Normal Gravity Research Articles

Simulated microgravity environment inhibits matrix mineralization during the osteoblast to osteocyte differentiation

This study investigates the effects of microgravity on the differentiation and mineralization of IDG-SW3 osteocyte-like cells to understand the response of bone cells to microgravity and develop strategies to mitigate bone loss in astronauts. IDG-SW3 cells were cultured in collagen-coated dishes and subjected to a 3D clinostat to simulate microgravity 14 days after initiating differentiation. The static group remained under normal gravity. Cells were analyzed on days 14, 18, 22, and 26. Alizarin red staining demonstrated a substantial and time-dependent increase in mineralization in the static group, whereas the microgravity group exhibited little detectable mineralization throughout the experimental period. Quantitative RT-PCR revealed significant upregulation of Rankl, Alpl, Dmp1, and Fgf23 and downregulation of Sost and Phex in the microgravity group. RNA sequencing on day 26 showed distinct gene expression profiles between conditions. Heatmaps highlighted upregulated genes (Ptgs2, Alpl, Comp, Atf4, Lox) and downregulated genes (Rspo2, Ank, Ptn, Mmp13, Aspn, Spp1) under microgravity. Gene ontology (GO) enrichment analysis indicated that upregulated genes were associated with cytoskeletal organization and receptor activities, while downregulated genes were linked to extracellular matrix components and immune response. These findings provide insights into the molecular mechanisms of bone loss in space and emphasize the importance of gravity in bone remodeling. Future studies should validate these genes' functions in osteocyte biology under microgravity.

Effect of Microgravity on Rare Earth Elements Recovery by Burkholderia cepacia and Aspergillus niger

Rare earth elements (REEs) are indispensable in modern industry and technology, driving an urgent demand for innovative, eco-friendly recovery technologies. As space exploration advances, the impact of microgravity on microorganisms has become a focal point, yet the effects on microbial growth and REEss recovery remain uncharted. This study investigates the biosorption of REEs by Burkholderia cepacia (B. cepacia) and Aspergillus niger (A. niger) from a mixed solution containing La, Ce, Pr, Nd, Sm, Er, and Y under varying initial concentrations, pH levels, and microgravity conditions. We observed that the medium’s pH rose with B. cepacia and fell with A. niger when cultured in normal gravity conditions, suggesting distinct metabolic responses. Notably, microgravity significantly altered microbial morphology and metabolite profiles, significantly enhancing REEs recovery efficiency. Specifically, the recovery of B. cepacia of Ce and Pr peaked at 100%, and A. niger achieved full recovery of all tested REEs at pH 1.5 (suboptimal growth conditions). This study pioneers the application of biosorption for the recovery of REEs in microgravity conditions, presenting a promising strategy for future resource exploitation by space biomining.

8380 Pituitary Stalk Interruption Syndrome, A Rare Cause of Panhypopituitarism

Abstract Disclosure: F. Abdulkarim: None. E. Alshdifat: None. P. Henriquez Feliz: None. J. Vargas-Jerez: None. T. Zahra: None. Pituitary Stalk Interruption Syndrome, A Rare Cause of Panhypopituitarism Faridat Abdulkarim, MD. Esra’a Alshdifat, MD. Pamela Henriquez Feliz, MD. Julia Vargas- Jerez, MD. and Tasneem Zahra, MD. Introduction: Pituitary stalk interruption syndrome (PSIS) is a rare congenital pituitary anatomical abnormality with reported incidence of 0.5 per 100,000 live births. It is characterized by the triad of thin or interrupted pituitary stalk, absent or ectopic posterior lobe and hypoplastic or aplastic anterior lobe seen on MRI. The anterior pituitary function is usually impaired however the posterior pituitary is usually intact and normal. We report a case of a Now 34-year-old Female who presented to the endocrine clinic with underdeveloped sexual characteristics. MRI done was consistent with PSIS. This is the second case of PSIS we report from our Institution. Case Presentation: A Now 34-year -old Hispanic American Female presented to our endocrine clinic with underdeveloped secondary sexual characteristics. She had panhypopituitarism, including Growth hormone deficiency and was treated with growth hormone from early childhood until age 13-14 years. She re-presented to our clinic at the age of 28 years after being lost to follow up for many years. On physical examination, she was 175cm tall, weighed 89.4kg and BMI 29.1kg/m2Patient has pre-pubertal breast, tanner stage 1, no axillary hair, small external genitalia with scanty pubic hair. Hormonal analysis revealed Estradiol <5 pg/mL (low), FSH 0.4 IU/L (low), LH <0.3 IU/L (low), Progesterone 0.1ng/mL (Low), Testosterone <2.5 ng/dL (8.4- 48.1ng/dl) Prolactin 22.3ng/mL (3.4-24.1 ng/ml), TSH 0.88uIU/mL (0.27-4.20), Free T4 0.5ng/dl (0.9-1.8) , ACTH 7.7pg/mL (7.2-63.3), Baseline AM Cortisol 0.7ug/dL (6.0-18.4) and 5.5 ug/dL after Cosyntropin test, IGF-1 17ng/mL (83-280). Urinalysis revealed normal specific gravity. Chromosome analysis with Normal Karyotype 46XX. Pelvic US revealed Markedly diminutive uterus and ovaries. MRI of the pituitary was highly suggestive of PSIS. She is currently being treated with levothyroxine and hydrocortisone Conclusion: PSIS is a rare congenital abnormality. Fortunately has good prognosis, however if left undiagnosed/untreated has high mortality mainly from Adrenal insufficiency and Myxedema coma. The patient discussed above, has underdeveloped sexual characteristics and primary amenorrheaLaboratory finding consistent with Panhypopituitarism with Normal prolactin which is the case in most patient with PSIS. Imaging revealed atrophic uterus and ovaries, and MRI revealed Findings which are highly suggestive of PSISShe previously had problems with outpatient clinic visits and medication compliance. However, she is currently compliant with hormonal replacement therapy which is the mainstay of treatment. Presentation: 6/3/2024

Enhancement of pool boiling under reduced gravity by the synergistic effect of non-uniform surface structure and electric field: A lattice Boltzmann study

In this paper, a novel non-uniformly structured surface with primary and secondary pillars is conceived to be coupled with the action of an electric field to enhance pool boiling under reduced gravity. On the surface, the secondary pillars are distributed diagonally. A three-dimensional thermal lattice Boltzmann (LB) model combined with an electric field model is employed to investigate the boiling heat transfer performance on the non-uniformly pillar-structured surface and the associated boiling enhancement mechanism. It is found that the synergistic effect of the non-uniform surface structure and the electric field leads to a non-equilibrium electric force that causes the bubbles to be pushed away from the center of the heating surface, which promotes an earlier departure of the bubbles and provides more paths for the fresh liquid replenishment. As a result, the boiling performance under reduced gravity can be significantly enhanced by utilizing such a synergistic effect, with both the critical heat flux (CHF) and the maximum heat transfer coefficient (HTC) on the non-uniformly pillar-structured surface exceeding those on a uniformly pillar-structured surface under normal gravity. Moreover, the influences of the distribution of the secondary pillars on the boiling performance under reduced gravity are also studied. It is shown that the non-uniformly pillar-structured surface whose secondary pillars are distributed diagonally performs much better than those with the secondary pillars being distributed crossly and centrally, and the synergistic effect of the non-uniform surface structure and the electric field results from tuning the distribution of the non-uniform electric force.

Towards enhanced elevated-temperature mechanical properties by regulation of eutectic structure in Al-Cu-Si alloys solidified under super-gravity field

High volume fraction of tri-phase eutectic structure is challenging to obtain in ternary alloys through conventional methods. Currently, we reported that super-gravity solidification can be utilized to obtain high-volume fraction Al-Al2Cu-Si tri-phase eutectic structure in Al-Cu-Si alloys. The refinement of the eutectic structure can be detected mainly due to the enhancement of mass transfer, affecting the nucleation rate and growth of eutectic phase in the Al-Cu-Si eutectic system. Interestingly, the refined Al2Cu and Si eutectic structures are stable even up to 300 °C thermal exposure without obvious coarsening, contributing to the enhancement of elevated-temperature mechanical properties (∼268.8±8.8 MPa at 300 °C), which is ∼51.9 % higher than those solidified under normal gravity field (∼177.0±1.9 MPa). The refinement and homogeneous distribution of more Al-Al2Cu-Si tri-phase eutectic structures provide better stress dispersion, favoring crack initiation and propagation within the tri-phase eutectics, resulting in a transition from brittle fracture to ductile fracture mode.

DNS of laboratory-scale turbulent premixed counterflow flames under elevated gravity conditions

In the present work, direct numerical simulations (DNSs) of laboratory-scale turbulent premixed counterflow flames are performed to understand the effect of elevated gravity on flame structures. In the DNS, a turbulent jet of CH4/N2/O2 mixture is injected in opposition to a stream of combustion product. Three cases were considered, i.e., one case with normal gravity and two cases with elevated gravity in different directions. The DNS results of the case under normal gravity conditions were found to be in good agreement with the experimental data. The turbulent flame speed is the highest in the case with elevated gravity aligned with the mean flame propagating direction, which is due to the increase in flame surface area and stretch factor. The gravity levels have a substantial influence on the flame extinction characteristics. It was observed that the flame front is pushed toward the direction of the gravity. When the elevated gravity antialigns with the mean flame propagating direction, the flame front travels across the stagnation plane toward the combustion product stream, leading to significant reactant dilution and flame extinction. The flame normal vector preferentially aligns with the most compressive strain rate for various gravity conditions. The tangential strain rate is the greatest (smallest) when elevated gravity antialigns (aligns) with the mean flame propagating direction. The impact of elevated gravity on the tangential strain rate at the flame fronts ultimately leads to a displacement in the flame front location relative to the stagnation plane, thereby influencing flame extinction.

Physical Modeling of Hydrate Dissociation in Sandy Sediment by Depressurization under Hypergravity and Normal Gravity Conditions

Physical Modeling of Hydrate Dissociation in Sandy Sediment by Depressurization under Hypergravity and Normal Gravity Conditions

Identifying Gravity-Related Artifacts on Ballistocardiography Signals by Comparing Weightlessness and Normal Gravity Recordings (ARTIFACTS): Protocol for an Observational Study.

Modern ballistocardiography (BCG) and seismocardiography (SCG) use acceleration sensors to measure oscillating recoil movements of the body caused by the heartbeat and blood flow, which are transmitted to the body surface. Acceleration artifacts occur through intrinsic sensor roll, pitch, and yaw movements, assessed by the angular velocities of the respective sensor, during measurements that bias the signal interpretation. This observational study aims to generate hypotheses on the detection and elimination of acceleration artifacts due to the intrinsic rotation of accelerometers and their differentiation from heart-induced sensor accelerations. Multimodal data from 4 healthy participants (3 male and 1 female) using BCG-SCG and an electrocardiogram will be collected and serve as a basis for signal characterization, model modulation, and location vector derivation under parabolic flight conditions from µg to 1.8g. The data will be obtained during a parabolic flight campaign (3 times 30 parabolas) between September 24 and July 25 (depending on the flight schedule). To detect the described acceleration artifacts, accelerometers and gyroscopes (6-degree-of-freedom sensors) will be used for measuring acceleration and angular velocities attributed to intrinsic sensor rotation. Changes in acceleration and angular velocities will be explored by conducting descriptive data analysis of resting participants sitting upright in varying gravitational states. A multimodal data set will serve as a basis for research into a noninvasive and gentle method of BCG-SCG with the aid of low-noise and synchronous 3D gyroscopes and 3D acceleration sensors. Hypotheses will be generated related to detecting and eliminating acceleration artifacts due to the intrinsic rotation of accelerometers and gyroscopes (6-degree-of-freedom sensors) and their differentiation from heart-induced sensor accelerations. Data will be collected entirely and exclusively during the parabolic flights, taking place between September 2024 and July 2025. Thus, as of June 2024, no data have been collected yet. The data will be analyzed until December 2025. The results are expected to be published by June 2026. The study will contribute to understanding artificial acceleration bias to signal readings. It will be a first approach for a detection and elimination method. Deutsches Register Klinische Studien DRKS00034402; https://drks.de/search/en/trial/DRKS00034402. PRR1-10.2196/63306.

Partial gravity flammability of cast PMMA rods in concurrent axial stagnation flow

Testing was performed in a partial gravity centrifuge drop vehicle in the Zero Gravity Research Facility with cast PMMA rods in concurrent axial buoyant stagnation flow to determine flammability limits as a function of partial gravity level. The partial gravity levels studied varied from 0.04 g to a simulated 1g for ambient oxygen concentrations from 13.2 % to 15.2 % O2 by volume at an average 57.6 kPa (8.4 PSIA) ambient pressure, which is very close to the anticipated Lunar habitat pressure. The PMMA flammability boundary as a function of oxygen concentration and gravity level has been determined at five gravity levels. Coriolis effects appear to be minimal in the stagnation region where the flame is stabilized while the tips of the flame do show some bending at the higher gravity levels. Lunar gravity levels are near the minimum in the oxygen - gravity level flammability boundary. This suggests that fire is a significant safety risk for future exploration missions to the Moon since materials are screened in normal gravity to evaluate their safe use in space. If normal gravity screening is not conservative, a material derating method will need to be applied to ensure the material is not flammable on the Moon. Since the blowoff boundary appears to be linear with forced flow velocity, it may be possible to conduct elevated forced flow blowoff testing that could then be extrapolated down to effective Lunar gravity levels to provide an oxygen delta between 1g and Lunar flammability limits to derate the material.

Response of Staphylococcus aureus physiology and Agr quorum sensing to low-shear modeled microgravity.

Staphylococcus aureus is commonly isolated from astronauts returning from spaceflight. Previous analysis of omics data from S. aureus low Earth orbit cultures indicated significantly increased expression of the Agr quorum sensing system and its downstream targets in spaceflight samples compared to ground controls. In this current study, the rotary cell culture system (RCCS) was used to investigate the effect of low-shear modeled microgravity (LSMMG) on S. aureus physiology and Agr activity. When cultured in the same growth medium and temperature as the previous spaceflight experiment, S. aureus LSMMG cultures exhibited decreased agr expression and altered growth compared to normal gravity control cultures, which are typically oriented with oxygenation membrane on the bottom of the high aspect rotating vessel (HARV). When S. aureus was grown in an inverted gravity control orientation (oxygenation membrane on top of the HARV), reduced Agr activity was observed relative to both traditional control and LSMMG cultures, signifying that oxygen availability may affect the observed differences in Agr activity. Metabolite assays revealed increased lactate and decreased acetate excretion in both LSMMG and inverted control cultures. Secretomics analysis of LSMMG, control, and inverted control HARV culture supernatants corroborated these results, with inverted and LSMMG cultures exhibiting a decreased abundance of Agr-regulated virulence factors and an increased abundance of proteins expressed in low-oxygen conditions. Collectively, these studies suggest that the orientation of the HARV oxygenation membrane can affect S. aureus physiology and Agr quorum sensing in the RCCS, a variable that should be considered when interpreting data using this ground-based microgravity model.IMPORTANCES. aureus is commonly isolated from astronauts returning from spaceflight and from surfaces within human-inhabited closed environments such as spacecraft. Astronaut health and immune function are significantly altered in spaceflight. Therefore, elucidating the effects of microgravity on S. aureus physiology is critical for assessing its pathogenic potential during long-term human space habitation. These results also highlight the necessity of eliminating potential confounding factors when comparing simulated microgravity model data with actual spaceflight experiments.

Gravitational change-induced alteration of the vestibular function and gene expression in the vestibular ganglion of mice

Gravity has profoundly influenced life on Earth, yet how organisms adapt to changes in gravity remains largely unknown. This study examines vestibular plasticity, specifically how the vestibular system responds to altered gravity. We subjected male C57BL/6J mice to hypergravity (2 G) followed by normal gravity (1 G) to analyze changes in vestibular function and gene expression. Mice showed significant vestibular dysfunction, assessed by righting reflex tests, which persisted for days but reversed at 1 G after exposure to 2 G. Gene expression analysis in the vestibular ganglion identified significant changes in 212 genes out of 49,585 due to gravitational changes. Specifically, 25 genes were upregulated under 2 G and recovered at 1 G after 2 G exposure, while one gene showed the opposite trend. Key neural function genes like Shisa3, Slc25a37, Ntn4, and Snca were involved. Our results reveal that hypergravity-induced vestibular dysfunction is reversible and highlight genes critical for adaptation.

Human cranial bone-derived mesenchymal stem cells cultured under simulated microgravity can improve cerebral infarction in rats

The efficacy of transplanting human cranial bone-derived mesenchymal stem cells (hcMSCs) cultured under simulated microgravity (sMG) conditions has been previously reported; however, their effect on cerebral infarction remains unknown. Here, we examined the efficacy of transplanting hcMSCs cultured in an sMG environment into rat models of cerebral infarction. For evaluating neurological function, hcMSCs cultured in either a normal gravity (1G) or an sMG environment were transplanted in rats 1 day after inducing cerebral infarction. The expression of endogenous neurotrophic, axonal, neuronal, synaptogenic, angiogenic, and apoptosis-related factors in infarcted rat brain tissue was examined using real-time polymerase chain reaction and western blotting 35 days after stroke induction. The RNAs of hcMSCs cultured under 1G or sMG environments were sequenced. The results showed that neurological function was significantly improved after transplantation of hcMSCs from the sMG group compared with that from the 1G group. mRNA expressions of nerve growth factor, fibroblast growth factor 2, and synaptophysin were significantly higher in the sMG group than in the 1G group, whereas sortilin 1 expression was significantly lower. RNA sequencing analysis revealed that genes related to cell proliferation, angiogenesis, neurotrophy, neural and synaptic organization, and inhibition of cell differentiation were significantly upregulated in the sMG group. In contrast, genes promoting microtubule and extracellular matrix formation and cell adhesion, signaling, and differentiation were downregulated. These results demonstrate that hcMSCs cultured in the sMG environment may be a useful source of stem cells for the recovery of neurological function after cerebral infarction.

Position dependence of the standing-wave radiation pressure quadrupole projection on a sphere applied to drop shape.

There have been decades of interest in using the ultrasonic radiation pressure of standing waves to deform nearly spherical objects. An analytical approach sometimes associated with the present author involves approximating projections of the radiation pressure on spheres small in comparison with the wavelength and calculating the response to that projection. In 1981, for small fluid spheres, some terms in the quadrupole projection were published along with the dependence on the size and location of the sphere. An associated application was the flattening of levitated drops in air which are attracted toward velocity antinodes of a standing wave having horizontal equiphase surfaces. In subsequent applications of those results, the predicted analytical dependence on the location of the drop is frequently neglected. For the case of small weakly deformed drops in air in normal gravity, that omission is shown to result in an overestimation of the deformation and of the magnitude of the quadrupole radiation pressure projection. The present discussion simplifies the early results when applied to oblate drops and illustrates the consequence of including the position dependence on the modified small deformation. For large trapped oblate bubbles in water (also reviewed), the shape and location depend on the size.

Defying the D2-law in fuel droplet combustion under gravity

We show both experimentally and theoretically for the first time that the widely used D2-law for describing the shrinking kinetics of a vaporizing droplet is not the true law for single burning droplets under the influence of gravity. Experimentally, the instantaneous diameter D for such a droplet is identified to obey a new kinetic law: Dn decreases linearly with time t, with the exponent n=2.53±0.30−2.69±0.14 for a variety of common liquid fuels such as alkanes and alcohols of low and high boiling hydrocarbons. Theoretically, we develop a phenomenological theory to show n=8/3≈2.67 well capturing the experimental values. The burning rate constant in this new D8/3-law no longer behaves like the thermal diffusivity α of the gas phase but turns into α3ℓ−7/3/g due to the additional inherent fluid-property-determined buoyancy length ℓ under the influence of the gravitational acceleration g. This non-square power law is purely transport determined. It is a consequence of simultaneous momentum, heat, and mass transfer resulted from buoyant convection setup by the blazing flame around the droplet, insensitive to combustion chemistry and detailed reaction kinetics. This study provides not only renewed insights into the multifaceted droplet combustion phenomenon but also possibly new paradigms for a better understanding or characterization of actual fuel droplet combustion processes in normal gravity environments.

Acceleration waveform reproduction control of hypergravity centrifugal shaking table based on data driven iterative learning control and two-degree-of-freedom control

The hypergravity centrifugal shaking table (HCST) is the most effective means for studying the disaster effects of rock and soil earthquakes, and the accurate control of acceleration waveform recurrence is the critical problem. This paper compares the dynamic characteristics of the normal gravity shaking table (NGST) and the HCST, highlighting the latter’s particularities, and analyzes the limitations of the existing control strategy. Meanwhile, a hypergravity unidirectional airborne shaking table (HUAST) is designed, and a data-driven iterative learning control and two-degree-of-freedom control-based acceleration waveform reproduction strategy is proposed and experimentally verified.

Dynamic cellular responses to gravitational forces: Exploring the impact on white blood cell(s).

In recent years, the allure of space exploration and human spaceflight has surged, yet the effects of microgravity on the human body remain a significant concern. Immune and red blood cells rely on hematic or lymphatic streams as their primary means of transportation, posing notable challenges under microgravity conditions. This study sheds light on the intricate dynamics of cell behavior when suspended in bio-fluid under varying gravitational forces. Utilizing the dissipative particle dynamics approach, blood and white blood cells were modeled, with gravity applied as an external force along the vertical axis, ranging from 0 to 2 g in parameter sweeps. The results revealed discernible alterations in the cell shape and spatial alignment in response to gravity, quantified through metrics such as elongation and deformation indices, pitch angle, and normalized center of mass. Statistical analysis using the Mann-Whitney U test underscored clear distinctions between microgravity (<1 g) and hypergravity (>1 g) samples compared to normal gravity (1 g). Furthermore, the examination of forces exerted on the solid, including drag, shear stress, and solid forces, unveiled a reduction in the magnitude as the gravitational force increased. Additional analysis through dimensionless numbers unveiled the dominance of capillary and gravitational forces, which impacted cell velocity, leading to closer proximity to the wall and heightened viscous interaction with surrounding fluid particles. These interactions prompted shape alterations and reduced white blood cell area while increasing red blood cells. This study represents an effort in comprehending the effects of gravity on blood cells, offering insights into the intricate interplay between cellular dynamics and gravitational forces.

Simulated microgravity impairs human NK cell cytotoxic activity against space radiation-relevant leukemic cells

Natural killer (NK) cells are an important first-line of defense against malignant cells. Because of the potential for increased cancer risk from astronaut exposure to space radiation, we determined whether microgravity present during spaceflight affects the body’s defenses against leukemogenesis. Human NK cells were cultured for 48 h under normal gravity and simulated microgravity (sμG), and cytotoxicity against K-562 (CML) and MOLT-4 (T-ALL) cells was measured using standard methodology or under continuous sμG. This brief exposure to sμG markedly reduced NK cytotoxicity against both leukemias, and these deleterious effects were more pronounced in continuous sμG. RNA-seq performed on NK cells from two additional healthy donors provided insight into the mechanism(s) by which sμG reduced cytotoxicity. Given our prior report of space radiation-induced human T-ALL in vivo, the reduced cytotoxicity against MOLT-4 is striking and raises the possibility that μG may increase astronaut risk of leukemogenesis during prolonged missions beyond LEO.

Dynamic response characteristics of microchannel evaporator in a mechanically pumped two-phase loop under hypergravity environment

The unique hypergravity environment and severe heat-dissipation requirements of modern fighter aircrafts pose serious challenges to the potential utilization of mechanically pumped two-phase loops (MPTLs), which are an efficient cooling technology. The microchannel evaporator is a key component of the MPTL system, and understanding its startup and operation characteristics is of great significance for design and optimization. In this context, an experimental MPTL system is built and fixed on a rotating platform, which is designed to generate hypergravity ranging from 0 g0 to 15.0 g0 (g0 = 9.8 m·s−2). The dynamic-response characteristics of the temperature, pressure, and flow rates during the startup and operation of the microchannel evaporator under various hypergravity conditions are investigated. The results indicate that different startup modes, namely gradual startup under low hypergravity and overshoot startup under high hypergravity, are achieved on the microchannel evaporator, even if the flow rate and heat flux are not changed, which is completely different from that under normal gravity. These two startup modes can be quantitatively recognized by two dimensionless numbers: the boiling number (Bo) and Froude number (Fr). A larger Bo or 1/Fr, which corresponds to a larger heat flux or hypergravity; both conditions contribute to the startup mode of the microchannel evaporator shifting from gradual to overshoot startup. During the operation of a microchannel evaporator, the competition between the elevated saturation temperature of the fluid and the induced Coriolis and centrifugal forces caused by hypergravity determines the wall-temperature variation of the evaporator. The dynamic wall temperature decreases under hypergravity below 2.5 g0, is stable with small fluctuations under hypergravity from 4.7 g0 to 7.5 g0, and increases for hypergravity larger than 11.0 g0.

Urban greenway planning: Identifying optimal locations for active travel corridors through individual mobility assessment

Greenways are planned for various goals including nature conservation and promoting mobility by foot or bike in urban areas. A challenge associated with designed greenways pertains to their underutilization for mobility. Due to their multi-functionality greenways are usually not designed with a focus on active mobility, and thus, do not necessarily correspond with daily mobility patterns. This study addresses this issue by devising a methodology for the identification of optimal locations for active urban greenways within a metropolitan expanse, strategically aligned with the day-to-day pursuits of its inhabitants. Distinguished from prior greenway research, this investigation emphasizes individual mobility and adds a novel perspective to greenway planning. The method was tested in the city of Mashhad in Iran. By employing the Analytic Hierarchy Process methodology in conjunction with a Geographic Information System (GIS) and a gravity formula, a meticulous selection process yielded 19 nodes (sites) deemed most suitable for greenway implementation, selected from a pool of 93 prospective nodes. These findings offer pragmatic insights into the expansion of greenways tailored to the daily activities of urban inhabitants, thus complementing established greenway paradigms and strengthening the mobility dimension and active travel corridors in urban greenway planning.

Skeletal muscle-on-a-chip in microgravity as a platform for regeneration modeling and drug screening

Microgravity has been shown to lead to both muscle atrophy and impaired muscle regeneration. The purpose was to study the efficacy of microgravity to model impaired muscle regeneration in an engineered muscle platform and then to demonstrate the feasibility of performing drug screening in this model. Engineered human muscle was launched to the International Space Station National Laboratory, where the effect of microgravity exposure for 7days was examined by transcriptomics and proteomics approaches. Gene set enrichment analysis of engineered muscle cultured in microgravity, compared to normal gravity conditions, highlighted a metabolic shift toward lipid and fatty acid metabolism, along with increased apoptotic gene expression. The addition of pro-regenerative drugs, insulin-like growth factor-1 (IGF-1) and a 15-hydroxyprostaglandin dehydrogenase inhibitor (15-PGDH-i), partially inhibited the effects of microgravity. In summary, microgravity mimics aspects of impaired myogenesis, and the addition of these drugs could partially inhibit the effects induced by microgravity.