Outflow Area Research Articles

Abstract 529: Statin Therapy Decreases Vascular Inflammation and Prolongs Patency in Murine Arteriovenous Fistula

Background: AVFs are the lifeline of dialysis patients, but can often occlude. The most common cause of AVF failure is inflammation-driven neointimal hyperplasia and thrombosis. Here, we investigated whether statin therapy with well-recognized anti-inflammatory properties can improve murine AVF patency, and further assessed the anti-inflammatory effects. Methods: One week prior to AVF creation, mice were randomized to oral atorvastatin 1.14mg/kg/day or control 100ul PBS (both n=10), administered by daily gavage. AVF were created using an end-to-side internal jugular vein and carotid artery anastomosis. AVF blood flow was measured (Transonic blood flow probe) at day 0 and weekly thereafter until occlusion (blood flow < 0.1ml/min). On day 6, CLIO-VT680, an inflammatory cell-targeted fluorescent nanoparticle, was injected intravenously (10mg/kg). 24 hours later, in vivo survival epifluorescence molecular imaging was performed to visualize inflammatory cell in the AVF venous outflow limb. Histopathological assessment of AVF was performed in on day 7 and 14 mice (6 statin each, 6 control each) to assess venous outflow area, AVF scarring via collagen, and adventitial macrophage content. Results: At day 7, the in vivo venous outflow cellular inflammation signal (CLIO-VT680 TBR) was significantly lower in statin-treated mice (3.5±0.16 vs 4.5±0.5 PBS, p=0.02). Adventitial macrophage content was significantly lower in statin group at day 14 (p=0.01). Positive AVF remodeling, a desirable feature for clinical AVF patency, was higher in the statin group as compared to the PBS group (p=0.02 at week 1, p=0.002 at week 2). In vivo, statin-treated animals exhibited greater AVF blood flow (BF) preservation from day 7 to day 14 (ΔAVF BF +0.14±0.2 ml/min vs. -0.79±0.32 ml/min PBS, p=0.02). The ΔAVF BF from day 7 to day 14 correlated inversely and significantly with the day 7 CLIO-VT680 cellular inflammation (r=-0.56, p=0.02), indicating that baseline inflammation may predict AVF failure. Kaplan Meier survival analysis showed median AVF patency in mice treated with statin was 28 days compared to 14 days in PBS treated group (p<0.05). Conclusion: Statin therapy prolongs AVF patency and preserves AVF blood flow in association with diminished AVF cellular inflammation.

Heat/mass transfer over the cavity squealer tip equipped with a full coverage winglet in a turbine cascade: Part 1 – Data on the winglet top surface

Heat/mass transfer characteristics on the winglet top surface for the cavity squealer tip equipped with a full coverage winglet has been investigated experimentally with the variation of h/s (tip gap height-to-span ratio) by employing the naphthalene sublimation technique. For a squealer rim height-to-span ratio of hst/s=3.75% and a winglet width-to-pitch ratio of w/p=10.55%, the tip gap is changed to be h/s=0.34%, 0.68%, 1.02%, 1.36%, and 1.70%. On the winglet top surface, high local heat/mass transfer rate is found (i) at the sites of the leading edge tip gap vortices, (ii) in the flow separation/reattachment area on the pressure-side winglet, (iii) in the upstream outflow area on the suction-side winglet, (iv) in the downstream outflow area on the suction-side winglet, and (v) in the area where the cavity fluid is discharged toward the trailing edge. On the other hand, very low local heat/mass transfer rate is observed in two separate areas on the suction-side winglet upstream of the mid-chord. In the case of very low h/s, the two separate low heat/mass transfer areas cannot be identified. Instead, a new high heat/mass transfer area is found near the mid-chord on the suction-side winglet. Average heat/mass transfer rate on the winglet top surface tends to increase consistently with increasing h/s, but it is always lower than that on the tip surface of the plane tip with no winglet.

Interobserver agreement on the echocardiographic parameters that estimate right ventricular systolic function in the early postoperative period of cardiac surgery

Primary objectiveTo know the variability of transthoracic echocardiographic parameters that assess right ventricular systolic function by analyzing interobserver agreement in the early postoperative period of cardiovascular surgery. Secondary objectiveTo assess the feasibility of these echocardiographic measurements. DesignA cross-sectional study, double-blind pilot study was carried out from May 2011 to February 2013. SettingCardiovascular postoperative critical care at the National Institute of Cardiology “Ignacio Chávez”, Mexico City, Mexico. PatientsConsecutive, non-probabilistic sampling. Fifty-six patients were studied in the postoperative period of cardiac surgery. InterventionThe first echocardiographic parameters were obtained between 6 and 8h after cardiac surgery, followed by blinded second measurements. Main variablesTricuspid annular plane systolic excursion (TAPSE), tricuspid annular peak systolic velocity on tissue Doppler imaging (VSPAT), diameters and right ventricular outflow area, tract fractional shortening. The agreement was analyzed by the Bland–Altman method, and its magnitude was assessed by the intraclass correlation coefficient (95% confidence interval). ResultsBoth observers evaluated TAPSE and VSPAT in 48 patients (92%). The average TAPSE was 11.68±4.53mm (range 4–27mm). Right ventricular systolic dysfunction was observed in 41 cases (85%) and normal TAPSE in 7 patients (15%). The average difference and its limits according to TAPSE were −0.917±2.95 (−6.821, 4.988), with a magnitude of 0.725 (0.552, 0.837); the tricuspid annular peak systolic velocity on tissue Doppler imaging was −0.001±0.015 (−0.031, 0.030), and its magnitude 0.825 (0.708, 0.898), respectively. ConclusionsVSPAT and TAPSE were estimated by both observers in 92% of the patients, these parameters exhibiting the lowest interobserver variability.

Acuerdo interobservador de los parámetros ecocardiográficos que estiman la función sistólica del ventrículo derecho en el postoperatorio temprano de cirugía cardiaca

Primary objectiveTo know the variability of transthoracic echocardiographic parameters that assess right ventricular systolic function by analyzing interobserver agreement in the early postoperative period of cardiovascular surgery. Secondary objectiveTo assess the feasibility of these echocardiographic measurements. DesignA cross-sectional study, double-blind pilot study was carried out from May 2011 to February 2013. SettingCardiovascular postoperative critical care at the National Institute of Cardiology “Ignacio Chávez”, Mexico City, Mexico. PatientsConsecutive, non-probabilistic sampling. Fifty-six patients were studied in the postoperative period of cardiac surgery. InterventionThe first echocardiographic parameters were obtained between 6-8hours after cardiac surgery, followed by blinded second measurements. Main variablesTricuspid annular plane systolic excursion (TAPSE), tricuspid annular peak systolic velocity on tissue Doppler imaging (VSPAT), diameters and right ventricular outflow area, tract fractional shortening. The agreement was analyzed by the Bland-Altman method, and its magnitude was assessed by the intraclass correlation coefficient (95% confidence interval). ResultsBoth observers evaluated TAPSE and VSPAT in 48 patients (92%). The average TAPSE was 11.68±4.53mm (range 4-27mm). Right ventricular systolic dysfunction was observed in 41 cases (85%) and normal TAPSE in 7 patients (15%). The average difference and its limits according to TAPSE were -0.917±2.95 (-6.821, 4.988), with a magnitude of 0.725 (0.552, 0.837); the tricuspid annular peak systolic velocity on tissue Doppler imaging was -0.001±0.015 (-0.031, 0.030), and its magnitude 0.825 (0.708, 0.898), respectively. ConclusionsVSPAT and TAPSE were estimated by both observers in 92% of the patients, these parameters exhibiting the lowest interobserver variability.

A Study of the Performances of Different Turbulence Schemes in Numerical Simulation of Hydrodynamics of a Semi-Closed Sea (Persian Gulf)

ABSTRACTComplex process of turbulent mixing in Persian Gulf that is a semi-closed sea makes it a good media to test the performance of different turbulence schemes. In this research, we used the 3D ocean model COHERENS (COupled Hydrodynamical Ecological model for REgioNal Shelf seas) for the Persian Gulf with the open boundary in the Hormuz Strait. Of the turbulence schemes for the vertical diffusion available in the COHERENS, we tested four models to investigate the hydrodynamic characteristics of the Persian Gulf. The results show that all of the schemes presented the sea surface salinity (SSS) distribution rather accurately but the k-l and flow-dependent models results have better agreements with observations. The most noticeable difference between the results of four schemes is the differences found in the simulation of turbulent parameters. The turbulent closure schemes generally provide better results, but the algebraic schemes show turbulent parameters far from reality and they do not show substantial changes with time. Generally, the vertical structures of turbulence in the water basins and parameterization of turbulence in water column is very sensitive to the selection of the type of the turbulence scheme. However, large-scale structures that take place within the inflow and outflow area are approximately quasi-horizontal, and the vertical small-scale turbulence does not affect them as much. As a result, they show less sensitivity to the performance of various turbulence schemes.

S0220301 脳動脈瘤治療用ステントにおける自己組織化マップを用いた最適形状解析

As evaluation of hemodynamics in an aneurysm, a lot of parameters have been introduced. However, the relationship between stent geometry and each hemodynamic parameter is not clear enough. We applied Self-organizing Maps (SOM) to search the detailed relationship between stent strut and hemodynamic parameters. Two thousands of stent design candidates evaluated with five hemodynamic parameters and 25 stent geometry parameters were stored during the optimization process. By using SOM software, 2,000 design candidates were visualized into 30 2D-maps while preserving their own features in the original 30-dimensional design space. Each map was divided into 20 clusters to characterize stent design and flow reduction. By comparing each cluster, critical design for reduction effect of each hemodynamic parameter is suggested. Strut placement on the inflow area is important to reduce maximum shear rate. In addition to the inflow area, strut on the outflow area is required to reduce velocity, vorticity, and average shear rate.

Changes of water quality of the Osówka stream flowing through ponds Syrenie Stawy in Szczecin (NW -Poland) in selected periods in the years 1994–2014

The aim of discernment changes in water quality of stream Osówka flowing through ponds Syrenie Stawy in Szczecin (NW-Poland) conducted in the years 1994–2014 the study of basic water chemistry indices in the Osówka Stream water inflow and outflow area of water in/from ponds Syrenie Stawy, which were used to calculate the value of the National Sanitation Foundation Water Quality Index (NSF-WQI). The NFS-WQI values were calculated on the basis of temperature, pH, dissolved oxygen (as a percentage of water saturation), BOD5and concentration of nitrates and total phosphates carried out in 1994–1995, 1999–2000, 2006–2007 and 2014, i.e. during time periods, and in particular the decrease in the amount of inflowing industrial pollution and the changes of anthropopressure related to the hydrotechnical works of stream Osówka and ponds Syrenie Stawy. In assessing according to the criteria of NFS WQI procedure – studied water quality corresponded good and medium to average quality. On the basis of the values and changes in values of NSF-WQI it has been shown that quality water flowing through ponds Syrenie Stawy in subsequent periods the was getting worse, while self-cleaning effect ofthe waters along the ponds Syrenie Stawy gradually increase, especially after hydrotechnical works. It has been estimatedthat the NSF-WQI procedure to assess the quality and discerning water quality changes in the flow ponds in long-time period, based on the basic physical and chemical water quality indices – can be useful to use in practice.

Experimental Model-Based Linearization of a S.I. Engine Gas Injector Flow Chart

Experimental tests previously executed by the authors on the simultaneous combustion of gasoline and gaseous fuel in a spark ignition engine revealed the presence of strong nonlinearities in the lower part of the gas injector flow chart. These nonlinearities arise via the injector outflow area variation caused by the needle impacts and bounces during the transient phenomena that take place in the opening and closing phases of the injector and may seriously compromise the air-fuel mixture quality control for the lower injection times, thus increasing both fuel consumption and pollutant emissions. Despite the extensive literature about the operation and modelling of fuel injectors, there are no known studies focused on the nonlinearities of the gas injector flow chart and on the way they can be reduced or eliminated. The authors thus developed a mathematical model for the prediction of mass injected by a spark ignition (S.I.) engine gas injector, validated through experimental data. The gas injector has been studied with particular reference to the complex needle motion during the opening and closing phases, which may strongly affect the amount of fuel injected. In this work, the mathematical model previously developed has been employed to study and determine an appropriate injection strategy in order to linearize the injector flow chart to the greatest degree possible. The injection strategy proposed by the authors is based on minimum injection energy considerations and may be easily implemented in current engine control units (ECU) without any hardware modification or additional costs. Once calibrated by means of simulation, this strategy has been validated by experimental data acquired on an appropriately equipped injector test bench. As a result, the real injector flow chart has been substantially improved, reducing its deviation from linearity to one third of the original flow chart, which is an excellent result, especially if the typical measurement dispersion of the injected mass is taken into account. The injection strategy proposed by the authors could extend the linear behaviour of gas injectors and improve the fuel supply by means of a simple software update of the ECU, thus obtaining higher engine efficiency and lower pollutant emissions.

Viscoelastic Fluid Model with Nonhomogeneous Boundary Conditions

We deal with a viscoelastic fluid model in a rectangle domain with nontrivial velocity at the inflow and outflow area and slip boundary condition at the rest of the boundary. For this model we investigate the existence of local in time solutions. Then we present 2D simulations and we discuss the possibility of the derivation of 1D model by limit passage with the height of the rectangle to zero. Moreover, we present few 1D models that we support by simulations.

Model-based optimization of injection strategies for SI engine gas injectors

A mathematical model for the prediction of the mass injected by a gaseous fuel solenoid injector for spark ignition (SI) engines has been realized and validated through experimental data by the authors in a recent work [1]. The gas injector has been studied with particular reference to the complex needle motion during the opening and closing phases. Such motion may significantly affect the amount of injected fuel. When the injector nozzle is fully open, the mass flow depends only on the upstream fluid pressure and temperature. This phenomenon creates a linear relationship between the injected fuel mass and the injection time (i.e. the duration of the injection pulse), thus enabling efficient control of the injected fuel mass by simply acting on the injection time. However, a part of the injector flow chart characterized by strong nonlinearities has been experimentally observed by the authors [1]. Such nonlinearities may seriously compromise the air-fuel mixture quality control and thus increase both fuel consumption and pollutant emissions (SI engine catalytic conversion systems have very low efficiency for non-stoichiometric mixtures). These nonlinearities arise by the injector outflow area variation caused by needle impacts and bounces during the transient phenomena, which occur in the opening and closing phases of the injector. In this work, the mathematical model previously developed by the authors has been employed to study and optimize two appropriate injection strategies to linearize the injector flow chart to the greatest extent. The first strategy relies on injection pulse interruption and has been originally developed by the authors, whereas the second strategy is known in the automotive engine industry as the peak and hold injection. Both injection strategies have been optimized through minimum injection energy considerations and have been compared in terms of linearization effectiveness. Efficient linearization of the injector flow chart has been achieved with both injection strategies, and a similar increase in injector operating range has been observed. The main advantage of the pulse interruption strategy lies on its ease of implementation on existing injection systems because it only requires a simple engine electronic control unit software update. Meanwhile, the peak and hold strategy reveals a substantial lack of robustness and requires expressly designed injectors and electronic components to perform the necessary voltage commutation.

The angle of insonation for Doppler measurements of left and right ventricular output in newborns and infants

Background: The angle of insonation can be an important determinant of Doppler-derived cardiac output measurements. It is known anatomically that there is a larger insonation angle for the left vs. right ventricular outflow area, but variability and calculated angles have not been described. The aim of this study was to describe the anatomical position of the left and right outflow areas and determine the geometric angle of insonation in newborn and infants. Methods: Magnetic resonance images of infants ≤ 2 years of age were explored. For each outflow, the position was determined relative to an anatomical reference point. To obtain the angle of insonation, the angle between the outflow and the hypothetical position of the ultrasound probe beam was calculated. Results: Forty-five patients were included with a median age of 71 days old. Anatomically, the left outflow is directed almost vertically upwards in sagittal images with a 40o angle to the right in coronal images. The right outflow is directed 53o upwards in sagittal images with a slight angle to the left on axial images. The median (range) angle of insonation for the left ventricular outflow area using the apical or subcostal view was 40° (22-51) and 28° (7-47) respectively, and 23° (2-40) for the right ventricular outflow area using the parasternal view. Conclusions: The median geometric angle of insonation of the left outflow was larger than the right. The variation within the group was large, but in each individual case the angle for left was larger than for right.

Benthic Protozoa and Metazoa living in deep anoxic and hydrogen sulfide conditions of the Black Sea: Direct observations of actively moving Ciliophora and Nematoda

This study was conducted to search for living fauna in seafloor sediments from nearly 300 m water depth in the outflow area of the Bosporus into the Black Sea. During our investigations we identified seven higher level meiobenthic taxa in the anoxic and sulfidic sediments at 296 m water depth: Gromiida, Ciliophora, Foraminifera (soft-shelled), Nematoda, Kinorhyncha, Harpacticoida and one taxonomically unknown form. Hence, these Black Sea sediments seem to be a natural habitat for some eukaryotes. Furthermore, direct microscopic observations of alive and actively moving fauna demonstrates the presence of two species of ciliates, one species of free-living nematodes, and one unknown organism. As evidence, the activity of these organisms was recorded with a video camera. This indicates that metazoa and protozoa can live in the Black Sea under these more extreme conditions. However, the environmental factors and the specific physiological and biochemical processes used by the benthic fauna to retain metabolic activity and facilitate survival under anoxic and sulfidic conditions are still unknown. As well the distribution of benthos as a whole and of the individual taxa in other sulfidic sediments of the Black Sea needs to be investigated. Nevertheless, the presented observation of alive benthic organisms opens new perspectives to study of metazoan and protozoan life in Black Sea sediments lacking oxygen and containing sulfide.

A mathematical model for the prediction of the injected mass diagram of a S.I. engine gas injector

A mathematical model of gaseous fuel solenoid injector for spark ignition engine has been realized and validated through experimental data. The gas injector was studied with particular reference to the complex needle motion during the opening and closing phases, which strongly affects the amount of fuel injected. As is known, in fact, when the injector nozzle is widely open, the mass flow depends only on the fluid pressure and temperature upstream the injector: this allows one to control the injected fuel mass acting on the “injection time” (the period during which the injector solenoid is energized). This makes the correlation between the injected fuel mass and the injection time linear, except for the lower injection times, where we experimentally observed strong nonlinearities. These nonlinearities arise by the injector outflow area variation caused by the needle bounces due to impacts during the opening and closing transients [1] and may seriously compromise the mixture quality control, thus increasing both fuel consumption and pollutant emissions, above all because the S.I. catalytic conversion system has a very low efficiency for non-stoichiometric mixtures. Moreover, in recent works [2, 3] we tested the simultaneous combustion of a gaseous fuel (compressed natural gas, CNG, or liquefied petroleum gas, LPG) and gasoline in a spark ignition engine obtaining great improvement both in engine efficiency and pollutant emissions with respect to pure gasoline operation mode; this third operating mode of bi-fuel engines, called “double fuel” combustion, requires small amounts of gaseous fuel, hence forcing the injectors to work in the non-monotonic zone of the injected mass diagram, where the control on air-fuel ratio is poor. Starting from these considerations we investigated the fuel injector dynamics with the aim to improve its performance in the low injection times range. The first part of this paper deals with the realization of a mathematical model for the prediction of both the needle motion and the injected mass for choked flow condition, while the second part presents the model calibration and validation, performed by means of experimental data obtained on the engine test bed of the internal combustion engine laboratory of the University of Palermo.

출구유로 단면적이 수직 환상공간 내부의 풀비등에 미치는 영향

To identify the effects of an outflow area on pool boiling heat transfer in a vertical annulus, three different flow restrictors were studied experimentally. For the test, a heated tube of smooth stainless steel and water at atmospheric pressure were used. Both annuli with open and closed bottoms were considered. To validate the effects of the outflow area on the heat transfer, the results of the annulus with the restrictor were compared with the data for the plain annulus without the restrictor. The reduction of the outflow area ultimately results in a decrease in the heat transfer. As the outflow area is very small, a slight increase in heat transfer is also observed. The major cause of this tendency is explained as the difference in the intensity of liquid agitation cause by the movement of coalesced bubbles. It is identified that the convective flow, pulsating flow, and evaporative mechanism are considered as the important mechanisms.

Indonesian Throughflow and monsoon activity records in the Timor Sea since the last glacial maximum

Abstract Indonesian Throughflow (ITF) is known to play an important role in the heat exchange between the Pacific and the Indian Oceans. However, our understanding of the long-term evolution of the ITF and, in particular, the mechanism of heat transport is limited. Here, we present a high-resolution foraminifera-based multi-proxy study in the main ITF outflow area of the Timor Sea, to reconstruct the ITF variability and to understand the relationship between the ITF changes and monsoon activity from the last glacial maximum (LGM) to the Holocene. Our results show that when the strong surface water ITF occurs, high productivity is related to the mixing of the upper water column owing to the wind-driven upwelling rather than the shoaling of the depth of thermocline (DOT). By contrast, the DOT is affected more strongly by the ITF than by the monsoonal wind-driven upwelling in the Indonesian Seas. During the LGM (23–19 ka) and middle Holocene (8–6 ka), warm surface water ITF was dominated owing to the lowered sea level and (or) the higher steric height difference between the western Pacific and eastern Indian Oceans as a result of the strong southeast monsoon. During the early Holocene (11–8 ka) and late Holocene (last ~ 6 ka), because of the postglacial high sea level, the strong northwest monsoon and heavy rains, large amounts of freshwater flowed into the Java Sea from the South China Sea (SCS). The freshwater plug at the southern tip of the Makassar Strait blocked the warm surface flow, thus initiating the enhanced thermocline ITF. In the Timor Sea, the changes in the vertical profile of the ITF were influenced by the glacio-eustatic sea-level changes that have modified the geometry of the pathways within the Indonesian Seas, as well as by the monsoon activity which was modulated by the changes in the insolation with a precessional cyclicity.

Formation of Barents Sea Branch Water in the north-eastern Barents Sea

The Barents Sea throughflow accounts for approximately half of the Atlantic Water advection to the Arctic Ocean, while the other half flows through Fram Strait. Within the Barents Sea, the Atlantic Water undergoes considerable modifications before entering the Arctic Ocean through the St. Anna Trough. While the inflow area in the south-western Barents Sea is regularly monitored, oceanographic data from the outflow area to the north-east are very scarce. Here, we use conductivity, temperature and depth data from August/September 2008 to describe in detail the water masses present in the downstream area of the Barents Sea, their spatial distribution and transformations. Both Cold Deep Water, formed locally through winter convection and ice-freezing processes, and Atlantic Water, modified mainly through atmospheric cooling, contribute directly to the Barents Sea Branch Water. As a consequence, it consists of a dense core characterized by a temperature and salinity maximum associated with the Atlantic Water, in addition to the colder, less saline and less dense core commonly referred to as the Barents Sea Branch Water core. The denser core likely constitutes a substantial part of the total flow, and it is more saline and considerably denser than the Fram Strait branch as observed within the St. Anna Trough. Despite the recent warming of the Barents Sea, the Barents Sea Branch Water is denser than observed in the 1990s, and the bottom water observed in the St. Anna Trough matches the potential density at 2000 m depth in the Arctic Ocean.Keywords: Dense water formation; Kara Sea; deep water; Atlantic Water(Published: 20 September 2013)Citation: Polar Research 2013, 32, 18905, http://dx.doi.org/10.3402/polar.v32i0.18905

Effects of the outflow area on saturated pool boiling in a vertical annulus

The outflow area has been varied to investigate its effect on pool boiling heat transfer in a vertical annular space. For the test, a smooth stainless steel tube of 19.1mm diameter and the water at atmospheric pressure have been used. The ratio of areas of the outflow and the gap space has been changed from 0.04 to 1.13. As the area ratio decreases a clear change in heat transfer is observed. Throughout the area ratios the heat transfer coefficient is increased or decreased depending on the main mechanisms of heat transfer. The major cause for the tendency is attributed to the formation of a lumped bubble around the upper regions of the annulus and the reduced flow rate.

Propulsive Performance of Ideal Detonation Turbine Based Combined Cycle Engine

A novel two-mode propulsion system based on detonation combustion, known as a detonation turbine based combined cycle engine (DTBCC), was proposed and thermodynamically analyzed for potential application to aircrafts whose flight Mach number is from 0 to 5. The obvious advantage of the two-mode system is that both modes share the same multidetonation chambers. The quasi-stable total temperature and total pressure for inlet conditions of the turbine could be realized in this hybrid pulse detonation engine. A key parameter (drive area ratio) was defined as the ratio of the outflow area at the head to the cross-sectional area of the detonation chamber. The calculated results showed that the increase of the drive area ratio led to the increase in the mass flow entering the turbine; however, this led to the decrease of the total inlet temperature, the total inlet pressure, and the expansion-pressure ratio of the turbine. Compared with an ideal turbojet engine, the inlet temperature of the turbine in a preturbine hybrid pulse detonation engine with a drive area ratio of 1 was 80 K lower than the former under the same pressure ratio and the same fuel-air ratio. In other words, the increase of the drive area ratio may improve the performance of this hybrid pulse detonation engine. Variation of the pressure ratio was adapted to varied flight Mach numbers by a change of the drive area ratio, which induced the enlargement of the operating range. Finally, a performance model was established to research the components’ characteristics and the propulsive performance of the engine. Preliminary performance estimates suggested that thrust and specific fuel consumption of the two-mode propulsion system were superior to the existing turbine based combined cycle designs.

HYPERTROPHIC CARDIOMYOPATHY (Past, Present and Future)

The disease entity as we have come to recognize it today was placed in proper perspective to a large extent due to the classification of the dcisorganized groups of cardiomyopathies into four distinet types by Goodwin et al. (1,2). However, the condition which comprises by far the most common disorder under the broad category of Hypertrophic Cardionyopathy i.e, the condition named Idiopathic Hypertrophic subaortic Stenosis (IHSS) in U.S.A and Hypertrophic Obstructive Cardiomyopathy (HOCM) in U.K was first accurately recognized by the British pathologist Donald Teare (3). Teare described described massive hypertrophy of the ventricular septum and adjacent walls, involving from a third to half of the left ventricle, in eight cases. Prior to Teare’s description, the earliest report of what appears to be a description of this condition is that of the German pathologist Schmincke who in 1907 described “hyperplasia” of the muscle mass of the left ventricular outflow area (4). In 1910 Bernheim’s description of right ventricular obliteration by left ventricular disease included cases with asymmetric left ventricular hypertrophy with very thickened septum which probably were cases.

Different fibroblast subpopulations of the eye: A therapeutic target to prevent postoperative fibrosis in glaucoma therapy

The aim of this study is the characterization of fibroblasts mainly responsible for fibrosis processes associated with trabeculectomy or microstent implantation for glaucoma therapy. Therefore we isolated human primary fibroblasts from choroidea, sclera, Tenon capsule, and orbital fat tissues. These fibroblast subpopulations were analysed in vitro for expression of the extracellular matrix components which are responsible for postoperative scarring in glaucoma therapy. For scarring the proteins of the collagen family are predominant and so we focused on the expression of collagen I, collagen III and collagen VI in every fibroblast subpopulation. Also, the extracellular matrix protein fibronectin which crosslinks collagen fibres or other extracellular matrix components and cell surfaces, was analyzed. Collagen I, III and VI were prominent in every fibroblast subpopulation. The highest amounts of collagen III were found in hCF and hOF, whereas the signal in hSF and hTF was negligible. Additionally, there is a link between scarring processes and proliferating potential of fibroblasts, in case of microstent implantation triggered through the infiltration of inflammatory cells. Thus we analyzed fibroblast subpopulations for the presence of TGF-β1 which is one of the most important cytokines involved in proliferation processes. TGF-β1 was prominent in all fibroblast subpopulations with lowest expression in hCF cultures. To prevent postoperative fibroblast proliferation we analyzed in vitro the proliferation-inhibitors paclitaxel and mitomycin C which are potential candidates in drug eluting drainage systems on ocular fibroblast subpopulations. These inhibitors arrest fibroblast proliferation and viability, being, however, not very specific and have a cytotoxic potential also on healthy tissues surrounding the microstent outflow area. Significant differences in protein synthesis of fibroblasts subpopulations which could be specific targets for inhibition may help to find out fibroblast specific inhibitors to prevent postoperative scarring and could prevent patients from secondary surgery after microstent implantation.