Effective Mass Research Articles

Giant tumefactive mesencephalothalamic Virchow-Robin space with triventricular hydrocephalus: a case-based systematic literature review.

The perivascular spaces of the brain are also known as Virchow-Robin spaces (VRSs). Dilated Virchow-Robin spaces in the brainstem are rare and mainly cause symptoms due to obstructive hydrocephalus, less frequently because of their size, mass effect, and impact on eloquent structures. We present a patient with giant tumefactive VRS with hydrocephalus and neurological symptoms who was treated with endoscopic third ventriculostomy (ETV) followed by microscopic cyst fenestration. On the basis of this observation, we performed a thorough review of the literature to evaluate different treatment options. An 11-year-old girl presented with a headache for 3months. The patient had a giant tumefactive mesencephalothalamic VRS with triventricular hydrocephalus. She was initially treated with endoscopic third ventriculostomy and multiple cyst fenestration. Symptomatic cyst regrowth required multiple cyst fenestrations via transcallosal transchoroidal (N = 2) and subtemporal approaches (N = 1) at the 2- and 4-year follow-ups. A literature review of these conditions allowed the detection of 12 cases (including our index case), and only 25% (3/12) of the patients underwent cyst fenestration 16.7% (2/12) required endoscopic fenestration and 8.3% (1/12) required microscopic fenestration. Giant mesencephalothalamic dVRSs are rare in the pediatric population. These patients are usually symptomatic due to obstructive hydrocephalus. Surgical options are endoscopic third ventriculostomy, ventricular shunt procedures, or direct cyst fenestration (microscopic or endoscopic). Close follow-up is mandatory owing to the risk of progression of the disease. Cyst fenestration resolves symptoms immediately, as it addresses both hydrocephalus and mass effects due to the cystic lesion in the same setting.

The effect of developmental temperature on olfaction in a moth revealed by its interaction with body mass

There is a growing interest in the effects of climate warming on olfaction, as temperature may affect this essential sense. In insects, the response of the olfactory system to developmental temperature might be mediated by body size or mass because body size and mass are negatively affected by developmental temperature in most ectotherms. We tested this hypothesis of a mass-mediated effect of developmental temperature on olfaction in the moth Spodoptera littoralis. We measured the olfactory sensitivity of male to female sex pheromone and five plant odors using electroantennography. We compared males reared at an optimal temperature (25 °C with a daily fluctuation of ±5 °C) and at a high temperature (33 ± 5 °C) close to the upper limit of S. littoralis. On average, the olfactory sensitivity of males did not differ between the two developmental temperatures. However, our analyses revealed an interaction between the effects of developmental temperature and body mass on the detection of the six chemicals tested. This interaction is explained by a positive relationship between antennal sensitivity and body mass observed only with the high developmental temperature. Our results show that the effect of developmental temperature may not be detected when organism size is ignored.

Conventional and old endovascular techniques for vertebral aneurysms still work in the era of flow diversion

BackgroundEndovascular management for vertebral artery dissecting aneurysms (VADA) is quite intricate which thereby necessitate different strategies per case. Our current study described various optimal strategies available for endovascular management of VADA other than flow diverter (FD).Results14 Patients presented with acute SAH and 4 patients with symptoms of mass effect. VADA were classified in 3 groups, viz contralateral vertebral artery is dominant group A (n = 5), co-dominant group B (n = 8) or group C hypoplastic (n = 5). Group A and B (n = 13) was further subdivided into three subtypes depending on location of aneurysm with respect to posterior inferior cerebellar artery (PICA), aneurysm proximal to the PICA, type I (n = 5); involving the PICA, type II (n = 1); and distal to the pica, type III (n = 4). Treatment strategy varied with type whether deconstructive or reconstructive methods using stents and coils in different fashion.ConclusionPreprocedural angiographic work up delineating the anatomical location of the aneurysm, contralateral vertebral artery dominancy and nearby perforator status along with location of PICA is imperative in selecting the safest and optimal endovascular therapy option.

Exploring novel Zn2SeX (X=S, Te) ternary chalcogenide: Studying the effect of chalcogen substitution on optoelectronic, and thermoelectric performance

Ternary-type semiconductor chalcogenide materials are distinguished by their outstanding thermal performance and tunable optoelectronic features. The electronic structure, optical, and transport features of novel Zn2SeX ternary (X=S, Te) semiconductors are investigated by employing the widely used density functional theory. Based on the band structure investigation, these materials were anticipated tohave a direct energy gap. The results demonstrated that direct energy losses were caused by the orbitals hybridization of S-p and the Se/Te-d in both materials. Compared to Zn2SeTe, Zn2SeS has a wider band gap at the Γ-point, meaning that electrons will have a lower effective mass and atoms possess a greater effective mass. The elements of the complex dielectric function and the significant optical properties were explored for potential use in optoelectronic applications. The unique peaks in I(ω) confirm extensive absorption in the UV range. They may be employed as very effective ultraviolet-reflecting materials based on the peaks in the reflection spectrum that have been observed. Since both materials positive Seebeck coefficient display p-type conductivity over the whole temperature range.

Effect of magnetic field on the Bose–Einstein condensation of quantum well exciton–polaritons

We theoretically investigate the nonlinear effects of a magnetic field on the relaxation process of exciton–polaritons toward Bose–Einstein condensation in GaAs quantum wells. Our study reveals that the modification of the exciton’s effective mass, Rabi splitting, and dispersion significantly alters the relaxation rate of polaritons as they approach condensation. By employing a quasi-stationary pump, we clarify the dynamics of the total and condensed polariton populations in response to varying magnetic field strengths. Notably, we demonstrate that under low-energy pumping conditions, the presence of a magnetic field significantly suppresses condensation. This suppression is attributed to the decreased scattering rate between energy levels, which is a consequence of the reduced steepness in the high-energy dispersion. Conversely, increasing both the pump energy and the magnetic field can enhance relaxation efficiency, leading to a substantially larger number of condensed polaritons.

Correlation of spin-orbit potential and effective mass

Correlation of spin-orbit potential and effective mass

Experimental and numerical investigation of arch concrete slabs subjected to underwater contact explosions with the inner arch side facing air

Arch structures with their inner arch side exposed to air and outer arch side exposed to water are often encountered in practical projects, and these engineering structures may be subjected to various explosive attacks during operation. This paper investigates the damage mechanism and dynamic response of arch concrete slabs with the inner arch side facing air against underwater contact explosions (UWCEs). The explosion tests of the arch concrete slab with the inner arch side facing air were carried out. The accuracy and applicability of the numerical model were verified by comparing with the explosion results. After that, the failure evolution and energy transition of the arch concrete slab with the inner arch side facing air were studied. The effects of different explosion masses, explosion distances, and reinforcement schemes on the antiknock performance of arch concrete slabs are further explored. The results show that as the explosive mass of UWCEs increases, the damage mode of the arch concrete slab with the inner arch side facing air changes from cracking along the longitudinal direction and local failure to spalling on the inner arch side and fragmentation of the contact specimens. The existence of curvature of the arch slab will cause the damage of the arch slab to intensify. The failure mode of the arch concrete slab changes from local failure to slight failure with cracks as the explosion distance increases. Increasing the longitudinal steel bars on the outer arch side can effectively inhibit the generation and development of cracks.

First-principles study of the electronic, optical adsorption, and photocatalytic water-splitting properties of a strain-tuned SiC/WS2 heterojunction

Heterojunction is widely acknowledged as a potent strategy as an effective means for achieving quality electronic, optical adsorption, and photocatalytic water-splitting properties. Strain also can regulate these properties effectively. In this study, we have fabricated and studied a heterojunction comprised SiC and WS2. Utilizing a first-principles method, we systematically investigated the SiC/WS2 heterojunction's structure, stability, electronic, and optical properties, as well as its photocatalytic water splitting characteristics under strain engineering. Our calculations reveal that the SiC/WS2 heterojunction is a type-II heterostructure with two stable structures, which exhibits a direct bandgap and well performance in the visible light region, facilitating efficient separation of photogenerated electron-hole pairs. We have explored and discussed the impacts of biaxial strain on the various properties. The bandgaps of System-A and B are 1.778 eV and 1.820 eV, respectively, without strain. Under strain from −6% to 10%, they initially rise, peak at 1.858 eV and 1.899 eV respectively at −2% strain, then decline. Without strain, effective mass mh/me for both structures are 1.642 and 1.673. Under positive strain, they increase, decrease, then increase again, peaking at 6% with 2.116 and 2.260. At −2% strain, values drop to 0.901 and 0.910 for A and B, respectively. Our calculations also demonstrate that the SiC/WS2 heterostructure qualifies as a promising photocatalytic material, fulfilling the criteria for water splitting under strain conditions of −4%, −2%, and 0%. And the heterojunction with System-B under −4% strain has the optimal performance in photocatalytic water splitting. At a strain of −4%, System-B achieves the maximum η′STH of 16.91%. In conclusion, our study not only offers fundamental insights into the utilization of SiC/WS2 heterojunctions for photocatalytic water splitting, but also provides the foundational design principles of heterojunctions.

Sex-specific associations between total and regional Fat-to-muscle Mass ratio and cardiometabolic risk: findings from the China National Health Survey

BackgroundThe fat-to-muscle mass ratio (FMR), integrating the antagonistic effects of fat and muscle mass, has been suggested as a valuable indicator to assess cardiometabolic health independent of overall adiposity. However, the specific associations of total and regional FMR with cardiometabolic risk are poorly understood. We aimed to examine sex-specific associations of total and regional FMR with single and clustered cardiometabolic risk factors (CRFs).Methods13,505 participants aged 20 years and above were included in the cross-sectional study. Fat mass and muscle mass were assessed using a bioelectrical impedance analysis device. FMR was estimated as fat mass divided by muscle mass in corresponding body parts (whole body, arm, leg, and trunk). Clustered CRFs was defined as the presence of two or more risk factors, including hypertension, elevated blood glucose, dyslipidemia, insulin resistance (IR), and hyperuricemia. IR was assessed by the triglyceride glucose (TyG) index. Multivariable logistic regression models were applied to explore the associations of FMR in the whole body and body parts with single and clustered CRFs.ResultsThe odds ratios (ORs) increased significantly for all single and clustered CRFs with the per quartile increase of total and regional FMR in both sexes (P for trend < 0.001), following adjustment for confounders. Among the regional parts, FMRs of the legs presented the strongest associations for clustered CRFs in both men and women, with adjusted OR of 8.54 (95% confidence interval (CI): 7.12–10.24) and 4.92 (95% CI: 4.24–5.71), respectively. Significant interactions (P for interaction < 0.05) were identified between age and FMRs across different body parts, as well as between BMI status and FMRs in different regions for clustered CRFs. Restricted cubic splines revealed significant non-linear relationships between FMRs of different body parts and clustered CRFs in both sexes (P for nonlinear < 0.05).ConclusionsFMRs in the whole body and different regions were significantly associated with single and clustered CRFs in the general Chinese population. The association between FMR and clustered CRFs was more pronounced in youngers than in the elderly.

A Detailed First‐Principles Study of the Structural, Elastic, Thermomechanical, and Optoelectronic Properties of Binary Rare‐Earth Tritelluride NdTe3

AbstractRare‐earth tritellurides (RTe3) are popular for their charge density wave (CDW) phase, magnetotransport properties, and pressure‐induced superconducting state among other features. In this literature, Density functional theory is exploited to study various properties of NdTe3. The calculated elastic and thermomechanical parameters, which are hitherto untouched for any RTe3, uncover soft, ductile, highly machinable, and damage‐tolerant characteristics, as well as highly anisotropic mechanical behavior of this layered compound. Its thermomechanical properties make it a prospective thermal barrier coating material. Band structure, density of states, Fermi surfaces, and various optical functions of the material are reported. The band structure demonstrates highly directional metallic nature. The highly dispersive bands indicate very low effective charge carrier mass for the in‐plane directions. The Fermi surfaces display symmetric pockets, including signs of nesting, bilayer splitting among others, corroborating previous works. The optical spectra expose high reflectivity across the visible region, while absorption is high in the ultraviolet region. Two plasma frequencies are noticed in the optical loss function. The optical conductivity, reflectivity, and absorption reaffirm its metallic properties. The electronic band structure manifests evidence of CDW phase in the ground state.

Bi Off‐Centering in Centrosymmetric BiOBr Leading to Ultrahigh Bifunctional Piezocatalytic Fuel Generation Efficiencies in Seawater

AbstractPiezocatalytic water‐splitting to simultaneously produce H2 and H2O2 has many potential advantages. However, the necessity to utilize materials having polar structures limits the choice of piezocatalysts. Herein, it is demonstrated that centrosymmetric BiOBr with oxygen defects can simultaneously produce H2 and H2O2 with ultrahigh efficiencies from pure and seawater without needing assistance from noble metals or scavengers. High‐pressure studies confirm that there are no non‐polar‐to‐polar phase transitions in BiOBr, though a novel isostructural phase is discovered. Computational studies reveal that oxygen vacancy distorts the BiOBr structure to induce charge‐localization and polarization. Furthermore, high pressure (i) reduces carrier effective masses and (ii) increases relative O‐2p contribution in the valence band maximum to assist catalysis and improve stability. The role of oxygen vacancy is confirmed by changing its concentration, which proportionally affects H2 evolution. The work paves the way for defect engineering to develop piezocatalysts from a large pool of non‐polar materials.

Novel stationary basket reactor for effective biomass delignification with deep eutectic solvent

Biomass pretreatment and conversion are crucial for sustainable development, but lack information on equipment that ensures effective mass transfer and easy biomass separation post-process. This work introduces a novel basket reactor with a stationary bed (StatBioChem) for biomass processing using deep eutectic solvents (DESs). We compared the delignification efficiencies of soft and hard biomass samples processed in the StatBioChem reactor, a stirred tank reactor (STR), and a commercial SpinChem® reactor. The StatBioChem design allowed DES to flow evenly through biomass in the basket, achieving the highest delignification degree, particularly for hard biomass. This effect was not observed in the SpinChem® basket reactor. High delignification led to increased glucose yields in subsequent enzymatic hydrolysis. The StatBioChem effectively combines the simplicity and efficiency of an STR with the ease of solvent recovery typical of basket reactors.

Fermi Rubik’s Cube in High-pressure Induced Chlorine-riched Compounds

Abstract In the quasi-free electron model, which is widely used in modern solid-state physics, the Fermi surface spreads into a sphere in the Brillouin zone, i.e., the Fermi Sphere. The Fermi Sphere exists widely in metal systems, no matter whether the crystal is in a body-center cubic, face-center cubic, or hexagonal close-packed lattice. Here, we report a class of compounds stabilized at high pressure with a Rubik's cubic Fermi surface, in which the representative example is P m-3n-CaCl3. Our quantum-mechanical variable- composition evolutionary simulations predicted the thermal stabilities of CaCl3, and the tight-binding model revealed its unique Fermi surface originates from the quasi-one- dimensional interaction, structural symmetric protection, and particle-hole symmetry breaking. Furthermore, by its flat and steep band structure, CaCl3 has a huge span of effective mass from 9.08×103 me (super-heavy) to 5.13×10-4 me on the Fermi level, which supplies an interesting platform for quasiparticle research.

The effect of mass and morphology on the mass assembly of galaxies

The pace at which galaxies grew into their current stellar masses and how this growth is regulated is still not fully understood, nor is the role that morphology plays in this process. We applied full spectral fitting techniques with pyPipe3D to the MaNGA sample to obtain its star formation and stellar mass histories and used these to investigate the mass assembly of galaxies by measuring how their specific star formation correlates to their stellar mass at different look-back times. We find that the correlation between these two parameters was shallower in the past. Galaxies used to have similar mass doubling times and the current negative correlation between the specific star formation and M$_ is primarily due to more massive galaxies 'dropping' off the main sequence earlier than less massive ones. Additionally, selecting the galaxies into bins based on their present-day morphology shows a segregation in specific star formation rate (sSFR) that is maintained even at high look-back times, showing that the factors that determine which morphology a galaxy ends up in are in place at very early times. Similarly, selecting them based on their current star formation status shows that, on average, currently retired galaxies used to have slightly a higher sSFR before the drop-off, whereas galaxies that have continued to form stars until today had a lower sSFR initially. We compare our results to a set of cosmic surveys, finding partial agreement in our results with several of them, though with significant offsets in redshift. Finally, we discuss how our results fit with certain theoretical models on galaxy evolution as well as cosmological simulations.

Does high-frequency resistance exercise offer additional benefits to older adults? learnings from a randomized controlled trial

ObjectiveResistance exercise is an effective strategy to improve muscle strength in older adults. A limited-load resistance would be flexible and suitable for community-based training. It was unclear whether high-frequency resistance exercise offer additional benefits to older adults. Here, we aimed to examine the effect of limited-load resistance exercise among different frequency on muscle parameters in older adults.MethodsThe current study was a single-blind, randomized controlled trial comparing the effectiveness of different-frequency resistance exercise in older adults. Change in skeletal muscle was estimated with a multi-frequency bioelectrical impedance analyzer. Demographics, physical examination, nutritional assessment, prealbumin and lymphocytes were also measured. Fisher’s precision probability test and baseline-adjusted generalized linear models were applied accordingly to analyze the influence of dose-different exercise on prevalence of sarcopenia, muscle parameters and body composition. A two-sided p value of < 0.05 was defined statistical significance.ResultsThe participants had a mean age of 71.96 years and close gender ratio. One hundred and twenty-seven participants (control 40; low-dose 46; high-dose 41) completed the 6-month exercise intervention. In contrast to control group, only high-dose exercise groups experienced improvements in muscle mass (0.66 kg, p < 0.001) and max grip strength (+ 2.17 kg, p < 0.001). There were significant dose-response effects of muscle mass (index), fat mass (index), max grip strength, 5-times sit to stand test, 6-minute walking test and visceral fat area (all ptrend <0.01).ConclusionsAs the proved dose-dependent effect, current findings supported high-frequency limited-load resistance exercise applied and extended among older adults in community.Trial RegistrationThis study was registered at Chinese Clinical Trial Registry Network (ChiCTR2200062007, Registered on 19 July 2022).

Can Renal Masses Cross Midline? – Report of Three Cases of Renal and Visceral Midline Shifts Due to Abdominal Mass Effect

Abstract Primary retroperitoneal structures, particularly kidneys, are considered ‘fixed’ to the posterior abdominal wall by fasciae and vascular pedicles from the great vessels. However, huge masses arising in the retroperitoneum – either benign or malignant – are found to exert a mass effect in the retroperitoneal and intraperitoneal compartments, resulting in ‘visceral midline shift’. We present three different cases of retroperitoneal swellings causing extreme anatomical distortions in the abdomen and their surgical implications.

Management of patients with adrenal myelolipoma: experience from a tertiary referral centre.

Adrenal myelolipomas are rare, benign, tumours of the adrenal cortex. This study reports the experience of a tertiary adrenal surgery referral centre's approach to the management of patients with adrenal myelolipoma. A retrospective observational cohort study was conducted on all adult patients (> 18years age) diagnosed with adrenal myelolipoma from January 1, 2014, to December 30, 2022. Demographics, imaging characteristics, histological diagnosis (where applicable) and follow-up data were compared between patients undergoing surgery and those referred to surveillance. Indications for operative intervention were recorded at the time of multidisciplinary team discussion, consisting of surgeons, endocrinology physicians, radiologists, pathologists and specialist nursing representatives. Of the 522 patients with an adrenal lesion discussed in adrenal tumour meeting between 2014 and 2022, n = 15 (2.8%) were diagnosed with adrenal myelolipoma. Of the 15 patients, 4 underwent adrenalectomy at first presentation (27%), while 1 patient underwent adrenalectomy after interval follow-up. Indications for operative intervention were as follows: 'indeterminate lesion' (n = 3), 'abdominal pain and size (> 4cm)' (n = 1) and 'mass effect on adjacent organs' (n = 1). The mean rate of lesion growth in patients referred for surveillance (n = 10) was 0.13cm/year. Histology confirmed adrenal myelolipoma as the diagnosis in all resected tumours. For patients with adrenal myelolipoma, the presence of symptoms and/or indeterminate features on imaging may be more clinically useful indications for operative intervention over size alone. The surveillance of adrenal myelolipomas, even in patients with adrenal lesions > 4cm, is a safe clinical strategy, provided the imaging characteristics are benign and patients remain asymptomatic.

Mediating role of inflammatory biomarkers in the causal effect of body composition on glycaemic traits and type 2 diabetes.

The aim was to investigate the mediating role of inflammatory biomarkers in the causal effect of body composition on glycaemic traits and type 2 diabetes. A retrospective observational study and a Mendelian randomization (MR) study were used. Observational analyses were performed using data from 4717 Chinese children and adolescents aged 6-18 years who underwent dual-energy X-ray absorptiometry for body composition. MR analyses were based on summary statistics from UK Biobank, deCODE2021, Meta-Analysis of Glucose and Insulin-Related Traits Consortium (MAGIC) and other large consortiums. Inflammatory biomarkers included leptin, adiponectin, osteocalcin, fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH). In a retrospective observational study, increased fat mass had a positive effect on homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of pancreatic beta cell function (HOMA-β) through FGF23, whereas fat-free mass produced the opposite effects. PTH and osteocalcin played significant roles in the association of fat mass and fat-free mass with fasting glucose, fasting insulin and HOMA-IR (all p < 0.05). Mediation MR results indicated that childhood body mass index affected glycaemic traits through leptin and adiponectin. There existed a causal effect of fat-free mass on type 2 diabetes via FGF23 (indirect effect: OR [odds ratio]: 1.14 [95% CI, confidence interval: 1.01-1.28]) and adiponectin (OR: 0.85 [95% CI: 0.77-0.93]). Leptin mediated the causal association of fat mass (indirect effect: β: -0.05 [95% CI: -0.07, -0.02]) and fat-free mass (β: 0.03 [95% CI: 0.01, 0.04]) with fasting glucose. Our findings suggest that different body compositions have differential influences on glycaemic traits and type 2 diabetes through distinct inflammatory biomarkers. The findings may be helpful in tailoring management of body composition based on inflammatory biomarkers with different glycaemic statuses.

The Influence of Effective Mass on the Striking Force of Lead Jab and Rear Cross Punches of Boxers

Background: Modern combat sports, including boxing, categorize participants by body mass to ensure fairness and safety. The effective mass, or the ability to maximize body mass during a punch, significantly impacts striking force. This study aims to explore the relationship between effective mass and striking force in lead jab and rear cross punches of boxers. Material and methods: Thirteen male boxers with an average body mass of 90.6 kg and average height of 184 cm participated. The study employed an AMTI MC12-2K force plate (AMTI, Watertown, MA, USA) and Noraxon Ultium EMG sensors (Noraxon, Scottsdale, AZ, USA) to measure impact force and acceleration. Each boxer performed five maximum-force strikes with both lead jab and rear cross techniques. Results: The rear cross punch generated significantly higher ground reaction force (1709.28 ± 486.62 N) compared to the lead jab (1182.56 ± 250.81 N). However, effective mass values were similar for both punches: lead jab (18.95 ± 5.29 kg, 21.51% of body mass) and rear cross (18.50 ± 5.56 kg, 21.04% of body mass). Higher body mass and longer training tenure positively correlated with higher effective mass. An inverse relationship was found between fist acceleration and effective mass. Conclusions: Effective mass plays a crucial role in punch biomechanics, with similar utilization between lead jab and rear cross punches despite the latter’s higher force. Training focused on optimizing body mass utilization and refining punch techniques can enhance punch effectiveness.

Fermion self-energy and effective mass in a noisy magnetic background

In this article, we consider the propagation of QED fermions in the presence of a classical background magnetic field with white-noise stochastic fluctuations. The effects of the magnetic field fluctuations are incorporated into the fermion and photon propagators in a quasiparticle picture, which we developed in previous works using the . By working in the very strong-field limit, here we explicitly calculate the fermion self-energy involving radiative contributions at first order in αem, in order to obtain the noise-averaged mass of the fermion propagating in the fluctuating magnetized medium. Our analytical results reveal a leading double-logarithmic contribution ∼[ln(|eB|/m2)]2 to the mass, with an imaginary part representing a spectral broadening proportional to the magnetic noise autocorrelation Δ. While a uniform magnetic field already breaks Lorentz invariance, inducing the usual separation into two orthogonal subspaces (perpendicular and parallel with respect to the field), the presence of magnetic noise further breaks the remaining symmetry, thus leading to distinct spectral widths associated with fermion and antifermion, and their spin projection in the quasiparticle picture. Published by the American Physical Society 2024