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Doppler velocimetry

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https://www.readbyqxmd.com/read/28457816/interventions-to-prevent-stillbirth
#1
REVIEW
Jessica M Page, Robert M Silver
Stillbirth is one of the most distressing complications of pregnancy and still occurs far too frequently. The rate of stillbirth has been decreasing worldwide but room for improvement remains even in high-income countries. Risk factors for stillbirth have been identified in an effort to detect those women at increased risk. However, risk factors are non-specific and do not identify most stillbirths. Strategies employed to screen the general population such as assessment of fetal activity, fetal growth screening and biomarkers have also been used to identify increased risk for stillbirth...
April 27, 2017: Seminars in Fetal & Neonatal Medicine
https://www.readbyqxmd.com/read/28456262/nonmechanical-compact-probe-for-cross-sectional-velocity-measurement-based-on-differential-laser-doppler-velocimetry
#2
K Maru, S Katsumi, R Matsuda
In this study, we propose and demonstrate a nonmechanical compact probe for cross-sectional velocity measurement based on differential laser Doppler velocimetry. The system introduces a method that combines simultaneous multipoint measurement using spatial encoding and nonmechanical scanning of measurement points, in which spatially encoded measurement points aligned along the transverse direction are scanned in the axial direction by changing the wavelength. The use of a waveguide-type LiNbO3 phase shifter array for serrodyne frequency shifting is feasible for the system based on fiber optics with an easily handled probe...
April 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28430305/turbulence-measurements-in-an-axial-rotary-blood-pump-with-laser-doppler-velocimetry
#3
Chan Y Schüle, Klaus Affeld, Max Kossatz, Christian O Paschereit, Ulrich Kertzscher
BACKGROUND: The implantation of rotary blood pumps as ventricular assist devices (VADs) has become a viable therapy for quite a number of patients with end-stage heart failure. However, these rotary blood pumps cause adverse events that are related to blood trauma. It is currently believed that turbulence in the pump flow plays a significant role. But turbulence has not been measured to date because there is no optical access to the flow space in rotary blood pumps because of their opaque casings...
April 18, 2017: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/28428653/doppler-velocimetry-of-the-orbital-arteries-in-patients-with-sickle-cell-anemia-relationship-with-biomarkers-of-hemolysis
#4
Thiago de Oliveira Ferrão, Paulo Ricardo Martins-Filho, Cleverton Aragão, Marlyson Santana, Allan Nascimento, Thayane Cardoso, Rosana Cipolotti
OBJECTIVE: To investigate orbital vascular resistance by Doppler velocimetry in patients with steady-state sickle cell anemia, as well as to characterize its relationship with biomarkers of hemolysis. MATERIALS AND METHODS: This was a cross-sectional study of two groups: 71 outpatients with sickle cell anemia; and 32 age- and gendermatched, healthy subjects (control group). All participants underwent Doppler velocimetry of the orbital arteries and laboratory tests...
March 2017: Radiologia Brasileira
https://www.readbyqxmd.com/read/28426506/applications-of-noninvasive-hemodynamic-monitoring-in-obstetric-management
#5
John T Sullivan
Clinicians managing obstetric patients are dependent on valid hemodynamic measurements to guide care. Heart rate and noninvasive blood pressure guide most current care. New hemodynamic monitors are being used to report research findings and are being investigated by clinicians for their value to supplement standard monitoring. These include arterial pulse contour analysis, Doppler velocimetry, and bioimpedance among others. This chapter serves to present these new devices with a critical review of their advantages and limitations, and most importantly the validity of their measurements...
June 2017: Clinical Obstetrics and Gynecology
https://www.readbyqxmd.com/read/28416375/automatic-and-manual-doppler-velocimetry-measurements-of-the-uterine-artery-in-pregnant-ewes
#6
Renato Travassos Beltrame, Lucas Buss Littig, Carolina Covre, Amanda de Barros Martins, Celia Raquel Quirino, R L D Costa
We aimed to compare measurements of speed and blood flow parameters obtained manually and automatically in the uterine arteries of pregnant ewes. Eighteen Santa Inês ewes, confirmed to be pregnant, were followed every 2 weeks until parturition. The systolic peak (PS), end diastolic velocity (ED), maximum and average speed in the cardiac cycle (TAMAX and TAMEAN, respectively), pulsatility index (PI), resistance index (RI) and the systole/diastole (S/D) ratio and body flow volume (BFV) was measured. We began the wave evaluation automatically, then the observer manually marked the beginning and end of the wave...
March 31, 2017: Animal Reproduction Science
https://www.readbyqxmd.com/read/28395328/cystic-endometrial-hyperplasia-pyometra-syndrome-in-bitches-identification-of-hemodynamic-inflammatory-and-cell-proliferation-changes
#7
Gisele Almeida Lima Veiga, Ricardo Henrique Miziara, Daniel Souza Ramos Angrimani, Paula Carvalho Papa, Bruno Cogliati, Camila Infantosi Vannucchi
Cystic endometrial hyperplasia (CEH)-pyometra syndrome is one of the most common diseases of noncastrated female dogs. However, determination of etiological mechanisms and differential diagnosis of CEH-pyometra syndrome are undefined. The aim of this study is to compare immunohistochemically the expression of cyclooxygenase-2 (COX-2) inflammatory mediator, Ki-67 antigen proliferation marker, vascular endothelial growth factor (VEGF-A) angiogenesis mediator and its FLT-1 and KDR receptors, and correlate with Doppler velocimetry of uterine artery and endometrial vascularization in bitches with CEH-pyometra syndrome...
January 1, 2017: Biology of Reproduction
https://www.readbyqxmd.com/read/28391461/toxicological-assessment-of-tungsten-oxide-nanoparticles-in-rats-after-acute-oral-exposure
#8
Srinivas Chinde, Naresh Dumala, Mohammed Fazlur Rahman, Sarika Srinivas Kalyan Kamal, Srinivas Indu Kumari, Mohammed Mahboob, Paramjit Grover
Advances in and the rapid growth of the nanotechnology sector have escalated manufacture of nanoparticles (NPs), resulting in a significant increase in the probability of exposure of humans and wildlife to these materials. Many NPs have been found to exert genotoxicity. Therefore, genotoxicity studies are mandatory to assess the toxicity of NPs as a concern of succumbing to genetic diseases and cancers are universal. Tungsten oxide (WO3) NPs are being explored extensively in various fields. However, the toxicological data of WO3 NPs by oral route in mammals is limited...
April 8, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28387869/genotoxicity-study-of-nickel-oxide-nanoparticles-in-female-wistar-rats-after-acute-oral-exposure
#9
Naresh Dumala, Bhanuramya Mangalampalli, Srinivas Chinde, Srinivas Indu Kumari, Mohammad Mahoob, Mohammad Fazlur Rahman, Paramjit Grover
Nanoparticles (NPs) apart from their widespread advantages and increased utilisation, have aroused concerns over their safe use. Nickel (II) oxides (NiO) NPs are used as catalysts, biosensors and in many of the consumer products. The increasing use of NiO NPs necessitates an improved understanding of their potential impact on the environment and human health. In this study, we investigated the acute genotoxic effects of NiO NPs by oral route administration with three different doses (125, 250 and 500 mg/kg bw)...
April 6, 2017: Mutagenesis
https://www.readbyqxmd.com/read/28372408/a-compact-fiber-optics-based-heterodyne-combined-normal-and-transverse-displacement-interferometer
#10
Bryan Zuanetti, Tianxue Wang, Vikas Prakash
While Photonic Doppler Velocimetry (PDV) has become a common diagnostic tool for the measurement of normal component of particle motion in shock wave experiments, this technique has not yet been modified for the measurement of combined normal and transverse motion, as needed in oblique plate impact experiments. In this paper, we discuss the design and implementation of a compact fiber-optics-based heterodyne combined normal and transverse displacement interferometer. Like the standard PDV, this diagnostic tool is assembled using commercially available telecommunications hardware and uses a 1550 nm wavelength 2 W fiber-coupled laser, an optical focuser, and single mode fibers to transport light to and from the target...
March 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28361046/endothelial-progenitor-cells-of-the-human-placenta-and-fetoplacental-circulation-a-potential-link-to-fetal-neonatal-and-long-term-health
#11
REVIEW
Diane L Gumina, Emily J Su
The fetoplacental circulation plays a key role in both short- and long-term outcomes, and aberrant flow indices as manifested by abnormal fetal Doppler velocimetry within this compartment have been associated with significant adverse consequences. These include fetal growth restriction, which often coexists with preeclampsia, and long-lasting medical issues as a result of both the underlying pathology and prematurity such as bronchopulmonary dysplasia, chronic lung disease, and neurodevelopmental delay. Furthermore, it is also clear that exposure to an abnormal in utero environment increases risk for long-term, adulthood issues such as cardiovascular disease...
2017: Frontiers in Pediatrics
https://www.readbyqxmd.com/read/28342532/shear-scaling-based-approach-for-irreversible-energy-loss-estimation-in-stenotic-aortic-flow-an-in-vitro-study
#12
Utku Gülan, Christian Binter, Sebastian Kozerke, Markus Holzner
Today, the functional and risk assessment of stenosed arteries is mostly based on ultrasound Doppler blood flow velocity measurements or catheter pressure measurements, which rely on several assumptions. Alternatively, blood velocity including turbulent kinetic energy (TKE) may be measured using MRI. The aim of the present study is to validate a TKE-based approach that relies on the fact that turbulence production is dominated by the flow's shear to determine the total irreversible energy loss from MRI scans...
March 12, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28335685/preterm-delivery-as-a-unique-pathophysiologic-state-characterized-by-maternal-soluble-fms-like-tyrosine-kinase-1-and-uterine-artery-resistance-during-pregnancy
#13
Jennifer K Straughen, Dawn P Misra, Laura Helmkamp, Vinod K Misra
BACKGROUND: Preterm delivery (PTD) may be characterized by altered interrelationships among angiogenic factors and measures of placental function. We analyzed the longitudinal relationship between maternal serum concentrations of soluble fms-like tyrosine kinase 1 (sFlt1), an important antiangiogenic factor, and uterine artery resistance in pregnancies resulting in preterm and term deliveries. METHODS: Data were collected in a longitudinal cohort study involving 278 women monitored at 6 to 10, 10 to 14, 16 to 20, 22 to 26, and 32 to 36 weeks of gestation...
January 1, 2017: Reproductive Sciences
https://www.readbyqxmd.com/read/28292588/endoscopy-after-esophagectomy-safety-demonstrated-in-a-porcine-model
#14
Vignesh Raman, Karen L Moodie, Obinna O Ofoche, Larry R Kaiser, Cherie P Erkmen
BACKGROUND: Endoscopy is useful in assessing conduit ischemia and anastomotic leaks after esophagectomy but poses a theoretical threat of anastomotic disruption. We used a porcine model to evaluate the safety of endoscopy after esophagectomy. METHODS: We performed esophagectomies in 10 live pigs and performed endoscopy with progressive air insufflation and continuous intraluminal pressure monitoring. We stopped insufflation when the intraluminal pressure reached a plateau...
February 9, 2017: Journal of Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28221297/optimal-epinephrine-concentration-and-time-delay-to-minimize-perfusion-in-eyelid-surgery-measured-by-laser-based-methods-and-a-novel-form-of-extended-wavelength-diffuse-reflectance-spectroscopy
#15
Rafi Sheikh, Ulf Dahlstrand, Khashayar Memarzadeh, Jonas Blohmé, Nina Reistad, Malin Malmsjö
OBJECTIVE: This study investigates the hypoperfusion effects of epinephrine in local anesthesia in eyelid surgery. A novel form of extended-wavelength diffuse reflectance spectroscopy was evaluated. METHODS: Blood perfusion in porcine eyelid flaps was measured using laser Doppler velocimetry and laser speckle contrast imaging, whereas the tissue response was measured using diffuse reflectance spectroscopy with a broad spectrum (450-1550 nm). Epinephrine was either injected cumulatively, 0...
February 17, 2017: Ophthalmic Plastic and Reconstructive Surgery
https://www.readbyqxmd.com/read/28186103/quantum-lock-in-force-sensing-using-optical-clock-doppler-velocimetry
#16
Ravid Shaniv, Roee Ozeri
Force sensors are at the heart of different technologies such as atomic force microscopy or inertial sensing. These sensors often rely on the measurement of the displacement amplitude of mechanical oscillators under applied force. The best sensitivity is typically achieved when the force is alternating at the mechanical resonance frequency of the oscillator, thus increasing its response by the mechanical quality factor. The measurement of low-frequency forces, that are below resonance, is a more difficult task as the resulting oscillation amplitudes are significantly lower...
February 10, 2017: Nature Communications
https://www.readbyqxmd.com/read/28157946/self-mixing-birefringent-dual-frequency-laser-doppler-velocimeter
#17
Junbao Chen, Hongbin Zhu, Wei Xia, Dongmei Guo, Hui Hao, Ming Wang
A self-mixing birefringent dual-frequency laser Doppler velocimeter (SBD-LDV) for high-resolution velocity measurements is presented in this paper. The velocity information of the object can be accurately extracted from the self-mixing Doppler frequency shift of the birefringent light-carried microwave signal. We generate a virtual stable light-carried microwave by using a birefringent dual-frequency He-Ne laser which further simplifies the structure of the light source. Moreover, the optical configuration based on the laser self-mixing interference brings benefits of compact optical setup, self-alignment, and direction discriminability...
January 23, 2017: Optics Express
https://www.readbyqxmd.com/read/28155328/advanced-laser-based-techniques-for-gas-phase-diagnostics-in-combustion-and-aerospace-engineering
#18
Andreas Ehn, Jiajian Zhu, Xuesong Li, Johannes Kiefer
Gaining information of species, temperature, and velocity distributions in turbulent combustion and high-speed reactive flows is challenging, particularly for conducting measurements without influencing the experimental object itself. The use of optical and spectroscopic techniques, and in particular laser-based diagnostics, has shown outstanding abilities for performing non-intrusive in situ diagnostics. The development of instrumentation, such as robust lasers with high pulse energy, ultra-short pulse duration, and high repetition rate along with digitized cameras exhibiting high sensitivity, large dynamic range, and frame rates on the order of MHz, has opened up for temporally and spatially resolved volumetric measurements of extreme dynamics and complexities...
March 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/28153658/first-trimester-alcohol-exposure-alters-placental-perfusion-and-fetal-oxygen-availability-affecting-fetal-growth-and-development-in-a-non-human-primate-model
#19
Jamie O Lo, Matthias C Schabel, Victoria H J Roberts, Xiaojie Wang, Katherine S Lewandowski, Kathleen A Grant, Antonio E Frias, Christopher D Kroenke
BACKGROUND: Prenatal alcohol exposure leads to impaired fetal growth, brain development, and stillbirth. Placental impairment likely contributes to these adverse outcomes, but the mechanisms and specific vasoactive effects of alcohol that links altered placental function to impaired fetal development remain areas of active research. OBJECTIVE: Recently, we developed magnetic resonance imaging techniques in nonhuman primates to characterize placental blood oxygenation through measurements of T2* and perfusion using dynamic contrast-enhanced magnetic resonance imaging...
March 2017: American Journal of Obstetrics and Gynecology
https://www.readbyqxmd.com/read/28152557/perinatal-outcome-of-placental-massive-perivillous-fibrin-deposition-a-case-control-study
#20
Louise Devisme, Claire Chauvière, Hélène Franquet-Ansart, Anastasia Chudzinski, Morgane Stichelbout, Véronique Houfflin-Debarge, Damien Subtil
OBJECTIVE: The objectives of the study are to describe the obstetric outcomes associated with massive perivillous fibrin deposition (MFD) compared with a control series and to determine if outcome differs according to the extent of fibrin deposition. METHOD: Retrospective case-control study based on placentas analyzed over a consecutive 12-year period. MFD was considered severe if it extended over more than 50% of the placenta and moderate between 25% and 50%. RESULTS: During the study period, MFD was observed on 71 placentas, 39 severe and 32 moderate...
April 2017: Prenatal Diagnosis
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