Small Volume Research Articles

Stability simulation analysis of targeted puncture in L4/5 intervertebral space for PELD surgery.

Introduction: The application prospects of percutaneous endoscopic lumbar discectomy (PELD) as a minimally invasive spinal surgery method in the treatment of lumbar disc herniation are extensive. This study aims to find the optimal entry angle for the trephine at the L4/5 intervertebral space, which causes less lumbar damage and has greater postoperative stability. To achieve this, we conduct a three-dimensional simulated analysis of the degree of damage caused by targeted puncture-based trephine osteotomy on the lumbar spine. Methods: We gathered clinical CT data from patients to construct a lumbar model. This model was used to simulate and analyze the variations in trephine osteotomy volume resulting from targeted punctures at the L4/5 interspace. Furthermore, according to these variations in osteotomy volume, we created Finite Element Analysis (FEA) models specifically for the trephine osteotomy procedure. We then applied mechanical loads to conduct range of motion and von Mises stress analyses on the lumbar motion unit. Results: In percutaneous endoscopic interlaminar discectomy, the smallest osteotomy volume occurred with a 20° entry angle, close to the base of the spinous process. The volume increased at 30° and reached its largest at 40°. In percutaneous transforaminal endoscopic discectomy, the largest osteotomy volume was observed with a 50° entry angle, passing through the facet joints, with smaller volumes at 60° and the smallest at 70°. In FEA, M6 exhibited the most notable biomechanical decline, particularly during posterior extension and right rotation. M2 and M3 showed significant differences primarily in rotation, whereas the differences between M3 and M4 were most evident in posterior extension and right rotation. M5 displayed their highest stress levels primarily in posterior extension, with significant variations observed in right rotation alongside M4. Conclusion: The appropriate selection of entry sites can reduce lumbar damage and increase stability. We suggest employing targeted punctures at a 30° angle for PEID and at a 60° angle for PTED at the L4/5 intervertebral space. Additionally, reducing the degree of facet joint damage is crucial to enhance postoperative stability in lumbar vertebral motion units.

Design of a Deployable Broadband Mesh Reflector Antenna for a SIGINT Satellite System Considering Surface Shape Deformation.

In this paper, we propose a deployable broadband mesh reflector antenna for use in signals intelligence (SIGINT) satellite systems, considering performance degradation due to shape deformation. To maximize gain by increasing the diameter of the reflector while reducing the weight of the antenna, the reflector of the antenna is designed using lightweight silver-coated Teflon mesh. The mesh reflectors are typically expanded by tension to maintain their parabolic structure; thus, shape deformation cannot be avoided. This shape deformation results in shape differences between the surface of the mesh reflector and the ideal parabolic reflector, thus resulting in the degradation of the performance of the mesh reflector antenna. To observe this degradation, we analyze antenna performance according to the number of arms, the number of joints, the feed distance, and the distance from the reflector center to each joint. The performance of the mesh reflector antenna is examined using an effective lossy conducting surface (ELCS) that has the same reflectivity as the silver-coated Teflon mesh to reduce simulation time and computing resources. The designed silver-coated Teflon mesh reflector and the double-ridged feed antenna are fabricated, and the bore-sight gain is measured using the three-antenna method. The measured bore-sight gain of the proposed antenna is 31.6 dBi at 10 GHz, and the measured and simulated results show an average difference of 3.28 dB from 2 GHz to 18 GHz. The proposed deployable mesh reflector antenna can be used in a variety of applications where small stowed volume is required for mobility, such as mobile high-gain antennas as well as satellite antenna systems. Through this study, we demonstrate that shape deformation of the mesh reflector surface significantly affects the performance of reflector antennas.

Comparison of Otsu and an adapted Chan–Vese method to determine thyroid active volume using Monte Carlo generated SPECT images

BackgroundThe Otsu method and the Chan–Vese model are two methods proven to perform well in determining volumes of different organs and specific tissue fractions. This study aimed to compare the performance of the two methods regarding segmentation of active thyroid gland volumes, reflecting different clinical settings by varying the parameters: gland size, gland activity concentration, background activity concentration and gland activity concentration heterogeneity.MethodsA computed tomography was performed on three playdough thyroid phantoms with volumes 20, 35 and 50 ml. The image data were separated into playdough and water based on Hounsfield values. Sixty single photon emission computed tomography (SPECT) projections were simulated by Monte Carlo method with isotope Technetium-99 m (^{text {99m}}Tc). Linear combinations of SPECT images were made, generating 12 different combinations of volume and background: each with both homogeneous thyroid activity concentration and three hotspots of different relative activity concentrations (48 SPECT images in total). The relative background levels chosen were 5 %, 10 %, 15 % and 20 % of the phantom activity concentration and the hotspot activities were 100 % (homogeneous case) 150 %, 200 % and 250 %. Poisson noise, (coefficient of variation of 0.8 at a 20 % background level, scattering excluded), was added before reconstruction was done with the Monte Carlo-based SPECT reconstruction algorithm Sahlgrenska Academy reconstruction code (SARec). Two different segmentation algorithms were applied: Otsu’s threshold selection method and an adaptation of the Chan–Vese model for active contours without edges; the results were evaluated concerning relative volume, mean absolute error and standard deviation per thyroid volume, as well as dice similarity coefficient.ResultsBoth methods segment the images well and deviate similarly from the true volumes. They seem to slightly overestimate small volumes and underestimate large ones. Different background levels affect the two methods similarly as well. However, the Chan–Vese model deviates less and paired t-testing showed significant difference between distributions of dice similarity coefficients (p-value <0.01).ConclusionsThe investigations indicate that the Chan–Vese model performs better and is slightly more robust, while being more challenging to implement and use clinically. There is a trade-off between performance and user-friendliness.

Facile preparation of UiO-66-Lys/PAN nanofiber membrane by electrospinning for the removal of Co(II) from simulated radioactive wastewater

In this study, metal-organic framework (MOF) nanofiber membranes (NFMs) UiO-66-Lys/PAN were prepared by electrospinning using polyacrylonitrile (PAN) as the matrix, UiO-66-NH2 as the filler, and lysine (Lys) as the functional monomer. The membranes were subsequently employed to extract cobalt ions from simulated radioactive wastewater. The findings showed that the best performance of the membrane was obtained with a 3 % MOF content (3%UiO-66-Lys/PAN). Specifically, the pure water flux (PWF) of the 3 % UiO-66-Lys/PAN membrane reached 872 L m−2 h−1 with a cobalt ion retention of 45.4 %. In addition, adsorption experiments indicated that the NFMs had a theoretical maximum adsorption capacity of 41.4 mg/g for cobalt ions. The Langmuir isotherm model and the pseudo-second-order kinetic model were observed in the adsorption process, suggesting that the membrane material showed uniform adsorption of cobalt ions on a monolayer level, with an endothermic absorption process. XPS analysis confirmed that 3%UiO-66-Lys/PAN facilitated the adsorption of cobalt ions through a coordination effect, with the N and O atoms serving as coordinating atoms. Moreover, the material displayed excellent radiation stability even when exposed to doses ranging from 20 to 200 kGy. This study validated the stability of the MOF NFMs under real irradiation with radioactive nuclides (60Co) and demonstrated efficient cobalt ion separation. This study has important practical implications for the treatment and disposal of small volumes of 60Co-containing radioactive wastewater for engineering applications.

A high-throughput small volume matrix based calibration using isotope dilution liquid chromatography tandem mass spectrometry analysis for 42 per and polyfluoroalkyl substances in groundwater

A novel method for the determination of per- and polyfluoroalkyl substances (PFAS) in groundwater is presented using a subsample, matrix-matched calibrators, 96-well plate solid phase extraction (SPE), and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Accuracy, precision, measurement of uncertainty (MOU), method detection limit (MDL), method quantitation limit (MQL), analytical measurement range, interferences/ion suppression, and analyte stability were determined as part of the in-house method validation. The method quantitates 42 PFAS compounds from nine different compound classes. Accuracy for the reference material (RM) and matrix spike (MS) ranged from 52.3 to 117.8 %, and precision for the MS and matrix spike duplicate (MSD) had a coefficient of variation (CV) from 2.0 % to 23.3 %. MDLs spanned from 0.07 to 1.97 ng L−1, with MQLs ranging from 0.20 to 5.90 ng L−1. Suppression studies determined that iron and manganese have effects on analytes that do not have paired isotopically labeled standards. The results from the in-house validation indicated that this Michigan Department of Health and Human Services laboratory developed test meets the necessary accuracy, precision, MDL, MQL and reporting limits requirement established by the laboratory's quality system essentials (QSEs) and select criteria from the Department of Defense (DoD) Quality Systems Manual for Environmental Laboratories and American Industrial Hygiene Association Laboratory Accreditation Program, LLC (AIHA LAP, LLC) accrediting International Standard Organization (ISO/IEC 17025:2017) check list.

Platelet-rich plasma - a revolutionary therapeutic option in multi-disciplinary indications

Background: Platelet-rich plasma (PRP) was originally described as a small volume of plasma that contains higher concentrations of platelets, compared to peripheral blood. Although currently the use of PRP in most indications is off-label, it is not prohibited. Initially, PRP was used for wound healing and tissue regeneration in fields such as orthopaedics, dermatology, maxillofacial surgery and dentistry.&#x0D; Aim of the study: The aim of this article was to present and summarise the modern production methods, the mechanism of action at the molecular and biochemical level and the most important uses and indications of PRP in present-day medicine.&#x0D; Material and methods: A cross-sectional search of relevant literature was performed in databases using accepted wording. Publications from 2003-2023 were included. The entire process has been supplemented with additional procedures to increase the reliability of this publication.&#x0D; Results: Orthopaedics has gained many minimally invasive therapeutic solutions thanks to PRP. Its effects on ligament and tendon tissues have been studied, where promising data have been proven. Also in aesthetic medicine and dermatology, many treatment strategies have been developed using PRP, mainly for the treatment of acne, androgenic alopecia and delaying tissue ageing as much as possible.&#x0D; Conclusion: Platelet-rich plasma has found application in the treatment of many conditions in orthopaedics, dermatology, aesthetic medicine and dentistry. It is characterised by good therapeutic efficacy, with relatively low risk. However, high-quality studies are still lacking to provide more reliable data.

THE SIMULTANEOUS QUANTIFICATION OF RIFAMPICIN AND ISONIAZID IN PATIENTS WITH TUBERCULOSIS APPLIED TO VOLUMETRIC ABSORPTIVE MICROSAMPLING DEVICES USING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

Objective: Rifampicin and isoniazid are the main tuberculosis treatment regimens requiring blood level measurement to optimize the treatment process. This study aims to analyze rifampicin and isoniazid quantitatively in volumetric absorptive microsampling (VAMS) prepared from a small volume of TB patients using HPLC. Methods: Analytes on the VAMS tip were extracted using 1000 ml of acetonitrile containing 10 µg/ml of cilostazol as an internal standard. Analytical separation was performed on the C-18 column at 40 ℃ with a mobile phase mixture of 50 mmol ammonium acetate buffer pH 5.0-acetonitrile-methanol (40:30:30), flow rate 0.5 ml/min. The analysis was carried out with the calibration curve over a range of 1.0–30 µg/ml for rifampicin and 0.4-20 µg/ml for isoniazid. Results: Analyte analysis in 21 patients showed that the measured value of rifampicin was 3.39–16.77 µg/ml, and isoniazid was 2.63–10.43 µg/ml at 2 h post-dose. 52.38% of patients had low blood concentrations in at least one of the drugs, 28.57% of the patients were in the therapeutic range, and 23.81% had a high blood concentration of isoniazid alone. Conclusion: The concentration of rifampicin and isoniazid in 21 tuberculosis patients varied. Dose adjustment is needed because most patients had low blood concentrations of one of the drugs, and a limited number had a high blood isoniazid concentration alone. Only some patients simultaneously had plasma concentrations within the target range of the drugs. This method was valid and reliably utilized for therapeutic drug monitoring of antituberculosis.

Physical temperature sensing of targets with shelters under indoor scenes by a revised Ku band microwave radiometer

This work is aimed to solve technical difficulties for microwave radiometers in Ku band and above under indoor scenes to detect physical temperatures of targets with shelters. Firstly, a revised microwave radiometer in Ku-band is developed with a novel calibration scheme. Secondly, in order to the designed radiometer pocess a high temperature accuracy for targets with shelters, crucial technical difficulties are investigated: 1) The long-neglected impact on temperature sensitivity of the single channel radiometer by the frequency stability of LO is analyzed and a LO with high frequency stability and small volume is designed. 2) The calibration accuracy deterioration caused by the receiver's nonideality is analyzed, and a novel calibration algorithm is proposed. 3) the method of plane wave spectrum (PWS) is proposed to derive the planar electric field in near field of the horn antenna for temperature inversion. 4) A more complete microwave thermal radiation transmission model of clothed human body is proposed. Thirdly, several experiments are set up and show that the designed radiometer can track physical temperatures of targets sheltered by cotton cloth relatively accurately, so that methods proposed for indoor near field applications are confirmed effective. Noteworthily, it is the first time in the microwave passive sensing domain that our work systematically proposes the temperature inversion theory for physical temperatures of targets with shelters accurately in noncontact under indoor scenes, and the design scheme for the microwave radiometer optimized portable along with a high temperature sensitivity applied for microwave security and medical monitoring.

Baroclinic factor in the stirring of waters of a sinking thermal with surrounding fresh water

The results of studying the process of stirring of a sinking thermal (small volume of denser water) with surrounding water are presented. The analysis of laboratory flows in a hydroflume has been allowed to identify the main peculiarities of the stirring of the thermal and the surrounding water. The essence of one of these features concluded in the presence of many high-gradient layers in the density field. The phase of an advective-rotational nature of the stirring of thermal waters with different density has been identified. Detailing of the evolution of the flow density structure was performed using the calculated flows on a 2d-nonlinear model of the dynamics of a fluid that is inhomogeneous in density. Features of the density structure are revealed using the values of local density gradients for the internal nodes of the computational grid. The density gradients along and across the streamlines were calculated. Quantitative estimates of the repeatability of high-gradient layers have shown significant variability in the flow density field. An analysis of the potential stability of the selected local regions of the flow has been carried out. The calculation of the Reynolds (Re) and Richardson (Ri) numbers has been allowed to assume a laminar nature of the flow, with the exception of two small zones in the back part of the sinking thermal. The role of the baroclinic mechanism of vorticity generation as a structure-forming factor in the formation of a distinguished stage of advective-vortex movement within interpenetration of thermal with surrounding water has shown.

Penetration of particles through vertical cracks

In a previous study, a new deposition model was developed to account for deposition of aerosol particles on the inner walls of small containers. In this article, the model applicability is extended by including deposition on horizontal surfaces, both upward-facing and downward-facing. After that, the model is applied to study a vital new issue, which is the penetration of aerosols to the indoors through vertical wall cracks. Previous studies, both theoretically and experimentally, never addressed penetration through vertical cracks. This study therefore aims to show the difference between penetration through vertical cracks and horizontal ones by applying the fourth-power model, which is very successful in describing deposition in small volumes. The penetration model formulated in this study takes into account, not only the thickness and depth of the crack, as usually happens in most penetration models, but all the three dimensions of the crack; thickness, depth and width. The obtained results are in a good agreement with the experimental data. This demonstrates the success of the extended fourth-power model in describing deposition inside cracks. Moreover, the results show a clear difference between vertical and horizontal cracks for the penetration of aerosols with diameter larger than ∼1μm. An application of the developed deposition and penetration models is presented, where a method for calculating the radioactive aerosols indoor concentrations is explained.

Effects of cage topology on ethylene adsorption mechanism in silver exchanged CHA and RHO zeolites: An Inelastic Neutron Scattering and Density Functional study

Zeolite-based adsorbents have been successfully used for many challenging separations due to their tunable properties. A particularly notable application involves the separation of light olefins from paraffins, wherein the molecular sieving properties of zeolites play a pivotal role. Additionally, the selective interaction of alkenes with transition metal cations, positioned within the channels and cavities of microporous zeolites, further enhances separation capabilities.This study aims to comprehensively characterize the interactions between ethylene and Ag+ exchanged zeolites, employing a multidisciplinary approach, combining Inelastic Neutron Scattering (INS), Infrared (IR) spectroscopy, Nuclear Magnetic Resonance (NMR), UV–Vis and Density Functional Theory (DFT) calculations. CHA and RHO, zeolites largely applied in gas separation processes, were chosen due to their similar small pore sizes and pore volume, but different cavity shapes and flexibilities.The interpretation of derived DFT Electron Density Difference, experimentally supported by 13C Solid State NMR results, provide an understanding of each framework’s role during the charge transfer mechanisms between ethylene and transition metal species. Specific deformations in the flexible framework of zeolite RHO explain a blueshift of the band at 400 cm−1 in the librational region of INS spectra compared to CHA. This structural change in RHO, represented by the conic shape of the cage 8-ring side pockets, increases steric effects over the adsorbate while rendering the metallic adsorption center less exposed within the zeolite’s cavity, finally leading to a weaker adsorption energy. The redshift of C=C stretching frequencies observed by IR spectroscopy and DFT calculations, as well as C=C and C-H bond lengthening of ethylene confirm the formation of π-complexes on silver in both zeolites and allowed a further evaluation of the effects of the different frameworks cages on the aforementioned interaction.

Early in life stressful events induce chronic visceral pain and changes in bladder function in adult female mice through a mechanism involving TRPV1 and alpha 1A adrenoceptors.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic pain disorder with multiple phenotypes, one of which is associated with an overactive adrenergic system. We investigated if the maternal deprivation model (MDM) in female and male mice mimics IC/BPS phenotype and if the overstimulation of alpha 1A adrenoceptor (A1AAR) and the crosstalk with transient receptor potential vanilloid-1(TRPV1) are involved in the generation of pain and bladder functional changes. C57BL/6 female and male mice were submitted to MDM. TRPV1knockout (KO) mice were used to study TRPV1 involvement. Silodosin administration to MDM mice was used to study A1AAR involvement. The primary outcome was chronic visceral pain measured by Von Frey filaments analysis (effect size: 3 for wild type, 3.9 for TRPV1KO). Bladder changes were secondary outcome measurements. Unpaired T test, Mann-Whitney test, one-way analysis of variance followed by Newman-Keuls multiple comparisons test, and Kruskal-Wallis followed by Dunn's multiple comparisons test were used where appropriate. MDM induces pain behavior in female and not in male mice. Bladder afferents seem sensitize as MDM also increase the number of small volume spots voided, the bladder reflex activity, and urothelial damage. These changes were similarly absent after A1AAR blockade with silodosin or by TRPV1 gene KO. The main limitation is the number/type of pain tests used. MDM induced in female mice is able to mimic IC/BPS phenotype, through mechanisms involving A1AAR and TRPV1. Therefore, the modulation of both receptors may represent a therapeutic approach to treat IC/BPS patients.

Experimental investigation and numerical analysis on the confined deflagration behavior of methane-air mixtures within the suppression of typical haloalkanes

To investigate the mechanisms of haloalkanes in promoting and inhibiting explosions in methane-air mixtures, the halon alternatives of CHF3, C3HF7, and C3H2F6 were selected as inhibitors. Experimental research was conducted in a 20-liter spherical explosion vessel to examine the promotional and inhibitory effects of these haloalkanes on methane-air mixtures. The adiabatic flame temperature, heat release rate, and concentrations of the key radicals were calculated. The results showed that C3H2F6, C3HF7, and CHF3 all exhibited a dual effect, initially promoting and subsequently inhibiting explosions in fuel-lean methane-air mixtures. The critical explosion suppression volume fractions of C3HF7 and CHF3 were 1.5 times and 2.25 times that of C3H2F6, respectively, for the suppression of methane explosion at Φ = 1.2. Furthermore, C3HF7 demonstrated a dual impact on the explosion of stoichiometric methane-air mixtures. From the perspective of reaction kinetics, for fuel-lean methane-air mixture (Φ = 0.8), a small volume of halogenated hydrocarbons led to an increase in the adiabatic flame temperature due to the heat release from critical fluorine-containing elementary reactions, thereby promoting the explosion. Under fuel-lean conditions, the introduction of a small volume of halogenated hydrocarbons led to an increase in the adiabatic flame temperature due to the heat release from critical fluorine-containing elementary reactions, thereby promoting the explosion. Simultaneously, these fluorine-containing reactions scavenged the key free radicals of H, O, and OH inhibiting the explosion process. These two effects competed with each other, ultimately determining the direction of the explosion process.

Intensifying the particle deposition from a colloidal solution for the purpose of liquid purification: Comparison of deposition mechanisms and rates

The deposition of particles from a layer of colloidal solution (water and microparticles) has been experimentally studied in the presence of laser heating. Instantaneous temperature and velocity fields are measured using a thermal imager and the Particle Image Velocimetry and the Particle Tracking Velocimetry methods. The unstable behavior of the velocity field in the presence of heating and a free liquid surface are assumed to be determined by the Bond number (Bo). Of interest is also an additional mechanism for the instability formation when the Peclet number (Pe) exceeds the critical value and when the ratio of characteristic velocities VT/Vavr > 1, where VT is the heat front velocity at the initial moment of laser heating, and Vavr is the average convection velocity. A new mechanism of particle deposition due to the use of local laser heating is proposed for the first time. The control over local heating and local deposition increases the particle deposition rate by 2–3 orders compared with that without convection. The particle deposition rate and the deposit area increase with increasing height of the liquid layer, reach maximum values at a critical height, and then decrease sharply with increasing height. The dependence for determining the area and mass of the deposit is proposed to take into account the deposition time, the height of the liquid layer and the rate of convection. The resulting particle deposition method and calculation method may be used in technologies related to the purification of liquid from solid impurities in small volumes, as well as in problems where deposition in a given direction is required to form an ordered nanocoating.

Evaluating environmental DNA detection of a rare fish in turbid water using field and experimental approaches.

Detection sensitivity of aquatic species using environmental DNA (eDNA) generally decreases in turbid water but is poorly characterized. In this study, eDNA detection targeted delta smelt (Hypomesus transpacificus), a critically endangered estuarine fish associated with turbid water. eDNA sampling in the field was first paired with a trawl survey. Species-specific detection using a Taqman qPCR assay showed concordance between the methods, but a weak eDNA signal. Informed by the results of field sampling, an experiment was designed to assess how turbidity and filtration methods influence detection of a rare target. Water from non-turbid (5 NTU) and turbid (50 NTU) estuarine sites was spiked with small volumes (0.5 and 1 mL) of water from a delta smelt tank to generate low eDNA concentrations. Samples were filtered using four filter types: cartridge filters (pore size 0.45 μm) and 47 mm filters (glass fiber, pore size 1.6 μm and polycarbonate, pore sizes 5 and 10 μm). Prefiltration was also tested as an addition to the filtration protocol for turbid water samples. eDNA copy numbers were analyzed using a censored data method for qPCR data. The assay limits and lack of PCR inhibition indicated an optimized assay. Glass fiber filters yielded the highest detection rates and eDNA copies in non-turbid and turbid water. Prefiltration improved detection in turbid water only when used with cartridge and polycarbonate filters. Statistical analysis identified turbidity as a significant effect on detection probability and eDNA copies detected; filter type and an interaction between filter type and prefilter were significant effects on eDNA copies detected, suggesting that particulate-filter interactions can affect detection sensitivity. Pilot experiments and transparent criteria for positive detection could improve eDNA surveys of rare species in turbid environments.

Cathodoluminescence spectroscopy of monolayer hexagonal boron nitride

Cathodoluminescence (CL) spectroscopy is a suitable technique for studying the luminescent properties of optoelectronic materials because CL has no limitation on the excitable bandgap energy and eliminates ambiguous signals due to simple light scattering and resonant Raman scattering potentially involved in the photoluminescence spectra. However, direct CL measurements of atomically thin two-dimensional materials have been difficult due to the small excitation volume that interacts with high-energy electron beams. Herein, distinct CL signals from a monolayer hexagonal BN (hBN), namely mBN, epitaxial film grown on a graphite substrate are shown by using a CL system capable of large-area and surface-sensitive excitation. Spatially resolved CL spectra at 13 K exhibited a predominant 5.5-eV emission band, which has been ascribed to originate from multilayered aggregates of hBN, markedly at thicker areas formed on the step edges of the substrate. Conversely, a faint peak at 6.04 ± 0.01 eV was routinely observed from atomically flat areas, which is assigned as being due to the recombination of phonon-assisted direct excitons of mBN. The CL results support the transition from indirect bandgap in bulk hBN to direct bandgap in mBN. The results also encourage one to elucidate emission properties of other low-dimensional materials by using the present CL configuration.

Optimising Al2O3–water nanofluid

BackgroundThis study explores how nanofluids can be optimised to improve heat transfer in various applications. A genetic algorithm that finds the optimal parameter configuration to achieve the best performance is studied and applied. The research focuses on the critical factors of heat transfer coefficient and pressure drop, which determine the efficiency of nanofluid-based systems.The main body of the abstractThe methodology involves artificial intelligence and multi-objective optimisation techniques. Results show that pressure drop and heat transfer coefficient have an inverse relationship. The study provides a range of optimal values for nanofluid temperature, particle size, and volume fraction.ResultsThe results show that the temperature, particle size, and volume fraction should be high. Another variation will be small particle size and small volume fractions with fluid temperature around 80 °C. The analysis yielded the following configuration with the optimal PEC. Temperature (oC), particle size (nm), volume fraction (%), heat transfer coefficient (kW/m2K), pressure drop (Pas), and PEC were 82.6 °C, 175.26 nm, 4.75%, 792.49 kW/m2K, 29.94 Pas, and 5.01.ConclusionsThe research highlights the potential of Al2O3–water nanofluids to maintain pressure drop and enhance heat transfer. It contributes to understanding nanofluid optimisation and provides practical insights for designing and selecting nanofluid systems that enhance heat transfer.

Torus counting and self-joinings of Kleinian groups

Abstract For any integer d ≥ 1 {d\geq 1} , we obtain counting and equidistribution results for tori with small volume for a class of d-dimensional torus packings, invariant under a self-joining Γ ρ &lt; ∏ i = 1 d PSL 2 ⁡ ( ℂ ) {\Gamma_{\rho}&lt;\prod_{i=1}^{d}\operatorname{PSL}_{2}(\mathbb{C})} of a Kleinian group Γ formed by a d-tuple of convex-cocompact representations ρ = ( ρ 1 , … , ρ d ) {\rho=(\rho_{1},\dots,\rho_{d})} . More precisely, if 𝒫 {\mathcal{P}} is a Γ ρ {\Gamma_{\rho}} -admissible d-dimensional torus packing, then for any bounded subset E ⊂ ℂ d {E\subset\mathbb{C}^{d}} with ∂ ⁡ E {\partial E} contained in a proper real algebraic subvariety, we have lim s → 0 ⁡ s δ L 1 ⁢ ( ρ ) ⋅ # ⁢ { T ∈ 𝒫 : Vol ⁡ ( T ) &gt; s , T ∩ E ≠ ∅ } = c 𝒫 ⋅ ω ρ ⁢ ( E ∩ Λ ρ ) . \lim_{s\to 0}{s^{\delta_{L^{1}}({\rho})}}\cdot\#\{T\in\mathcal{P}:% \operatorname{Vol}(T)&gt;s,\,T\cap E\neq\emptyset\}=c_{\mathcal{P}}\cdot\omega_{% \rho}(E\cap\Lambda_{\rho}). Here δ L 1 ⁢ ( ρ ) {\delta_{L^{1}}(\rho)} , 0 &lt; δ L 1 ⁢ ( ρ ) ≤ 2 / d {0&lt;\delta_{L^{1}}(\rho)\leq 2/\!{\sqrt{d}}} , denotes the critical exponent of the self-joining Γ ρ {\Gamma_{\rho}} with respect to the L 1 {L^{1}} -metric on the product ∏ i = 1 d ℍ 3 {\prod_{i=1}^{d}\mathbb{H}^{3}} , Λ ρ ⊂ ( ℂ ∪ { ∞ } ) d {\Lambda_{\rho}\subset(\mathbb{C}\cup\{\infty\})^{d}} is the limit set of Γ ρ {\Gamma_{\rho}} , and ω ρ {\omega_{\rho}} is a locally finite Borel measure on ℂ d ∩ Λ ρ {\mathbb{C}^{d}\cap\Lambda_{\rho}} which can be explicitly described. The class of admissible torus packings we consider arises naturally from the Teichmüller theory of Kleinian groups. Our work extends previous results of [H. Oh and N. Shah, The asymptotic distribution of circles in the orbits of Kleinian groups, Invent. Math. 187 2012, 1, 1–35] on circle packings (i.e., one-dimensional torus packings) to d-torus packings.

Deciphering fibroblast-induced drug resistance in non-small cell lung carcinoma through patient-derived organoids in agarose microwells.

Patient-derived organoids (PDOs) serve as invaluable 3D tumor models, retaining the histological complexity and genetic heterogeneity found in primary tumors. However, the limitation of small sample volumes and the lack of tailored platforms have hindered the research using PDOs. Within the tumor microenvironment, cancer-associated fibroblasts play a pivotal role in influencing drug sensitivity. In this study, we introduce an agarose microwell platform designed for PDO-based tumor and tumor microenvironment models, enabling rapid drug screening and resistance studies with small sample volumes. These microwells, constructed using 3D printing molds, feature a U-shaped bottom and 200 μm diameter. We successfully generated co-culture spheroids of non-small cell lung carcinoma (NSCLC) cells, including NCI-H358 or A549, and NSCLC PDOs F231 or F671 with fibroblast cell line, WI-38. Our results demonstrate the production of uniformly-sized spheroids (coefficient of variation <30%), high viability (>80% after 1 week), and fibroblast-induced drug resistance. The PDOs maintained their viability (>81% after 2 weeks) and continued to proliferate. Notably, when exposed to adagrasib, a KRASG12C inhibitor, we observed reduced cytotoxicity in KRASG12C-mutant spheroids when co-cultured with fibroblasts or their supernatant. The fibroblast supernatant sustained proliferative signals in tumor models. Taking into account the physical features, viability, and drug resistance acquired through supernatants from the fibroblasts, our platform emerges as a suitable platform for in vitro tumor modeling and the evaluation of drug efficacy using patient-derived tissues.

MAMMOTH-Subaru. V. Effects of Cosmic Variance on Lyα Luminosity Functions at z = 2.2–2.3

Cosmic variance introduces significant uncertainties into galaxy number density properties when surveying the high-redshift Universe with a small volume. Such uncertainties produce the field-to-field variance σ g of galaxy numbers in observational astronomy, which significantly affects the luminosity function (LF) measurement of Lyα emitters (LAEs). For most previous Lyα LF studies, σ g is often adopted from predictions by cosmological simulations, but barely confirmed by observations. Measuring cosmic variance requires a huge sample over a large volume, exceeding the capabilities of most astronomical instruments. In this study, we demonstrate an observational approach for measuring the cosmic variance contribution for z ≈ 2.2 Lyα LFs. The LAE candidates are observed using the narrow band and broad band of the Subaru/Hyper Suprime-Cam in eight independent fields, making the total survey area ≃11.62 deg2 and a comoving volume of ≃8.71 × 106 Mpc3. We report a best-fit Schechter function with parameters α = −1.75 (fixed), LLyα*=5.95−0.96+1.22×1042 erg s−1, and ϕLyα*=5.26−1.27+1.65 × 10−4 Mpc−3 for the overall Lyα LFs. After clipping out the regions that may bias the cosmic variance measurements, we calculate σ g by sampling LAEs within multiple pointings on the field image. We investigate the relation between σ g and survey volume V, and fit a simple power-law σg=k×V105Mpc3β . We find best-fit values of −1.399−0.156+0.160 for β and 1.249−0.193+0.213 for k. We compare our measurements with predictions from simulations and find that the cosmic variance of LAEs is likely larger than that of general star-forming galaxies.