dynamic extracellular neurochemical changes. The EA at limb acupoints of the lower limbs induces a decrease in glucose, an increase in lactate metabolites and a decrease in the lactate/glucose ratio. Moreover, the increased lactate/glucose ratio suggests that the cell has an increased anaerobic glucose metabolism.

During these last years, the substantially biological field effect transistors (BioFET) are one of the most abundant classes of electronic sensors for biomolecular detection. The determination of glucose levels using these biosensors, especially in the medical diagnosis and food industries, is gaining popularity. Among them, ion-sensitive field effect transistor (ISFET) is considered one of the most intriguing approaches in electrical biosensitivity technology. The glucose sensor ISFET detects the glucose molecule by catalyzing glucose to gluconic acid and hydrogen peroxide in the presence of oxygen. In this paper, first of all we examine some of the main advantages in this field, the perspective of applications and the main issues in order to stimulate a broader interest in the development of biosensors based on ISFET and to extend their applications for a reliable and sensitive glucose analysis. Thereafter, a biosensor with field effect sensitive to the ions for the detection of glucose is modeled analytically. In the proposed model, the glucose concentration is presented according to the gate voltage. The simulated data show that the analytical model can be used with an electrochemical glucose sensor to predict mechanism’s behavior of detection in the biosensors.

Mathematical modeling is very helpful for noninvasive investigation of glucose-insulin interaction. In this paper, a new time-delay mathematical model is proposed for glucose-insulin endocrine metabolic regulatory feedback system incorporating the $\beta$-cell dynamic and function for regulating and maintaining bloodstream insulin level. The model includes the insulin degradation due to glucose interaction. The dynamical behavior of the model is analyzed and two-dimensional bifurcation diagrams with respect to two essential parameters of the model are obtained. The results show that the time-delay in insulin secretion in response to blood glucose level, and the delay in glucose drop due to increased insulin concentration, can give rise to complex dynamics, such as periodic oscillation. These dynamics are consistent with the biological findings and period doubling cascade and chaotic state which represent metabolic disorder that may lead to diabetes mellitus.

A mathematical model for Intra-Venous Glucose Tolerance Test (IVGTT) with explicit glucose–insulin interaction is presented as a system of delay differential equation with discrete time delays and its important mathematical features are analyzed. This model includes the positivity and boundedness of the solution. An unique equilibrium point is found and its local stability is investigated. Using the Lyapunov functional approach, we show the global stability of the unique equilibrium point. The length of delay that preserves the stability is estimated. Sensitivity analysis is performed on a delay differential equation model for IVGTT that suggests the parameter value has a major impact on the model dynamics. Numerical calculations are performed to support and elaborate the analytical findings.

Some of the questions involved in the formulation of a new model for a physiological phenomenon, when the model represents a dynamical system, concern its qualitative behavior. The determination of the stability of a particular dynamical system is usually made analytically, from a linearization of the system around an equilibrium point. This analytic proof may often be complicated or impossible, leading to the imposition of conditions on the relative magnitude of the model structural parameters or to other partial results. We discuss a general technique whereby a probabilistic judgement is made on the stability of a dynamical system, and we apply it to the study of a particular delay differential system modelling the relationship between insulin secretion and glucose uptake. This technique is applicable in case experimental material is available: a stability criterion is obtained via the usual linearization around an equilibrium point and its distribution is approximated from the estimated dispersion of the model parameters. The probability that the stability criterion is such as to make the model stable can then be computed directly. While the conclusion is probabilistic in nature, it is generally applicable to a vast class of models.

In this paper, we first fabricated a nanoPt modified platinum electrode. Then through a simple method, the electrode surface was introduced with a submonolayer of bismuth that acted as an effective promoter. Cyclic voltammetry and other characterizations were employed. The obtained Bi^III/nanoPt/Pt electrode exhibited two greatly increased oxidation peaks at negative and positive potential areas, respectively. The signals were far larger than that of platinum electrode because of the large true surface area of nanoparticles and the catalysis of bismuth adsorbed on platinum. In the presence of bismuth, the platinum active sites could combine with more OH^- from bismuth hydroxyl to form a new active site for the oxidation of glucose. The prepared Bi^III/nanoPt/Pt electrode given high sensitivity and excellent linearship to glucose detection and showed the potential application in the areas of electrocatalysis or electroanalysis.

In this work, we electrochemically developed a palladium–polypyrrole composite film on a silicon semiconductor support, and then studied its electrocatalytic activity — as an anode — towards the oxidation of glucose in an alkaline medium. The obtained electrode is characterized by various physicochemical techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray fluorescence (XRF). The results show that the presence of the polymer film on the Si support improves the conductivity of the latter and that the presence of palladium on the polymer film is at the origin of the reactivity of the electrode for glucose oxidation.

This work presents the preparation of a gold-polypyrrole (Au-PPy) composite film on a silicon (Si) semiconductor supported by electrodeposition, and the study of its electrocatalytic activity as an anode catalyst for the glucose oxidation reaction in alkaline media. The microstructure of the as-prepared Au-PPy film is characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that the presence of the polymer film on the Si support improves the conductivity of the latter and enables better distribution of the Au microparticles on the electrode surface, thus helping to increase their catalytic activity for glucose oxidation.

Exploring the Role of Glutathione in the Regulation of Immune Cell Function.

Does Oxidative Damage Cause Poor Healing?

Pathogenesis of Atopic Dermatitis in Singapore.

Proteomics and Colorectal Cancer Metastasis: Bird's-Eye View on Current Scenario and Our Contribution.

Zebrafish: A Small Fish Model for a Big Human Disease.

The Reign of a New Dictator: Circulating MicroRNA in Diabetes.

Engineering Artificial Vascularized Bone Grafts for the Repair of Large Bone Defects.

A 'Nano' Era for Blood Glucose Sensing.

Ancient Medicine with Newer Roles: Potential Role of Celastrol in the Treatment of Multiple Myeloma.

Proteins, Proteome and Proteomics.

A Novel Promising Biomarker and Therapy Target of Liver Cancer.

Understanding Diabetes

Prediabetes: The Gap between the Onset of Disease and Initiation of Treatment.

Diabetes: A Dietitian’s Perspective.

Use of Modelling for Better Diabetes Care.

No More Highs and Lows with Toujeo®: A New and Improved Insulin Injection.

Diagnosis of diabetes is usually achieved by obtaining a single reading of blood-glucose concentration value from the Oral Glucose Tolerance Test (OGTT). However, the result itself is inadequate in providing insight into the glucose-regulatory etiology of diabetes disease disorder, which is important for treatment purposes. The objective of this project was to conduct clinical simulation and parametric identification of OGTT model for diagnosis of diabetic patient, so as to classify diabetic or at-risk patients into different categories, depending on the nature of their blood-glucose tolerance response to oral injestion of a bolus of glucose. In other words, the patient classification depends on how the blood-glucose concentration varies with time; i.e. how much does it peak, how long does it takes to reach its peak value, how fast does it return to the fasting value, etc. during the oral glucose tolerance test.

To represent this blood-glucose concentration [y(t)] regulatory dynamics, the model selected is a second-order differential equation, of blood-glucose concentration response to a bolus of ingested glucose Gδ(t). This model was then applied to the test subjects by making the model solution-expression for y(t) match the monitored clinical data of blood-glucose concentration at different time intervals, through clinical simulation and parametric identification. The solutions obtained from the model to fit the clinical data were different for normal and diabetic test subjects. The clinical data of "normal" subjects could be simulated by means of an under-damped solution of the model, as: y(t) = (G/ω)e^-ωtsin ωt. The data of "diabetic" patients needed to be simulated by means of an over-damped solution of the model, as: y(t) = (G/ω)e^-Atsin hωt, where G represents the magnitude of the impulse input Gδ(t) to the model (in gms of glucose per litre of blood pool volume), ω is the damped oscillatory frequency of the model, w_n is the natural frequency of the system and .

In order to facilitate differential diagnosis, we developed a non-dimensional diabetic index (DI) expressed as: [Ay_maxT_d/GT_max]. This index can be used to facilitate the diagnosis of diabetes as well as for assessing the risk to becoming diabetic.

Subjective cognitive decline (SCD), characterized by self-perceived subtle cognitive impairment ahead of the appearance of explicit and measurable cognitive deficits, is regarded as the preclinical manifestation of the pathological change continuum of Alzheimer’s disease (AD). We were committed to exploring the amyloid and glucose metabolic signatures related to imminent brain metabolic changes in SCD subjects. This study included 39 subjects (mean age = 71.9 years; 14 males and 25 females) diagnosed with SCD disease and 39 gender-matched healthy controls (HCs) (mean age = 75.2; 16 males and 23 females) with brain [18F] fluorodeoxyglucose positron emission tomography (PET) images and [18F] florbetapir PET images. The standardized uptake value ratios (SUVRs) of PET images within the regions of interest (ROIs) were calculated. Inter-group SUVR differences were assessed by two-sample $t$-testing and receiver operating characteristic curve (ROC) analyses. A generalized linear model (GLM) was employed to evaluate the correlations between amyloid and FDG uptake. Compared with HCs, SCD subjects showed significantly increased amyloid SUVR, as well as significantly increased glucose SUVR in the olfactory, amygdala, thalamus, heschl gyrus, superior and middle temporal gyrus and temporal pole (all $P<0.05$). The amyloid SUVR of thalamus was found to have a better ROC result (area under the curve (AUC): 0.77, 95% confidence interval (CI): 0.66–0.86) in the HC group, as was the case with the glucose SUVR of the middle temporal gyrus (AUC: 0.83, 95% CI: 0.73–0.91). There were significant positive correlations between amyloid and glucose SUVRs ($P<0.05$). The amyloid SUVR of the thalamus showed a significantly better main effect (odd ratio $=$ 2.91, 95% CI: 1.44–6.7, $P<0.001$), and the glucose SUVR of the heschl gyrus indicated an enhanced main effect (odd ratio $=$ 5.08, 95% CI: 1.86–18.15, $P<0.001$). SCD subjects demonstrated significant amyloid accumulation and glucose hypermetabolism in specific brain regions, and amyloid pathology overlapped with regions of glucose abnormality. These findings may advance the understanding of imminent pathological changes in the SCD stage and help to provide clinical guidelines for interventional management.

Glucose-, galactose- and lactose-containing photosensitizers based on derivatives of chlorophyll a and bacteriochlorophyll a were synthesized with the use of [3+2] cycloaddition between sugar azides and triple bond derivatives of chlorins and bacteriochlorins. Unlike bacteriochlorin cycloimide, chlorin was detected to form a Cu-complex during the click reaction. An approach to the synthesis of metal-free glycosylated chlorins was developed with the use of "protection" by Zn²⁺ cation and subsequent demetalation. It is based on the action of alkynyl chlorin e₆ derivative Zn-complex, which is resistant to the substitution by copper cation. Bacteriochlorin p cycloimide conjugate with per-acetylated β-D-lactose was obtained and shown to become water-soluble after unblocking of the lactose hydroxy functions. NMR studies allowed for the elucidation of structure, tautomeric form and conformation of the obtained compounds.

This review summarizes the applications of metallophthalocyanine (MPc) and metallo-porphyrin (MP) complexes as electrocatalysts immobilized onto various electrodes for the detection of hydrogen peroxide and glucose. The uses of MPc and MP complexes as electron mediators for the detection of glucose at glucose oxidase modified surfaces are discussed.

The synthesis of derivatives bearing glucose or galactose units linked by an acrylate spacer to one free meso position of a bis-aryl-porphyrin macrocycle was developed and characterized by standard spectroscopic techniques. The new mono-substituted gluco- and galacto-porphyrin derivatives 5–8 present an alternative to the widespread tetra-aryl porphyrin functionalization. Singlet oxygen studies showed a comparable singlet oxygen production with TPP. Furthermore, the less bulky architectures here synthesized present an opportunity to enhance the PDT and PDI capabilities of glycoporphyrins with a simple synthetic modification at one of the meso positions.

The development of peroxidase mimics with enhanced peroxidase-like activity is critical to building a convenient and fast glucose colorimetric sensor. Herein, a porphyrin-based conjugated microporous polymer (FePCMP) was synthesized through a Pd-/CuI catalyzed Sonogashira coupling reaction. The FePCMP exhibited specific and superior POD-like activity evaluated by the fast oxidation of 3,3$\prime$,5,5$\prime$-tetramethylbenzidine (a chromogenic substrate, TMB) to form the blue product (oxTMB) in the presence of H₂O₂. The outstanding POD-like activity is mainly ascribed to the Fe-N₄ active sites and the cross-linked porous framework of FePCMP. Furthermore, the FePCMP was applied in selective colorimetric detection of glucose through a glucose oxidase biocatalytic cascade reaction with a low detection limit (LOD) of 0.031 $\mu$M in the linear range of 0.2–5 $\mu$M. This study not only provided a new method for the design and synesis of specific POD-like nanozymes, but also the prepared FePCMP can be used as a POD-like enzyme for the colorimetric detection of other molecules, such as cholesterol, acetylcholine, etc.

We report on the sensitive detection of glucose using silicon nanowire array field-effect-transistor (SiNW-FET) upon illumination. The uniformly distributed and size-controlled SiNWs were fabricated by "top-down" approach. The fabricated SiNW-FET device was evaluated for detection of glucose in the range of 100–900 mg/dL. The SiNW-FET shows enhanced sensitivity of 0.988 ± 0.030 nA (mg/dl)^-1 upon illumination at 480 nm light as compared to without illumination as 0.486 ± 0.014 nA (mg/dL)^-1. The presented SiNW-FET device is fast, stable and sensitive to light as well as to bio analyte, and hence can be utilized as sensitive biological sensing platform.

In this study, a novel imprinted polymer based on 3-aminophenylboronic acid (APBA)-functionalized CdTe quantum dots (QDs) was synthesized and used to sensitively and selectively detect glucose. In the process of synthesis, the boronic acid in the APBA could combine covalently with vicinal diol compounds, directing imprinting process, and the APBA-modified CdTe QDs were used as the solid supports. By this method, the prepared molecular imprinting polymers (MIPs)-APBA/CdTe QDs show high selectivity, high sensitivity and good stability. Under optimal conditions, a linear relationship was obtained covering the linear range of 0–1.5mmol/L with a correlation coefficient of 0.99833 and a high imprinting factor about 5.71. Furthermore, the prepared MIPs-APBA/CdTe QDs were successfully applied to detect glucose in human serum samples. This work provides a new way to synthesize an excellent stability and efficient imprinted polymer based on CdTe QDs for convenient, fast and highly selective detection of glucose.

The direct synthesis of metal-organic frameworks (MOFs) with acidic and basic active sites is challenging due to the introduction of functional groups by post-functionalization method often jeopardize the framework integrity. Herein, we report the direct synthesis of acid-base bi-functional MOFs with tuning acid-base strength. Employing modulated hydrothermal (MHT) approach, microporous MOFs named UiO-66-NH₂ was prepared. Through the ring-opening reaction of 1,3-propanesultone with amino group, UiO-66-NH₂-SO₃H-type catalysts can be obtained. The synthesized catalysts were well characterized and their catalytic performances were evaluated in one-pot glucose to 5-HMF conversion. Results revealed the acid-base bi-functional catalyst possessed high activity and excellent stability. This work provides a general and economically viable approach for the large-scale synthesis of acid-base bi-functional MOFs for their potential use in catalysis field.

In this paper, a new and one-pot electrodeposition method was expanded for the preparation of NiS nanoparticles-based electrochemical biosensor using metal-ion complexes as a precursor. Thioacetamide was used to control the production rate of NiS nanoparticles for the first time. The proposed electrochemical sensor was characterized by energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscope (FESEM), cyclic voltammograms (CV), and electrochemical impedance spectra (EIS). Experiment parameters were optimized. Under the optimized condition, the prepared NiS-based biosensor exhibited excellent electrocatalytic oxidation of H₂O₂ and glucose due to their small size. It provided fast and sensitive strategy for detecting H₂O₂ and glucose in the range of 1–5000 and 1–1000$\mu$M. The detection limit of 0.257 and 0.3$\mu$M was obtained for H₂O₂ and glucose. The mechanisms were also analyzed. The proposed biosensor exhibited excellent anti-interference and repeatability. Furthermore, it was applied in the actual sample analysis, such as human blood serum.