Flat Valve Research Articles

Description of the pseudocryptic species Conticribra weissflogiopsis sp. nov. (Thalassiosirales, Bacillariophyta) isolated from brackish waters in Korea, based on its cingulum structure and molecular analysis

We describe the new fultoportulate diatom species, Conticribra weissflogiopsis, isolated from brackish waters in Korea, based on morphological characters and molecular data. The new species is characterized by having areolae venation with internal (semi-) continuous cribra, a flat valve face, a single marginal rimoportula replacing a marginal fultoportula, a subcentral ring of the valve face fultoportulae, and a dextral pattern of cingulum structure. The overall valve structure of C. weissflogiopsis resembles that of C. weissflogii; however, the cingulum structure differs between the two species—C. weissflogiopsis has a dextral offset of band opening in the cingulum, whereas C. weissflogii has a sinistral offset. Phylogenetic analysis of the nuclear small subunit ribosomal DNA (SSU rDNA) revealed that C. weissflogiopsis is located in the Conticribra clade. Further, the pairwise genetic distance based on the SSU rDNA and the internal transcribed spacer 2 (ITS2) indicated that C. weissflogiopsis is a distinct Conticribra species. On the basis of the morphology and molecular phylogeny, we expand the hypothesis regarding the morphological evolution of Conticribra species.

Two new species of monoraphid diatom (Bacillariophyceae) from South of China

Two new monoraphid diatoms, Psammothidium hainanii Kociolek & Liu sp. nov. and Platessa guagnzhouae Liu & Kociolek sp. nov., are described. Both species were collected from southern China, from Hainan and Guangzhou province, respectively. Psammothidium hainanii is distinguished from other species by its unique outline and rectangular central area on the rapheless valve. Platessa guangzhouae has uniseriate areolae in both valves, similar to some Psammothidium species, but it also has features of a flat valve, terminal raphe fissures lacking, a hyaline ring round the margin, and one areola at the end of each stria. Based on these features we have placed it in the genus Platessa. The bow-tie shaped central area on the raphe valve and uniseriate areolae on the rapheless valve help to separate it from other Platessa species.

Fracture Analysis of the Weld Alloy Plate of Flat Valve

In order to optimize the well control equipments of nitrogen drilling, the wellhead equipments have been inspected and analyzed systematically, and the failure analysis has been performed for the fracture at the through hole of two valve plates of flat valve at the side outlet of the multi-function four-way valve in this paper. The fracture reason of the valve plates is explored from macroscopic morphology analysis, chemical composition analysis, mechanical property test, SEM analysis and macroscopic analysis respectively. SEM scanning shows that more precipitates have been separated out nickel-based solid solution in Ni60 welded alloy layer. The spectrum analysis shows that these precipitate phases are rich chromium evolution phases. The valve plate cracks are originated in the welded alloy layer. The final fracture of valve plate is a cleavage fracture and the mechanism is brittle fracture.

Accurate Assessment of Aortic Stenosis

Aortic valve (AV) stenosis is one of the most common valvular diseases and is the third most common cardiovascular disease in developed countries. It occurs in ≈2.8% of patients ≥75 years of age and can occur because of degenerative calcification and congenital valvular defects such as bicuspid AVs or rheumatic disease.1–3 Calcific aortic stenosis (AS) is associated with increased leaflet stiffness and a narrowed AV orifice, resulting in increased pressure gradients across the valve. The presence of a bicuspid AV significantly increases the risk of AS.4 The natural history of AS is a prolonged asymptomatic period, with progressive reduction of the AV orifice area due to sclerosis initially, culminating in calcific AS. This is accompanied by a corresponding increase in the transaortic pressure gradient (Δ P ) and myocardial pressure overload. Through the preload reserve, the left ventricle (LV) compensates for the increased workload until the sarcomeres stretch to their maximum diastolic length. Once the preload reserve is exhausted, increases in afterload are accompanied by a reduction in stroke volume (SV), resulting in afterload mismatch. Ultimately, this causes LV hypertrophy, associated with an enlargement of cardiac myocytes and increased LV wall thickness.5 Initial diagnosis of AS typically occurs during routine physical examination with the presence of a heart murmur, click, or other abnormal sounds, but undiagnosed patients may experience the onset of severe symptoms such as angina, syncope, and heart failure. Without intervention, patient mortality typically occurs within 5 years of the onset of symptoms.6–11 Multiple studies and reviews have focused on the clinical aspects of this disease, including disease progression, markers of disease severity, treatment guidelines, and outcomes.1–3,6,12–16 Very few reviews have focused on the hemodynamic principles underlying AS and on comparing data obtained across different …

Comparison of two new species of astogloia Bacillariophyceae) with other small members of section Ellipticae

In this study, seven Mastogloia species belonging of the section Ellipticae are morphologically described through scanning electron microscopy, including two new taxa M. matthaei and M. stellae. They were collected as epiphytes on seagrasses from several tropical (Indonesia), subtropical (Egypt, Greece, Republic of Malta, Turkey) and temperate (Slovenia, Italy) regions of the world. All these species show typical characters of the Hustedt’s section Ellipticae: elliptical valve outline, a flat valve surface and rounded apices. Moreover, this study provides novel information on the frustule ultrastructure and gives update of their current geographical distribution. Some nomenclatural inconsistencies have been resolved with the typification of M. ovulum and the related species, M. emarginata, from the original Miang Besar material in the Hustedt collection.

Two new <i>Orthoseira</i> species (Bacillariophyceae) from lava tubes on Île Amsterdam and Big Island (Hawai΄i)

Two new species of Orthoseira from lava tubes on Île Amsterdam and Big Island (Hawai΄i) are described using light and scanning electron microscopy: Orthoseira johansenii Lowe & Kociolek sp. nov., from Hawai’i, and O. verleyenii Van de Vijver sp. nov., from the subantarctic. Both species have flat valve surfaces, the striae on the mantle are composed of uniseriate areolae and the valve face areolae are small and more or less irregularly scattered, occupying almost 2/3 of the total valve face surface. The areolae in O. johansenii are occluded by an internal velum; no velum was detected in O. verleyenii. In the centre of the valve is a small central hyaline area with 1–6 carinoportulae in O. verleyenii, 2–4 in O. johansenii. A distinct ring of marginal linking spines or straight, non-linking spines are present at the valve face/mantle junction. No caverns or internal undulations are present. Internal valves have not been encountered. Both Orthoseira johansenii and O. verleyenii have valves of about the same dimensions. The two species differ in that O. verleyenii shows a rather regular striation pattern near the valve face/mantle junction is noted whereas this is not the case in O. johansenii. Moreover, O. johansenii short slits between the carinoportulae on the internal valve side are absent whereas in O. verleyenii most valves possesses these slits. The two new species are compared with others in this small (ca. 15 species) genus. The biogeographic implications of species separated by 15,000 km are discussed.

Quantitative analysis strengthens qualitative assessment: a case study of Devonian brachiopod species

Species recognition attributed to the brachiopod family Atrypidae is evaluated based on qualitative and quantified morphological characters. I identified two brachiopod species—Pseudoatrypa lineata and Pseudoatrypa devoniana—from a rich assemblage of brachiopods recovered from the middle Devonian Genshaw Formation of the Traverse Group. Qualitative examination suggested that the former had fine-medium-sized ribbing, a narrow hinge line, widened anterior, moderately steep mid-anterior fold, domal shaped dorsal valve, and an inflated ventral valve in contrast to the coarse ribbing, widened hinge line, narrow anterior, gentle mid-anterior fold, arched-shape dorsal valve, and flat ventral valve of the latter. The shell outline appears rounded for P. lineata and elongated for P. devoniana. Quantitative assessment of the morphological characters on the dorsal, ventral, anterior, and posterior regions of the valves of the two species using geometric morphometric and statistical analyses suggests that the morphologies of the two species are considerably different (P \( \ll \) 0.01). Thus, qualitative differences between the two atrypid species were further corroborated by quantitative results. This emphasizes the fact that these two species of Pseudoatrypa were indeed different from each other. This study highlights the necessity of incorporating quantified morphological characters to successfully investigate the taxonomic distinctness of fossil invertebrates to the species level.

A new species of Eucocconeis (Bacillariophyceae) from North America

A new diatom species, Eucocconeis americana, is described from eastern North America. The new species differs from previously reported representatives of Eucocconeis Cleve by relatively flat valves and the characteristic shape of the central areas in both raphe and rapheless valves. We present details on the frustule structure and size variation, and compare the new species with other representatives of Eucocconeis. This new species was found in rivers and streams from the eastern USA characterized by low conductivity and pH.

New species and combinations in monoraphid diatoms (family Achnanthidiaceae) from North America

This article clarifies the taxonomy and nomenclature of several monoraphid diatom species found in rivers and lakes of North America. The morphology of these diatoms is studied with light and electron microscopy. A new combination Rossithidium anastasiae (Kaczmarska) Potapova is introduced for a species common in both Europe and North America and often misidentified as Achnanthes linearis (W. Smith) Grunow or R. linearis (W. Smith) Round et Bukhtiyarova. Achnanthes harveyi Reimer, often found in eastern North America, is transferred to Psammothidium Bukhtiyarova & Round on the basis of the convex raphe valve, uniseriate striae, and raphe structure. A new Psammothidium species, P. pennsylvanicum Potapova is described and compared with the most similar taxon, P. semiapertum (Hustedt) Aboal. Diatoms originally described as Achnanthes lutheri Hustedt and A. stewartii Patrick are transferred to the genus Platessa Lange-Bertalot on the basis of biseriate striae, flat valves, and the absence of terminal raphe fissures. Two new Platessa species, P. kingstonii Potapova and P. bahlsii Potapova are described from the eastern USA and compared with most similar species, P. lutheri (Hustedt) Potapova and P. conspicua (A. Mayer) Lange-Bertalot, respectively. Achnanthes lanceolata var. abbreviata Reimer, found in the southeastern USA, is shown to possess multiseriate striae and relatively long terminal raphe fissures characteristic for the genus Planothidium Round & Bukhtiyarova, to which it is transferred.

Actinocyclus nipponicus sp. nov. and A. bradburyii sp. nov. (Bacillariophyta) from Miocene lacustrine sediments of the proto-Japan Sea

Hayashi T., Saito-Kato M. and Tanimura Y. 2012. Actinocyclus nipponicus sp. nov. and A. bradburyii sp. nov. (Bacillariophyta) from Miocene lacustrine sediments of the proto-Japan Sea. Phycologia 51: 98–112. DOI: 10.2216/11-17.1Fossil nonmarine Actinocyclus species, A. nipponicus sp. nov. and A. bradburyii sp. nov., are described from Miocene lake sediments in the Yamato Bank, the central part of the Japan Sea. Actinocyclus nipponicus is characterized by an inflated valve composed of a nearly flat valve face and an inclined mantle, a bullulate valve wall, fascicles sectioned by combinations of independent areola rows and hyaline stripes, loculate areolae with external cribra, rimoportulae at ends of hyaline stripes in the mantle, a single pseudonodulus at the valve face/mantle junction and well-developed spines. On the other hand, A. bradburyii is characterized by a noninflated valve composed of a nearly flat valve face and a very gently inclined mantle, a bullulate valve wall, loculate areolae with external cribra, fascicles sectioned by combinations of independent areola rows and hyaline stripes, rimoportulae at ends of hyaline stripes in the mantle, a single pseudonodulus within the valve face and misshapen cribra behind the pseudonodulus. In A. nipponicus, fascicles are composed of parallel areola rows in large valves, but are composed of radial areola rows in small valves. Additionally, in both A. nipponicus and A. bradburyii, changes in the number of rimoportulae (fascicles) occur as a function of valve size. Actinocyclus nipponicus and A. bradburyii are the most similar to A. trapeziformis and A. cupreus, respectively.

Analysis on Dynamic Performance of FlatValve in Water Hydraulic Piston Pump

Dynamic performance of a water hydraulic piston pump with flat valves was analyzed．Its mathematic model was established and influence factors were studied by simulation. The results show that reducing clearance volume, lighting spool quality and increasing spring stiffness are favorable to promote the performance of flat valve. In addition, higher vacuum degree and too high rotational speed will make flat valve delay more seriously. Work pressure also has influence on the opening delay to flat valve．

Homogenisation in the dairy process - conventional processes and novel techniques

Milk and dairy products are typical examples of high pressure homogenized commodities. High pressure homogenization is therefore a well established process and realized at around 10 Mio tons per year in the dairy industry. Milk and dairy products are homogenized to improve product properties such as color, consistency, taste, creaming stability, creaminess and mouthfeel [1]. The basic idea of high pressure homogenization is to pressurize an emulsion premix up to several hundred bars and then pump it through a disruption system (full stream homogenisation). State of the art as disruption systems are flat valves. Besides conventional flat valves a simple or complex orifice type of valves like the interaction chamber of Microfluidics® may also serve as disruption system [2]. Within the talk, different disruption systems will be compared with regard to disruption effectiveness and power efficiency. As high pressure is required for droplet disruption into the submicron range high investment, energy and maintenance costs result from high pressure homogenization processes. The product active ingredients are subjected to intense mechanical and thermal stresses. Problems in term of costs, maintenance and ingredient degradation may be overcome by a novel micro-structured orifice called “Simultaneous Emulsification and Mixing” (SEM) [3], which will be presented in the second part of the talk. It combines the two unit operations ‘mixing’ and ‘emulsification’ in one single process unit, which results in significant energy and cost reduction, product quality improvement and process intensification. For this, an additional stream (e.g skim milk for dairy processes) is injected directly into the droplet disruption zone of a high-pressure disruption system. The design of these SEM-valves is based on CFD simulations of local flow conditions. The fabrication of the valve is realized with micro process engineering tools. The influences of product and process parameters on energy efficiency and product quality are discussed for the dairy process.

Experimental Study on the Flat Valve for Use of Suction and Discharge of Power Sprayer

Experimental Study on the Flat Valve for Use of Suction and Discharge of Power Sprayer

Spring molybdenum enrichment in scallop shells: a potential tracer of diatom productivity in temperate coastal environments (Brittany, NW France)

Abstract. Skeletal molybdenum/calcium ([Mo]/[Ca])shell ratios were examined in shells of the Great Scallop Pecten maximus collected in temperate coastal environments of Western Europe (42 to 49° N). These ratios were determined by quantitative LA-ICP-MS analyses of daily striae taken every third day (i.e. a temporal resolution of 3 days) in 36 flat valves (2-years old; 3 shells/year). Variations of ([Mo]/[Ca])shell ratios were significant and reproducible for scallops from the same population, from different years (1998–2004) and temperate coastal locations (NW France). The [Mo]/[Ca])shell ratios exhibit typical profiles characterized by a background content, below the detection limit for this method (<0.003 μmol/mol) for most of the shell growth period, which is punctuated by a significant transient enrichment (0.031–2.1 μmol/mol) mainly occurring from May to June. The Bay of Brest (France) was investigated in particular because of its long term observations on scallop communities, environmental variables, and high resolution analyses of dissolved Mo in bottom seawater in 2000. In 2000, dissolved Mo exhibited a significant increase in concentration just preceding the maximum ([Mo]/[Ca])shell ratio. Both the intense monitoring survey in 2000 and over the 7-year period indicates that the ([Mo]/[Ca])shell maximum is directly influenced by spring changes of environmental conditions at the sediment water interface (SWI), occurring subsequent to the intense and periodic spring bloom. Spring maxima of ([Mo]/[Ca])shell ratios are closely correlated to the extent of silicic acid and nitrate depletion in seawater between winter and late spring (r2=0.878 and 0.780, p<0.05, n=6) that reflects diatom uptake and productivity in the Bay of Brest. The Mo inputs in bottom waters and subsequent shell enrichment are thus suggested to be directly or indirectly influenced by such biogenic material input at the SWI. The [Mo]/[Ca])shell records thus reveal unexpected biogeochemical cycles of Mo influenced by coastal spring productivity, faithfully recorded in scallop shells.

High frequency Barium profiles in shells of the Great Scallop <i>Pecten maximus</i>: a methodical long-term and multi-site survey in Western Europe

Abstract. Skeletal barium/calcium ([Ba]/[Ca])shell ratios were measured every third daily striae in 39 flat valves of the Great Scallop Pecten maximus collected in temperate coastal environments of Western Europe. A methodical evaluation of the ([Ba]/[Ca])shell ratio was performed for the first time and demonstrates that ([Ba]/[Ca])shell profiles are reproducible for several scallop individuals from the same population (2-year old; 3 shells/year), over a 7-year period (1998–2004), and from different coastal environments in France (42–49° N). As previously determined in the shells of other bivalve species, ([Ba]/[Ca])shell profiles generally exhibited a background ratio punctuated by two transient maxima occurring in early and late summer. Background partition coefficient (DBa=0.11±0.03, in 2000) was similar to that previously reported in P. maximus shells, suggesting a direct shell uptake of dissolved seawater Ba (Gillikin et al., 2008). The 7-year survey in the Bay of Brest of the high frequency ([Ba]/[Ca])shell profiles in the scallop's shell was exploited to better constrain both the occurrence and the amplitude of the summer Ba relative enrichments as influenced by environmental processes. Seawater Ba contents in 2000 underlined significant particulate Ba inputs at the sediment water interface (SWI) during ([Ba]/[Ca])shell peak events. These Ba inputs are thus suggested to be subsequently induced by a pelagic biogenic process, which mainly occurs under summer post-bloom conditions in relationship to the cycling of particulate organic matter and associated Ba. The long term survey reveals that such pelagic Ba cycling processes are responsible for particulate Ba inputs to the sediment water interface (SWI). Subsequent indirect Ba uptake by the bivalve results in higher ([Ba]/[Ca])shell ratios, in that archived Ba within the shell cannot be used as a direct paleo productivity tracer. Our methodical approach, based on a multi-year and multi-site-survey of ([Ba]/[Ca])shell ratio in Scallop bivalves, allows us to establish the potential application of such high frequency archives for further biogeochemical and ecological investigations of bivalves in the coastal environment.

Characterizing Idiomatic Organization in Music: A Theory and Case Study of Musical Affordances

A theory of idiomaticism is developed and illustrated using music for B- flat valve trumpet. Physical measures were collected from two trumpet performers and used to construct a computer model of the instrument/performer. Using this model, several works composed by both trumpet virtuosi and non-trumpet players were analyzed. A conceptual distinction is made between measures of performance difficulty (how hard it is to play a particular passage) and measures of performance idiomaticism (how well suited a passage is to a specific instrument). Methods for characterizing both difficulty and idiomaticism are described. In general, the results suggest that detailed modeling of the mechanics of performance can help to pinpoint aspects of musical organization that arise from performance idioms or affordances. Repercussions for ethnomusicology, historical musicology and music analysis are discussed. Submitted 2009 June 8; accepted 2009 July 15.

Substrate exploitation and resistance to biotic disturbance in the brachiopod Terebratalia transversa and the bivalve Pododesmus macrochisma

To test the hypothesis that epifaunal bivalves are more resistant to biotic disturbance than brachiopods, I evaluated abundances and body size of the brachiopod Terebratalia transversa and the anomiid bivalve Pododesmus macrochisma, which co-occur in the San Juan Islands (Washington State, USA, eastern Pacific). The proportion of bare space correlated with intensity of biotic disturbance had negative effects and surface rugosity had positive effects on abundance of T. transversa. Both rugophilic settlement and post-settlement mortality of juveniles due to biotic disturbance restrict T. transversa to crevices and complex substrates formed by solitary ascidians and giant barnacles. Its juveniles are under-represented on flat substrates, implying lower survivorship than in crevices, where juveniles are common. Abundance of the byssally-cemented bivalve P. macrochisma is negatively affected by rugosity and does not decrease with increasing bare space. P. macrochisma size patterns do not differ between crevices and flat substrates. Flat valves and high post-settlement mobility probably increase its juvenile survivorship under grazing pressure. T. transversa is not able to re-attach after settlement and is thus less resistant to grazing effects than P. macrochisma. This study supports the hypothesis that brachiopods are more negatively affected by biotic disturbance than epibyssate bivalves. Although brachiopods can be less preyed upon by carnivorous predators than epibyssate bivalves, T. transversa is affected more negatively by grazing than P. macrochisma. The evolutionary decline of brachiopod abundance in shallow habitats may represent responses to a heavy pressure on juveniles by grazers that evolved during the Mesozoic.

A fossil freshwater Thalassiosira, T. inlandica sp. nov. (Bacillariophyta), with semicontinuous cribra and elongated marginal fultoportulae

T. Hayashi, Y. Tanimura and H. Sakai. 2007. A fossil freshwater Thalassiosira, T. inlandica sp. nov. (Bacillariophyta), with semicontinuous cribra and elongated marginal fultoportulae. Phycologia 46: 353–362. DOI: 10.2216/06-60.1A fossil freshwater diatom species, Thalassiosira inlandica sp. nov., is described from Pleistocene lacustrine sediments of the Kathmandu Basin on the southern slope of the Nepal Himalaya. Thalassiosira inlandica is characterized by (1) a nonplicated (flat) valve face, (2) networks of ribs and costae, (3) semicontinuous cribra composed of the aggregate of many pore rows, (4) absence of valve face fultoportula, (5) elongated marginal fultoportulae, and (6) multiple rimoportulae in the mantle area. This new species is compared with allied taxa based on several morphological characters.

Cymatium (Gastropoda: Ranellidae) living inside the mantle cavity of the pterioidean bivalves Atrina, Pinna and Pecten

Cymatium (Gastropoda: Ranellidae) living inside the mantle cavity of the pterioidean bivalves Atrina, Pinna and Pecten

A comparison of the morphology and ultrastructure of the diatoms (Bacillariophyceae) Discostella stelligera and D. elentarii from two lakes in Fiordland, New Zealand

Morphological and ultrastructural variability of the diatoms, Discostella stelligera and Discostella elentarii, were examined from lakes Te Anau and Manapouri, located in Fiordland on the South Island of New Zealand. The objectives of this study were to examine and compare the size variability, frustule morphology, and ultrastructural detail of these taxa, which were recently collected from locations of a different origin than the type localities. To support the current descriptions of the newly erected genus of Discostella and recently described species, D. elentarii, information on morphological characteristics across valve patterns was compared. A principal components analysis of the external valve features of D. stelligera and D. elentarii measured by light microscopy did not separate the two taxa. This close similarity in external morphology highlights the need to optically dissect the valves underneath the light microscope to clearly differentiate between the convex/concave nature of the D. stelligera valves compared with the flat valve of D. elentarii. New external and internal morphological details of D. elentarii were documented with a field emission scanning electron microscope.