30-mm Depth Research Articles

Evaluation of the proper chest compression depth for neonatal resuscitation using computed tomography: A retrospective study.

This study was created to assess whether a 30-mm depth of chest compression (CC) is sufficient and safe for neonatal cardiopulmonary resuscitation.This retrospective analysis was performed with chest computed tomography scans of neonates in 2 hospitals between 2004 and 2018. We measured several chest parameters and calculated heart compression fraction (HCF) using the ejection fraction formula. We evaluated whether one-third of the external anterior-posterior (AP) diameter and HCF with them are the equivalent to 25-, 30-, 35 mm and HCF with them, respectively, and the number of individuals with over-compression (internal chest AP diameter − compressed depth <10 mm) to estimate a safe CC depth. We divided the patients into term and preterm groups and compared their outcomes.In total, 63 of the 75 included individuals were analyzed, and one-third of the external lengths was equivalent to 30 ± 3 mm (P < .001). When the patients were divided into term (n = 53) and preterm (n = 10) groups, the equivalent depth was 30 ± 3 mm in the term group (P < .001) and 25 ± 2.5 mm in the preterm group (P = .004). The HCF with 30 mm was equivalent to that for one-third of the external length (P < .001). When we simulated CCs with a 30-mm depth, over-compression occurred more frequently in the preterm group (20%) compared to the term group (1.9%) (P = .014).A 30-mm depth could be appropriate for sufficient and safe neonatal resuscitation. Shallower CC should be considered in preterm babies.

MagNI: A Magnetoelectrically Powered and Controlled Wireless Neurostimulating Implant.

This paper presents the first wireless and programmable neural stimulator leveraging magnetoelectric (ME) effects for power and data transfer. Thanks to low tissue absorption, low misalignment sensitivity and high power transfer efficiency, the ME effect enables safe delivery of high power levels (a few milliwatts) at low resonant frequencies ( ∼250kHz) to mm-sized implants deep inside the body (30-mm depth). The presented MagNI (Magnetoelectric Neural Implant) consists of a 1.5-mm 2 180-nm CMOS chip, an in-house built 4×2mm ME film, an energy storage capacitor, and on-board electrodes on a flexible polyimide substrate with a total volume of 8.2mm 3. The chip with a power consumption of 23.7 μW includes robust system control and data recovery mechanisms under source amplitude variations (1-V variation tolerance). The system delivers fully-programmable bi-phasic current-controlled stimulation with patterns covering 0.05-to-1.5-mA amplitude, 64-to-512- μs pulse width, and 0-to-200-Hz repetition frequency for neurostimulation.

Microwave Sensing of Acoustically Induced Local Harmonic Motion: Experimental and Simulation Studies on Breast Tumor Detection

Sensing acoustically induced local harmonic motion using a microwave transceiver system may provide useful information for detecting nonpalpable tumors in dense breast tissue. For this purpose, we propose the harmonic motion microwave Doppler imaging method, in which the first harmonic of the phase modulated signal due to local harmonic motion is sensed. This signal is related to the dielectric, elastic, and acoustic properties of the vibrating region. The purpose of this paper is twofold: 1) to demonstrate the concept of this method with experiments using phantom materials mimicking the elastic and electrical properties of the breast tissue and 2) to investigate the effect of fibroglandular region size and vibration frequency on the received signal, using numerical simulations. A breast phantom with a tumor phantom inclusion (5-mm diameter and 7-mm height) inside fibroglandular region is constructed for the experimental study. The response due to a focused ultrasound probe is linearly scanned at 30-mm depth from the phantom surface, and the Doppler signal level is tracked using a spectrum analyzer. It is shown that the tumor phantom is resolvable inside the surrounding fibroglandular region with about a 3–5-dB decrease in the signal level. The simulations, using the finite-difference time-domain method, show that the received signal level depends on the relative size of the fibroglandular region with respect to the vibrating region size. Further experimental and numerical studies are needed to investigate the feasibility of this method and to optimize the imaging system design.

Plane-Wave Compounding in Automated Breast Volume Scanning: A Phantom-Based Study

The goal of this study was to assess whether it is viable to implement plane-wave imaging in the Automated Breast Volume Scanner (ABVS) to speed up the acquisition process. This would allow breath-hold examinations, thus reducing breathing artifacts without loss of imaging quality. A calibration phantom was scanned in an Automated Breast Volume Scanner-mimicking setup using both dynamic receive focusing with a fixed transmit focus and unfocused plane-wave compounding. Contrast-to-noise ratio and lateral resolution were compared using two beamforming schemes, delay-and-sum and Stolt's f–k algorithm. Plane-wave compounding using only 11 compounding angles and Stolt's f–k algorithm provided image quality similar to that of focused transmission with dynamic receive focusing (contrast-to-noise ratios = 10.3 and 10.8 dB for Stolt's f–k migration with Hann apodization and focused transmission, respectively; full width at half-maximum = 0.38 and 0.4 mm, respectively; all at 30-mm depth with transmit focus at 30 mm) with a higher signal-to-noise ratio at all depths. Furthermore, a full 3-D volume of a breast-mimicking phantom was scanned using this optimal set of compounding angles and different speeds (10, 20 and 50 mm/s) to assess the impact of scanning time on image quality. Only minor differences in contrast-to-noise ratio were found (cyst 1: 6.0 ± 0.3 dB, cyst 2: 5.5 ± 0.2 dB, cyst 3: 5.7 ± 0.5 dB). These differences could not be correlated to the movement speeds, indicating that acquisition speed does not significantly affect image quality. Our results suggest that plane-wave imaging will enable breath-hold automated breast volume scanning examinations, eliminating breathing artifacts while otherwise preserving similar image quality.

Influence of ultrasonic scattering in the calculation of thermal dose in ex-vivo bovine muscular tissues

This study explores the effect of ultrasound scattering on the temperature increase in phantoms and in samples of ex-vivo biological tissue through the calculation of the thermal dose (TD). Phantoms with different weight percentages of graphite powder (0–1%w/w, different scattering mean free paths, ℓS) and ex-vivo bovine muscle tissue were isonified by therapeutic ultrasound (1MHz). The TD values were calculated from the first 4min of experimental temperature curves obtained at several depths and were compared with those acquired from the numerical solution of the bio-heat transfer equation (simulated with 1MHz and 0.5–2.0Wcm−2). The temperature curves suggested that scattering had an important role because the temperature increments were found to be higher for higher percentages of graphite powder (lower ℓS). For example, at a 30-mm depth and a 4-min therapeutic ultrasound application (0.5Wcm−2), the TDs (in equivalent minutes at 43°C) were 7.2, 17.8, and 58.3 for the phantom with ℓS of 4.35, 3.85, and 3.03mm, respectively. In tissue, the inclusion of only absorption or full attenuation in the bio-heat transfer equation (BHTE) heat source term of the simulation leads to under- or overestimation of the TD, respectively, as compared to the TD calculated from experimental data. The experiments with phantoms (with different scatterer concentrations) and ex-vivo samples show that the high values of TD were caused by the increase of energy absorption due to the lengthening of the propagation path caused by the changing in the propagation regime.

Potential of a no-touch pincer ablation procedure for small hepatocellular carcinoma that uses a multipolar radiofrequency ablation system: An experimental animal study

Treatment of hepatocellular carcinoma located on the liver surface is frequently difficult because direct puncture of the tumor must be avoided during needle insertion. The aim of this study was to investigate the utility of a no-touch pincer ablation procedure that uses a multipolar radiofrequency ablation (RFA) system for a tumor located on the liver surface. The experimental animals were three pigs, and RFA was performed with two internally cooled bipolar electrodes. Three ablative procedures were compared: linear insertion at regular 13-mm intervals (pattern 1; virtual target tumor size, <10 mm); fan-shape insertion, maximum interval 20 mm (pattern 2; virtual target tumor size, <15 mm); and 25 mm (pattern 3; virtual target tumor size, <20 mm). All electrodes were inserted at a 30-mm depth. For patterns 1 and 2, ablation was performed on three other parts of the liver, and for pattern 3, ablation was performed on two other parts. For the median transverse and longitudinal diameter to the shaft, with the pattern 1 procedure, the ablative areas were 32 mm × 30 mm, and with the pattern 2 procedure, the ablative areas were 27 mm × 30 mm with carbonization of the liver surface. In contrast, with the pattern 3 procedure, the ablative areas were 45 mm × 26 mm; however, the ablative margin did not reach the surface, and carbonization was not apparent. The no-touch pincer ablation procedure (with an electrode interval of ≤20 mm) may be useful when performed with two internally cooled bipolar electrodes for small nodules that protrude from the liver surface.

Pavement Performance of Asphalt Surface Course Containing Reclaimed Asphalt Pavement (RAP)

Abstract Reclaimed asphalt pavement (RAP) provides many advantages. The performance of a provincial road with an asphalt surface course containing RAP in Zhejiang, China was evaluated. The surface course was prepared by central plant hot mix recycling and virgin asphalt concrete. An AC-13 was chosen as gradation design in all mixes. The performance of asphalt mixture (containing 0 %, 10 %, 20 %, and 30 % RAP) was evaluated in the laboratory for fatigue resistance condition, moisture susceptibility, high-temperature stability, and low-temperature anti-cracking. Based on the laboratory results, the provincial road was constructed consisting of three sections (corresponding to 0 %, 10 %, and 20 % RAP content) in surface course with a 30-mm depth. The field site has been inspected and observed for 4 years. The field testing included deflection, skid resistance, permeable performance, and evenness evaluations. The laboratory test results show that all the testing indices satisfied the demand of the specifications, except moisture susceptibility and low temperature anti-cracking performance of the recycled asphalt concrete, including 30 % RAP. The inspection data proved that a small percentage of RAP unaffected the surface course performance, but RAP ratios greater than 20 % are not suitable in the mainline for high-volume roadways.

Spinal Cord Injury in a Child Caused by an Accidental Dural Puncture with a Single-Shot Thoracic Epidural Needle

Spinal Cord Injury in a Child Caused by an Accidental Dural Puncture with a Single-Shot Thoracic Epidural Needle

Micropenetrometer for In Situ Measurement of Soil Surface Strength

Soil surface characteristics greatly influence seedling emergence, water infiltration, and soil erosion. A portable micropenetrometer was designed to measure the strength of the soil surface (or crust) as an indirect measure of soil surface characteristics in the field. The penetrometer is designed to operate on a 12 V DC battery and is controlled by a portable microcomputer. Penetrometer measurements can be made a few millimeters apart along 1-m long transects with a small (1.6 mm) probe in order to evaluate spatial patterns of crust strength. Laboratory and field measurements show that the penetrometer is capable of detecting detailed differences in the nearsurface soil (0–4 mm depth) that result from different physical, chemical, and management-related conditions. Penetration measurements from 0 to 30-mm depth at 0.1-mm depth increments reflected differences in the structure of the surface soil layer due to irrigation method by detecting sequences of aggregates and pores as the probe penetrated the soil. These results indicate that the micropenetrometer is capable of detecting and quantifying differences in soil surface characteristics influencing physical processes at the soil surface.

Effects of different clearing treatments on the seed-bank dynamics of an invasive Australian shrub, Acacia cyclops, in the Southwestern Cape, South Africa

Acacia cyclops is an invasive shrub of natural vegetation in the fynbos biome of South Africa. Its large soil-stored seed banks make eradication difficult. In this study, a dense, mature stand of A. cyclops was cleared using four commonly applied treatments. Few seeds above 30-mm depth in the soil profile survived burning treatments, and percentage viability was reduced at depths up to 40 mm. Seed germinability was not enhanced by fire. Seedling emergence and mortality, monitored over 13 months post-clearing, were much higher following non-burning and ‘fell and burn’ treatments than ‘burn standing’ and ‘fell, pile and burn’ treatments. Nevertheless, the pattern of seedling emergence and survival was similar in all treatments, with survival low until October, 9 months post-clearing. Although all treatments resulted in significant reductions in seed density 1 year post-clearing, burning treatments were more effective than the non-burning treatment. The ‘burn standing’ treatment killed more seeds than the ‘fell and burn’ treatment, and may be recommended where labour costs are prohibitive. Since all treatments induced a rapid seed-bank decline in A. cyclops, it is recommended that the choice of treatment be dictated by other factors, such as possible effects on the recovery of indigenous plant species.

Photosynthetic Potential and Light-Dependent Oxygen Consumption in a Benthic Cyanobacterial Mat

The potential to carry out oxygenic photosynthesis after prolonged burial below the photic zone was studied at 0.1-mm depth intervals in the thick, laminated Microcoleus chthonoplastes mats growing in Solar Lake, Sinai. The buried mat community lost about 20% of its photosynthetic potential with depth per annual layer down to 8- to 10-year-old layers at a 14-mm depth. In some of the older layers, below a 30-mm depth, light-dependent oxygen consumption which increased with increasing light intensity was observed. Possible mechanisms for this phenomenon are (i) pseudocyclic electron transport (Mehler reaction), (ii) interactions between respiratory electron transport and photosynthetic electron transport, (iii) photorespiration, and (iv) photooxidation.

The effect of reduced tillage of an irrigated silty soil and of a mulch on seedling emergence, growth and yield of maize ( Zea mays) harvested for silage

Maize was grown for 1 season as a row-crop on raised beds in a factorial experiment on reduced tillage. The effects of 2 passes of a spring-tined cultivator (Treatment C), of a small 70-mm wide rotary-hoe, ahead of the seeder (Treatment R) and of a mulch (Treatment M) on emergence, growth and yield of maize were determined. Treatment C produced a coarse tilth (41% aggregates > 20-mm diameter; 9% aggregates 0.5–2 mm) in the top 30 mm of pre-irrigated beds of a silty soil. Treatment R produced a fine seed-bed (4% aggregates > 20-mm diameter; 21% aggregates 0.5–2 mm), 70 mm wide and 30 mm deep, along each of the 2 sowing-lines. In the same pass, 2 rows of maize were sown at a depth of 25 mm into the wet soil. In the mulched treatments (M), where 5 t ha −1 of barley straw was applied after the crop was sown, to cover the bed, the water content around the seed (0–30-mm depth) over the first 9 days after the crop was sown was 29–74% higher than in the unmulched treatments (M 0). For example, 1 day after the crop was sown, the water content of soil around the seed was 21% in Treatment M, close to field capacity, and 14% in Treatment M 0. In Treatment M, the temperature around the seed (25-mm depth) at 15.00 h over the first 9 days after the crop was sown was almost always significantly lower than in Treatment M 0; for example, the maximum temperatures of Treatments M and M 0 were 32 and 41°C, respectively. Either Treatment M or R, but not Treatment C hastened emergence of maize seedlings and increased percentage final emergence. There were no significant effects of any treatments on plant yield. However, there was a trend within Treatment M for either Treatments R or C to increase yields.

Bacterial contribution to manganese oxidation in a deep coastal sediment

The characteristics of Mn(II) removal from sediment porewater and the potential role of manganese-oxidizing bacteria in this process were examined in sediments from a 335-m deep station in the Laurentian Trough of the St. Lawrence estuary. Manganese-oxidizing bacteria were most abundant in the thin layer of oxidized surface sediment, where Mn(II) removal rates were also fastest. The first-order rate constants for Mn(II) removal decreased from 1·2 × 10 3 day −1 to 6·6 day −1 over the first 30-mm depth. In experimental slurries, sediments removed Mn(II) from reduced zone porewater by a two-step process: a rapid saturation of Mn(II) binding sites was followed by a slower O 2-enhanced removal rate which paralleled the apparent rate of Mn(II) oxidation. Sodium azide and mercuric chloride were tested specifically for their usefulness as bacterial poisons in sediment slurry systems. Sodium azide interfered with Mn(II) removal at low concentrations and was not an effective poison. Mercuric chloride inhibited bacterial activity at concentrations far lower than those at which significant interference of Mn(II) removal occurred. The response of sediment slurries treated with mercuric chloride indicated that the initial oxidation of sorbed Mn(II) was not bacterially-mediated under the experimental conditions tested.

Persistence and distribution of pollution indicator bacteria on land used for disposal of piggery effluent.

Numbers of pollution indicator bacteria (fecal coliforms and fecal streptococci) were assessed on land to which effluent from intensively housed pigs had been applied. Topsoil (to a 30-mm depth) was found to provide a more favorable environment for fecal coliform persistence than was pasture or subsoil. Times required for a 90% reduction in number (T90) in topsoil (calculated by linear regression of log counts obtained in a 6-week period after effluent application) ranged from 7 to 20 days (mean T90, 11 days). T90 values for fecal coliforms fell within this range irrespective of the season of application and for a number of soil types and climatic conditions. The range in die-off times was encountered irrespective of the fecal coliform count in the applied effluent or the application regimen (125 to 1,000 kg of elemental nitrogen in the form of effluent per ha; return periods, 3 to 12 months). Autumn and winter conditions were conducive to the persistence of a survivor tail of these bacteria at 10(1) to 10(3) cells per g of topsoil. Fecal streptococci survived similarly on soil and pasture (T90, ca. 14 days) and appeared slightly more suited to survival in the environment than did fecal coliforms. Contamination of subsoils after effluent applications occurred at a rate well in excess of the infiltration capacity of the soil, presumably by percolation of the effluent through soil cracks. Contamination levels of subsoils in the experimental area generally remained low.