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In magnetic resonance imaging (MRI), the scan time for acquiring an image is relatively long, resulting in patient uncomfortable and error artifacts. Fortunately, the compressed sensing (CS) and parallel magnetic resonance imaging (pMRI) can reduce the scan time of the MRI without significantly compromising the quality of the images. It has been found that the combination of pMRI and CS can better improve the image reconstruction, which will accelerate the speed of MRI acquisition because the number of measurements is much smaller than that by pMRI. In this paper, we propose combining a combined CS method and pMRI for better accelerating the MRI acquisition. In the combined CS method, the under-sampled data of the K-space is performed by taking both regular sampling and traditional random under-sampling approaches. MRI image reconstruction is then performed by using nonlinear conjugate gradient optimization. The performance of the proposed method is simulated and evaluated using the reconstruction error measure, the universal image quality Q-index, and the peak signal-to-noise ratio (PSNR). The numerical simulations confirmed that, the average error, the Q index, and the PSNR ratio of the appointed scheme are remarkably improved up to 59, 63, and 39% respectively as compared to the traditional scheme. For the first time, instead of using highly computational approaches, a simple and efficient combination of CS and pMRI is proposed for the better MRI reconstruction. These findings are very meaningful for reducing the imaging time of MRI systems.

A cost-effective and green technique was performed for the synthesis of silver nanoparticles (AgNPs) from a plant resource using Citrus maxima peel (CMP) extract as a reducing agent. The formation of AgNPs was confirmed by UV-Vis Spectroscopy at the wavelength range of 400−500 nm. The optimized conditions for the AgNPs synthesis using CMP extract as a reducing agent were determined. At these conditions, the X-ray diffraction (XRD) and the high-resolution transmission electron microscopy (HRTEM) results revealed the face-centered cubic structure of AgNPs had a highly crystalline with the particle size in a range of 10−20 nm. The Fourier transform infrared spectroscopy (FT-IR) demonstrated the presence of flavonoid, terpenoid, phenolic, and glycosides in phytochemical compositions of CMP extract which can act as the reducing agents for AgNPs formation. The antibacterial effect of the AgNPs was evaluated against Methicillin-resistant Staphylococcus aureus (MRSA) by implementing the minimum inhibitory concentration (MIC), minimum batericidal concentration (MBC), and the zone of inhibition tests. The AgNPs exhibited effective antibacterial activity against bacteria with an average diameter of inhibition zones of 11.7 mm, the MIC of 8.27 µg/mL, and the MBC of the 16.54 µg/mL.

Near-infrared transillumination imaging is useful in many biomedical applications such as human biometrics and animal experiments. Using near-infrared (NIR) light, we can able to obtain a two dimensional (2D) transillumination image of the internal absorption structure such as blood vessel structure, liver ... in a small animal body. If we can obtain projection images from many orientations, we can reconstruct a three dimensional (3D) image using various computed tomography techniques. In previous studies of our group, even with a simple system (light-emitting diode (LED)'s array and low-cost camera), we can obtain the blood vessel transillumination image of the human arm. In this paper, we propose preliminary research on the development of a computed tomography (CT) scanner prototype of human body parts using transillumination imaging.

In this paper, ultra-wideband (UWB) Doppler radar signatures from walking human subjects are processed with the state-space method (SSM) to analyze compressed radar echoes for the first time. A new mathematical model is proposed to detect the human walking strides using UWB radar, while micro-Doppler ( $\mu $ -D) features are extracted for gait analysis using short-time SSM (STSSM). To distinguish $\mu $ -D signatures of different subjects’ body parts, the SSM used for the characterization of radar target signatures and sensor fusion is applied on a sliding short-time window to enhance the resolution of feature extraction from data collected on a dismount. This method of the application of SSM to sliding short-time data is validated with a full-wave electromagnetic (EM) simulation of a walking subject using the Boulic model that represents the human kinematics. An EM scattering model is then utilized to compare the performance of a short-time Fourier transform with STSSM. Experimental results show that STSSM can be successfully applied to identify multiple $\mu $ -D trajectories in real experimental data, thus demonstrating the capability to positively identify human motions (right foot, left foot, and torso) even in a low signal-to-noise ratio environment.

The American Academy of Pediatrics recommends all infants born at37 weeks gestation spend a period of observation in a car seat prior to hospital discharge to assess for apnoea, bradycardia or oxygen desaturation. The most recent Cochrane review suggested further studies to determine if the infant car seat challenge (ICSC) accurately predicts the risk of clinically adverse events. We reviewed our experience with the ICSC and the polysomnogram (PSG) to determine if the ICSC accurately predicts the risk of adverse events when compared with the PSG.Retrospective chart review of all infants in our institution who had an ICSC and a PSG between January 2005 and December 2008.785 infants had ICSCs. In addition, 313 infants (56.6%) had an abnormal PSG, even though the vast majority, 158 (88.3%), passed their ICSC. There were no significant differences in gestational age at birth, birth weight, chronological age at study or postmenstrual age at study between infants who either passed or failed the ICSC with those who passed or failed the PSG. The sensitivity of the ICSC was 0.11 and specificity was 0.96. The positive predictive value of the ICSC was 0.77 and the negative predictive value was 0.45.The ICSC has a low negative predictive value (0.45) when compared with the PSG as a reference standard for identifying adverse cardiorespiratory events. Although less time consuming and cumbersome than extended polysomnography, the ICSC is not a reliable substitute.

Evidence of surfactant inactivation by meconium has led to the use of exogenous surfactant therapy in the management of meconium aspiration syndrome (MAS). Liquid assisted ventilation has been shown to improve the cardiopulmonary function in lungs with high surface tension. We compared exogenous surfactant therapy with liquid assisted ventilation in the management of experimental acute meconium aspiration injury. Thirty-two newborn lambs were ventilated at peak inspiratory pressures of 13–16 cm H2O, positive end expiratory pressure of 3–4 cm H2O, fractional inspired oxygen concentration (F1O2) of 1.0, and a respiratory frequency range between 30 and 35 breaths/min. Baseline arterial blood gases, pulmonary function, and arterial blood pressure measurements were taken. All lambs were given 2–3 ml/kg of an unfiltered 25% meconium solution. Lambs were then randomized into either gas-ventilated meconium control, or one of three treatment groups: 1) surfactant; 2) partial liquid ventilation (PLV); or 3) total liquid ventilation (TLV) for 4 hours after meconium injury. All treated groups demonstrated a significant increase in arterial oxygenation (P < 0.05); surfactant and PLV-treated lambs demonstrated significantly decreased arterial PCO2 (P < 0.05). Compliance in all groups increased compared with injury values; compliance of the TLV group increased more than in all other treatment groups (P < 0.05). In addition, lung histology of the TLV group demonstrated clear, intact alveolar epithelium and homogeneously expanded alveoli, while no such improvement was evident in the other groups. These data suggest roles for both exogenous surfactant therapy and liquid assisted ventilation techniques in the management of MAS. Pediatr Pulmonol. 1996; 21:316–322. © 1996 Wiley-Liss, Inc.

Brain-stem auditory evoked potentials (BAEPs) were elicited by bone conducted stimuli in the very immature lamb following delivery, wherein liquid ventilation techniques were utilized to control cardiopulmonary and acid-base conditions, independent of umbilical-placenta support. Unlike previous studies of the in utero fetal lamb in which the BAEP could not be elicited by earphone delivered stimuli until 117 days gestation, our results demonstrate that the BAEP emerges at least as early as 106 days gestation in the lamb and consists of a full complement of readily discernible and reproducible wave forms. In addition, the results demonstrate substantial maturation of the BAEP from 106 to 122 days gestation during which time there is a significant decrease in absolute and interpeak latencies with an increase in developmental age. It is concluded that the ability to elicit the BAEP utilizing bone conduction at this early stage of gestation is related to improved stimuli delivery. Furthermore, this study demonstrates the feasibility and flexibility afforded by liquid ventilation and bone conduction BAEP techniques to study brain-stem function at particularly vulnerable stages of development.

The inherent mechanical characteristics of the airways are determined in part by their elastic and viscoelastic properties. As compliant structures during early development, the airways are susceptible to significant distention and collapse, depending on the proportionality between airway volume and transmural pressure. To characterize the age-related changes in airway mechanical properties, the elastic and viscoelastic behavior of in vivo tracheal segments were evaluated in preterm and newborn lambs over a wide range of developmental age (108 to 154 days postconceptional age). Tracheal pressure-vol relationships and concomitant airway compliance measurements were used to determine elastic behavior. Calculations of the tracheal relaxation time constant on the same tracheal segments were used to evaluate airway viscoelastic behavior. Data demonstrated a significant (p less than 0.01) correlation with developmental age. With increasing age, the airways were found to be less compliant, and the tracheal relaxation time constant was observed to decrease. The difference in elastic properties of the trachea, in vivo compared to in vitro, suggest that neural-humoral and surrounding connective tissue factors may affect the elasticity of the developing airway. Although the modulating effects of smooth muscle tone and supporting connective tissue assist in the control of airway dimension and resistance to airflow in the intact airway, the age-related differences in the elastic properties may be a factor that predisposes the more immature airway to positive pressure-induced damage.

ABSTRAn. The mechanical properties of the newborn piglet gallbladder were evaluated in both the stimulated and unstimulated states. The pressure-volume relationships, compliance, and the estimated active tension of the gallbladder were determined in 10 newborn piglets (2-7 days of age). Agonist stimulation was achieved by administration of histamine (25 pg/kg/h) and cholecystokinin (CCK) (60 ngjkglh). Both histamine and CCK increased the intracholecystic pressure at the 50% resting volume from 12.4 cm Hz0 to 18.9 and 15.5 cm H20, respectively. This resulted in a significant (p c 0.05) increase in the active tension. However, no significant changes were observed in the gallbladder compliance after stimulation. These findings characterize the mechanical properties of the normal neonatal gallbladder. The low magnitude of intracholecystic pressure response to agonist stimulation, when compared to adult data, may explain the occurrence of decreased neonatal choledochal bile flow. (Pediatr Res 18:1181-1184,1984) Abbreviation CCK, cholecystokinin

In this report, an experimental approach and newly designed apparatus for liquid ventilation of preterm animals are described. Findings of age-related changes in cardiopulmonary function of this animal preparation are presented. Thirty-one lambs, 102-137 days gestation (term 147 +/- 3 days), were studied. The carotid artery, jugular vein, and trachea of the exteriorized fetus were cannulated under local anesthesia. Immediately after cesarean section delivery, ventilation commenced; warmed (39 degrees C) and oxygenated (PIO2 greater than 500 Torr) liquid fluorocarbon (RIMAR 101) was delivered to the lung by a mechanically assisted liquid ventilation system. Skeletal muscle paralysis, low-dose exogenous buffering, and thermal support were maintained during the 3-h experiment. Pulmonary gas exchange, acid-base status, and cardiopulmonary and metabolic function were assessed. By utilizing these techniques, effective arterial oxygenation, CO2 elimination, acid-base status, and cardiovascular stability were supported independent of gestational age. The results demonstrate a developmental increase in specific lung compliance and mean arterial pressure and decrease in heart rate and systemic O2 consumption per kilogram with advancing gestational age. These findings demonstrate that liquid ventilation negates the dependency of effective pulmonary gas exchange on surfactant development, thereby extending the limits of viability of the immature extrauterine lamb. As such this new experimental approach is useful for the study of physiological development over an age range previously limited to fetal animal preparations and, therefore, may provide insight regarding adaptation of the premature to the extrauterine environment.

Summary: The relationship between pulmonary function and the migration of meconium to distal airways was determined in 10 rabbits (mean weight 2.6 kg) after insufflation of a meconium-saline mixture (1-2 ml/kg). Animals were anesthetized, cannulated, intubated, and mechanically ventilated with 100% oxygen. Lung mechanical dysfunction was most severe during the early phase of meconium migration, 15 min postinsufflation. Substantial increases in inspiratory lung resistance (RI) and expiratory lung resistance (RE) suggest that the site of obstruction at 15 min was the large airways. A decrease in dynamic lung compliance with unchanged static compliance characterizes the obstruction as partial. At 15 min and throughout the migration process, RE was greater than RI, demonstrating a check-valve effect. This phenomenon was substantiated by an increased functional residual capacity (FRC) in all rabbits, presumably due to gas trapping. Secondary to these changes, marked hypoxemia, hypercapnea, and acidosis developed in spite of assisted ventilation with 100% oxygen. At 60 and 120 min postinsufflation, both RI and RE decreased as compared to 15 min. This suggests that the predominant site of obstruction shifted to medium and small airways concomitant with the migration of meconium. Widespread and uneven distribution of meconium still produced significant frequency dependence of lung compliance. Static compliance remained unchanged, indicating that meconium does not affect surface-active or tissue properties of the lung within 120 min postinsufflation. These data suggest that effective respiratory management after meconium aspiration is dependent on the degree of meconium migration, as reflected by pulmonary mechanics. Speculation: Significant effects of meconium aspiration on lung function are attributable to migrating obstructive phenomena, which result in a more severe lung dysfunction in earlier stages postinsufflation of meconium than in progressively later stages. It is appealing to speculate that noninvasive pulmonary function measurements made in newborn infants may quantitate the degree of mechanical obstruction and meconium migration in the airways. This information would provide guidelines for effective respiratory management of infants with meconium aspiration syndrome (MAS). Based on the present animal model, elevated oxygen therapy should be employed early to offset the severe hypoxemia. In addition, the check-valve effect (RE > RI) indicates the use of a low I/E ratio in assisted ventilation. It has been shown that continuous positive airway pressure improves arterial oxygen tension in some newborns with MAS. However, in light of the mechanical dysfunction resulting in an increased FRC, caution is recommended in the use of end distending pressure within 2 hr after meconium aspiration.

Cardiopulmonary function was evaluated in very preterm lambs (106 +/- 0.7 S.E. days gestation, 1.66 +/- 0.12 S.E. kg birth weight) during fluorocarbon ventilation. Lambs were delivered by cesarean section after epidural anesthesia. Indwelling arterial, venous, and tracheal cannulae were placed before clamping the cord. Lambs were then mechanically ventilated with oxygenated fluorocarbon for approximately 2 h. During this period it was possible to maintain adequate gas exchange and stable cardiac function. Transpulmonary pressure, liquid flow, and tidal volume tracings enabled determination of lung compliance, CL = 0.58 +/- 0.12 S.E. ml X cmH2O-1 X kg-1, inspiratory resistance, RI = 3600 +/- 604 S.E. cmH2O X liter-1 X sec-1, and expiratory resistance, RE = 4034 +/- 2183 S.E. cmH2O/liter/sec. Lung compliance of the 106-day-old fluorocarbon-filled lung is similar to the more mature 138-143-day-old air-filled lung in preterm lambs. Based on the data presented herein we have extended the viability of the preterm lamb to the limit of pulmonary capillary development rather than that of the pulmonary surfactant system.

Serial serum zinc concentrations were measured in 31 relatively well, growing premature infants during the first 26 weeks of life. Zinc concentrations declined progressively from 17.9 mumol (1.17 mg/l) at birth (normal adult value) to 8.9 mumol (0.58 mg/l) at 6 weeks of age despite a zinc intake of greater than 13.7 mumol (900 micrograms)/kg/day after the second week of life. The serum zinc increased after 16 weeks of age to 10.7 mumol/dl (0.7 mg/l). No infant demonstrated clinical signs of zinc deficiency. This data may serve as a reference against which serum zinc concentrations in other premature infants may be compared in order to help define the deficiency state.

Cardiovascular parameters were evaluated in the extrauterine preterm lamb (EPL) (GR 1:107.27±.51 SE dys gestation, 1.56±.47 SE kg BW, n=11;GR II:121.40±.53 SE dys gestation, 2.54±.16 SE kg BW, n=9) at different levels of arterial oxygenation during early development. Utilizing liquid ventilation with an oxygenated and warmed fluorocarbon (RIMAR 101) effective pulmonary gas exchange (PaO2 =24-289, PaCO2 =30-45, pH=7.25-7.45) and thermal stability were achieved. Mean arterial pressure (MAP), heart rate (HR), arterial gas tensions, blood chemistry and core temperature were monitored throughout the experiments. HR and MAP in conjunction with previously reported fetal data were statistically analyzed as a function of arterial oxygen content (CaO2=4-25 vol %) and age. Neither group demonstrated a significant change in HR or MAP until CaO2, fell below 13.30 vol %. Below this level, HR increased (p< 0.01) from 201 to 250 b/min @ CaO2=6.0 vol % and little change in MAP (38 mm Hg) was seen in GR I. In contrast, GR II showed a significant decrease in HR (p< 0.01) from 195 to 140 b/min @ CaO2 =5.0 vol % and increase in MAP (p< 0.01) from 41 to 56 mm Hg is @ CaO2 =6.0 vol %. These findings expand our understanding of age-related cardiovascular compensation over a range of arterial oxygenation previously unobtainable at this early stage of development. (Supported by NIH Grant HL/HD 30525).

Liquid ventilation (LV) with oxygenated fluorocarbon (RIMAR 101R) was utilized to develop an extrauterine preterm lamb model. Fifteen preterm lambs ranging in age from 106 to 142 days gestation (0.70 to 0.95 gestation) were studied. At elective cesarean section, the fetal carotid artery, jugular vein and trachea were cannulated. The umbilical cord was clamped and the lamb was liquid ventilated through the tracheostomy. Controlled LV was delivered over 2 hrs at an FRC = 30 ml/kg; tidal volume = 15 ml/kg; frequency = 5-9 brth/min. Normothermia was maintained by radiant (heat lamp) and convective (warmed liquid fluorocarbon) heat exchange. Dextrose (6 mg/kg/min) and bicarbonate (1 mEq/kg/hr) were continuously infused. Hemodynamic parameters during LV ranged from: heart rate = 146-202 b/min; mean arterial pressure = 40-80 mmHg; central venous pressure = 0.7-9.8 mm/Hg; O2 consumption = 1.38-11.8 ml/min/kg. Stable gas exchange was demonstrated with; PaO2 = 158-222 mmHg; PaCO2 = 34-38 mmHg; and pH = 7.28-7.39. The extrauterine model provides general accessibility of the preterm animal thus enabling the necessary instrumentation for comprehensive evaluation. Of further importance, the viability of preterm animals is extended to an earlier gestational age, thereby enlarging the scope of developmental research. (Supported by NIH Grant HL22843 and 5T32HL0741405)

To study the effect of surface tension (ST) on lung mechanics during early development, in vivo pressure-volume and lung compliance/kg (CI) determinations were made in preterm lambs. GR I (n=31; 122-140 days gestation; 2.25-3.90 kg BW) were gas ventilated and GR II (n=14; 106-138 days gestation; 1.10-3.40 kg BW) were liquid ventilated with oxygenated fluorocarbon (RIMAR 101). After effective ventilation (PaO2>60 mmHg; PaCO2=30-45 mmHg) and acid-base status (pH=7.25-7.45) were achieved, pulmonary function was evaluated (30-60 mins postnatally). Regression analysis showed significantly different relationships between CL and age for GR I (r=0.95; p

Serial serum copper (Cu) and ceruloplasmin (Cerlp) concentrations were followed for an average of 14 weeks in 25 well, growing AGA premature infants (mean GA=30 wks., mean B.W.=1181gms.) fed standard infant formulas. Serum Cu and Cerlp, low at birth, gradually increased over the first 5 months of life. No relationship between Cu intake (μg/kg) and serum Cu concentrations was seen as serum Cu was lowest when intake was highest. The ratio of Cerlp/Cu was constant (x=.28) except for the first 72hrs. of life when the ratio was significantly lower (p=.00007). The data suggests: 1. serum Cu is controlled by factors other than dietary intake; 2. Cerlp production relative to serum Cu increases significantly over the first week of life; 3. Changes in serum Cu are paralleled by proportional changes in Cerlp after the first 72 hrs. of life.

Serial serum copper and ceruloplasmin concentrations were monitored in 2 groups of parenterally alimented premature infants. Group I (n=10, mean BW=1317gms., mean GA=30.9 weeks) did not receive copper supplementation. Group II (n=8, mean BW=1415gms., mean GA=30.5 weeks) received 100μg/kg/day of supplemental Cu as Cu chloride. Group III (n=48, mean BW=1217gms., mean GA=30 weeks) were growing premature infants receiving ≥150ml/kg of standard premature infant formula by 2 weeks of age. Serum Cu and cerulo concentrations: 1. were significantly lower in Gp. III as compared to Gps. I & II during the 3rd, 4th, and 5th weeks of study; 2. were not significantly different between Gps. I & II throughout the 5 week study period. Concl: Serum Cu and cerulo concentrations do not reflect intake and cannot be used to assess sufficiency in the parenterally alimented infant.

Serial serum zinc (Zn) concentrations were measured from birth to a mean age of 16 weeks in 17 well, AGA, singleton, premature infants (mean GA=30 wks., mean B.W.=1253gms.) and compared to serum Zn concentrations in 4 sets of premature twins (mean GA=30 wks., mean individual B.W.=1104gms.) who were followed to a mean age of 18 weeks. All infants were fed standard infant formulas. Average weekly daily weight gain, linear growth, caloric, protein, and Zn intake were not significantly different between the two groups. Serum Zn concentrations measured in the first 72 hrs. of life averaged 170μg/dl in the singleton infants and 144μg/dl in the twins (p=.3). Hypozincemia (serum Zn

To investigate the acute airway obstruction phenomenon seen in neonates with meconium aspiration syndrom,pulmonary function was studied in 7 rabbits(mean2.6kg) after insufflation of meconiumsaline fluid(1-2ml/kg). Animals were anesthetized,cannulated,intubated and mechanically ventilated with 100% O2. Measurements of transpulmonary pressure,flow,volume and functional residual capacity(FRC) enabled calculation of dynamic(CL)and specific(CS) lung compliance and inspiratory(RI)and expiratory(RE) lung resistance before(control) and after(15,60,120min) insufflation of meconiumsaline mixture. Arterial blood gases,pH,and ΔA-a were also done. For all animals mean control values were: CL=1.40±0.24SE ml/cmH2O kg; CS=0.098±0.025SE ml/cmH2O/ml; RI=12.1±3.3SE cmH2O/L/sec; RE= 18.1±3.0SE cmH2O/L/sec; FRC=33.3±1.7SE ml/kg; PaO2=496±12SE mmHg; PaCO2=41.1±2.8SE mmHg; pH=7.37±0.03SE; ΔA-a=175±12SE mmHg. At 15 min post insufflation mean values of RE(p

The auditory brain-stem response (ABR) and cardiopulmonary function (as determined by the mean blood pressure [MBP], heart rate, arterial blood gases [ABG], and pH were evaluated in 9 preterm lambs ranging in age from 106-125 days gestation (70-85% term). Following epidural anesthesia of the ewe, the uterus was opened, the fetal head exposed, and a saline-filled rubber glove placed over the snout to prevent inspiration of air. Two platinum-alloy needle electrodes were inserted subdermally just posterior and inferior to the pinnae, another at vertex, and one in the snout area for ground. Click stimuli were generated and delivered by a bone conduction vibrator driven by 100 usec pulses of alternating polarity. Even the youngest group of animals revealed clearly defined 8th nerve and brain-stem response components. The latencies of waves 3,4, and 5 and the interpeak latency 1-5 decreased significantly as a function of age. Results of physiologic measures and the ABR data across subjects revealed a significant negative correlation between MBP and the latencies of waves 4 and 5 and the 1-5 interpeak latency and were suggestive of a possible inverse relationship between the wave 1 latency and pH. These findings demonstrate the presence of the ABR as early as 70% gestation as well as the sensitivity of the ABR to MBP and acid-base balance at this stage of development. (Supported by NIH Grant HL/HD 30525).