Long-term vascular access ports as a means of sedative administration in a rodent fMRI survival model

The purpose of this study is to develop a rodent functional magnetic resonance imaging (fMRI) survival model with the use of heparin-coated vascular access devices. Such a model would ease the administration of sedative agents, reduce the number of animals required in survival experiments and eliminate animal-to-animal variability seen in previous designs. Seven male Sprague-Dawley rats underwent surgical placement of an MRI-compatible vascular access port, followed by implantable electrode placement on the right median nerve. Functional MRI during nerve stimulation and resting-state functional connectivity MRI (fcMRI) were performed at times 0, 2, 4, 8 and 12 weeks postoperatively using a 9.4 T scanner. Anesthesia was maintained using intravenous dexmedetomidine and reversed using atipamezole. There were no fatalities or infectious complications during this study. All vascular access ports remained patent. Blood oxygen level dependent (BOLD) activation by electrical stimulation of the median nerve using implanted electrodes was seen within the forelimb sensory region (S1FL) for all animals at all time points. The number of activated voxels decreased at time points 4 and 8 weeks, returning to a normal level at 12 weeks, which is attributed to scar tissue formation and resolution around the embedded electrode. The applications of this experiment extend far beyond the scope of peripheral nerve experimentation. These vascular access ports can be applied to any survival MRI study requiring repeated medication administration, intravenous contrast, or blood sampling

CHEMO-PROTECTIVE EFFECT ON HEPATO-RENAL TOXCICITY AND CYTOTOXIC ACTIVITY OF LIPOIDAL MATTER OF ATRIPLEX LINDLEYI MOQ

Objective: Bromobenzene (BB) is frequently encountered in table-ready foods as contaminant residues. Therefore, the present study is designed to evaluate the petroleum ether extract of Atriplex lindleyi to attenuate the hepato-renal injury induced by BB exposure and study its cytotoxic activity against different human cell line as well as to describe the chemical composition of the petroleum ether extract. Methods: The phytochemical study of petroleum ether extract was implemented using both GC/MS and column chromatography analysis. The isolated compounds were identified using different spectroscopic analysis. Hepato-renal assay, rats were intraperitonealy injected bromobenzene at a dose 460 mg/kg BW. The petroleum ether extract as well as Hepaticum were administrated orally twice a week for three consecutive weeks with a dose 150 & 100 mg/kg body weight, respectively. Liver marker enzymes, liver function indices and kidney function tests were estimated. The cytotoxic activity of, petroleum ether extract was assessed by the mitochondrial dependent reduction of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide). Results: Forty two compounds as well as sixteen fatty acids were identified in unsaponifiable and saponifiable fractions, respectively. Unsaponifiable fraction constituted of hydrocarbons (73.39% of total unsaponifiable matter), alcoholic (0.88%) and steroidal compounds (2.22%). Furthermore, column chromatography of petroleum ether extract afforded nonsterol tritrepenoids; olean-12-en-3,11-dione (1), β-amyrenone (2), erythrodiol I (3), Lupeol (4) as well as sterol triterpenoids; cholesterol (5) and mixture of β-sitosterol and stigmasterol (6). Compounds 1, 3 and 5 are first reported from Atriplex lindleyi. In addition, GC/MS analysis of the main fraction isolated from column chromatography revealed phytol as a major component. Drastic changes were observed after BB intoxication in liver function parameters; kidney disorder indices and certain oxidative stress markers. Treatment with petroleum ether extract improved all biochemical parameters under investigation as well as the histopathology of liver and kidney. Petroleum ether extract showed growth inhibition of HepG2 and MCF7 human cells by 44.8 and 29.9%, respectively at 100 µg/ml. Conclusion: The petroleum ether extract of A. lindleyi contains bioactive compounds exhibiting hepato-renal protection and cytotoxic activity

Improved Animal Model for Vibration Injury Study

Hand-Arm Vibration Syndrome is a debilitating condition that affects millions of power-tool users in the  U.S. Research into its etiology has been hampered by deficiencies in animal models used for vibration studies.  Our objective was to design an animal vibration injury model that: 1) vibrates only the studied limb, not  the body; and 2) avoids anaesthesia, thus allowing purer focus on physiological effects of vibration while  reducing pain and distress for the animals, thereby enhancing their well-being. We compared advantages  and disadvantages of several models, studying body temperature, body weight, tissue perfusion, vascular  pathohistology, and general animal condition. Our model uses an apparatus that limits vibration to one  body part and a specially designed cage that minimizes animal stress and suffering, eliminating the need for  anaesthesia. It is ideal for the study of vibration injury, providing tissue damaged purely by vibration that  can be used for pathohistology and biochemical study.

Converse mode piezoelectric coefficient for lead zirconate titanate thin film with interdigitated electrode

The use of interdigitated electrodes (IDEs) in conjunction with ferroelectric thin films shows many attractive features for piezoelectric MEMS applications. In this work, growth of {1 0 0}-textured lead zirconate titanate (PZT) thin films was achieved on insulating MgO buffered, oxidized silicon substrates. IDEs were fabricated by lift-off techniques and cantilevers were formed by dicing. The deflection upon application of a sweeping voltage was measured as large signal response in parallel to the ferroelectric polarization (PV loop). Likewise, the small signal piezoelectric response was measured in parallel to the capacitance-voltage (CV) measurement. In this way, a complete picture of the ferroelectric-piezoelectric element was obtained. From the deflection, the in-plane piezoelectric stress in the PZT thin film was derived and, from this, the effective piezoelectric coefficients. For the latter, two types were defined: an engineering type corresponding to the average value along the IDE, which can directly be compared to coefficient of a parallel plate electrode (PPE) capacitor and a second one that approximately yields the idealized coefficient governing between the electrode fingers. The IDE structures were experimentally compared with PPE structures of identical film thickness. The resulting coefficients were of opposite sign, as expected. In spite of a much better polarization loop, the IDE device showed a lower average piezoelectric stress. The estimated peak value between the fingers was about the same as in the PPE device, corresponding to about 20 C m(-2). Nevertheless, the result is very promising for cases where compressive piezoelectric stresses are required and for preventing cracking due to large piezoelectric tensile stresses in PPE systems

Complex reconstructions in head and neck cancer surgery: decision making

Defects in head and neck after tumor resection often provide significant functional and cosmetic deformity. The challenge for reconstruction is not only the aesthetic result, but the functional repair. Cancer may involve composite elements and the in sano resection may lead to an extensive tissue defect. No prospective randomized controlled studies for comparison of different free flaps are available. There are many options to cover defects and restore function in the head and neck area, however we conclude from experience that nearly all defects in head and neck can be closed by 5 different free flaps: radial forearm flap, free fibula flap, anterior lateral thigh flap, lateral arm flap and parascapular flap

Innovative steel I-girder under bending having hollow tubular flanges

Hollow tubular flange girders (HTFG) overcome the weakness of the conventional I-sections to resist the lateral buckling. This leads to higher capacity, resulting in fewer steel quantities and reducing the carbon emissions from the steel industry. This paper presents a numerical analysis to investigate the behavior of HTFG under bending and validate the AISC design equations. The gain of the bending capacity is found similar in different flange classes but decreases with the reduction of the web class. The capacity for the compact section is higher than the yielding moment, but the section could not be fully yielded. The AISC in slender web is very conservative, unlike for non-compact web. Adjustments of the plastic limit and adaptation in terms of torsion constant are proposed, and the results show good agreement. The reduction of the embodied carbon caused by the material saving after using HTFG is calculated for a case study