Crescent Shape Research Articles

Genetic Modifiers of Hemoglobin Expression from a Clinical Perspective in Hemoglobinopathy Patients with Beta Thalassemia and Sickle Cell Disease

Hemoglobinopathies, namely β-thalassemia and sickle cell disease (SCD), are hereditary diseases, characterized by molecular genetic aberrations in the beta chains of hemoglobin. These defects affect the normal production of hemoglobin with severe anemia due to less or no amount of beta globins in patients with β-thalassemia (quantitative disorder), while SCD is a serious disease in which a mutated form of hemoglobin distorts the red blood cells into a crescent shape at low oxygen levels (qualitative disorder). Despite the revolutionary progress in recent years with the approval of gene therapy and gene editing for specific patients, there is an unmet need for highlighting the mechanisms influencing hemoglobin production and for the development of novel drugs and targeted therapies. The identification of the transcription factors and other genetic modifiers of hemoglobin expression is of utmost importance for discovering novel therapeutic approaches for patients with hemoglobinopathies. The aim of this review is to describe these complex molecular mechanisms and pathways affecting hemoglobin expression and to highlight the relevant investigational approaches or pharmaceutical interventions focusing on restoring the hemoglobin normal function by linking the molecular background of the disease with the clinical perspective. All the associated drugs increasing the hemoglobin expression in patients with hemoglobinopathies, along with gene therapy and gene editing, are also discussed.

Performance improvement of Savonius hydrokinetic turbine using upstream crescent shape deflector

Performance improvement of Savonius hydrokinetic turbine using upstream crescent shape deflector

Deformation dynamics of an oil droplet into a crescent shape during intermittent motion

Deformation dynamics of an oil droplet into a crescent shape during intermittent motion

Bessel–Bessel–Gaussian vortex laser beams

Abstract We obtain and investigate Bessel–Bessel–Gaussian vortex beams (BBG beams) with the complex amplitude being equal to a product of the Gaussian function with two Bessel functions, whose arguments are expressed as complicated radicals including the cylindrical coordinates and a free parameter that defines the shape of the intensity distribution. If this parameter is small, the intensity has the shape of an inhomogeneous ring. For larger values of this parameter, the intensity has the shape of two arcs or ‘crescents’, oriented by their concave sides to each other. The complex amplitude of such beams is derived in explicit form for an arbitrary distance from the waist. We demonstrate that the BBG beams rotate upon propagation anomalously fast: at a distance much shorter than the Rayleigh length, the intensity distribution is already rotated by almost 45°, whereas typically, the rotation angle of vortex Gaussian beams is equal to the Gouy phase. It is also shown that the parameter of the BBG beam allows controlling its topological charge (TC): when the parameter value is positive and increases, the beam TC also increases stepwise by an even number. Besides, we study two other similar vortex BBG beams: either with four local intensity maxima, lying on the Cartesian coordinates axes, or with one intensity maximum with a crescent shape, whose center is on the horizontal axis. The derived three new families of asymmetric vortex laser beams, whose complex amplitude is described by explicit analytical expressions at an arbitrary distance from the waist, extend the variety of laser beams that can be used for manipulating and rotating microparticles, free space data transmission, and in quantum informatics.

Barchan‐Barchan Dune Repulsion Investigated at the Grain Scale

AbstractBarchans are eolian dunes of crescent shape found on Earth, Mars and other celestial bodies. Among the different types of barchan‐barchan interaction, there is one, known as chasing, in which the dunes remain close but without touching each other. In this paper, we investigate the origins of this barchan‐barchan dune repulsion by carrying out grain‐scale numerical computations in which a pair of granular heaps is deformed by the fluid flow into barchan dunes that interact with each other. In our simulations, data such as position, velocity and resultant force are computed for each individual particle at each time step, allowing us to measure details of both the fluid and grains that explain the repulsion. We show the trajectories of grains, time‐average resultant forces, and mass balances for each dune, and that the downstream barchan shrinks faster than the upstream one, keeping, thus, a relatively high velocity although in the wake of the upstream barchan. In its turn, this fast shrinkage is caused by the flow disturbance, which induces higher erosion on the downstream barchan and its circumvention by grains leaving the upstream dune. Our results help explaining the mechanisms behind the distribution of barchans in dune fields found on Earth and Mars.

Dynamic and stability analysis of crescent geometry-possessing textured journal bearing using nanolubricant

PurposeThis study aims to find the dynamic performance parameters of the journal bearing with micro geometries patterning the arc (crescent) shape textures provided in three specific regions of the journal bearing: the full, the second half and the increasing pressure region. The dynamic behavior of textured journal bearings has been analyzed by computing dynamic parameters and linear and non-linear trajectories.Design/methodology/approachThe lubricant flows between the bearing and journal surface are governed by Reynold’s equation, which has been solved by finite the element method. The dynamic performance parameters such as stiffness, damping, threshold speed, critical mass and whirl frequency ratio are examined under various operating conditions by considering various ranges of eccentricity ratios and texture depths. Linear and non-linear equations of motion have been solved with Ranga–Kutta method to get journal motion trajectories. Also, the impact of adding aluminum oxide and copper oxide nanoparticles to the base lubricant in combination with arc-shaped textures is analyzed to further see any enhancement in the performance parameters.FindingsThe findings demonstrated that direct stiffness and damping parameters increased to their maximum level with six textures in the pressure-increasing region when compared with the untextured surface. Also, nanoparticle additives showed improvements above the highest value attained with no inclusion of additives in the same region or quantity of textures.Originality/valueEngineers may design bearings with improved stability and overall performance if they understand how texture form impacts dynamic properties.

Stream hydrology controls on ice cliff evolution and survival on debris-covered glaciers

Abstract. Ice cliffs are melt hot spots that contribute disproportionately to melt on debris-covered glaciers. In this study, we investigate the impact of supraglacial stream hydrology on ice cliffs using in situ and remote sensing observations, streamflow measurements, and a conceptual geomorphic model of ice cliff backwasting applied to ice cliffs on Kennicott Glacier, Alaska. We found that 33 % of ice cliffs (accounting for 69 % of the ice cliff area) are actively influenced by streams, while half are nearer than 10 m from the nearest stream. Supraglacial streams contribute to ice cliff formation and maintenance by horizontal meandering, vertical incision, and debris transport. These processes produce an undercut lip at the ice cliff base and transport clasts up to tens of centimeters in diameter, preventing reburial of ice cliffs by debris. Stream meander morphology reminiscent of sedimentary river channel meanders and oxbow lakes produces sinuous and crescent ice cliff shapes. Stream avulsions result in rapid ice cliff collapse and local channel abandonment. Ice cliffs abandoned by streams are observed to be reburied by supraglacial debris, indicating a strong role played by streams in ice cliff persistence. We also report on a localized surge-like event at the glacier's western margin which drove the formation of ice cliffs from crevassing; these cliffs occur in sets with parallel linear morphologies contrasting with the crescent planform shape of stream-driven cliffs. The development of landscape evolution models may assist in quantifying the total net effect of these processes on steady-state ice cliff coverage and mass balance, contextualizing them with other drivers including supraglacial ponds, differential melt, ice dynamics, and collapse of englacial voids.

Fabrication of Crescent Shaped Microparticles for Particle Templated Droplet Formation.

Crescent-shaped hydrogel microparticles are shown to template uniform volume aqueous droplets upon simple mixing with aqueous and oil media for various bioassays. This emerging "lab on a particle" technique requires hydrogel particles with tunable material properties and dimensions. The crescent shape of the particles is attained by aqueous two-phase separation of polymers followed by photopolymerization of the curable precursor. In this work, the phase separation of poly(ethylene glycol) diacrylate (PEGDA, Mw 700) and dextran (Mw 40000) for tunable manufacturing of crescent-shaped particles is investigated. The particles' morphology is precisely tuned by following a phase diagram, varying the UV intensity, and adjusting the flow rates of various streams. The fabricated particles with variable dimensionsencapsulate uniform aqueous droplets upon mixing with an oil phase. The particles are fluorescently labeled with red and blue emitting dyes at variable concentrations to produce six color-coded particles. The blue fluorescent dye shows a moderate response to the pH change. The fluorescently labeled particles are able to tolerate an extremely acidic solution (pH 1) but disintegrate within an extremely basic solution (pH 14). The particle-templated droplets are able to effectively retain the disintegrating particle and the fluorescent signal at pH 14.

Direct observation of a crescent-shape chromosome in expanded Bacillus subtilis cells

Bacterial chromosomes are folded into tightly regulated three-dimensional structures to ensure proper transcription, replication, and segregation of the genetic information. Direct visualization of chromosomal shape within bacterial cells is hampered by cell-wall confinement and the optical diffraction limit. Here, we combine cell-shape manipulation strategies, high-resolution fluorescence microscopy techniques, and genetic engineering to visualize the shape of unconfined bacterial chromosome in real-time in live Bacillus subtilis cells that are expanded in volume. We show that the chromosomes predominantly exhibit crescent shapes with a non-uniform DNA density that is increased near the origin of replication (oriC). Additionally, we localized ParB and BsSMC proteins – the key drivers of chromosomal organization – along the contour of the crescent chromosome, showing the highest density near oriC. Opening of the BsSMC ring complex disrupted the crescent chromosome shape and instead yielded a torus shape. These findings help to understand the threedimensional organization of the chromosome and the main protein complexes that underlie its structure.

Filament structure and subcellular organization of the bacterial intermediate filament–like protein crescentin

The protein crescentin is required for the crescent shape of the freshwater bacterium Caulobacter crescentus (vibrioides). Crescentin forms a filamentous structure on the inner, concave side of the curved cells. It shares features with eukaryotic intermediate filament (IF) proteins, including the formation of static filaments based on long and parallel coiled coils, the protein's length, structural roles in cell and organelle shape determination and the presence of a coiled coil discontinuity called the "stutter." Here, we have used electron cryomicroscopy (cryo-EM) to determine the structure of the full-length protein and its filament, exploiting a crescentin-specific nanobody. The filament is formed by two strands, related by twofold symmetry, that each consist of two dimers, resulting in an octameric assembly. Crescentin subunits form longitudinal contacts head-to-head and tail-to-tail, making the entire filament non-polar. Using in vivo site-directed cysteine cross-linking, we demonstrated that contacts observed in the in vitro filament structure exist in cells. Electron cryotomography (cryo-ET) of cells expressing crescentin showed filaments on the concave side of the curved cells, close to the inner membrane, where they form a band. When comparing with current models of IF proteins and their filaments, which are also built from parallel coiled coil dimers and lack overall polarity, it emerges that IF proteins form head-to-tail longitudinal contacts in contrast to crescentin and hence several inter-dimer contacts in IFs have no equivalents in crescentin filaments. Our work supports the idea that intermediate filament-like proteins achieve their shared polymerization and mechanical properties through a variety of filament architectures.

Microstructure, Hardness and Corrosion Resistance of Al-TiC MMC Prepared by Laser Cladding on AZ31B Magnesium Alloy

Magnesium alloy is extensively used in aircraft, automobiles, and electronic industries due to its low density, high specific strength, and enhanced machinability. However, low hardness and poor corrosion resistance limit its application. In this work, an Al-TiC metal matrix composite (MMC) was prepared on AZ31B magnesium alloy via laser cladding. The effects of laser power and TiC content on the microstructure, hardness, and corrosion resistance of the MMC were investigated. The results showed that the MMC with 10% TiC had a hardness of 184 HV0.1, which was 3.5 times higher than 52 HV0.1 of the substrate. The current density of MMC with 10% TiC was 3.90 × 10−7 A/cm2, which was three orders of magnitude lower than 5.45 × 10−4 A/cm2 of the substrate. Due to more intermetallic compounds (IMCs) and TiC particles, the MMC with 30% TiC had higher hardness. The increased laser power would not change the phase composition, but it contributed to the formation of a concave crescent shape, promoted the diffusion of Mg, and induced the formation of a thicker Al3Mg2 transition layer. Modifications in the TiC concentration markedly influenced the coating’s microstructural characteristics.

Severe Traumatic Brain Injury Induced Coagulopathy in Pediatric: An Important Lesson with Literature Review

Children with coagulopathy had a greater mortality rate after moderate to severe traumatic brain injury (TBI). The purpose of the current study was to examine the most recent relevant literature in relation to the therapy of TIC in pediatric isolated severe TBI patients. A 5 years old boy presented to emergency department with decrease of consciousness after hit by a motorcycle. He was referred from the district hospital without proper stabilization within 3 hours after the injury. From the blood examination, hemoglobin level was 8.1 g/dl, base deficit -9.9mEq/L with PTT and aPTT no coagulation suggesting coagulopathy. Emergency non-contrast head computed tomography was performed and showed anterior skull base fracture with discontinuity in left squamous suture suggesting a diastases fracture with an air hypodensity lesion in left frontal area suggesting a pneumocephalus. There was also a hyperdense lesion with crescent shape in frontal and interhemispheric region suggesting subdural hematoma. Delayed operation for almost 6 hours was advocated due to transfusion of whole blood and fresh frozen plasma to correct coagulopathy. The operation was successful, the patient was survived but upon 2 years follow up, the patient still wasn’t able to perform normal daily activity. Localized injury at the brain manifesting in systemic coagulopathy requires special care. Several steps need to be evaluated before surgery but it should not delay the attempt of controlling the source of coagulopathy by it means lesion in the brain. Our case demonstrates the important of recognizing and managing coagulopathy in severe traumatic brain injury.

Constraining the magnetic field geometry of the millisecond pulsar PSR J0030+0451 from joint radio, thermal X-ray, andγ-ray emission

Context.With the advent of multi-wavelength electromagnetic observations of neutron stars – spanning many decades in photon energies – from radio wavelengths up to X-rays andγ-rays, it has become possible to significantly constrain the geometry and the location of the associated emission regions.Aims.In this work, we use results from the modelling of thermal X-ray observations of PSR J0030+0451 from the Neutron Star Interior Composition Explorer (NICER) mission and phase-aligned radio andγ-ray pulse profiles to constrain the geometry of an off-centred dipole that is able to reproduce the light curves in these respective bands simultaneously.Methods.To this aim, we deduced a configuration with a simple dipole off-centred from the location of the centre of the thermal X-ray hot spots. We show that the geometry is compatible with independent constraints from radio andγ-ray pulsations only, leading to a fixed magnetic obliquity ofα ≈ 75° and a line-of-sight inclination angle ofζ ≈ 54°.Results.We demonstrate that an off-centred dipole cannot be rejected by accounting for the thermal X-ray pulse profiles. Moreover, the crescent shape of one spot is interpreted as the consequence of a small-scale surface dipole on top of the large-scale off-centred dipole.

Perioperative Right Ventricular Dysfunction and Abnormalities of the Tricuspid Valve Apparatus in Patients Undergoing Cardiac Surgery.

Right ventricular (RV) dysfunction frequently occurs after cardiac surgery and is linked to adverse postoperative outcomes, including mortality, reintubation, stroke, and prolonged ICU stays. While various criteria using echocardiography and hemodynamic parameters have been proposed, a consensus remains elusive. Distinctive RV anatomical features include its thin wall, which presents a triangular shape in a lateral view and a crescent shape in a cross-sectional view. Principal causes of RV dysfunction after cardiac surgery encompass ischemic reperfusion injury, prolonged ischemic time, choice of cardioplegia and its administration, cardiopulmonary bypass weaning characteristics, and preoperative risk factors. Post-left ventricular assist device (LVAD) implantation RV dysfunction is common but often transient, with a favorable prognosis upon resolution. There is an ongoing debate regarding the benefits of concomitant surgical repair of the RV in the presence of regurgitation. According to the literature, the gold standard techniques for assessing RV function are cardiac magnetic resonance imaging and hemodynamic assessment using thermodilution. Echocardiography is widely favored for perioperative RV function evaluation due to its accessibility, reproducibility, non-invasiveness, and cost-effectiveness. Although other techniques exist for RV function assessment, they are less common in clinical practice. Clinical management strategies focus on early detection and include intravenous drugs (inotropes and vasodilators), inhalation drugs (pulmonary vasodilators), ventilator strategies, volume management, and mechanical support. Bridging research gaps in this field is crucial to improving clinical outcomes associated with RV dysfunction in the near future.

Concurrent Kink and Sausage Waves in A Crescent Shaped Structure Over A Limb Prominence

Abstract A Crescent shaped prominence Structure (CS), over the solar west limb is studied using EIS/HINODE and AIA/SDO. First, the time varying positions of the top and below borders of the CS, along with its central axis are derived. Time evolutions of the Doppler shifts, and Line width of Fe XII 195.119 line are studied over the CS borders. Transverse kink oscillations are observed both in the Solar-Y direction and in the Doppler shifts over the observers’ LOS. One explanation could be the oscillatory direction of the main kink wave build an angle with the observers LOS. This angle is calculated to be equal to 27 degrees for the CS top border. The main kink amplitude velocity and periods are obtained to be 5.3 $\rm km/s$, and 33.4 minutes, respectively. The anti-correlation observed between the brightness and thickness of the CS (with -178.1○) suggests the presence of sausage modes with periods of 20.8 minutes. Based on the AIA imaging, it is suggested that the occurred jets and their afterward dimming are responsible to trigger the sausage mode. The average electron densities of the CS over the time of the study is obtained to be log($\rm n_e$)=9.3$\rm [cm^{-3}]$. The Alfvén velocity, magnetic field, and energy flux of the observed fast kink mode over the CS are estimated to be 16.7 $\rm km/s$, 2.79 $\rm G$, 41.93 $\rm W/m^2$. Considering the magnetic flux conservation inside the CS, expanding the CS cross section, causes the magnetic field to decay with the rate of $\rm 4.95 \times 10^{-4} \, G/sec$.

Experimental study of the stability of crescent barchan shape in subaqueous dune evolution in unsteady water flow

A water tunnel experiment adopting the frequency conversion technology is conducted to investigate the evolution of subaqueous barchan dune driven by the periodic water flow. The kinematic and morphological characteristics of the barchan dune evolution are derived through the imaging processing. Results exhibit a good correlation between the dune kinematics and the periodic variation of water flow, which indicates that the unsteadiness is transmitted from the fluid phase to the sand phase with nearly no inertia. The stable crescent barchan shape under unsteady flow is found. Meanwhile, this crescent barchan shape breaks and reconstructs periodically during the variation of unsteady flow, which implies a flexible compromise between the dune system and the propelling force. This study suggests that the stability of crescent barchan shape can be robust under unsteady flow, which brings new understandings of the morphological stability of sand dune evolution.

Disk and Envelope Streamers of the GGD 27-MM1 Massive Protostar

We present new Atacama Large Millimeter/submillimeter Array 0.98 mm observations of the continuum emission and several molecular lines toward the high-mass protostellar system GGD 27-MM1, driving the HH 80-81 radio jet. The detailed analysis of the continuum and the CH3CN molecular emission allows us to separate the contributions from the dust content of the disk (extending up to 190 au), the molecular content of the disk (extending from 140–360 au), and the content of the envelope, revealing the presence of several possible accretion streamers (also seen in other molecular tracers, such as CH3OH). We analyze the physical properties of the system, producing temperature and column density maps, and radial profiles for the disk and the envelope. We qualitatively reproduce the trajectories and line-of-sight velocities of the possible streamers using a theoretical model approach. An ad hoc model of a flared disk comprising a hot dust disk embedded in cold gas fits the H2S emission, which revealed the molecular disk as a crescent shape with a prominent central absorption. Another fit to the central absorption spectrum suggests that the absorption is probably caused by different external cold layers from the envelope or the accretion streamers. Finally, the analysis of the rotation pattern of the different molecular transitions in the molecular disk suggests that there is an inner zone devoid of molecular content.

Understanding Sickle cell disease: Causes, symptoms, and treatment options.

Sickle cell disease (SCD) is a hereditary blood disorder characterized by the production of abnormal hemoglobin molecules that cause red blood cells to take on a crescent or sickle shape. This condition affects millions of people worldwide, particularly those of African, Mediterranean, Middle Eastern, and South Asian descent. This paper aims to provide an overview of SCD by exploring its causes, symptoms, and available treatment options. The primary cause of SCD is a mutation in the gene responsible for producing hemoglobin, the protein that carries oxygen in red blood cells. This mutation has abnormal hemoglobin called hemoglobin S, which causes red blood cells to become stiff and sticky, leading to various health complications. Patients with SCD may experience recurrent pain, fatigue, anemia, and increased infection susceptibility. Treatment options for SCD focus on managing symptoms and preventing complications. This includes pain management with analgesics, hydration, and blood transfusions to improve oxygen delivery. Hydroxyurea, a medication that increases the production of fetal hemoglobin, is commonly used to reduce the frequency and severity of pain crises. Additionally, bone marrow or stem cell transplants can cure select individuals with severe SCD. Finally, understanding the causes, symptoms, and treatment options for SCD is crucial for healthcare professionals, patients, and their families. It enables early diagnosis, effective symptom management, and improved quality of life for individuals with this chronic condition.

A crescent-shaped imprinted microgel adsorbent with near-infrared light-responsive performance for selective adsorption of Lead(II)

Smart hydrogel adsorbent with high selectivity and“on–off”switching ability is vital for the effective elimination of heavy metal pollution, but its simple fabrication remains a serious task. To address this, a facile strategy via an oil-in-water-in-oil (O1/W/O2) droplet microreactor was proposed to prepare polydopamine-coated imprinted microgel adsorbents (DMHIIPs) with crescent shape, and then as-prepared smart adsorbent with near-infrared (NIR) light-responsive performance was used to selectively remove lead ions (Pb(II)) from aqueous solution. The critical solution temperature (LCST) of DMHIIPs is 44.2 °C, resulting from the increase of thermal change and decrease of entropy change during swelling. DMHIIPs have high photothermal conversion efficiency and stability, and the temperature of DMHIIPs dispersion (0.5 mg/L) can be rapidly heated to above 50 °C under NIR (808 nm, 1.0 W cm−2) irradiation for 10 min. The adsorption capacity of Pb(II) on DMHIIPs elevates from 128.0 mg g−1 to 135.2 mg g−1, when the solution temperature increases from 20 °C to 40 °C, but this value significantly reduces to 59.2 mg g−1 at 60 °C. Pseudo-second-order can be well described the kinetic results of DMHIIPs, confirming chemisorption is the rate-limiting step. Desorption ratio of DMHIIPs is 36.5% in 30 min under NIR irradiation, and it can be increased to 63.2% When combining NIR irradiation with the using of elution agent. In addition, the obtained DMHIIPs has excellent selectivity coefficient (k) for competitive Cu(II) (7.20), Cd(II) (23.31), and Ni(II) (39.33), respectively. This work demonstrates a new strategy to NIR-responsive imprinted microgel adsorbent provides a new perspective for controlling the adsorption process of heavy metal pollution.

Defining Ideal Pretarsal Rolls Through a Morphometric Analysis in Asians.

Pretarsal rolls are a crucial aesthetic feature. Despite numerous studies conducted on periorbital aesthetics, there remains a dearth of research on the ideal pretarsal rolls. This study aimed to investigate 4 aesthetic characteristics of ideal pretarsal rolls: presence, width, proportion, and morphology. Respondents (385, including 80 aesthetic specialists) were presented with 7 series of images of pretarsal rolls, including 2 series of pretarsal roll existence, 2 series of varying widths, 2 series of different ratios between pretarsal roll and palpebral fissure height, and 1 series about morphology. Participants were asked to rank each image within a given series from most attractive to least attractive. The rankings were then analyzed according to population demographics. The majority of respondents deemed images with pretarsal rolls to be more aesthetically pleasing (P < .001) than those without such features. Additionally, pretarsal rolls with a width of 5 mm (P < .001), a ratio to palpebral fissure height of 0.5:1 (P < .001), and a crescent shape (P < .001) were perceived as the most attractive. Moreover, individuals aged 40 or younger exhibited a significant preference for images with pretarsal rolls compared to older groups (P < .001), and females displayed a greater inclination toward a medium ratio of pretarsal roll to palpebral fissure height than males did (0.5:1 P = .003, 0.618:1 P < .001). This study validates the optimal characteristics of pretarsal rolls, which provides insight into pretarsal roll aesthetics and holds significant implications for surgical planning and effect assessment in future periocular procedures involving pretarsal rolls.