Interstitial Level Research Articles

Is the masked continuous glucose monitoring system clinically useful for predicting hemoglobin A1C in type 1 diabetes?

The masked continuous glucose monitoring system (Masked-CGMS) differs from standard CGMSs in three ways: (1) there is no feedback to the user so that no immediate regimen changes can be made; (2) it can only be worn for up to 5 days; and (3) there are no alarms to warn of hyperglycemia or hypoglycemia. Since 2008 masked-CGMS has become popular for identifying reasons that a patient's hemoglobin A1C does not correlate closely with his or her capillary blood glucose measurements. To date only one study addressing the clinical utility of Masked-CGMS for improving A1C in diabetes has been published. No studies are available specifically examining the variability and correlation of Masked-CGMS and A1C. We performed 156 Masked-CGMS studies (40 patients studied sequentially a maximum of four times each) in type 1 diabetes patients. We then analyzed the resulting interstitial glucose levels obtained from the Masked-CGMS compared with an A1C measurement performed within 1 week of the Masked-CGMS study. There was a very low correlation between the A1C and the Masked-CGMS-derived mean interstitial glucose level. This statistic did not provide sufficiently predictive information to be clinically useful for changing an individual patient's intensive insulin therapy regimen. Our data demonstrate that a very weak correlation exists between 5 days of masked CGMS and a concurrently measured A1C level. For the individual type 1 diabetes patient, this relationship would unlikely to be clinically useful in altering the individual's treatment regimen.

Shear Stress Induced by an Interstitial Level of Slow Flow Increases the Osteogenic Differentiation of Mesenchymal Stem Cells through TAZ Activation

Shear stress activates cellular signaling involved in cellular proliferation, differentiation, and migration. However, the mechanisms of mesenchymal stem cell (MSC) differentiation under interstitial flow are not fully understood. Here, we show the increased osteogenic differentiation of MSCs under exposure to constant, extremely low shear stress created by osmotic pressure-induced flow in a microfluidic chip. The interstitial level of shear stress in the proposed microfluidic system stimulated nuclear localization of TAZ (transcriptional coactivator with PDZ-binding motif), a transcriptional modulator of MSCs, activated TAZ target genes such as CTGF and Cyr61, and induced osteogenic differentiation. TAZ-depleted cells showed defects in shear stress-induced osteogenic differentiation. In shear stress induced cellular signaling, Rho signaling pathway was important forthe nuclear localization of TAZ. Taken together, these results suggest that TAZ is an important mediator of interstitial flow-driven shear stress signaling in osteoblast differentiation of MSCs.

Diesel particle composition after exhaust after-treatment of an off-road diesel engine and modeling of deposition into the human lung

Regional deposition of diesel particles in the human lungs was analyzed and the chemical composition of inhaled particles was investigated. The off-road diesel engine with a diesel particulate filter (DPF) or a selective catalytic reduction (SCR) unit and without any exhaust after-treatment system was used. Around 85–95% of the measured particles were of ultrafine size and 53–84% of those nanoparticles. Over 70% of the deposited particles under 0.1µm and about 45–70% of the deposited particles from 0.1 to 1µm reach also the alveolar–interstitial level. Elements analyzed in particles were C, O, Fe, Si, Ti, Na, K, Ca, Mg, Ba, Mn, Zn, Cu, Cl, P, S and N. The proportion of PAHs in the measured particle mass was 0.05% and carcinogenic ones represented 1.3% of the total PAHs. The DPF system removed particles efficiently and up to 99% of the particles were removed. The total number of particles deposited in the lungs was generally lower when DPF was used compared to other setups. These particles contained though the largest variety of elements, which are commonly considered harmful to humans. Therefore it is difficult to conclude, whether exhaust particles from a diesel engine with a DPF unit would be less harmful to human health.

Contribution of calpain to myoglobin efflux from cardiomyocytes during ischaemia and after reperfusion in anaesthetized rats

Calpain activation has a putative role in ischaemia-reperfusion injury of cardiomyocytes. This study clarified the in vivo contribution of calpain to disruption of cardiomyocyte sarcolemma during ischaemia and after reperfusion in anaesthetized rats. Using a microdialysis technique in the hearts of anaesthetized rats, we investigated the effects of the calpain inhibitors on myocardial interstitial myoglobin level in the ischaemic region during coronary occlusion and after reperfusion. The calpain inhibitors were administered locally via a dialysis probe. Two durations of coronary occlusion were tested. Thirty-minute coronary occlusion: dialysate myoglobin concentration increased markedly from 385 ± 46 ng mL(-1) at baseline to 3701 ± 527 ng mL(-1) at 20-30 min of occlusion. After reperfusion, dialysate myoglobin concentration further increased, reaching a peak (12 296 ± 1564 ng mL(-1) ) at 10-20 min post-reperfusion and then declined gradually. The calpain inhibitors, MDL-28170 and SNJ-1945 did not change dialysate myoglobin concentration during occlusion but attenuated the increase after reperfusion to 6826 ± 1227 and 8130 ± 938 ng mL(-1) at 10-20 min post-reperfusion (P < 0.05), respectively. Ninety-minute coronary occlusion: dialysate myoglobin concentration increased from 516 ± 33 ng mL(-1) at baseline to 5463 ± 387 ng mL(-1) at 80-90 min after occlusion. After reperfusion, there was no significant increase in dialysate myoglobin concentration. MDL-28170 did not affect dialysate myoglobin concentration during occlusion or after reperfusion. Calpain contributes to sarcolemmal disruption immediately after reperfusion following 30-min coronary occlusion, but has little effects during ischaemia and after reperfusion in 90-min coronary occlusion.

Photoluminescence Properties of ZnO Thin Film Prepared by Sol-Gel Route

Temperature dependent photoluminescence (PL) properties of ZnO thin film prepared by sol-gel route were investigated. The excitonic-related emission peak at 3.336 eV dominates the spectra, and is attributed to the recombination of excitons bound to structural defects (DBX). Moreover, its thermal activation energy is 5.7 meV obtained by using least-squares fitting method. Compared to its larger localization energy, we propose that there exists a nonradiative relaxation path with energy released during the formation of DBX. The observed peak position of blue emission is in line with theoretical energy interval between the interstitial zinc level and valence band.

Glucose predictability, blood capillary permeability, and glucose utilization rate in subcutaneous, skeletal muscle, and visceral fat tissues

This study suggests an approach for the comparison and evaluation of particular compartments with modest experimental setup costs. A glucose level prediction model was used to evaluate the compartment's glucose transport rate across the blood capillary membrane and the glucose utilization rate by the cells. The glucose levels of the blood, subcutaneous tissue, skeletal muscle tissue, and visceral fat were obtained in experiments conducted on hereditary hypertriglyceridemic rats. After the blood glucose level had undergone a rapid change, the experimenter attempted to reach a steady blood glucose level by manually correcting the glucose infusion rate and maintaining a constant insulin infusion rate. The interstitial fluid glucose levels of subcutaneous tissue, skeletal muscle tissue, and visceral fat were evaluated to determine the reaction delay compared with the change in the blood glucose level, the interstitial fluid glucose level predictability, the blood capillary permeability, the effect of the concentration gradient, and the glucose utilization rate. Based on these data, the glucose transport rate across the capillary membrane and the utilization rate in a particular tissue were determined. The rates obtained were successfully verified against positron emission tomography experiments. The subcutaneous tissue exhibits the lowest and the most predictable glucose utilization rate, whereas the skeletal muscle tissue has the greatest glucose utilization rate. In contrast, the visceral fat is the least predictable and has the shortest reaction delay compared with the change in the blood glucose level. The reaction delays obtained for the subcutaneous tissue and skeletal muscle tissue were found to be approximately equal using a metric based on the time required to reach half of the increase in the interstitial fluid glucose level.

Resveratrol blunts the positive effects of exercise training on cardiovascular health in aged men

Ageing is thought to be associated with decreased vascular function partly due to oxidative stress. Resveratrol is a polyphenol, which in animal studies has been shown to decrease atherosclerosis, and improve cardiovascular health and physical capacity, in part through its effects on Sirtuin 1 signalling and through an improved antioxidant capacity. We tested the hypothesis that resveratrol supplementation enhances training-induced improvements in cardiovascular health parameters in aged men. Twenty-seven healthy physically inactive aged men (age: 65 ± 1 years; body mass index: 25.4 ± 0.7 kg m(-2); mean arterial pressure (MAP): 95.8 ± 2.2 mmHg; maximal oxygen uptake: 2488 ± 72 ml O2 min(-1)) were randomized into 8 weeks of either daily intake of either 250 mg trans-resveratrol (n = 14) or of placebo (n = 13) concomitant with high-intensity exercise training. Exercise training led to a 45% greater (P < 0.05) increase in maximal oxygen uptake in the placebo group than in the resveratrol group and to a decrease in MAP in the placebo group only (-4.8 ± 1.7 mmHg; P < 0.05). The interstitial level of vasodilator prostacyclin was lower in the resveratrol than in the placebo group after training (980 ± 90 vs. 1174 ± 121 pg ml(-1); P < 0.02) and muscle thromboxane synthase was higher in the resveratrol group after training (P < 0.05). Resveratrol administration also abolished the positive effects of exercise on low-density lipoprotein, total cholesterol/high-density lipoprotein ratio and triglyceride concentrations in blood (P < 0.05). Resveratrol did not alter the effect of exercise training on the atherosclerosis marker vascular cell adhesion molecule 1 (VCAM-1). Sirtuin 1 protein levels were not affected by resveratrol supplementation. These findings indicate that, whereas exercise training effectively improves several cardiovascular health parameters in aged men, concomitant resveratrol supplementation can blunt these effects.

Effect of annealing temperature and CuO on microstructure and optical band gap of CuxZn1−xO thin films

CuxZn1−xO thin films were prepared by the sol–gel process. Microstructure, surface topography and optical properties were studied by X-ray diffractometry, atom force microscopy, UV–Vis spectrophotometer and fluorescence spectrometer. The monoclinic CuO phase has been observed in CuxZn1−xO (x=0.05, 0.10, and 0.15) thin films annealed at 800°C. Preferential c-axis orientation of the CuxZn1−xO thin films annealed at 800°C increases with the increase of x value. The annealing temperature and CuO component have great effect on the absorption coefficient of CuxZn1−xO thin films in the visible region. The decrease of optical band gap may be attributed to the reduction of the fraction of the amorphous phase and stoichiometry deficiency of ZnO due to CuO doping. The deep level emission in ZnO thin film originates from oxygen vacancy and oxygen interstitial defects. The violet emission peaked at about 400nm has been assigned to the electron transition from zinc interstitial level and the valence band.

Sympathetic afferent stimulation inhibits central vagal activation induced by intravenous medetomidine in rats

To examine whether sympathetic afferent stimulation (SAS) inhibits central vagal activation induced by α2 -adrenergic stimulation. In anaesthetized Wistar-Kyoto rats, a cardiac microdialysis technique was applied to the left ventricle, and the effect of α2 -adrenergic stimulation by medetomidine on myocardial interstitial acetylcholine (ACh) levels was examined in the absence (n = 6) or the presence (n = 6) of SAS delivered from the left stellate ganglion. The effect of electrical vagal efferent stimulation on myocardial interstitial ACh release was also examined in the absence or the presence of SAS (n = 6). Intravenous medetomidine (0.1 mg kg(-1) ) significantly increased myocardial interstitial ACh levels in the absence of SAS (from 1.95 ± 0.79 to 3.36 ± 1.61 nM, P < 0.05), but not in the presence of SAS (from 1.67 ± 0.67 to 2.01 ± 0.78 nM). In contrast, electrical vagal nerve stimulation increased myocardial interstitial ACh level to the same degree regardless of SAS (from 1.66 ± 0.16 to 3.93 ± 0.72 nM without SAS vs. 4.05 ± 0.89 nM with SAS). Sympathetic afferent stimulation inhibited medetomidine-induced ACh release, but not electrical stimulation-induced ACh release, suggesting that SAS inhibited medetomidine-induced vagal activation via central mechanisms. While central vagal activation by α2 -adrenergic agonists could be an alternative to electrical vagal activation, blocking sympathetic afferent input may be important to increase the efficacy of α2 -adrenergic agonists in enhancing vagal nerve activity.

Neurotoxic amyloid beta oligomeric assemblies recreated in microfluidic platform with interstitial level of slow flow

Alzheimer's disease is accompanied by progressive, time-dependent changes of three moieties of amyloid beta. In vitro models therefore should provide same conditions for more physiologic studies. Here we observed changes in the number of fibrils over time and studied the correlation between amyloid beta moieties and neurotoxicity. Although the number of fibrils increased dramatically, the change in neurotoxicity with time was small, suggesting that fibrils make little contribution to neurotoxicity. To study the neurotoxicity of diffusible moieties by regulating microenvironments, we created a bio-mimetic microfluidic system generating spatial gradients of diffusible oligomeric assemblies and assessed their effects on cultured neurons. We found amyloid beta exposure produced an atrophy effect and observed neurite extension during the differentiation of neural progenitor cells increased when cells were cultured with continuous flow. The results demonstrate the potential neurotoxicity of oligomeric assemblies and establish a prospective microfluidic platform for studying the neurotoxicity of amyloid beta.

Influence of different growth environments on the luminescence properties of ZnO nanorods grown by the vapor–liquid–solid (VLS) method

ZnO nanorods (NRs) are grown in different atmospheres (argon, air, oxygen and nitrogen) by using the vapor–liquid–solid (VLS) method. The influence of different growth atmospheres on the luminescence properties has been investigated by using the photoluminescence (PL), cathodoluminescence (CL) and electroluminescence (EL) spectra measurements at room temperature. The PL spectra investigations reveal that the air, the oxygen and the nitrogen growth atmospheres have strongly affected the oxygen interstitial (Oi) and oxygen vacancy (VO) related deep level emission (DLE) bands in ZnO and this fact is also found consistent with the cathodoluminescence (CL) and electroluminescence (EL) spectra investigations. The color rendering investigations reveal that the growth atmospheres have also influenced the color quality of the emitted light. These results indicate that the defects related emissions from the band gap of ZnO NRs can be tuned by using different growth atmospheres. These results can be useful for the development of white light emitting diodes (WLEDs).

An integrated microfluidic device for characterizing chondrocyte metabolism in response to distinct levels of fluid flow stimulus

In this work, we presented a novel integrated microfluidic perfusion system to generate multiple parameter fluid flow-induced shear stresses simultaneously and investigated the effects of distinct levels of fluid flow stimulus on the responses of chondrocytes, including the changes of morphology and metabolism. Based on the electric circuit analogy, two devices were fabricated, each with four chambers to enable eight different shear stresses spanning over four orders of magnitude from 0.007 to 15.4 dyne/cm2 with computational fluid dynamics analysis. Chondrocytes subjected to shear stresses (7.5 and 15.4 dyne/cm2) for 24 h reoriented their cytoskeleton to align with the direction of flow. Meanwhile, the collagen I, collagen II and aggrecan expression of chondrocytes increased in different ranges, respectively. Furthermore, interleukin-6 as a proinflammatory cytokine can be detected at shear stress of 7.5 and 15.4 dyne/cm2 in mRNA level. These results indicated that fluid flow was beneficial for chondrocyte metabolism at interstitial levels (0.007 and 0.046 dyne/cm2), but induced an increase in fibrocartilage phenotype with increasing magnitude of stimulation. Moreover, a moderate level of flow stimulus (7.5 dyne/cm2) could also result in detrimental cytokine release. This work described a simple and versatile way to rapidly screen cell responses to fluid flow stimulus from interstitial shear stress level to pathological level, providing multi-condition fluid flow-induced microenvironment in vitro for understanding deeply chondrocyte metabolism, cartilage reconstruction and osteoarthritis etiology.

Effect of dietary protein on post‐prandial glucose in patients with type 1 diabetes

In flexible insulin therapy, determination of the prandial insulin dose only takes into account the carbohydrate content of the evening meal, and not the protein content. Protein can, however, contribute to gluconeogenesis. We compared the glycaemic effect of a standard evening meal with that of a test evening meal enriched in protein. The present study was conducted in 28 C-peptide negative patients with type 1 diabetes. Two evening meals that were similar in content, except that one was enriched by the addition of 300g of 0%-fat fromage frais, were taken on two consecutive days. Insulin doses were maintained exactly the same before both evening meals. Patients were monitored with a continuous glucose-monitoring device. Patients ate similar quantities at both evening meals, except for protein (21.5g more at the test evening meal). The preprandial insulin dose was 0.96(0.4)U per 10g carbohydrates. After correction for differences of interstitial glucose at the start of the evening meals, both interstitial and capillary glucose levels were similar after both evening meals, except for the late-post-prandial interstitial glucose level. We found no effect of dietary protein on post-prandial-, overnight- or late-night glucose levels in patients with type 1 diabetes. This confirms that dietary proteins need not be included in the calculation of prandial insulin dose.

New Insights into Mechanisms of Cardioprotection Mediated by Thyroid Hormones

Heart failure represents the final common outcome in cardiovascular diseases. Despite significant therapeutic advances, morbidity and mortality of heart failure remain unacceptably high. Heart failure is preceded and sustained by a process of structural remodeling of the entire cardiac tissue architecture. Prevention or limitation of cardiac remodeling in the early stages of the process is a crucial step in order to ameliorate patient prognosis. Acquisition of novel pathophysiological mechanisms of cardiac remodeling is therefore required to develop more efficacious therapeutic strategies. Among all neuroendocrine systems, thyroid hormone seems to play a major homeostatic role in cardiovascular system. In these years, accumulating evidence shows that the “low triiodothyronine” syndrome is a strong prognostic, independent predictor of death in patients affected by both acute and chronic heart disease. In experimental models of cardiac hypertrophy or myocardial infarction, alterations in the thyroid hormone signaling, concerning cardiac mitochondrion, cardiac interstitium, and vasculature, have been suggested to be related to heart dysfunction. The aim of this brief paper is to highlight new developments in understanding the cardioprotective role of thyroid hormone in reverting regulatory networks involved in adverse cardiac remodeling. Furthermore, new recent advances on the role of specific miRNAs in thyroid hormone regulation at mitochondrion and interstitial level are also discussed.

ZnSe/ZnSe:Ag Nanoparticles: Synthesis, Characterizations, Optical and Raman Studies

Nanoparticles (NPs), grown in liquid media, stand out over other classes of inorganic nanomaterials due to the high degree of control with which their crystal structure, size, shape, and surface functionalities can be engineered in the synthesis stage and to the versatility with which they can be processed and implemented into a large spectrum of devices and processes. In present work pure and Ag-doped ZnSe NPs were successfully synthesized from the solution phase chemistry and investigated with respect to their structural and optical properties. The resulting powder consists of nanocrystalline particles were characterized by X-ray diffraction (XRD), UV-Visible spectroscopy, photoluminescence spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX) techniques and Raman spectroscopy. A UV emission peak was observed from the excitons transition at 380 nm in the room temperature photo luminescent (PL) spectra. The blue emission band was assigned to the Zn interstitial and vacancy level transition. Even though Ag ions known to act as an efficient non-radiative loss center for near band gap emission (NBE), a decreased NBE is obtained at room temperature even for a nominal Ag concentration. XRD data analysis shows that the Ag dopant atoms are incorporated into the cubic ZnSe host lattice.

In Vivo Noninvasive Monitoring of Glucose Concentration in Human Epidermis by Mid-Infrared Pulsed Photoacoustic Spectroscopy

The noninvasive determination of glucose in the interstitial layer of the human skin by mid-infrared spectroscopy is reported. The sensitivity for this measurement was obtained by combining the high pulse energy from an external cavity quantum cascade laser (EC-QCL) tunable in the infrared glucose fingerprint region (1000-1220 cm(-1)) focused on the skin, with a detection of the absorbance process by photoacoustic spectroscopy in the ultrasound region performed by a gas cell coupled to the skin. This combination facilitates a quantitative measurement for concentrations of skin glucose in the range from <50 mg/dL to >300 mg/dL, which is the relevant range for the glucose monitoring in diabetes patients. Since the interstitial fluid glucose level is representative of the blood glucose level and follows it without significant delay (<10 min), this method could be applied to establish a noninvasive, painless glucose measurement procedure that is urgently awaited by diabetes patients. We report here the design of the photoacoustic experiments, the spectroscopy of glucose in vivo, and the calibration method for the quantitative determination of glucose in skin. Finally, a preliminary test with healthy volunteers and volunteers suffering from diabetes mellitus demonstrates the viability of a noninvasive glucose monitoring for patients based on the combination of infrared QCL and photoacoustic detection.

Moving from a Cytotoxic to a Cytokinic Approach in the Blood Purification Labyrinth: Have We Finally Found Ariadne’s Thread?

For almost three decades, researchers have invested in strategies that involved removal of excess inflammatory mediators from the circulation (that is, the "cytotoxic" approach). Blood purification techniques using an extracorporeal device can indeed non-specifically remove a wide array of inflammatory mediators from the circulation. In animal models, this multimediator targeting or pleiotropic approach was shown to downregulate systemic inflammation and to restore immune homeostasis. In this issue, Namas et al. seriously challenge this cytotoxic hypothesis and propose to replace it by a cytokinic approach. In a rodent model of sepsis, these authors elegantly demonstrate that hemoadsorption using a large surface-area polymer could reduce and, more importantly, relocalize and reprogram sepsis-induced acute inflammation, while simultaneously lowering infectious burden and liver damage. Although challenging, this new theory can be considered complementary to the existing cytotoxic hypotheses by coupling reduced endothelial damage at the interstitial level (cytotoxic approach) with the concept of reprogramming leucocytes and mediators toward infected tissue, thus emptying the bloodstream of important promoters of remote organ damages (cytokinic approach).

Abstract 144: Interstitial Formation of Adenosine and Inosine Is Proarrhythmic Through Adenosine A1 Receptor in the Developing Heart

We previously established that exogenous adenosine (ADO) induces transient arrhythmias in the developing heart via the ADO A1 receptor (A1AR) and downstream activation of NADPH oxidase/ERK and PLC/PKC pathways. We assessed the hypothesis that both endogenous ADO and its derived compound inosine (INO) can simultaneously act in an autocrine/paracrine manner and induce rhythm and conduction disturbances. The validated model of the spontaneously beating heart obtained from 4-day-old chick embryos was used. The basal ADO/INO ratio determined by HPLC was approximately 10. Blockade of Equilibrative Nucleoside Transporters (ENTs) by dipyridamole, which is known to increase interstitial ADO level, induced transient atrial dysrhythmias and atrio-ventricular blocks in 70% of the hearts (n=30) and, in parallel, increased ERK2 phosphorylation. When extracellular conversion of AMP to ADO by ecto-5’-nucleotidase/CD73 was inhibited by AOPCP, the dipyridamole-induced arrhythmias were prevented. The dipyridamole-induced arrhythmias and ERK2 phosphorylation were prevented by the specific antagonist of the A1AR (DPCPX) but not by antagonists of A2AAR ( SCH58261 ), A2BAR (MRS1754) or A3AR (MRS1523). Interestingly, inhibition by EHNA of the conversion of ADO to INO by adenosine deaminase was not proarrhythmic whereas exogenous INO (500 µM) induced arrhythmias which were prevented by DPCPX. In conclusion, these findings suggest that endogenous ADO and INO in the interstitial compartment of the developing heart can provoke transient pacemaking and conduction disturbances via A1AR and downstream ERK activation in an autocrine/paracrine manner. Overall, our results provide new insights into the mechanisms underlying cardiac dysfunction when a hypoxic-ischemic episode induces local overproduction of ADO and INO

Recirculation usually precedes malignant edema in middle cerebral artery infarcts

In patients with large middle cerebral artery (MCA) infarcts, maximum brain swelling leading to cerebral herniation and death usually occurs 2-5days after onset of stroke. The study aimed at exploring the pattern of compounds related to cerebral energy metabolism in infarcted brain tissue. Forty-four patients with malignant MCA infarcts were included after decision to perform decompressive hemicraniectomy (DHC). Cerebral energy metabolism was in all patients monitored bedside by 1-3 microdialysis catheters inserted into the infarcted hemisphere during DHC. In 29 of the patients, one microdialysis catheter was also placed in the non-infarcted hemisphere. MCA blood-flow velocity was monitored bilaterally by transcranial Doppler ultrasound. The interstitial glucose levels were in both sides within normal limits throughout the monitoring period. Mean lactate/pyruvate (LP) ratio was very high in infarcted tissue immediately after DHC. The ratio slowly decreased but did not reach normal level during the study period. In the infarcted hemisphere, MCA blood-flow velocities increased from approximately 42cm/s 1day prior to DHC (nine of nine patients) to approximately 60cm/s at day 4. Normal interstitial glucose level in the infarcted hemisphere in combination with substantial MCA blood-flow velocities bilaterally even before DHC was performed indicates that malignant brain swelling usually commences when the embolus/thrombosis has been largely resolved and recirculation of the infarcted area has started. The protracted increase of the LP ratio in infarcted tissue might indicate mitochondrial dysfunction.

Effect of Cu ions on the morphology, structure and luminescence properties of ZnO nanorod arrays prepared by hydrothermal method

Well-aligned ZnO nanorod arrays with different average diameters were grown by hydrothermal method in the presence of Cu ions in the deposition solution. Cu ions significantly inhibit diameter growth of ZnO nanorods and influence the luminescence properties. Quantitative analyses reveal that Cu ions were not incorporated into the synthesized nanorods. Photoluminescence spectra show that a weak ultraviolet emission and a strongly broad visible emission band in yellow region under ultraviolet light excitation for as-grown ZnO nanorods. The intensity of yellow emission bands decreases with Cu ions concentration increasing and the peak position has a blue-shift after low temperature thermal treatment. Photoluminescence spectra under different excitation energies and photoluminescence excitation spectra reveal that the yellow emission bands and green (blue) emission bands are associated with zinc interstitial related shallow donor level and oxygen vacancies related deep donor level as initial states, respectively. A plausible growth mechanism has been proposed to explain the narrowed diameter for ZnO nanorods in the presence of Cu ions based on crystallographic habits of wurtzite hexagonal.