Layered Fabrication of Branched Networks Using Lindenmayer Systems

A current challenge impeding the growth of bone tissue engineering is the lack of functional scaffolds of geometric sizes greater than 10mm due to the inability of cells to survive deep within the scaffold. It is hypothesized that these scaffolds must have an inbuilt nutrient distribution network to sustain the uniform growth of cells. In this paper, we seek to enhance the design and layered fabrication of scaffold internal architecture through the development of Lindenmayer systems, a graphical language based theory to create nutrient delivery networks. The scaffolds are fabricated using the Texas Instruments DLP™ system through UV‐photopolymerization to produce polyethylene glycol hydrogels with internal branch structures. The paper will discuss the Lindenmayer system, process planning algorithms, layered fabrication of samples, challenges and future tasks.Mechanical Engineerin

Relationship between antihypertensive medications and cognitive impairment: Part II. Review of Physiology and animal studies

Purpose of Review There is an established association between hypertension and increased risk of poor cognitive performance and dementia including Alzheimer’s disease; however, associations between antihypertensive medications (AHM) and dementia risk are less clear. An increased interest in AHM has resulted in expanding publications; however, none of the recent reviews provide comprehensive review. Our extensive review includes 24 mechanistic animal and human studies published over the last 5 years assessing relationship between AHM and cognitive function. Recent Findings All classes of AHM showed similar result patterns in animal studies. The mechanism by which AHM exert their effect was extensively studied by evaluating well-established pathways of AD disease process, including amyloid beta (Aβ), vascular, oxidative stress and inflammation pathways, but only few studies evaluated the blood pressure lowering effect on the AD disease process. Summary Methodological limitations of the studies prevent comprehensive conclusions prior to further work evaluating AHM in animals and larger human observational studies, and selecting those with promising results for future RCTs

A novel single-chip RF-voltage-controlled oscillator for bio-sensing applications

A novel interdigiated capacitance (IDC) based affinity biosensor system is presented that detects C-Reactive Protein (CRP), a risk marker for cardiovascular diseases, and transmit the information to a distance location wirelessly. The biosensor system consist of a voltage controlled oscillator (VCO) and an IDC. In the presence of CRP the capacitance of the IDC changes and this directly reflects to the oscillation frequency of the VCO. In the presence of 800 ng/ml antigen the frequency of the system shifts from 1.9438 GHz to 1.94175 GHz and with 64 ug/ml frequency shifts from 1.95975 GHz to 1.94875 GHz with -120 dBc/Hz phase noise

Relationship between antihypertensive medications and cognitive impairment: Part I. review of human studies and clinical trials

Purpose of review: There is an established association between hypertension and increased risk of poor cognitive performance and dementia including Alzheimer’s disease; however, associations between antihypertensive medications (AHMs) and dementia risk are less consistent. An increased interest in AHM has resulted in expanding publications; however, none of the recent reviews are comprehensive. Our extensive review includes 15 observational and randomized controlled trials (RCTs) published over the last 5 years, assessing the relationship between AHM and cognitive impairment. Recent findings: All classes of AHM showed similar result patterns in human studies with the majority of study results reporting point estimates below one and only a small number of studies (N = 15) reporting statistically significant results in favor of a specific class. Summary: Only a small number of studies reported statistically significant results in favor of a specific class of AHM. Methodological limitations of the studies prevent definitive conclusions. Further work is now needed to evaluate the class of AHM and cognitive outcomes in future RCTs, with a particular focus on the drugs with the promising results in both animals and human observational studies

Infrared luminescence of annealed germanosilicate layers

Cataloged from PDF version of article.In the light of growing importance of semiconductor nanocrystals for photonics, we report on the growth and characterization of annealed germanosilicate layers used for Ge nanocrystal formation. The films are grown using plasma enhanced chemical vapor deposition (PECVD) and post-annealed in nitrogen at temperatures between 600 and 1200 degrees C for as long as 2 h. Transmission electron microscopy (TEM), Raman scattering and photoluminescence spectroscopy (PL) has been used to characterize the samples both structurally and optically. Formation of Ge precipitates in the germanosilicate layers have been observed using Raman spectroscopy for a variety of PECVD growth parameters, annealing temperatures and times. Ge-Ge mode at similar to 300 cm(-1) is clearly observed at temperatures as low as 700 degrees C for annealing durations for 45 min. Raman results indicate that upon annealing for extended periods of time at temperatures above 900 degrees C; nanocrystals of few tens of nanometers in diameter inside the oxide matrix and precipitation and interdiffusion of Ge, forming SiGe alloy at the silicon and oxide interface take place. Low temperature PL spectroscopy has been used to observe luminescence from these samples in the vicinity of 1550 nm, an important wavelength for telecommunications. Observed luminescence quenches at 140 K. The photoluminescence data displays three peaks closely interrelated at approximately 1490,, 1530 and 1610 nm. PL spectra persist even after removing the oxide layer indicating that the origin of the infrared luminescent centers are not related to the Ge nanocrystals in the oxide layer. (C) 2013 Elsevier B.V. All rights reserved

A non-destructive technique for the on-line quality control of green and baked anodes

Carbon anodes play an important role in the electrolytic production of aluminum. They have a significant economic and environmental impact. Carbon anodes are made of dry aggregates, composed of petroleum coke, recycled rejects, and butts, bound by coal tar pitch. Due to several factors, defects (cracks/pores) appear in anodes during the fabrication process, affecting their quality. It is thus essential to control the quality of anodes before their use in the electrolysis cell. Current practice for the quality evaluation (visual inspection, core analysis) gives limited information. As an alternative to this practice, electrical resistivity measurements can be used. Electrical resistivity is one of the key indicators for anode quality and its homogeneity. A simple and non-destructive method has been developed for the specific electrical resistivity measurement of anodes (SERMA) for on-line control of anode quality. Various tests have been carried out at both lab scale and industrial scale. In this study, the electrical resistivity distributions in the lab-scale anodes were measured and compared with those of the tomography analysis. The method is able to detect defective anodes even before the baking process

Effects of combined general anesthesia and thoracic epidural analgesia on cytokine response in patients undergoing laparoscopic cholecystectomy

Background: Severe postoperative pain is not often experienced in laparoscopic cholecystectomy. Anesthesia, surgery, and pain are stressful and cause different reactions in neuro‑immuno‑endocrine systems. Many factors such as the pharmacological effect of the drugs used, as well as the type and depth of anesthesia, can affect these reactions.Objective: The aim of this study was to evaluate the effect of the combination of general anesthesia and thoracic epidural analgesia (TEA) on cytokine reaction in laparoscopic cholecystectomy.Study Design: Prospective, randomized clinical comparative study.Materials and Methods: Sixty adult patients scheduled for elective laparoscopic cholecystectomy were divided into four groups. Group saline (Group S), group fentanyl (Group F), group bupivacaine (Group B), and group levobupivacaine (Group L) were infused with saline, saline and fentanyl, bupivacaine and fentanyl, and levobupivacaine and fentanyl, respectively, via epidural catheter before surgical incision.Results: There were no differences among groups in the demographic features, heart rate, mean arterial pressure, and peripheral oxygen saturation values. Group L had lower visual analogue scale value compared to the other postoperative groups (P < 0.01). In all groups, interleukin‑6 (IL‑6), IL‑8, and IL‑10 levels started to increase at 2 h and returned to the basal level at 24 h. IL levels increased in most of the epidural saline‑administered group compared to other groups (P < 0.05).Conclusion: Combined general anesthesia and TEA provided pain control and hemodynamic stability more efficiently during the first 24 h of the intraoperative and postoperative period by suppressing cytokine levels. However, we determined that this effect was more obvious with the local anesthetic and opioid combination.Keywords: Bupivacaine, combined‑general‑epidural anesthesia, inflammatory cytokines, laparoscopic cholecystectomy, levobupivacain

The effect of CoQ10 and vitamin E on serum total sialic acid, lipid-bound sialic acid, some trace elements and minerals in rats induced with doxorubicin

This study was designed to evaluate the effect of CoQ10 and vitamin E on serum total sialic acid (TSA), lipid bound sialic acid (LSA) and some elements in rat administered doxorubicin (DXR). Cu levels were increased in the group treated with DXR + vitamin E in comparison with DXR (p<0.05) and CoQ10 groups (p = 0.001). Furthermore, copper levels were increased in the group treated with DXR + CoQ10 in comparison with CoQ10 group (p < 0.05). Zn levels were decreased in the group treated with DXR + vitamin E in comparison with CoQ10 group (p < 0.05). Mg levels were decreased in subjects treated with DXR + vitamin E in comparison with the control group values (p < 0.05). Particularly, the observed increase in Cu levels in rats from DXR + vitamin E group might be due to the decrease of vitamin E. However, the oxidative damage could be as a result of DXR occurence and may be helpful to clinicians in chemotherapy using anthracycline.Key words: Doxorubicin, total sialic acid (TSA), lipid bound sialic acid (LSA), trace elements, minerals

A new nanocrystalline diamond-based biosensor for the detection of cardiovascular risk markers

In this paper, a new method to probe associative interactions of C-reactive protein (CRP) antigen with CRP antibody immobilized on a gold-interdigitated diamond electrodes was investigated. The CRP antigen detection was performed by capacitive/dielectric-constant measurements. Our results showed that the dynamic detection range using optimized conditions for a given antibody concentration (100 μg/ml) was found to be in the range 25-800 ng/ml of CRP-antigen. Biosensor developed in this study can be potentially used for detection of elevated CRP levels in suspected subjects for early diagnosis