Partial Interruption Research Articles

Calibration and Evaluation of Link Congestion Functions: Applying Intrinsic Sensitivity of Link Speed as a Practical Consideration to Heterogeneous Facility Types within Urban Network

This paper explores the use of archived data to calibrate volume delay functions (VDFs) and updates their input parameters (capacity and free-flow speed) for planning applications. The sensitivity analysis of speed to change in congestion level is performed to capture functional characteristics of VDFs in modeling specific facility types. Different sensitivity characteristics shown by the VDFs indicate that each function is suitable to a particular facility type. The results of sensitivity analysis are confirmed by the root mean square percent error (RMSPE) values calculated using the Orlando Urban Area Transportation Study (OUATS) model results and observed data. The modified Davidson’s function exhibits remarkable performance in nearly all facility types. The strength of the modified Davidson’s function across a broad range of facilities can be attributed to the flexibility of its tuning parameter, μ. Fitted Bureau of Public Road (BPR) and conical delay functions show lower RMSPE for uninterrupted flow facilities (freeways/expressways, managed lanes) and higher values for toll roads (which might have partial interruptions due to toll booths) and signalized arterials. Akcelik function underperforms on freeways/expressways and managed lanes but shows some improvements for toll roads and superior results for the signalized arterials. This was a desired strength of Akcelik function when modeling link travel speed on facilities where stopped delays were encountered.

1905 INTRAPERICARDIAL CONTROL DURING INFERIOR VENA CAVAL THROMBECTOMY WITHOUT CARDIOPULMONARY BYPASS

You have accessJournal of UrologyKidney Cancer: Advanced (II)1 Apr 20131905 INTRAPERICARDIAL CONTROL DURING INFERIOR VENA CAVAL THROMBECTOMY WITHOUT CARDIOPULMONARY BYPASS Mukul Patil, Jeremy Montez, Jeffrey Loh-Doyle, Eila Skinner, Donald Skinner, Anne Schuckman, and Siamak Daneshmand Mukul PatilMukul Patil Los Angeles, CA More articles by this author , Jeremy MontezJeremy Montez Los Angeles, CA More articles by this author , Jeffrey Loh-DoyleJeffrey Loh-Doyle Los Angeles, CA More articles by this author , Eila SkinnerEila Skinner Stanford, CA More articles by this author , Donald SkinnerDonald Skinner Los Angeles, CA More articles by this author , Anne SchuckmanAnne Schuckman Los Angeles, CA More articles by this author , and Siamak DaneshmandSiamak Daneshmand Los Angeles, CA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2324AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Inferior vena cava (IVC) tumor thrombectomy is an advanced procedure requiring experienced urologic & anesthesia teams due to complex hemodynamic considerations. Cardiopulmonary bypass is often used by a second surgical team, but introduces additional risk. Control of the IVC within the pericardium obviates the need for CP bypass for intrahepatic (Level II), supradiaphragmatic (Level III) & selected intra-atrial (Level IV) cases. We present our experience with intrapericardial control during IVC tumor thrombectomy. METHODS From 1978 to 2012, 101 patients underwent extirpative surgery with intrapericardial IVC control. This technique was performed in all cases of Level II (n=38) and III (n=37) thrombi, and in select cases of Level I (infrahepatic, n=7) & Level IV (n=17). Surgical approach was through a right thoracoabdominal incision, allowing access to the pleural cavity & pericardium. Intrapericardial control was obtained with a Rumel tourniquet with test occlusion to confirm hemodynamic stability. Splanchnic arteries, contralateral renal vein, and infrarenal IVC were controlled prior to occlusion of the porta hepatis. IVC tumor thrombectomy was then completed, followed by additional procedures when indicated (ie, IVC resection/partial interruption, filter placement, cavoscopy). RESULTS Of 101 patients, 98 underwent successful extirpation (97%). Intraoperative mortality occurred in three patients (massive pulmonary embolism, n=2, uncontrollable hemorrhage, n=1). Median Pringle maneuver time was 14 min (3-30). Additional procedures included IVC resection or partial interruption (n=41), IVC filter placement (n=9) and vena cavoscopy (n=16). Cavoscopy permitted visualization of residual tumor thrombus in 3 patients. Median length ventilator dependence was 1 day, median ICU stay was 5 days, and median length of stay was 11 days. Pathology revealed renal cell carcinoma (n=92), adrenocortical carcinoma (n=1), urothelial carcinoma (n=1), and nephroblastoma (n=1). Extensive lymphadenectomy was performed in 96 patients, revealing nodal metastasis in 35 patients (38%). Thirty-two patients with RCC were alive at an average of 35.7 months after surgery (0.3-198). Of those deceased, mean overall survival after surgery was 24.2 months (0.03-117). CONCLUSIONS Intrapericardial control of the IVC allows a single surgical team to safely perform tumor thrombectomy for intrahepatic and supradiaphragmatic thrombi. This approach obviates the need for cardiopulmonary bypass and eliminates associated morbidity. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e781 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Mukul Patil Los Angeles, CA More articles by this author Jeremy Montez Los Angeles, CA More articles by this author Jeffrey Loh-Doyle Los Angeles, CA More articles by this author Eila Skinner Stanford, CA More articles by this author Donald Skinner Los Angeles, CA More articles by this author Anne Schuckman Los Angeles, CA More articles by this author Siamak Daneshmand Los Angeles, CA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

High-pitch Dual-source Computed Tomography Pulmonary Angiography in Freely Breathing Patients

To investigate pulmonary arterial (PA) enhancement, image noise, and artifacts related to breathing and heart motion in patients with suspected pulmonary embolism. Seventy-six consecutive patients underwent computed tomographic pulmonary angiography (CTPA) in dual-source high-pitch mode (pitch 3.0, 100 kV, 180 mAs, 50 mL contrast material) without breathing commands. PA enhancement, image noise, signal to noise ratio, overall image quality, incidence of total or partial interruption of the contrast column in the PAs, and heart motion-related and breathing-related artifacts of the diaphragm and pulmonary structures were recorded. Mean central and peripheral PA attenuation was 404 ± 104 and 453 ± 119 HU; mean image noise was 11 ± 2 HU; mean examination time was 0.67 ± 0.09 s; and mean dose-length product was 142 ± 31 mGy cm. There were no motion artifacts of the diaphragm or pulmonary vessels related to breathing or heart motion. There was no case of partial or total interruption of the contrast column in the PA tree. No examination was rated nondiagnostic. High-pitch dual-source CTPA in freely breathing patients effectively produces images that are free of artifacts related to breathing and cardiac motion. Hence, Valsalva-related artifacts can be eliminated using this technique.

Evaluation of sinus meningiomas in the region of interest by high-resolution three dimensional contrast-enhanced magnetic resonance venography

To determine the value of high-resolution three dimensional contrast enhanced magnetic resonance venography (3D CE-MRV) in evaluating sinus meningiomas in the region of interest (ROI). Twenty patients with sinus meningiomas underwent 3D CE-MRV with ROI preoperatively (including 9 patients postoperatively). We observed the changes of venous sinus adjacent the tumor. All patients received high-resolution image, the single acquisition time was about 11.4 s, and the voxel value was about 1.3 mm3. The images of 20 patients showed the change of the sinus clearly, 6 of which with integral sinus, 14 with sinus invaded at various degrees, including 5 with sinus occlusion and 9 with stenosis. CE-MRV also showed 4 patients with clear sinuses, 1 with narrow sinus, partial interruption, and 4 with sinus removed after the surgery. Application of high-resolution 3D CE-MRV in ROI in sinus meningiomas may help obtain a series of high-resolution images in a short time, show the relationship between the tumor and venous sinus, display the degree of invasion of venous sinus clearly, provide information for the surgical treatment, and evaluate the change of sinus after the surgery.

Curative Resection of Hepatocellualr Carcinoma Using Modified Glissonean Pedicle Transection versus the Pringle Maneuver: A Case Control Study

Objective: The Glissonean pedicle transection method of liver resection has been found to shorten operative time and minimize intraoperative bleeding during liver segmentectomy. We have compared the feasibility, effectiveness, and safety of the Glissonean pedicle transection method with the Pringle maneuver in patients undergoing selective curative resection of large hepatocellualr carcinoma (HCC).Methods: Eligible patients with large (> 5 cm) nodular HCC (n = 50) were assigned to undergo curative hepatectomy using the Glissonean pedicle transection method (n = 25) or the Pringle maneuver (n = 25). Partial interruption of the infrahepatic inferior vena cava was incorporated to further reduce bleeding from liver transection. The primary outcome measure was postoperative changes in liver function from baseline. Secondary outcomes included operating time, volume of intraoperative blood loss/transfusion, and time to resolution of ascites.Results: The two groups were comparable in age, sex, site and size of the liver tumor, segment or lobe intended to be resected, and liver function reserve, and the results were not significant statistically. All patients underwent successful major hepatectomies using the assigned method, with the extent of major hepatectomy comparable in the two groups (P = 0.832). The Glissonean approach was associated with shorter hepatic inflow interruption (30.0 ± 12.0 min vs. 45.0 ± 13.0 min, P < 0.001), lower volume of blood loss (145.0 ± 20.0 mL vs. 298.0 ± 109.0 mL, P < 0.001), reduced requirement for transfusion (0.0 ± 0.0 mL vs. 200.0 ± 109.0 mL, P < 0.0001), and more rapid resolution of ascites (9.5 ± 1.2 d vs. 15.3 ± 2.4 d, P < 0.001). Postoperative liver function measures were comparable in the two groups, and the results were not significant statistically.Conclusion: The Glissonean pedicle transection method is a feasible, effective, and safe technique for hepatic inflow control during the curative resection of large nodular HCCs.

Partial interruption of axonal transport due to microtubule breakage accounts for the formation of periodic varicosities after traumatic axonal injury

Due to their viscoelastic nature, white matter axons are susceptible to damage by high strain rates produced during traumatic brain injury (TBI). Indeed, diffuse axonal injury (DAI) is one of the most common features of TBI, characterized by the hallmark pathological profiles of axonal bulbs at disconnected terminal ends of axons and periodic swellings along axons, known as “varicosities.” Although transport interruption underlies axonal bulb formation, it is unclear how varicosities arise, with multiple sites accumulating transported materials along one axon. Recently, axonal microtubules have been found to physically break during dynamic stretch injury of cortical axons in vitro. Here, the same in vitro model was used in parallel with histopathological analyses of human brains acquired acutely following TBI to examine the potential role of mechanical microtubule damage in varicosity formation post-trauma. Transmission electron microscopy (TEM) following in vitro stretch injury revealed periodic breaks of individual microtubules along axons that regionally corresponded with undulations in axon morphology. However, typically less than a third of microtubules were broken in any region of an axon. Within hours, these sites of microtubule breaks evolved into periodic swellings. This suggests axonal transport may be halted along one broken microtubule, yet can proceed through the same region via other intact microtubules. Similar axonal undulations and varicosities were observed following TBI in humans, suggesting primary microtubule failure may also be a feature of DAI. These data indicate a novel mechanism of mechanical microtubule damage leading to partial transport interruption and varicosity formation in traumatic axonal injury.

Tratamiento de la hipercolesterolemia y prevención de las enfermedades cardiovasculares mediante la inhibición de la reabsorción de ácidos biliares con resincolestiramina

Cholestyramine resin is a bile acid sequestrant that reduces low-density-lipoprotein cholesterol (LDL-c) through partial interruption of enterohepatic bile acid circulation. This drug has no systemic effects and consequently can be used in women of reproductive age, in children and in patients with muscular, liver or renal disorders. Cholestyramine resin should be administered separately from other drugs. This agent boosts the lipidlowering effect of statins, as well as that of fibrates, nicotinic acid and ezetimibe. Adding cholestyramine resin to statin therapy reduces LDL-c by an additional 20%, equivalent to a 3-fold increase in the statin dose. A meta-analysis of eight clinical trials found that resins reduced mortality from cardiac causes by 30% (OR 0.70; 95% CI 0.50–0.99), a figure not lower than that observed with statins. Cholestyramine resin reduces postprandial glycemia and glycosylated hemoglobin and consequently is of particular interest in the treatment of hypercholesterolemia in patients with metabolic syndrome or type 2 diabetes who have failed to achieve LDL-c targets with statin monotherapy. Previously used resin preparations often produced gastrointestinal intolerance, while the new galenical preparations of cholestyramine resin used at a dose of 4–8 grams (1–2 sachets) per day – sufficient to obtain a lipid-lowering effect – are usually well tolerated.

Conditional control of quantum beats in a cavity QED system

We probe a ground-state superposition that produces a quantum beat in the intensity correlation of a two-mode cavity QED system. We mix drive with scattered light from an atomic beam traversing the cavity, and effectively measure the interference between the drive and the light from the atom. When a photon escapes the cavity, and upon detection, it triggers our feedback which modulates the drive at the same beat frequency but opposite phase for a given time window. This results in a partial interruption of the beat oscillation in the correlation function, that then returns to oscillate.

Les ruptures partielles de la coiffe des rotateurs. Signification pathogénique et stratégie médico-chirurgicale actuelle

Partial-thickness rotator cuff tears comprise a partial interruption of the continuity of the tendon, with no relation to glenohumeral joint and subacromial bursa, as opposed to complete tears or the rotator cuff, and essentially affect the supraspinatus tendon. These might be in the form of bursal side tears, articular side tears or intrasubstance tears. Partial bursal side tears are explained by an impingement syndrome. Partial articular side tears are explained by a degeneration of the tendon and may be favoured by a trauma in patients over 40. In younger patients, partial bursal side tears may be due to an anterior instability, a posterior-superior glenoid impingement or to a trauma. The frequency of partial intrasubstance tears is probably underestimated because of the difficulties of diagnosis, now improved by magnetic resonance imaging. The therapeutic strategy depends on the age of the patient, the anatomic type and the extent of the lesion.

A 011 Cardioprotection with Beta-blockers and Statins in Major Vascular Surgery

The measurement of individual respiratory chain complexes is an important component of the investigation of diseases due to mitochondrial dysfunction. We have evaluated assays which measure complexes I to IV in human skeletal muscle mitochondria and in addition optimized these assays to provide sensitive and reliable diagnostic techniques, particularly in situations where a partial interruption at a single complex needs to identified. Using several established methods of membrane disruption we have found that optimal activities of complexes I and II are obtained by freeze-thawing the mitochondria in hypotonic potassium phosphate buffer, whereas complex III and IV activities are markedly increased by the addition of the detergent n-dodecyl-β-D-maltoside. Complex I activity is measured in the presence of 2.5 mg · ml−1 bovine serum albumin, which increases rotenone sensitivity, and we have shown that NADH-cytochrome b5 reductase makes an important contribution to the rotenone-insensitive NADH-ubiquinone oxidoreductase activity. Complex II activity is measured after preincubation of the mitochondrial fraction with succinate to fully activate the complex. Complex I and III activities are dependent upon the length of the isoprenoid chain of the ubiquinone and ubiquinol, respectively. These assays have been used to establish a control range.

Learning to Eat

This article argues that the biomedical logic behind the treatment of eating disorders attempts to substitute many of the economic, adaptative and symbolic reasons that have historically and ethnographically conditioned eating habits in all cultures for exclusively dietetic reasons. Thus, when nutritional rehabilitation is used as a therapeutic tool, rather than restoring food culture (i.e. the set of food representations and practices learned and shared by the members of a particular social group), it involves an enculturation in dietetic normalization largely devoid of the sociocultural functions attributed to food. Because of their normative parallelism with the following of any diet (e.g. the use of highly-specific competencies, mechanisms and protocols), these prescriptions hinder not only the therapeutic success of the treatment but also the social integration of the people undergoing treatment due to the partial interruption and routinization of daily life that they involve.

Synthesis, photophysics and electroluminescence of new vinylene-copolymers with 2,4,6-triphenylpyridine kinked segments along the main chain

Two new vinylene alternating copolymers F and C that contained 2,4,6-triphenylpyridine as a common moiety and fluorene or carbazole, respectively, as an alternating moiety were prepared by Heck coupling. They showed an outstanding thermal stability being stable up to approximately 350 °C and had relatively high glass transition temperatures (140 and 111 °C). The existence of the 2,4,6-triphenylpyridine kinked units along the polymer backbone caused a partial interruption of the π-conjugation. The copolymers emitted blue-green light with emission maximum at 446–464 nm and quantum yields of 0.52 and 0.28 in THF solution. The electrochemical properties of copolymers F and C, including HOMO and LUMO levels, were estimated from their cyclic voltammograms. Their electroluminescence (EL) emission maxima (greater than 500 nm) showed significant red-shifts relative to the PL maxima, which has been explained by the direct cross recombination transition between electrons and holes trapped on carbazole or triphenylpyridine subunits. Moreover, the emission colors transform gradually with increasing bias and approach to white color at about 30 ∼ 35 V. The maximal luminance (maximal luminance efficiency) of the EL devices (ITO/PEDOT:PSS/ F or C/Ca/Al) were 647 cd/m 2 (0.13 cd/A) or 615 cd/m 2 (0.10 cd/A), respectively.

Hydrogen Absorption in Transition Metal Silicides: La3Pd5Si-Hydrogen System

Pressure-composition isotherm measurements show that the ternary lanthanum palladium silicide phase La3Pd5Si absorbs reversibly up to 5 hydrogen atoms per formula unit at 550 K and 14 bar hydrogen pressure. In-situ synchrotron and neutron powder diffraction reveals three phases, an alpha-phase having the limiting composition La3Pd5SiD approximately 1.6 at low deuterium pressure (at up to 9.5 bar D2 and 550 K), a beta-phase La3Pd5SiD approximately 2.30-4 at intermediate deuterium pressure (<9.5 bar D2 and 550 K), and a relatively unstable gamma-phase La3Pd5SiD approximately 5 at high deuterium pressure (obtained at 75 bar D2 and 293 K). While the alpha and beta phases retain the symmetry of the H-free La3Pd5Si (space group Imma), the gamma-phase undergoes a symmetry lowering (a(gamma) approximately a(beta), b(gamma) approximately 3b(beta) and c(gamma) approximately c(beta), V(gamma) approximately 3V(beta), space group Pmnb). The structure of the alpha-phase contains isolated [Pd-D-Pd] fragments, which are joined into polymeric (-Pd-D-Pd-)n zig-zag chains in the beta-phase. In the gamma-phase some D sites depopulate, while new D sites are occupied, thus leading to a partial interruption of the zig-zag chains and the formation of isolated [D-Pd-D-Pd] and [D-Pd-D-Pd-D] fragments. This unexpected behavior can be attributed to the onset of repulsive Si-D and D-D interactions (Si-D > 3.0 A, D-D > 2.1 A) that divide the structure into Si-poor slabs that absorb hydrogen and Si-rich slabs that do not. The competition between silicon and deuterium which act as a transition metal ligand is further underlined by the fact that Pd atoms having one Si ligand are capable of forming Pd-D bonds, whereas Pd atoms having two Si ligands are not.

Kinematic evaluation of gestural and repetitive single joint movements of the arm after posteroventral pallidotomy, subthalamotomy or both procedures combined in two Parkinson’s disease patients: two case studies

Two patients with severe Parkinson's disease undergoing partial or complete ablative interruption of basal ganglia (BG) output are presented. One patient who underwent bilateral subthalamotomy, and a second who underwent unilateral posteroventral pallidotomy, followed 7 years later by a bilateral subthalamotomy because of contralateral disease progression, were studied. In addition to the usual clinical evaluation, changes in joint kinematics observed during unconstrained, skilled multi-joint movement and repetitive single joint (RSJ) movement of the wrist were studied. Clinical UPDRS items referred to hand movements contralateral to the procedure, and instrumental measurement of RSJ improved in both patients after either pallidotomy or subthalamotomy. When both BG outflow paths were interrupted as was the case in the second patient (bilateral subthalamotomy after the initial pallidotomy), no added clinical improvement was observed, RSJ even deteriorated slightly. Instrument-based studies for movement alteration detection after simultaneous ablation of the globus pallidus and the subthalamic nucleus of these two patients showed greater sensitivity than clinical evaluation alone. Complex gestural movement performance remained unaffected after partial (subthalamotomy or pallidotomy) or complete interruption of BG outflow (case 2), indicating BG compensatory capacity after total outflow interruption remained intact.

After Virologic Rebound, Should T-20 Be Continued?

For patients who do not achieve full HIV suppression on potent combination antiretroviral therapy, the key management question is whether to continue or stop the drugs that are incompletely suppressive. The SMART study demonstrated that stopping antiretroviral therapy completely is not a good strategy (ACC Nov 29 2006), but partial treatment interruption may be a viable approach for selected patients. For some agents (such as 3TC), clinical trial data verify that the drug has continued activity and favorable effects despite high-level resistance. For other agents, however, the situation is less clear, and a particularly vexing decision is whether to continue T-20. T-20 is difficult …

Partial treatment interruption of a protease inhibitor (PI)-based HAART regimen reduces drug-related toxicities,

Partial treatment interruption of a protease inhibitor (PI)-based HAART regimen reduces drug-related toxicities,

Partial treatment interruption of a protease inhibitor (PI)-based HAART regimen reduces drug-related toxicities,

Partial treatment interruption of a protease inhibitor (PI)-based HAART regimen reduces drug-related toxicities,

Evaluation of Esophageal Peristalsis in Patients with Esophageal Tumors: Initial Experience with Cine MR Imaging

We evaluated esophageal peristalsis in patients with esophageal tumors by cine MR using steady-state free precession (SSFP) sequence and correlated the alteration of the esophageal peristalsis with clinical symptoms and tumor stages. Thirteen patients with pathologically proven esophageal tumors, including 12 esophageal cancers and one submucosal leiomyoma, underwent cine MRI using true fast imaging with steady precession (trueFISP) sequence, which is one SSFP sequence, after contrast-enhanced MR scanning for clinical purposes. A total of 120 serial images were obtained within 60 s through the plane along the long axis of the esophagus while patients chewed gum. The serial trueFISP images were evaluated for the presence, frequency, speed of progression, and passage of peristalsis through the tumor. The data from cine MRI were compared with clinical symptoms and tumor stages. Peristalsis was clearly identified in all patients. Seven patients with complete interruption of peristalsis had dysphagia; one with partially impaired peristalsis could intake solid foods with discomfort; and two with partially impaired peristalsis and three with preserved peristalsis remained asymptomatic. Patients with complete or partial interruption of peristalsis had Stage T3 or T4 esophageal cancer. In conclusion, trueFISP cine MR imaging enables direct visualization of esophageal peristalsis in relation to esophageal tumors. Complete interruption of peristalsis causes dysphagia, whereas partial interruption of and preserved peristalsis usually do not cause digestive problems. Interruption of peristalsis may indicate impaired muscle function caused by invasion of advanced esophageal cancers.

Luminescent poly(phenylene vinylene) derivatives with m‐terphenyl or 2,6‐diphenylpyridine kinked segments along the main chain: Synthesis, characterization, and stimulated emission

AbstractTwo new poly(phenylene vinylene)s containing m‐terphenyl or 2,6‐diphenylpyridine kinked units along the main chain were synthesized and were used as luminescent and laser materials. They were prepared from Heck coupling of 2,5‐didodecyloxy‐1,4‐divinylbenzene with 4,4″‐dibromo‐3′‐phenyl‐m‐terphenyl or 2,6‐di(4‐bromophenyl)‐4‐phenylpyridine. The kinked units along the main chain caused a partial interruption of the conjugation leading to emission at a shorter wavelength as compared with poly(p‐phenylene vinylene). The polymers presented blue‐green emission in solution and green‐yellow emission in the solid state with photoluminescence maxima at 465–497 and 546–550 nm, respectively. Polymer containing 2,6‐diphenylpyridine segments emitted at a longer wavelength than that containing m‐terphenyl and displayed higher quantum yields in solution (0.61 and 0.40, respectively). The influence of the solvent and polymer concentration on the photoluminescence characteristics was investigated. The photoluminescence properties of protonated polymer containing 2,6‐diphenylpyridine segments were investigated both in solution and in film. Amplified spontaneous emission and tunable laser action were also obtained from the two polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2214–2224, 2004

Epipelagic mesozooplankton distribution and abundance over the Mascarene Plateau and Basin, south-western Indian Ocean

The crescent shaped Mascarene Plateau (south-western Indian Ocean), some 2200 km in length, forms a partial barrier to the (predominantly westward) flow of the South Equatorial Current. Shallow areas of the Mascarene Plateau effectively form a large shelf sea without an associated coastline. Zooplankton sampling transects were made across the plateau and also the basin to the west, to investigate the role the partial interruption of flow has on zooplankton biomass and community structure over the region. Biomass data from optical plankton counter (OPC) analysis, and variability in community structure from taxonomic analysis, appear to indicate that the obstruction by the plateau causes upwelling, nutrient enrichment and enhanced chlorophyll and secondary production levels downstream. The Mascarene Basin is clearly distinguishable from the ridge itself, and from the waters to the south and north, both in terms of size-distributed zooplankton biomass and community structure. Satellite remote sensing data, particularly remotely-sensed ocean colour imagery and the sea surface height anomaly (SSHA), indicate support for this effect. A correlation was found between OPC biovolume and SSHA and sea surface temperature (SST), which may indicate the physical processes driving mesozooplankton variability in this area. Biomass values away from the influence of the ridge averaged 24 mg m -3 , but downstream of the ridge biomass averaged 263 mg m -3 . Copepods comprised 60% of the mean total organisms. Calanoid copepod numbers varied considerably between regions, being lowest away from the influence of the plateau, where higher numbers of the cyclopoid copepods Oithona spp., Corycaeus spp. and Oncaea spp., and the harpacticoid Microsetella spp. were found.