Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 7 de 7
Filter
Add more filters










Database
Language
Publication year range
1.
J Appl Physiol (1985) ; 133(6): 1349-1355, 2022 Dec 01.
Article in English | MEDLINE | ID: mdl-36326472

ABSTRACT

Spaceflight associated neuro-ocular syndrome (SANS) is associated with acquired optic disc edema, hyperopia, and posterior globe flattening in some astronauts during long-duration spaceflight possibly due to the headward fluid redistribution in microgravity. The goal of this study was to assess whether strict head-down tilt (HDT) bed rest as a spaceflight analog would produce globe flattening and whether centrifugation could prevent these changes. Twenty-four healthy subjects separated into three groups underwent 60 days of strict 6° HDT bed rest: one control group with no countermeasure (n = 8) and two countermeasure groups exposed to 30 min daily of short-arm centrifugation as a means of artificial gravity (AG), either intermittent (iAG, n = 8) or continuous (cAG, n = 8). Magnetic resonance images (MRI) were collected at baseline, HDT-day 14, HDT-day 52, and 3 days after bed rest. An automated method was applied to quantify posterior globe volume displacement compared with baseline scans. On average, subjects showed an increasing degree of globe volume displacement with bed rest duration (means ± SE: 1.41 ± 1.01 mm3 on HDT14 and 4.04 ± 1.19 mm3 on HDT52) that persisted post-bed rest (5.51 ± 1.26 mm3). Application of 30 min daily AG did not have a significant impact on globe volume displacement (P = 0.42 for cAG and P = 0.93 for iAG compared with control). These results indicate that strict 6° HDT bed rest produced displacement of the posterior globe with a trend of increasing displacement with longer duration that was not prevented by daily 30 min exposure to AG.NEW & NOTEWORTHY Head-down tilt (HDT) bed rest is commonly used as a spaceflight analog for investigating spaceflight associated neuro-ocular syndrome (SANS). Posterior ocular globe flattening has been identified in astronauts with SANS but until now has not been investigated during HDT bed rest. In this study, posterior ocular globe volume displacement was quantified before, during, and after HDT bed rest and countermeasures were tested for their potential to reduce the degree of globe flattening.


Subject(s)
Gravity, Altered , Space Flight , Humans , Head-Down Tilt , Bed Rest , Astronauts , Magnetic Resonance Imaging
2.
Water Environ Res ; 94(8): e10777, 2022 Aug.
Article in English | MEDLINE | ID: mdl-36004674

ABSTRACT

Dual upflow reactive filtration by a slowly moving sand bed with continuously renewed, hydrous ferric oxide-coated sand is used for removing polluting substances and for meeting the ultralow 0.05 mg/l total phosphorus discharge permit limits at a 1.2 million liters per day (0.32 million gallons per day) water resource recovery facility in Plummer, Idaho, in the United States. A life cycle assessment (LCA) of this reactive filtration installation was carried out to assess the environmental hotspots in the system and analyze alternative system configurations with a focus on CO2 equivalent (CO2 e) global warming potential, freshwater and marine eutrophication, and mineral resource scarcity. "What if" scenarios with alternative inputs for the energy, metal salts, and air compressor optimization show trade-offs between the impact categories. Key results that show a comparative reduction of global warming potential include the use of Fe versus Al metal salts, the use of renewable energy, and the energy efficiency benefit of optimizing process inputs, such as compressor air pressure, to match operational demand. The LCA shows a 2 × 10-2  kg CO2 e footprint per cubic meter of water, with 47% from housing concrete, and an overall freshwater eutrophication impact reduced by 99% versus no treatment. The use of renewable hydropower energy at this site isolates construction concrete as a target for lowering the CO2 e footprint. PRACTITIONER POINTS: The main LCA eco-impact hotspots in this dual reactive filtration tertiary treatment are construction concrete and the ferric sulfate used. Iron salts show smaller impact in global warming, freshwater eutrophication, and mineral resource scarcity than "what if scenario" aluminum salts. The energy mix for this site is predominantly hydropower; other energy mix "what if" scenarios show larger impacts. Operational energy efficiency and thermodynamic analysis show that fine tuning the air compressor helps reduce carbon footprint and energy use. LCA shows a favorable 2 x 10-2 kg CO2e/m3 water impact with 99% reduction of freshwater eutrophication potential versus no treatment.


Subject(s)
Phosphorus , Wastewater , Carbon Dioxide , Ferric Compounds , Minerals , Salts , Sand , Wastewater/analysis , Water
3.
HardwareX ; 11: e00253, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35509920

ABSTRACT

The physiological oxygen levels for several mammalian cell types in vivo are considered to be hypoxic (low oxygen tension), but the vast majority of in vitro mammalian cell culture is conducted at atmospheric oxygen levels of around 21%. In order to understand the impact of low oxygen environments on cells, oxygen levels need to be regulated during in vitro culture. Two common methods for simulating a hypoxic environment are through the regulation of gas composition or chemical induction. Chemically mimicking hypoxia can have adverse effects such as reducing cell viability, making oxygen regulation in cell culture chambers crucial for long-term culture. However, oxygen-regulating cell culture incubators and commercial hypoxia chambers may not always be a viable option due to cost and limited customization. Other low-cost chambers have been developed, but they tend to lack control systems or are fairly small scale. Thus, the objective of this project was to design and develop a low-cost, open-source, controllable, and reproducible hypoxia chamber that can fit inside a standard cell culture incubator. This design allows for the control of O2 between 1 and 21%, while maintaining CO2 levels at 5%, as well as monitoring of temperature, pressure, and relative humidity. Testing showed our hypoxia chamber was able to maintain CO2 levels at 5% and hypoxic O2 levels at 1% and 5% for long-term cell culture. This simple and easy-to-manufacture design uses off the shelf components, and the total material cost was $832.47 (USD).

4.
Front Neuroimaging ; 1: 879098, 2022.
Article in English | MEDLINE | ID: mdl-37555174

ABSTRACT

Background: Understanding the relationship between cerebrospinal fluid (CSF) dynamics and intrathecal drug delivery (ITDD) injection parameters is essential to improve treatment of central nervous system (CNS) disorders. Methods: An anatomically detailed in vitro model of the complete CSF system was constructed. Patient-specific cardiac- and respiratory-induced CSF oscillations were input to the model in the subarachnoid space and within the ventricles. CSF production was input at the lateral ventricles and CSF absorption at the superior sagittal sinus. A model small molecule simulated drug product containing fluorescein was imaged within the system over a period of 3-h post-lumbar ITDD injections and used to quantify the impact of (a) bolus injection volume and rate, (b) post-injection flush volume, rate, and timing, (c) injection location, and (d) type of injection device. For each experiment, neuraxial distribution of fluorescein in terms of spatial temporal concentration, area-under-the-curve (AUC), and percent of injected dose (%ID) to the brain was quantified at a time point 3-h post-injection. Results: For all experiments conducted with ITDD administration in the lumbar spine, %ID to the brain did not exceed 11.6% at a time point 3-h post-injection. Addition of a 12 mL flush slightly increased solute transport to the brain up to +3.9%ID compared to without a flush (p < 0.01). Implantation of a lumbar catheter with the tip at an equivalent location to the lumbar placed needle, but with rostral tip orientation, resulted in a small improvement of 1.5%ID to the brain (p < 0.05). An increase of bolus volume from 5 to 20 mL improved solute transport to the brain from 5.0 to 6.3%ID, but this improvement was not statistically significant. Increasing bolus injection rate from 5 to 13.3 mL/min lacked improvement of solute transport to the brain, with a value of 6.3 compared to 5.7%ID. Conclusion: The in vitro modeling approach allowed precisely controlled and repeatable parametric investigation of ITDD injection protocols and devices. In combination, the results predict that parametric changes in lumbar spine ITDD-injection related parameters and devices can alter %ID to the brain and be tuned to optimize therapeutic benefit to CNS targets.

5.
J R Soc Interface ; 18(177): 20200920, 2021 04.
Article in English | MEDLINE | ID: mdl-33906382

ABSTRACT

Spaceflight is known to cause ophthalmic changes in a condition known as spaceflight-associated neuro-ocular syndrome (SANS). It is hypothesized that SANS is caused by cephalad fluid shifts and potentially mild elevation of intracranial pressure (ICP) in microgravity. Head-down tilt (HDT) studies are a ground-based spaceflight analogue to create cephalad fluid shifts. Here, we developed non-invasive magnetic resonance imaging (MRI)-based techniques to quantify ophthalmic structural changes under acute 15° HDT. We specifically quantified: (i) change in optic nerve sheath (ONS) and optic nerve (ON) cross-sectional area, (ii) change in ON deviation, an indicator of ON tortuosity, (iii) change in vitreous chamber depth, and (iv) an estimated ONS Young's modulus. Under acute HDT, ONS cross-sectional area increased by 4.04 mm2 (95% CI 2.88-5.21 mm2, p < 0. 000), while ON cross-sectional area remained nearly unchanged (95% CI -0.12 to 0.43 mm2, p = 0.271). ON deviation increased under HDT by 0.20 mm (95% CI 0.08-0.33 mm, p = 0.002). Vitreous chamber depth decreased under HDT by -0.11 mm (95% CI -0.21 to -0.03 mm, p = 0.009). ONS Young's modulus was estimated to be 85.0 kPa. We observed a significant effect of sex and BMI on ONS parameters, of interest since they are known risk factors for idiopathic intracranial hypertension. The tools developed herein will be useful for future analyses of ON changes in various conditions.


Subject(s)
Head-Down Tilt , Weightlessness , Healthy Volunteers , Humans , Magnetic Resonance Imaging , Weightlessness Simulation
6.
HardwareX ; 7: e00097, 2020 Apr.
Article in English | MEDLINE | ID: mdl-35495209

ABSTRACT

There is a need for a small-scale, laboratory treadmill to investigate impacts of neonatal locomotion on neuromuscular and musculoskeletal development in small animal models. Adult mice and rats are routinely assessed using commercially available treadmills, but these treadmills can be relatively expensive and they may lack features needed to evaluate developing animals. Therefore, to overcome these limitations, a new treadmill was designed, built and calibrated. This open-source treadmill was designed specifically for neonatal and postnatal mice and rats, and it fits within a neonatal incubator. By using predominantly off-the-shelf and 3D printed components, and a microcontroller, this treadmill was low cost and easy to reproduce. The design also included variable incline, and a transparent belt and enclosures for video and gait analysis. A touchscreen interface provided user-friendly control over belt speed and run time. Moreover, validation experiments showed high accuracy in belt speed control, allowing for tightly regulated experimental conditions. Overall, this new low-cost, open-source, variable speed and incline treadmill can be used to advance understanding of neonatal locomotion, and neuromuscular and musculoskeletal development.

7.
J Nepal Health Res Counc ; 17(2): 193-199, 2019 Aug 04.
Article in English | MEDLINE | ID: mdl-31455933

ABSTRACT

BACKGROUND: Appropriate utilization of maternal health care services is very important tool to reduce the maternal and child morbidity and mortality rate. This study was conducted to assess the utilization of maternal health care services by the women for their last pregnancy in one year period and to find out it's association with selected variables. METHODS: Descriptive cross sectional study was conducted for one year by using semi-structured questionnaire among 285 mothers residing at slums area of Dharan sub-metropolitan city after taking written consent from them. Ethical clearance was obtained from Institutional Review Committee, BPKIHS and Dharan Sub-metropolitan city office. Simple random sampling followed by snowball sampling method was used to collect the data by interview method. RESULTS: Majority (95.1%) had one Antenatal visit, 60.4% had initiated antenatal visit at first trimester and 78.99% had completed 4 or more antenatal visits. Only 35.8% had taken complete dose of iron and calcium. Majority 262 (91.92%) respondents have taken Tetanus Toxoid immunization and among them only 74.42% had taken 2 dose of TT injection. Women who delivered in health facility accounted for 70.9% but only 28.8% went for postnatal visit. Majority (65.3%) received health advice during postnatal period. Nearly 40% respondents used family planning after post partum period .There was significant association between utilization of antenatal and delivery services with Educational status of respondents and their husbands and number of pregnancy and between utilization of postnatal services with occupation of husband. CONCLUSIONS: Utilization of maternal health care services, antenatal services utilization were satisfactory whereas postnatal services and family planning services utilization were very poor. Utilization of maternal health services should be encouraged by conducting public awareness programmes.


Subject(s)
Maternal Health Services/statistics & numerical data , Poverty Areas , Adult , Cross-Sectional Studies , Female , Humans , Nepal , Pregnancy , Surveys and Questionnaires , Utilization Review
SELECTION OF CITATIONS
SEARCH DETAIL
...