First report of rust caused by Puccinia paullula on Monstera deliciosa and M. adansonii in Japan.

Monstera deliciosa Liebm. and M. adansonii Schott. (Araceae) have been cultivated for the commercial production in Hachijo Island, Tokyo, Japan, since the 1950s. A rust disease producing uredinial sori was found on the leaves of M. deliciosa and M. adansonii in the fields on Hachijo Island in February 2021. Symptoms were first observed on the leaf surfaces as small chlorotic spots, which expanded and became brown to reddish-brown, and produced uredinia with abundant urediniospores. The disease occurred on the whole island including the farm land, symptom incidence ranged from 5 to 30%. To confirm the pathogenicity of this rust fungus, ten plant species of Araceae (M. deliciosa, M. adansonii, Alocasia macrorrhizos, Anthurium andreauum, Dieffenbachia maculata, Epipremnum mirabile, E. pinnatum, Philodendron scandens, Spathiphyllum sp., Syngonium podophyllum) were inoculated with urediniospores obtained from infected samples on M. deliciosa and M. adansonii. Urediniospores were suspended in distilled water (1 × 106 conidia/ml) and sprayed on healthy plants. The inoculated plants were kept in a dark chamber at about 25°C for 48 h, and then transferred to a greenhouse. After 40 days, uredinia were reproduced only on M. deliciosa and M. adansonii. Morphological characteristics of the urediniospores obtained from inoculated monstera plants matched those obtained from the field plants and used as inoculum, thus fulfilling Koch's postulates. No symptoms were observed on the other plant species inoculated. For identification of the rust fungus, dry specimens obtained from both naturally infected plants and inoculated plants were used for morphological observations. Urediniospores with pedicels emerging from the stomata were densely aggregated, globose, and 24.8-29.3 µm (n = 30). Their walls were brown, echinulate, and 1.4-2.2 µm thick. Telia were found in the specimens collected in July and August. The teliospores with pedicels emerging from the stomata were two-celled, ellipsoid, and 21.3-27.5 × 19.5-23.4 µm. Their walls were pale yellow, smooth, and 1.0-1.9 µm thick. Morphological differences among the specimens on M. deliciosa and M. adansonii were not observed. These morphological characteristics were consistent with the description of P. paullula (Sydow and Sydow 1913). For molecular identification, the large subunit (LSU) rDNA and cytochrome oxidase III (cox3) were amplified. LRust1R, LR3, and LR5 (Vilgalys and Hester 1990) primers were used for sequencing of LSU region. Cox3_F (5'-GTTCAGTATGTTATTTTAACG-3') and cox3_R (5'-ATAGGAATAGTCAAACAACATC-3') primers were constructed here based on the P. paullula sequences (KX999927) for the cox3 region. The sequences were deposited in the GenBank as accession numbers OK509070, OK509071, LC663719 and LC663720. BLAST analysis showed that LSU and cox3 sequences shared 98.8% (902/913 nts) and 100% (632/632 nts) identities with P. paullula, KX999886 and KX999927 (Marin-Felix et al. 2017). This is the first report of a rust disease of M. deliciosa and M. adansonii caused by P. paululla in Japan. The rust fungi has been reported as the pathogen on the species of Amorphophallus, Rhaphidophora and Monstera (Sydow and Sydow 1913, Shaw 1991, Chen et al. 2009). The occurrence of this disease should be monitored because it can reduced yield and commercial value of monstera plants. All the specimens used in the experiments were deposited in the National Museum of Nature and Science, Japan (TNS-F82068-82077).

Surveys of Viruliferous Alate Aphid of Plum pox virus in Prunus mume Orchards in Japan.

Plum pox virus (PPV) is transmitted by infected buds and aphids. It is important to analyze the outbreak trends and viruliferous rate of aphids in areas where the occurrence of PPV is reported, so as to develop strategies for disease control. Between April 2011 and December 2012, yellow insect-trapping adhesive plates were placed for 2 days at a time each week in an area where PPV is occurring in Japan. Outbreak trends were analyzed based on the trapped alate aphid samples, and up to 50 of them were tested per week to identify species and determine the rate of viruliferous specimens. Although the number of aphids varied according to survey year, three peaks were noticeable in each year. Based on the sequence data for the mitochondrial cytochrome c oxidase I region, approximately 40 different species of aphid were trapped in both years. Of the five dominant species of aphids identified during the 2 years, Aphis spiraecola was trapped in large numbers. PPV-positive aphids were higher in fall onward, when the total number of trapped aphids decreased, than in spring and summer, when a larger number of aphids was caught. PPV transmission tests using the most abundant species revealed that A. spiraecola, A. craccivora, A. gossypii, and Rhopalosiphum maidis were transmitters, although A. spiraecola is likely of epidemiological significance.

Three distinct blue-green color pathways in a mammalian retina.

In mammalian retinae, the first steps in the process of discrimination of color are mediated by color-opponent neurons that respond with opposite polarity to signals from short (S, blue) and longer wavelength (M, green or L, red) cones. Primates also contain a second system that is different from M and L cones. Although pathways responding to the onset of S-cone stimulation (S-ON) are well known, the existence of bipolar cells and retinal ganglion cells that respond to the offset of S-cone stimulation (S-OFF) has been controversial. We have recorded from and stained three different types of S/M color-opponent ganglion cells in the rabbit retina that are distinguished by the polarity of their responses to S-cone stimulation, the stratification pattern of their dendrites, and the distinct mechanisms underlying their color-opponent responses. We describe an S-ON and an S-OFF pathway formed by amacrine cells inverting the S-ON signal. Most importantly, we also provide both anatomical and physiological evidence for a direct S-OFF pathway dependent on an S-OFF cone bipolar cell. The results indicate a greater diversity of pathways for processing of signals from S-cones than previously suspected.

ON inputs to the OFF layer: bipolar cells that break the stratification rules of the retina.

The vertebrate retina is a distinctly laminar structure. Functionally, the inner plexiform layer, in which bipolar cells synapse onto amacrine and ganglion cells, is subdivided into two sublaminae. Cells that depolarize at light offset ramify in sublamina a; those that depolarize at light onset ramify in sublamina b. The separation of ON and OFF pathways appears to be a fundamental principle of retinal organization that is reflected throughout the entire visual system. We show three clear exceptions to this rule, in which the axons of calbindin-positive ON cone bipolar cells make ribbon synapses as they pass through the OFF layers with three separate cell types: (1) dopaminergic amacrine cells, (2) intrinsically photosensitive ganglion cells, and (3) bistratified diving ganglion cells. The postsynaptic location of the AMPA receptor GluR4 at these sites suggests that ON bipolar cells can make functional synapses as their axons pass through the OFF layers of the inner plexiform layer. These findings resolve a long-standing question regarding the anomalous ON inputs to dopaminergic amacrine cells and suggest that certain ON bipolar cell axons can break the stratification rules of the inner plexiform layer by providing significant synaptic output before their terminal specializations. These outputs are not only to dopaminergic amacrine cells but also to at least two ON ganglion cell types that have dendrites that arborize in sublamina a.

Adult rats exposed to low-doses of di-n-butyl phthalate during gestation exhibit decreased grooming behavior.

Developmental neurotoxicity of low-dose di-n-butyl phthalate (DBP) to rats was studied. Pregnant rats were orally given DBP at doses less than 1.0 mg/kg/day during gestation period. The body weight of all dams and their offspring as well as the offspring's motor function showed no significant adverse effect. At 21 weeks, behaviors of male rats were examined by placing into a test cage. The rats born from dams exposed to 10 microg DBP/kg/day exhibited a significant decrease of grooming. This indicates low-dose DBP adversely affects emotional stability in a novel environment.

A magnetically levitated centrifugal blood pump with a simple-structured disposable pump head.

A magnetically levitated centrifugal blood pump (MedTech Dispo) has been developed for use in a disposable extracorporeal system. The design of the pump is intended to eliminate mechanical contact with the impeller, to facilitate a simple disposable mechanism, and to reduce the blood-heating effects that are caused by motors and magnetic bearings. The bearing rotor attached to the impeller is suspended by a two degrees-of-freedom controlled radial magnetic bearing stator, which is situated outside the rotor. In the space inside the ringlike rotor, a magnetic coupling disk is placed to rotate the rotor and to ensure that the pump head is thermally isolated from the motor. In this system, the rotor can exhibit high passive stiffness due to the novel design of the closed magnetic circuits. The disposable pump head, which has a priming volume of 23 mL, consists of top and bottom housings, an impeller, and a rotor with a diameter of 50 mm. The pump can provide a head pressure of more than 300 mm Hg against a flow of 5 L/min. The normalized index of hemolysis of the MedTech Dispo is 0.0025 +/- 0.0005 g/100 L at 5 L/min against 250 mm Hg. This is one-seventh of the equivalent figure for a Bio Pump BPX-80 (Medtronic, Inc., Minneapolis, MN, USA), which has a value of 0.0170 +/- 0.0096 g/100 L. These results show that the MedTech Dispo offers high pumping performance and low blood trauma.

The morphological characterization of orientation-biased displaced large-field ganglion cells in the central part of goldfish retina.

The vertebrate retina has about 30 subtypes of ganglion cells. Each ganglion cell receives synaptic inputs from specific types of bipolar and amacrine cells ramifying at the same depth of the inner plexiform layer (IPL), each of which is thought to process a specific aspect of visual information. Here, we identified one type of displaced ganglion cell in the goldfish retina which had a large and elongated dendritic field. As a population, all of these ganglion cells were oriented in the horizontal axis and perpendicular to the dorsal-ventral axis of the goldfish eye in the central part of retina. This ganglion cell has previously been classified as Type 1.2. However, the circuit elements which synapse with this ganglion cell are not yet characterized. We found that this displaced ganglion cell was directly tracer-coupled only with homologous ganglion cells at sites containing Cx35/36 puncta. We further illustrated that the processes of dopaminergic neurons often terminated next to intersections between processes of ganglion cells, close to where dopamine D1 receptors were localized. Finally, we showed that Mb1 ON bipolar cells had ribbon synapses in the axonal processes passing through the IPL and made ectopic synapses with this displaced ganglion cell that stratified into stratum 1 of the IPL. These results suggest that the displaced ganglion cell may synapse with both Mb1 cells using ectopic ribbon synapses and OFF cone bipolar cells with regular ribbon synapses in the IPL to function in both scotopic and photopic light conditions.

Synaptic input to OFF parasol ganglion cells in macaque retina.

A Neurobiotin-injected OFF parasol cell from midperipheral macaque retina was studied by reconstruction of serial ultrathin sections and compared with ON parasol cells studied previously. In most respects, the synaptic inputs to the two subtypes were similar. Only a few of the amacrine cell processes that provided input to the labeled OFF parasol ganglion cell dendrites made or received inputs within the series, and none of these interactions were with the bipolar cells or other amacrine cells presynaptic to the OFF parasol cell. These findings suggest that the direct inhibitory input to OFF parasol cells originates from other areas of the retina. OFF parasol cells were known to receive inputs from two types of diffuse bipolar cells. To identify candidates for the presynaptic amacrine cells, OFF parasol cells were labeled with Lucifer yellow by using a juxtacellular labeling technique, and amacrine cells known to costratify with them were labeled via immunofluorescent methods. Appositions were observed with amacrine cells containing immunoreactive calretinin, parvalbumin, choline acetylatransferase, and G6-Gly, a cholecystokinin precursor. These findings suggest that the inhibitory input to parasol cells conveys information about several different attributes of visual stimuli and, particularly, about their global properties.

A novel fluorescent tracer for visualizing coupled cells in neural circuits of living tissue.

Gap junctions have diverse roles in a wide variety of tissues and have recently become a subject of intense investigation in neural circuits where synchrony and oscillations may play an important part. In circuits where gap junctions are present, the possibility arises of identifying intercommunicating cells via introduction of tracer into one cell and observing its spread into its coupled neighbors. Staining the coupled cells by this means opens the door to many vital techniques including paired-cell electrophysiology, RT-PCR, and morphological characterization of previously unknown coupled cells. Tracers commonly used at the present time are not generally suitable for these purposes in many tissues, including neurons. This paper describes how a fluorescent nuclear tracer, Po-pro-1, can be used to visualize coupled cells in several types of retinal neurons thought to be comprised of different connexin proteins including Cx36, Cx45, Cx50, and Cx57.

Feasibility of a miniature centrifugal rotary blood pump for low-flow circulation in children and infants.

In this study, a seal-less, tiny centrifugal rotary blood pump was designed for low-flow circulatory support in children and infants. The design was targeted to yield a compact and priming volume of 5 ml with a flow rate of 0.5-4 l/min against a head pressure of 40-100 mm Hg. To meet the design requirements, the first prototype had an impeller diameter of 30 mm with six straight vanes. The impeller was supported with a needle-type hydrodynamic bearing and was driven with a six-pole radial magnetic driver. The external pump dimensions included a pump head height of 20 mm, diameter of 49 mm, and priming volume of 5 ml. The weight was 150 g, including the motor driver. In the mock circulatory loop, using fresh porcine blood, the pump yielded a flow of 0.5-4.0 l/min against a head pressure of 40-100 mm Hg at a rotational speed of 1800-4000 rpm using 1/4" inflow and outflow conduits. The maximum flow and head pressure of 5.25 l/min and 244 mm Hg, respectively, were obtained at a rotational speed of 4400 rpm. The maximum electrical-to-hydraulic efficiency occurred at a flow rate of 1.5-3.5 l/min and at a rotational speed of 2000-4400 rpm. The normalized index of hemolysis, which was evaluated using fresh porcine blood, was 0.0076 g/100 l with the impeller in the down-mode and a bearing clearance of 0.1 mm. Further refinement in the bearing and magnetic coupler are required to improve the hemolytic performance of the pump. The durability of the needle-type hydrodynamic bearing and antithrombotic performance of the pump will be performed before clinical applications. The tiny centrifugal blood pump meets the flow requirements necessary to support the circulation of pediatric patients.

Magnetically suspended centrifugal blood pump with a radial magnetic driver.

A new magnetic bearing has been designed to achieve a low electronic power requirement and high stiffness. The magnetic bearing consists of 1) radial passive forces between the permanent magnet ring mounted inside the impeller rotor and the electromagnet core materials in the pump casing and 2) radial active forces generated by the electromagnets using the two gap sensor signals. The magnetic bearing was assembled into a centrifugal rotary blood pump (CRBP) driven with a radial, magnetic coupled driver. The impeller vane shape was designed based upon the computational fluid dynamic simulation. The diameter and height of the CRBP were 75 mm and 50 mm, respectively. The magnetic bearing system required the power of 1.0-1.4 W. The radial impeller movement was controlled to within +/- 10 microm. High stiffness in the noncontrolled axes, Z, phi, and theta, was obtained by the passive magnetic forces. The pump flow of 5 L/min against 100 mm Hg head pressure was obtained at 1,800 rpm with the electrical to hydraulic efficiency being greater than 15%. The Normalized Index of Hemolysis (NIH) of the magnetic bearing CRBP was one fifth of the BioPump BP-80 and one half of the NIKKISO HPM-15 after 4 hours. The newly designed magnetic bearing with two degrees of freedom control in combination with optimized impeller vane was successful in achieving an excellent hemolytic performance in comparison with the clinical centrifugal blood pumps.

Quantitative analysis of development and aging of genital corpuscles in glans penis of the rat.

The aim of the present postnatal developmental study was to determine densities of unique genital corpuscles (GCs) in glans penis of developing and aged rats. GCs were identified as corpuscular endings consisting of highly branched and coiled axons with many varicosities, which were immunoreactive for protein gene product 9.5. In addition, GCs were immunoreactive for calcitonin gene-related peptide and substance P, but not for vasoactive intestinal polypeptide and neuropeptide Y. GCs were not found in the glans penis of 1 week old rats. Densities of GCs were low at 3 weeks, significantly increased at 5 and 10 weeks, reached the peak of density at 40 weeks, and tended to decrease at 70 and 100 weeks. Sizes of GCs were small in 3 weeks old rats, increased at 5 and 10 weeks, reached the peak-size at 40 weeks and reduced in size at 70 and 100 weeks. Considering sexual maturation of the rat, the results reveal that GCs of the rat begins to develop postnatal and reaches to the peak of their development after puberty and continues to exist until old age, in contrast to prenatal and early postnatal development of other sensory receptors of glabrous skin.

In vivo nitric oxide concentration in the vitreous of rat eye.

Nitric oxide (NO) has been proposed to mediate light-adaptation in the vertebrate retina. However, the in vivo NO concentration in the retina is not known. We measured NO in the vitreous adjacent to the retina of the rat eye using NO-selective electrodes under various light conditions. The rats were kept under a 12:12 h light/dark cycle with lights on from 08:00 to 20:00 h. NO during the daytime in the light remained constant at 0.85+/-0.41 microM (n=10), and decreased after dark-adaptation, while NO during the nighttime in darkness was 0.55+/-0.27 microM (n=5), and increased in the light. The vitreous NO initially increased rapidly to flicker, but then decreased as the flicker continued. We found that the diurnal change of NO in the vitreous depended on the ambient light condition.

A new design for a compact centrifugal blood pump with a magnetically levitated rotor.

A compact centrifugal blood pump has been developed using a radial magnetic bearing with a two-degree of freedom active control. The proposed magnetic bearing exhibits high stiffness, even in passively controlled directions, and low power consumption because a permanent magnet, incorporated with the rotor, suspends its weight. The rotor is driven by a Lorentz force type of built-in motor, avoiding mechanical friction and material wear. The built-in motor is designed to generate only rotational torque, without radial and axial attractive forces on the rotor, leading to low power consumption by the magnetic bearing. The fabricated centrifugal pump measured 65 mm in diameter and 45 mm in height and weighed 0.36 kg. In the closed loop circuit filled with water, the pump provided a flow rate of 4.5 L/min at 2,400 rpm against a pressure head of 100 mm Hg. Total power consumption at that point was 18 W, including 2 W required for magnetic levitation, with a total efficiency of 5.7%. The experimental results showed that the design of the compact magnetic bearing was feasible and effective for use in a centrifugal blood pump.

Properties of the ON bistratified ganglion cell in the rabbit retina.

The identity of the types of different neurons in mammalian retinae is now close to being completely known for a few mammalian species; comparison reveals strong homologies for many neurons across the order. Still, there remain some cell types rarely encountered and inadequately described, despite not being rare in relative frequency. Here we describe in detail an additional ganglion cell type in rabbit that is bistratified with dendrites in both sublaminae, yet spikes only at light onset and has no response bias to the direction of moving bars. This ON bistratified ganglion cell type is most easily distinguished by the unusual behavior of its dendritic arbors. While dendrites that arborize in sublamina b terminate at that level, those that ascend to arborize in sublamina a do not normally terminate there. Instead, when they reach the approximate radius of the dendrites in sublamina b, they dive sharply back down to ramify in sublamina b. Here they continue to course even further away from the soma at the same level as the branches wholly contained in sublamina b, thereby forming an annulus of secondary ON dendrites in sublamina b. This pattern of branching creates a bistratified dendritic field of approximately equal area in the two sublaminae initially, to which is then added an external annulus of dendrites only in sublamina b whose origin is entirely from processes descending from sublamina a. It is coupled to a population of wide-field amacrine cells upon which the dendrites of the ganglion cell often terminate.

Histamine receptors of cones and horizontal cells in Old World monkey retinas.

In primates the retina receives input from histaminergic neurons in the posterior hypothalamus that are active during the day. In order to understand how this input contributes to information processing in Old World monkey retinas, we have been localizing histamine receptors (HR) and studying the effects of histamine on the neurons that express them. Previously, we localized HR3 to the tips of ON bipolar cell dendrites and showed that histamine hyperpolarizes the cells via this receptor. We raised antisera against synthetic peptides corresponding to an extracellular domain of HR1 between the 4th and 5th transmembrane domains and to an intracellular domain near the carboxyl terminus of HR2. Using these, we localized HR1 to horizontal cells and a small number of amacrine cells and localized HR2 to puncta closely associated with synaptic ribbons inside cone pedicles. Consistent with this, HR1 mRNA was detected in horizontal cell perikarya and primary dendrites and HR2 mRNA was found in cone inner segments. We studied the effect of 5 µM exogenous histamine on primate cones in macaque retinal slices. Histamine reduced I(h) at moderately hyperpolarized potentials, but not the maximal current. This would be expected to increase the operating range of cones and conserve ATP in bright, ambient light. Thus, all three major targets of histamine are in the outer plexiform layer, but the retinopetal axons containing histamine terminate in the inner plexiform layer. Taken together, the findings in these three studies suggest that histamine acts primarily via volume transmission in primate retina.

Two distinct types of ON directionally selective ganglion cells in the rabbit retina.

Mammalian retinas contain about 20 types of ganglion cells that respond to different aspects of the visual scene, including the direction of motion of objects in the visual field. The rabbit retina has long been thought to contain two distinct types of directionally selective (DS) ganglion cell: a bistratified ON-OFF DS ganglion cell that responds to onset and termination of light, and an ON DS ganglion cell, which stratifies only in the ON layer and responds only to light onset. This division is challenged by targeted recordings from rabbit retina, which indicate that ON DS ganglion cells occur in two discriminably different types. One of these is strongly tracer-coupled to amacrine cells; the other is never tracer-coupled. These two types also differ in branching pattern, stratification depth, relative latency, and transience of spiking. The sustained, uncoupled ON DS cell ramifies completely within the lower cholinergic band and responds to nicotine with continuous firing. In contrast, the transient, coupled ON DS ganglion cell stratifies above the cholinergic band and is not positioned to receive major input from cholinergic amacrine cells, consistent with its modest response to the cholinergic agonist nicotine. Much data have accrued that directional responses in the mammalian retina originate via gamma-aminobutyric acid (GABA) release from the dendrites of starburst amacrine cells (Euler et al., 2002). If there is an ON DS ganglion cell that does not stratify in the starburst band, this suggests that its GABA-dependent directional signals may be generated by a mechanism independent of starburst amacrine cells.

Components and properties of the G3 ganglion cell circuit in the rabbit retina.

Each point on the retina is sampled by about 15 types of ganglion cell, each of which is an element in a circuit also containing specific types of bipolar cell and amacrine cell. Only a few of these circuits are well characterized. We found that intracellular injection of Neurobiotin into a specific ganglion cell type targeted by fluorescent markers also stained an asymmetrically branching ganglion cell. It was also tracer-coupled to an unusual type of amacrine cell whose dendrites were strongly asymmetric, coursing in a narrow bundle from the soma in the dorsal direction only. The dendritic field of the ganglion cell stratifies initially in sublamina b (the ON layers), but with few specializations and branches, and then more extensively in sublamina a (the OFF layers) at the level of the processes of the coupled amacrine cell. Intersections of the ganglion and amacrine cell processes contain puncta immunopositive for Cx36. Additionally, we found that the dopaminergic amacrine cell makes contact with both the ganglion cell and the amacrine cell, and that a bipolar cell immunopositive for calbindin synapses onto the sublamina b processes of the ganglion cell. Dopamine D(1) receptor activation reduced tracer flow to the amacrine cells. We have thus targeted and characterized two poorly understood retinal cell types and placed them with two other cell types in a substantial portion of a new retinal circuit. This unique circuit comprised of pronounced asymmetries in the ganglion cell and amacrine cell dendritic fields may result in a substantial orientation bias.

Dynamic characteristics of a magnetically levitated impeller in a centrifugal blood pump.

Centrifugal blood pumps that employ hybrid active/passive magnetic bearings to support noncontact impellers have been developed in order to reduce bearing wear, pump size, the power consumption of the active magnetic bearing, and blood trauma. However, estimates made at the design stage of the vibration of the impeller in the direction of passive suspension during pump operation were inaccurate, because the influence of both the pumping fluid and the rotation of the impeller on the dynamic characteristics was not fully recognized. The purpose of this study is to investigate the dynamic characteristics in a fluid of a magnetically levitated rotating impeller by measuring both the frequency response to sinusoidal excitation of the housing over a wide frequency range and the displacement due to input of a pulsatile flow during left ventricular (LV) assist. The excitation tests were conducted under conditions in which the impeller was levitated in either air or water, and with or without rotation. The experimental and analytical results indicate that vibration of the impeller due to the external force in water was decreased, compared with that in air due to the hydraulic force of water. The axial resonant frequency rose quadratically with rotational speed, and the tilt mode had two resonant frequencies while rotating due to the gyroscopic effect. With the pump inserted into a mock systemic circulatory loop, the dynamic stability of the impeller when pulsatile pressure was applied during LV assist was verified experimentally. The amplitudes of vibration in response to the pulsatile flow in the passively constrained directions were considerably smaller in size than the dimensions of initial gaps between the impeller and the pump housing.

Feasibility of a TinyPump system for pediatric CPB, ECMO, and circulatory assistance: hydrodynamic performances of the modified pump housing for implantable TinyPump.

The TinyPump is a miniature centrifugal blood pump with an extremely small priming volume of 5 ml, allowing blood transfusion free cardiopulmonary bypass as well as extracorporeal membrane oxygenation in pediatric patients. In this study, a new pump housing with the angled inlet port (25 degrees toward impeller center with respect to the flow axis) was designed to optimize the pump displaced volume and to extend the application of the TinyPump to implantable support The fluid dynamic performance analysis revealed that the head pressure losses increased from 3 to 17 mm Hg in comparison with straight port design as the pump rotational speed increased from 2,000 to 4,000 rpm. This was probably caused by perturbed flow patterns at the site of the inlet bent port area and streamline hitting the off-center of the impeller. No significant effect on pumping efficiency was observed because of modification in inlet port design. Modification in the inflow and outflow port designs together with the drive mechanism reduces the height of the pump system, including the motor, to 27 mm yielding the displaced volume of 68 ml in comparison with 40 mm of the paracorporeal system with the displaced volume of 105 ml. Further analysis in terms of hemolytic as well as antithrombogenic performance will be carried out to finalize the housing design for the implantable version of the TinyPump.