Adjacent Valves Research Articles

A Rare Combination of Double Orifice Mitral Valve With Noncompaction of Left Ventricle

A 52-year-old gentleman, with a diagnosis of triple vessel coronary artery disease, underwent coronary artery bypass grafting. Intraoperative transesophageal echocardiography revealed an incidental diagnosis of double orifice mitral valve (DOMV) along with left ventricular noncompaction (LVNC). Three-dimensional zoom views showed the medial and lateral orifices of the DOMV and its relationship with adjacent valves (Figure 1, left atrial view; Figure 2, left ventricular view). In the midesophageal 2-chamber view (Figure 3A), the Chin index confirmed the LVNC.

Impact of isolation valves location on resilience of water distribution systems

ABSTRACT The isolation valves are crucial components of water distribution systems (WDS) that are used to shut down a segment of the network to repair or replace failed pipes. In this paper, an algorithm to find adjacent valves to isolate a failed pipe was proposed and the global resilience analysis method was implemented to find out the critical segments based on the isolation valves. The method was applied to Net3 network with three different isolation valve configurations. The location of isolation valves changed the resilience of the WDS considerably. The critical pipes and segments were also varied with different valve configurations. More than 60% of the most critical pipes are different between N valves and N-1 valves configurations. The resilience of limited valves configuration (with 52 valves) was 22% and 15% less than the resilience of N valves and N-1 valves configurations with 228 and 105 valves, respectively. Furthermore, with adding valves to the critical segments, the resilience can be enhanced noticeably.

Anatomic and surgical factors affecting the switch from minimally invasive transthoracic occlusion to open surgery during ventricular septal defect repair.

This study aimed to investigate the specific causes for switching patients from minimally invasive transthoracic occlusion to surgical repair under cardiopulmonary bypass (CPB). By retrospectively analyzing 340 cases, we sought to provide the clinical reference for improving the success rate of minimally invasive transthoracic device closure of ventricular septal defect (VSD). Among the 340 patients who underwent transthoracic closure of VSDs in the past 3 years at our hospital, 26 patients needed to be switched to surgical repair under CPB due to failure of transthoracic closure. We investigated the causes by retrospectively analyzing the findings from preoperative transthoracic echocardiography (TTE), intraoperative transesophageal echocardiography (TEE) and surgical exploration. Among the 340 patients who underwent transthoracic closure of VSDs, 26 patients (7.65%) were switched to surgical repair under CPB, which included 11 cases of membranous aneurysm (13.10%), 13 cases of perimembranous type (6.22%) and 2 cases of intracristal type (5.00%) according to their anatomic classifications. Among the 186 patients who underwent transthoracic closure during the first 17 months, 20 patients (10.75%) were switched to surgical repair under CPB. The main causes were failure of the delivery system to pass through the VSD in 7 patients, obvious residual shunts after releasing the occluder in 5 patients, significant shedding or shifting after releasing the occluder in 4 patients, significant regurgitation in adjacent valves in 3 patients and severe intraoperative complication (bleeding) in 1 patient. Among the 154 patients who underwent transthoracic closure during the late 17 months, 6 patients (3.90%) were switched to surgical repair under cardiopulmonary bypass. The main causes were significant residual shunts after releasing the occluder in 3 patients, significant regurgitation in adjacent valves in 2 patients after releasing the occluder and failure of the delivery system to pass through the VSD in 1 patient. Among all the anatomic classifications, membranous aneurysm VSD had the highest risk for switching from minimally invasive transthoracic closure to surgical repair under CPB. During the early period, the surgeons were not yet skilled with the minimally invasive transthoracic closure procedure, and the main causes of switching to surgical repair under CPB were that the delivery system could not pass through the ventricular septal defect and significant residual shunts persisted after releasing the occluder. In contrast, in the late period, the surgeons were skilled with the minimally invasive transthoracic closure procedure, and the main causes were significant residual shunts and obvious regurgitation in adjacent valves after releasing the occluder.

상수관망에서의 밸브에 의한 관의 부분적 격리와 상수관망의 효율성 평가

최근의 상수관망의 안전도 확보, 부가적 용수공급로 확보, 그리고 관(管)내 배수를 위한 부분적인 상수관망의 격리문제가 대두 되면서 이를 위한 밸브역할의 중요성이 인식되고 있다. 기본적인 상수관망에서의 밸브역할은 물의 흐름과 압력조절 그리고 관 파괴와 오염물 확산시 부분적 관의 격리라고 할 수 있다. 이중 본 논문에서는 관의 격리 기능을 중심으로 밸브를 해석한다. 관의 파괴로 인한 부분적인 상수관망의 격리시에 일반적으로 그 관만이 아닌 주변의 다른 관들도 함께 격리가 될 수 있으며 이것은 격리하고자하는 관에 설치된 밸브배치에 따라 달라진다. 본 논문에서는 밸브의 배치에 따라 함께 격리되는 관들을 하나의 단위로 보며 이것을 "Segment"라 부른다. Segment에 따라 실제 격리되는 관의 범위가 주어지며 이것에 따라 전체 상수관망을 나눈 후 각 밸브의 중요도와 상수관망의 효율성 평가에 이용한다. 효율성 평가를 위해 7개의 효율성 지수를 제안하며 실제 상수관망에 적용하여 사용성을 검증한다. Recent concerns regarding protecting, identifying, isolating, redundant routing and dewatering of subsystems of water distribution networks have led to the realization of the importance of valves in these systems. Valves serve two purposes namely, flow and pressure control and isolating subsystems due to breakage or contaminant containment. In this paper, valves are considered from the point of view of subsystem isolation. When a water main is required to be closed, it may be in general necessary to close several other pipes in addition to the broken pipe itself depending on the distribution of adjacent valves. This set of pipes is defined as a segment. In this paper a segment analysis for isolating pipes is present and based on the segment analysis, we suggested the Valve Importance Index and the 7 performance indicators to evaluate the system performance. The suggested methodology is applied to a real network to verify the applicability of the methodology.

Sternoclavicular septic arthritis: review of 180 cases.

We review 170 previously reported cases of sternoclavicular septic arthritis, and report 10 new cases. The mean age of patients was 45 years; 73% were male. Patients presented with chest pain (78%) and shoulder pain (24%) after a median duration of symptoms of 14 days. Only 65% were febrile. Bacteremia was present in 62%. Common risk factors included intravenous drug use (21%), distant site of infection (15%), diabetes mellitus (13%), trauma (12%), and infected central venous line (9%). No risk factor was found in 23%. Serious complications such as osteomyelitis (55%), chest wall abscess or phlegmon (25%), and mediastinitis (13%) were common. Staphylococcus aureus was responsible for 49% of cases, and is now the major cause of sternoclavicular septic arthritis in intravenous drug users. Pseudomonas aeruginosa infection in injection drug users declined dramatically with the end of an epidemic of pentazocine abuse in the 1980s. Sternoclavicular septic arthritis accounts for 1% of septic arthritis in the general population, but 17% in intravenous drug users, for unclear reasons. Bacteria may enter the sternoclavicular joint from the adjacent valves of the subclavian vein after injection of contaminated drugs into the upper extremity, or the joint may become infected after attempted drug injection between the heads of the sternocleidomastoid muscle. Computed tomography or magnetic resonance imaging should be obtained routinely to assess for the presence of chest wall phlegmon, retrosternal abscess, or mediastinitis. If present, en-bloc resection of the sternoclavicular joint is indicated, possibly with ipsilateral pectoralis major muscle flap. Empiric antibiotic therapy may need to cover methicillin-resistant Staphylococcus aureus (MRSA).

PINNULARIA SOFIA VAN DE VIJVER & LE COHU SPEC. NOV., A NEW SPINE-BEARING, CHAIN-FORMING PINNULARIA SPECIES FROM THE SUB-ANTARCTIC REGION

The spine-bearing diatom Pinnularia sofia Van de Vijver & Le Cohu spec. nov. is described from the sub-Antarctic Heard Island. The morphology of this species was examined using the scanning electron microscopy (SEM). The most striking feature of the new taxon is the presence of three groups of wart-like or spathulate spines that connect adjacent valves to form short chains comprising 2 to 6 individuals. The taxonomical position of the new taxon is discussed, comparing it with similar freshwater Pinnularia taxa present on the same island, such as P. subantarctica (Manguin) Van de Vijver & Le Cohu and its variety elongata (Manguin) Van de Vijver & Le Cohu, as well as the elusive P. circumducta Manguin. A short review is made of all spine-bearing and/or colonial Pinnularia taxa described so far. Notes on its ecology are included.

Observations on Chaetoceros salsugineus (Chaetocerotales, Bacillariophyceae): first record of this bloom-forming diatom in a European estuary

Examination of material obtained from the Urdaibai estuary (North Spain) during a 2 year phytoplankton sampling programme revealed a rare species of the genus Chaetoceros, C. salsugineus Takano. The morphology of this small (4·0×5·5 µm) member of the subgenus Hyalochaetae has been described using both light and electron microscopy. Regarding the original material, two new features have been observed: longer chains up to 24 cells and a new type of aperture, bisected by the fusion of central protuberances of adjacent valves. This bloom-forming diatom reached high densities in the poly-euhaline zone of the estuary closely related with high temperatures, denoting its neritic and summer preferences. Maximal cell densities (106–107 cells l−1) were reached in August and September when the water column was completely mixed and the salinity and temperature were about 31 psu and 20°C, respectively. This is the first report of C. salsugineus in Europe and contributes to the knowledge of the morphological and ecological features of this species. Relationships with other small species of the subgenus Hyalochaetae are also discussed.

Thermal optimization of a micro valve array

This paper describes the thermal optimization of an array of thermopneumatically actuated microvalves. The valve density achieved in the current prototype amounts to 100 valves per square inch. Thin valve membranes of less than 3 μm thickness allow for low temperature actuation. In order to reduce thermal cross talk between adjacent valves, cooling channels and insulating trenches have been introduced. It could be shown that these features reduce thermal cross talk and thus enhance array performance. The effectiveness of the cooling channels was characterized both experimentally and by means of finite element simulations. Since available theories for convective heat transfer showed some discrepancies for the examined device, the average heat transfer coefficient was determined experimentally. The comparison of computational simulation results and infra-red measurements showed good agreement. Finite element models allow reliable prediction and optimization of the performance of high-density valve arrays.

Fibrous obstruction within the left ventricular outflow tract associated with ventricular septal defect: A pathologic study

Objectives. We examined the nature of ridges within the left ventricular outflow tract associated with ventricular septal defects that might be found by echocardiography.Background. Echocardiography displays even small ridges well. Surgical removal of such ridges at the time of defect closure is recommended.Methods. We examined 37 heart specimens with ventricular septal defects with a ridge, noting its nature and relation to the defect and adjacent valves. We excluded left ventricular outflow tract obstruction associated with complex lesions.Results. Defects were perimembranous in 25 specimens, muscular in 8 and part of an atrioventricular septal defect in 5. Some hearts had multiple defects. Many of the original reports had not mentioned ridges. Three distinct ridge patterns were found. The first (n = 18) was a fold of endocardial tissue related to the membranous septum. The second (n = 12) was a defect of a fibrous nature; in 8 this was a discrete, protuberant fibrous ridge, and in 4 the obstruction was diffuse, which we termed keloidal. The third pattern (n = 7) lay circumferentially around the ventricular septal defect, seemingly associated with the defect's attempted spontaneous diminution in size. Endocardial folds were not found in specimens from patients > 5 years old. Fibrous and keloidal lesions, which may represent a continuum of progression, generally were found in specimens from older patients. Histologic studies of 17 specimens confirmed the morphologic findings. The endocardial folds were endothelial tissue, whereas the fibrous and keloidal ridges were of fibrous tissue, as were circumferential lesions. All specimens had mitral-semilunar valvular continuity.Conclusions. Endocardial fold and circumferential lesions appear to be benign. The endocardial folds arose from the membranous ventricular septum, were not protuberant and usually were found in younger patients. The fibrous ridges, in contrast, were protuberant and were always associated with the underlying muscle of the outlet septum. These pathologic distinctions may facilitate echocardiographic diagnosis and prognosis.

Structure of lymphatics in rat cecum with special reference to submucosal collecting lymphatics endowed with smooth muscle cells and valves. I. A scanning electron microscopic study.

The three-dimensional structure of lymphatic vessels in the rat cecum was studied by KOH-collagenase digestion/scanning electron microscopy (SEM), and corrosion casting/SEM. Abluminal surfaces of the lymphatic vessels show flat elliptical nuclear regions and flat cytoplasmic processes interdigitated with adjacent ones. The lymphatic capillaries closed by interdigitations of flat endothelial processes at their initial portion begin at the various levels of the mucosa. They descend and pass through the muscularis mucosa to connect with the lymphatic vessels in the submucosa. They form polygonal meshwork, the distances between intersections being about 0.2-0.5 mm. They also have valves, the distances between adjacent valves being about 0.1-0.6 mm. Most of the submucosal lymphatic vessels are surrounded by either periendothelial cells or typical smooth muscle cells. The polygonal meshworks made up of stellate periendothelial cells with many irregular processes embrace the initial segment of the collecting lymphatics. As they proceed proximally, the periendothelial cells become elongated and branch out by threes or fours, thus presenting the appearance of smooth muscle cells. These branches are connected side by side and run obliquely along the vessels, thus forming polygonal meshworks around the vessels. The more proximal collecting lymphatic vessels are surrounded by circularly oriented smooth muscle cells. Our results indicate that most of the lymphatic vessels in the submucosa are collecting ones and possess smooth muscle cells as well as valves. This suggests that the lymphatic vessels in the submucosa actively contract and propel the lymph towards the mesenteric lymphatic vessels.

Venous valve anatomy and morphometry: studies on the duckling using vascular corrosion casting.

The anatomy and morphometry of venous values associated with the vasculature of the head of the duckling were studied using vascular corrosion casting and scanning electron microscopy. All valves encountered were bicuspid, and casts typically exhibited slight expansions at valve sinuses and deep slits at the sites of valve leaflets. The locations, numbers, and orientations of endothelial nuclei on all surfaces of the valves were clearly revealed by imprints in the casting resin. Endothelial cell densities were significantly higher on the surfaces of valve leaflets (about 10 cells/1,000 micron2) than on other venous surfaces (about 7 cells/1,000 micron2). Endothelial nuclei on the medial surface of the valve leaflet were oriented parallel to the long axis of the vessel, whereas those on the lateral surface were oriented perpendicular to that axis. The close proximities of valves in some vessels and the presence of anomalies such as the sharing of leaflets by adjacent valves were readily demonstrated with the corrosion-casting techniques. These methods provide a useful means for studying the fine, three-dimensional details of venous valve anatomy.

VALVE AND BAND MORPHOLOGY OF SOME FRESHWATER DIATOMS. III. PRE‐ AND POST‐AUXOSPORE FRUSTULES AND THE INITIAL CELL OFMELOSIRA ROESEANA1

ABSTRACTFrustules of a clonal culture ofMelosira roeseanaRabenh. were examined with light and scanning electron microscopy. Vegetative valves in the post‐auxospore (full size) stage exhibit a larger width/length ratio than those in the pre‐auxospore (size‐reduced) stage. Cells form chains by linking spines of adjacent valves which occur at the periphery of the valve face‐mantle junction. Three or jour large pores occur at the center of the valve face, with the diameter of each pore tapering from the inner to the outer valve surface; these pores are often occluded by siliceous processes. Features ofM. roeseana,not shown previously forMelosira,include a “stepped” mantle, on only one of the two valves resulting from the same cell division, flattened processes attached to short siliceous stalks on the valve face, disk‐like processes on the mantle, and an open girdle band with up to eight antiligulae. Siliceous scales on the surface of the initial cell are remnants of the auxospore wall. The epivalve of the initial cell is larger in diameter than the hypovalve, and both valves lack linking spines and a step on the valve surface. The initial, cell epicingulum consists of only two bands; the hypocingulum has up to seven. Initial cells with four or more hypocingular bands divide to form new post‐auxospore filaments.Melosira roeseanashould not be included in the genusMelosiraas it is presently defined by the type species,M. nurnmuloidesC. Ag. Major differences include irregular linking spines, a closed pseudoloculate valve construction, and labiate processes on the valve face and mantle ofM. nummuloides,compared with well‐defined linking spines, a valve constructed of a basal siliceous layer perforated by poroid areolae, and labiate processes lacking on the valve ofM. roeseana.

VALVE AND BAND MORPHOLOGY OF SOME FRESHWATER DIATOMS I. FRAGILARIA CAPUCINA VAR. MESOLEPTA1,2

ABSTRACT Acid cleaned cells from clonal cultures of Fragilaria capucina var. mesolepta Rabh. were examined with light and scanning electron microscopy. Recently isolated cells are linear‐lanceolate in shape with a median constriction. After several transfers over 25 mo, cells exhibit size diminution resulting in small elliptically shaped valves. Adjacent valves are united to one another by interlocking marginal spines. Every valve has an apical pore field at each apex. A single labiate process is present infrequtently, appearing underdeveloped most often in size‐reduced cells. The girdle region consists of two cingula, each composed of a series of underlapping bands. Each pleura in the series is a discontinuous ring with a central ligula. A survey of past ultrastructure studies on the freshwater Fragilariaceae reveals that the occurrence of the apical pore field and labiate process are likely key characteristics for the family. The apical pore field of Diatoma, Asterionella and Tabellaria is positioned on the valve face, whereas the apical pore field of F. capucina var. mesolepta is located on the valve mantle, the girdle region of F. capucina var. mesolepta is basically similar to that of Gomphonema parvulum (Kütz.) Grun.

A Scanning Electron Microscope Study of the Frustule Structure of the Freshwater Diatom Melosira Granulata (Ehr.) Ralfs

Frustules of the freshwater diatom Melosira granulata (Ehr.) Ralfs from a freshwater diatomite of Miocene age and recent frustules of this species from Reelfoot Lake, Tennessee were examined under a scanning electron microscope to determine fine structure generally not seen or poorly seen with the conventional light microscope.The terminology used to describe frustule structure in this study was originated by Hendy.Melosira granulata generally grows in chains of two connected frustules with each frustule containing two valves or halves. The connection between frustules is accomplished by the encasing of the adjacent valves of two frustules by a structure called the girdle (Fig. 1a).