FR System Research Articles

An anticancer agent, pyrvinium pamoate inhibits the NADH–fumarate reductase system—a unique mitochondrial energy metabolism in tumour microenvironments

Increased glycolysis is the principal explanation for how cancer cells generate energy in the absence of oxygen. However, in actual human tumour microenvironments, hypoxia is often associated with hypoglycemia because of the poor blood supply. Therefore, glycolysis cannot be the sole mechanism for the maintenance of the energy status in cancers. To understand energy metabolism in cancer cells under hypoxia-hypoglycemic conditions mimicking the tumour microenvironments, we examined the NADH-fumarate reductase (NADH-FR) system, which functions in parasites under hypoxic condition, as a candidate mechanism. In human cancer cells (DLD-1, Panc-1 and HepG2) cultured under hypoxic-hypoglycemic conditions, NADH-FR activity, which is composed of the activities of complex I (NADH-ubiquinone reductase) and the reverse reaction of complex II (quinol-FR), increased, whereas NADH-oxidase activity decreased. Pyrvinium pamoate (PP), which is an anthelmintic and has an anti-cancer effect within tumour-mimicking microenvironments, inhibited NADH-FR activities in both parasites and mammalian mitochondria. Moreover, PP increased the activity of complex II (succinate-ubiquinone reductase) in mitochondria from human cancer cells cultured under normoxia-normoglycemic conditions but not under hypoxia-hypoglycemic conditions. These results indicate that the NADH-FR system may be important for maintaining mitochondrial energy production in tumour microenvironments and suggest its potential use as a novel therapeutic target.

DWT Feature Extraction Based Face Recognition using Intensity Mapped Unsharp Masking and Laplacian of Gaussian Filtering with Scalar Multiplier

Face recognition under varying illumination and poses at certain angles is challenging, and hence improved edge prominence and contrast enhancement techniques are an effective approach to solve this problem. This paper proposes two novel techniques, namely, Intensity Mapped Unsharp Masking (IMUM) which provides a much finer outline of the face image by reducing the background intensity, and Laplacian of Gaussian based filtering with Scalar Multiplier (LOGSM) which provides an improved edge detection. Individual stages of the FR System are examined and an attempt is made to improve each stage. A Binary Particle Swarm Optimization (BPSO) based feature selection algorithm is used to search the feature vector space for the optimal feature subset. Experimental results, obtained by applying the proposed algorithm on ORL, UMIST, Extended YaleB, ColorFERET face databases, show that the proposed system outperforms other FR systems. A significant increase in the overall recognition rate and a substantial reduction in the selected features are observed.

Qualitative comparison of coronary angiograms between 4 french catheters with an Advanced Cardiovascular Injection System and 6 french catheters with manual injection

This study aimed to test whether advanced cardiovascular injection (ACI) via 4 French (Fr) catheters is more advantageous than manual injection with 6 Fr catheters. For coronary angiography, proponents of contrast media ACI believe it utilizes smaller-diameter catheters when compared with manual injection, without compromising the quality of the angiogram, and has the potential to reduce the amount of contrast used and lessen the use of closure devices. In a prospective study, 200 consecutive patients referred for elective coronary angiography were randomized to standard 6 Fr catheters with manual injection versus 4 Fr catheters with ACI. The study's primary endpoint is the quality of the coronary angiogram. Secondary endpoints include groin complications, utilization of closure devices, and volume of contrast media. Thirty-six patients who underwent ad hoc percutaneous coronary intervention were excluded from the analysis. The final analysis included 80 patients treated with 4 Fr catheters with ACI and 84 patients treated with 6 Fr catheters with manual injection. The groups had similar demographic and clinical characteristics. The quality of the angiogram was similar between groups with the exception of more left coronary sinus flush with 4 Fr catheters (3.57 ± 1.1 vs. 2.98 ± 0.9, P < 0.001) and less closure device use with 4 Fr (25 vs. 71.4%, P < 0.01) compared to 6 Fr catheters. The procedure duration, volume of contrast used, vascular complications, and time to ambulation were similar between groups (all P > 0.05). 4 Fr diagnostic catheters with ACI offer similar quality coronary angiograms, similar rates of vascular complications, procedure duration, contrast used, and time to ambulation, but have a significantly lesser need for closure devices compared to the 6 Fr system with manual injection.

Zinc‐based compounds as smoke suppressant agents for an aerospace epoxy matrix

AbstractSmoke is considered to be the main hazard of fires involving epoxy resins but its production depends on many variables, principally the chemical character and the burning rate of the polymer plus the availability of oxygen. The work reported aimed to study the smoke suppressant effect and flammability performance of zinc‐based compounds (FR system) in epoxy matrix composites used in the aerospace and aeronautical industry. The flammability performance of neat and FR‐loaded systems was screened using microcombustion calorimetry, while smoke generation, in terms of carbon monoxide (CO) and carbon dioxide (CO2) production, was analysed under dynamic conditions using cone calorimetry. Final results indicate that the dispersion of zinc borate and zinc hydroxystannate (ZHS) into epoxy matrices leads to a significant variation in flame retardant properties reducing both total heat release by about 25 and 30%, respectively, and heat release capacity by about 30 and 50%, respectively. The system containing ZHS shows an enhancement in all smoke suppressant properties; both tin compounds (zinc stannate (ZS) and ZHS) give a reduction of CO2/CO ratio from 41 to 25 for ZS and from 41 to 36 for ZHS compared to neat matrix. Copyright © 2010 Society of Chemical Industry

An approach to recognize interacting features from B-Rep CAD models of prismatic machined parts using a hybrid (graph and rule based) technique

This paper presents a new hybrid (graph + rule based) approach for recognizing the interacting features from B-Rep CAD models of prismatic machined parts. The developed algorithm considers variable topology features and handles both adjacent and volumetric feature interactions to provide a single interpretation for the latter. The input CAD part model in B-Rep format is preprocessed to create the adjacency graphs for faces and features of associated topological entities and compute their attributes. The developed FR system initially recognizes all varieties of the simple and stepped holes with flat and conical bottoms from the feature graphs. A new concept of Base Explicit Feature Graphs and No-base Explicit Feature Graphs has been proposed which essentially delineates between features having planar base face like pockets, blind slots, etc. and those without planar base faces like passages, 3D features, conical bottom features, etc. Based on the structure of the explicit feature graphs, geometric reasoning rules are formulated to recognize the interacting feature types. Extracted data has been post-processed to compute the feature attributes and their parent–child relationships which are written into a STEP like native feature file format. The FR system was extensively tested with several standard benchmark components and was found to be robust and consistent. The extracted feature file can be used for integration with various downstream applications like CAPP.

New Developments in Flow-Through Apparatus for Measurement of Adsorption Mass-Transfer Rates by Frequency Response Method

A new flow-through frequency response method based on a sinusoidal modulation of pressure is developed to measure gas adsorption equilibria and kinetics simultaneously. The transfer phenomena of pure N2 and O2 gases in carbon molecular sieve are investigated for different pressures and particle sizes by this method. Also, this apparatus has been extended to measure data for mixtures at different compositions at atmospheric pressure and room temperature. This is the first application of the flow FR system for a mixture. A negative cross-term diffusivity is reported. It shows that for co-diffusion, the fast diffusing molecule O2 is decelerated by the slow diffusing molecule N2, and the slower moving molecule N2 is sped up by the faster moving O2. The main-term diffusivities agree with the pure component diffusivities.

Comparison of 6 and 7 French guiding catheters for percutaneous coronary intervention: Results of a randomised trial with a vascular ultrasound endpoint

To perform a randomized, ultrasound controlled trial to define the procedural and clinical advantages and limitations of 6 French (Fr) compared with 7 Fr transfemoral coronary intervention in the stenting era. The use of 7 Fr guiding catheters may facilitate Percutaneous Coronary Intervention (PCI), but may be associated with increased vascular complications when compared with 6 Fr catheters. Patients undergoing PCI considered suitable for either a 6 or 7 Fr sheath and guiding catheter system were included. All vascular sheaths were removed with assisted manual compression. Femoral vascular ultrasounds were performed prior to hospital discharge and interpreted by a vascular surgeon blinded to treatment assignment. The primary endpoint was a composite of significant vascular complications including major haematoma, retroperitoneal haematoma, pseudoaneurysm, arterio-venous fistula, or femoral venous or arterial thrombosis. During the study, 414 patients (mean age 61+/-11 years, 27% females) were randomly assigned to 6 Fr or 7 Fr sheath groups. The incidence of major vascular complications was 5.7% in the 6 Fr group and 3.9% in the 7 Fr group (P=0.383). There was no significant difference in procedural or angiographic success between the groups. The use of contrast volume was higher in the 7 Fr group (157+/-58 ml vs. 144+/-58 ml; P=0.029). There was a trend toward better operator satisfaction with the 7 Fr guide (P=0.08). This prospective, randomized trial indicates no reduction in major peripheral vascular complications with the use of smaller guiding catheters in PCI. There was less contrast used in the 6 Fr group, which may benefit some patient subsets, however operators tended to prefer the larger 7 Fr system. The target coronary anatomy and need for complex device intervention should mandate the choice of guiding catheter size, not a perceived impact on vascular complications.

Use of a 3 French system for balloon aortic valvuloplasty in infants

For infants with valvar aortic stenosis, balloon aortic valvuloplasty has supplanted surgical valvotomy as the initial treatment of choice at most institutions. Technological innovations have resulted in further miniaturization of balloon dilation catheters, allowing this procedure to be performed through smaller sheath sizes. Currently, the Tyshak-Mini balloon dilation catheter (B. Braun Medical) allows passage of up to an 8 mm dilation balloon catheter through a 3 Fr hemostatic sheath. The efficacy of this system for the treatment of valvar aortic stenosis in infants less than 6 months of age was evaluated in 20 patients undergoing 22 procedures. Mean age at the time of intervention was 26 +/- 46 days. Mean transvalvar gradient was 76 +/- 22 mm Hg prior to balloon dilation. Following balloon valvuloplasty, residual gradient was 26 +/- 12 mm Hg, reflecting a mean change in peak-to-peak gradient of 49 +/- 19 mm Hg. Postintervention increase in aortic insufficiency was one grade or less in 19/22 procedures, two grades in 2 procedures, and three grades in 1 procedure. There were no significant vascular complications reported immediately following the procedure. Repeat valvuloplasty was performed in three patients in which the 3 Fr system was used in two patients. The 3 Fr system for balloon aortic valvuloplasty in infants less than 6 months of age is effective and safe.

Effect of three different housing systems on immune responses and body weight of chicken lines divergently selected for antibody responses to sheep red blood cells

There is an urgent need for knowledge on the effects of alternative housing conditions on parameters of health and production in current food animals, which are usually selected for a prolonged period for production traits. Thus, it is as yet unknown, whether genotype or environmental factors, or both, are major determinants of these traits. Therefore, as a model, the effects of keeping layers in three different types of housing: solitary in battery cages (BC), on a colony basis in a barn provided with litter and perches (BPL) and free range housing with access to the outdoors (FR), respectively, on immune competence and body weight (gain) of chicken lines divergently selected for high (H line) or low (L line) antibody responses to sheep red blood cells (SRBCs), next to a random bred control (C) line were studied. Antibody responses to keyhole limpet haemocyanin (KLH), Escherichia coli lipopolysaccharide (LPS) and ovalbumin (OVA) were significantly higher in the H line as compared to the C and L lines in all three housing systems, whereas in vitro mitogenesis of peripheral blood leukocytes to concanavalin (Con) A, and body weight (BW) were significantly higher in the L line in all three housing systems. No differences between the lines were found with respect to phagocyte activity. Housing conditions affected antibody responses to KLH, i.e. birds kept solitary in BC, and birds kept in BPL systems showed significantly higher antibody responses to KLH, than birds kept in the FR system. Also in vitro T-cell responses to KLH were significantly higher in BC birds than in the FR birds, but T cell responses to Con A were higher in the FR birds. Antibody responses to KLH, but also LPS and OVA were significantly affected by a housing×time interaction. Titers to these three antigens remained at a higher level in the BC then in the FR system. Birds kept in battery cages were heavier, and produced their first eggs approximately 2 and 3 weeks earlier than birds in the BPL and the FR system, respectively. The absence in the present study of significant interactions between line and housing systems on immune competence suggests that regardless of genotype, the animals respond similarly to different environments. The modulation of the magnitude of specific, but not innate immune responses in the three lines by environmental (housing) conditions suggest that the environment may favour types of specific immune responses. In addition, our data suggest that specific genotypes and specific environments may be additive in disease resistance.

Incorporation of a grafted brominated monomer in glass fiber reinforced polypropylene to improve the fire resistance

Glass fiber reinforced polypropylene composites have been flame retarded using a brominated acrylate as both monomer (PBB-MA) and polymer (PBB-PA), associated with Sb 2O 3 (Sb/Br) and Mg(OH) 2. We have shown that the brominated monomer can react either by grafting onto the polymer matrix or onto the glass fibers or by polymerizing around the Sb 2O 3 particles. We have highlighted that the efficiency of this FR system is connected to its high bromine content and to its reactivity with polypropylene. We have observed that grafting of brominated monomer onto glass fibers does not strongly modify the fire properties of the composites. We have demonstrated that the action of PBB-MA/Sb 2O 3 can be improved in reinforced PP by combination with Mg(OH) 2, which delays ignition. Improvement of the fire properties of the composites has been achieved to the detriment of mechanical properties which are strongly affected by the presence of the brominated polyacrylate.

Five French (5 Fr) guiding catheters for percutaneous coronary angioplasty and stent placement: An initial feasibility study.

Thirty patients were treated with percutaneous coronary intervention (PCI) using a 5 Fr guiding catheter. A recently developed, mechanically advantaged hand injector was used to deliver contrast and achieved excellent visualization through the 5 Fr system. Stent sizes ranged from 2.25 to 4.00 mm in diameter and from 8 to 24 mm in length. All primary lesions were successfully treated. The average contrast use was 70 cc per case. There were no major complications and only one minor femoral hematoma. In selected patients, a balloon angioplasty and stent placement can be performed safely and successfully with 5 Fr guiding catheters using currently available products. This technique creates a smaller arterial puncture site, which may obviate the need for a closure device and allow early and safe ambulation. With 5 Fr systems, it appears that contrast usage is reduced, thereby potentially decreasing cost and morbidity. Cathet. Cardiovasc. Intervent. 51:352-357, 2000.

Percutaneous Transluminal Coronary Angioplasty Using 6 Fr Guiding Catheters: A Matched Study with 8 Fr Guiding Catheters

Coronary angioplasty using 6 Fr guiding catheters has been described. This study was based on matching a prospective 105 coronary angioplasty procedures performed using 6 Fr guiding catheters (group I) with 100 other prospectively collected procedures performed through 8 Fr catheters (group II). Procedural variables such as quantity of contrast injected, total duration of the angioplasty, and vessel opacification were collected, as well as the success rate and local vascular complications. The two groups were identical regarding the baseline clinical and angiographic characteristics (age, sex, clinical indication, type of the lesion, and the size of the artery attempted). Success rate was similar between both groups (94.2% and 95% for groups I and II, respectively). Cross‐over from 6 Fr to 8 Fr system was needed in two cases (one for inadequate back‐up support, the other for a long dissection and inadequate vessel opacification). The use of 6 Fr guiding catheters was possible in such acute situations as myocardial infarction or scent delivery for coronary dissections. The quantity of contrast injected through the 6 Fr catheters (164 ± 74 mL) was significantly less than through the 8 Fr ones (217 ± 92 mL; P ± 0.01). On the other hand, the mean duration of the procedure was slightly longer using the 6 Fr system (40 ± 18 min vs 34.4 ± 18 min for groups I and II, respectively; P &lt; 0.02). There was no difference between the two groups regarding the local vascular complications. This study demonstrates the feasibility of PTCA using 6 Fr guiding catheters in a variety of clinical indications, with a smaller quantity of contrast than in the 8 Fr ones, but a slightly longer duration. The other potential advantages of 6 Fr guiding catheters (lower rate of local complications, less blood loss) have not been proven in this study. (J Interven Cardiol 1996;9:373–379)