Small Volume Research Articles

Detection of Salmonella Typhi bacteriophages in surface waters as a scalable approach to environmental surveillance.

Environmental surveillance, using detection of Salmonella Typhi DNA, has emerged as a potentially useful tool to identify typhoid-endemic settings; however, it is relatively costly and requires molecular diagnostic capacity. We sought to determine whether S. Typhi bacteriophages are abundant in water sources in a typhoid-endemic setting, using low-cost assays. We collected drinking and surface water samples from urban, peri-urban and rural areas in 4 regions of Nepal. We performed a double agar overlay with S. Typhi to assess the presence of bacteriophages. We isolated and tested phages against multiple strains to assess their host range. We performed whole genome sequencing of isolated phages, and generated phylogenies using conserved genes. S. Typhi-specific bacteriophages were detected in 54.9% (198/361) of river and 6.3% (1/16) drinking water samples from the Kathmandu Valley and Kavrepalanchok. Water samples collected within or downstream of population-dense areas were more likely to be positive (72.6%, 193/266) than those collected upstream from population centers (5.3%, 5/95) (p=0.005). In urban Biratnagar and rural Dolakha, where typhoid incidence is low, only 6.7% (1/15, Biratnagar) and 0% (0/16, Dolakha) river water samples contained phages. All S. Typhi phages were unable to infect other Salmonella and non-Salmonella strains, nor a Vi-knockout S. Typhi strain. Representative strains from S. Typhi lineages were variably susceptible to the isolated phages. Phylogenetic analysis showed that S. Typhi phages belonged to the class Caudoviricetes and clustered in three distinct groups. S. Typhi bacteriophages were highly abundant in surface waters of typhoid-endemic communities but rarely detected in low typhoid burden communities. Bacteriophages recovered were specific for S. Typhi and required Vi polysaccharide for infection. Screening small volumes of water with simple, low-cost (~$2) plaque assays enables detection of S. Typhi phages and should be further evaluated as a scalable tool for typhoid environmental surveillance.

Analytical modeling of the electrical conductivity of CNT-filled polymer nanocomposites

Electrical conductivity of most polymeric insulators can be drastically enhanced by introducing a small volume fraction [Formula: see text] of conductive nanofillers. These nanocomposites find wide-ranging engineering applications from cellular metamaterials to strain sensors. In this work, we present a mathematical model to predict the effective electrical conductivity of carbon nanotubes (CNTs)/polymer nanocomposites accounting for the conductivity, dimensions, volume fraction, and alignment of the CNTs. Eshelby’s classical equivalent inclusion method (EIM) is generalized to account for electron-hopping—a key mechanism of electron transport across CNTs, and is validated with experimental data. Two measurements, namely, the limit angle of filler orientation and the probability distribution function, are used to control the alignment of CNTs within the composites. Our simulations show that decreasing the angle from a uniformly random distribution to a fully aligned state significantly reduces the transverse electrical conductivity, while the longitudinal conductivity shows less sensitivity to angle variation. Moreover, it is observed that distributing CNTs with non-uniform probability distribution functions results in an increase in longitudinal conductivity and a decrease in transverse conductivity, with these differences becoming more pronounced as the volume fraction of CNTs is increased. A reduction in CNT length decreases the effective electrical conductivity due to the reduced number of available conductive pathways while reducing CNT diameter increases the conductivity.

Development and Validation of HPLC-FLD Analysis of Perampanel in MEPS-Processed Rat Plasma Sample

Perampanel, a novel α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist, is registered for the adjunctive treatment of patients (aged ≥ 12 years) with refractory partial-onset seizures. A simple high-performance liquid chromatographic method fluorescence detection (HPLC-FLD) was developed to analyze perampanel in rats’ plasma and validated for bioanalytical purposes. Rats’ plasma (50 µL) was processed by microextraction packed sorbent (MEPS). The analytes were separated using a Hypersil Gold octadecyl silane column (250 × 4.6 mm internal diameter, 5 μm particle size) with isocratic elution. A mobile phase consisting of acetonitrile–methanol–water (275:275:450, v/v/v; containing 50 µL triethylamine and pH adjusted to 3.25 with orthophosphoric acid) was used in this analysis. The flow rate was 1.25 mL/min. Analytes were monitored at an excitation wavelength of 285 nm and an emission wavelength of 430 nm. The linearity range for this validated method was from 3.75 to 300 ng/mL. No endogenous peaks were found in the elution of analytes in drug-free rats’ plasma. Intra- and inter-batch reproducibility studies demonstrated accuracy and precision within the acceptance criteria. The results indicate that the present method is simple, selective, reproducible, and suitable for the analysis of perampanel in small volume samples. The robustness of the method was accessed using MODDE® design of experiments software version 12.5.

On the spinal venous sinus of Alligator mississippiensis.

The epidural space of the American alligator (Alligator mississippiensis) is largely filled by a continuous venous sinus. This venous sinus extends throughout the trunk and tail of the alligator, and is continuous with the dural sinuses surrounding the brain. Segmental spinal veins (sl) link the spinal venous sinus (vs) to the somatic and visceral venous drainage. Some of these sl, like the caudal head vein along the occipital plate of the skull, are enlarged, suggesting more functional linkage. No evidence of venous valves or external venous sphincters was found associated with the vs; the relative scarcity of smooth muscle in the venous wall of the sinus suggests limited physiological regulation. The proatlas (pr), which develops between the occipital plate and C1 in crocodylians, is shaped like a neural arch and is fused to the dorsal surface of the vs. The present study suggests that the pr may function to propel venous blood around the brain and spinal cord. The vs effectively encloses the spinal dura, creating a tube-within-a-tube system with the (smaller volume) spinal cerebrospinal fluid (CSF). Changes in venous blood pressure, as are likely during locomotion, would impact dural compliance and CSF pressure waves propagating along the spinal cord.

Multi-wavelength confocal displacement sensing using a highly dispersive flat-field concave grating.

A multi-wavelength confocal displacement sensor based on a flat-field concave grating (FFCG) was proposed and designed; the large dispersion and small volume of the FFCG make it an ideal candidate for replacing the complex dispersive lens group. The designed displacement sensor was calibrated by displacement meter, and the characteristics were measured. Consequently, for the proposed displacement sensor, the displacement range of 6.8mm was measured with the R-square linearity evaluation coefficient of 0.998, and the sensitivity preceded 17.1nm/mm. The resolution of the displacement sensor was characterized by 70µm, as well as a full width at half maximum (FWHM) fluctuating around 1.63nm, indicating high precision and accuracy in displacement measurement. Moreover, the stability and reliability of the sensor were verified within 20min, with no significant wavelength shifts, and gentle power fluctuations of 557.73 counts at 520nm and 563.67 counts at 545.05nm, respectively.

Did the COVID-19 transform consumers’ orthodox behavior?: A systematic literature review

The study aimed to explore new aspects and dimensions of consumer behavior during COVID-19. Hence, significant changes in consumer behavior were identified, and the characteristics, similarities, and differences of these behavioral approaches were discovered to obtain the purpose. The systematic literature review was conducted using the PRISMA-ScR method, which is a systematic procedure for screening and analyzing the chosen literature. The study found four major changes in consumer behavior; panic buying (large volume, short-run), stockpiling (large volume, long-run), impulse buying (small volume, short-run), and sustainable buying behavior (small volume, long-run). Moreover, this study explored the correlations and differences among these behaviors. The authors constructed an innovative framework that examines the characteristics of panic buying, stockpiling, impulse buying, and sustainable buying behavior, drawing upon existing work in the field. As this paper explains the characteristics and underlying reason for the transformed behavior, this paper can contribute to the literature on consumer behavior during uncertain situations. This study can help marketers, government, and policymakers to understand consumer behavior changes and their causes in any emergency circumstance. Furthermore, using this study's findings, decision-makers could develop and adopt inventory management, supply chain management, and sustainable consumption policies and strategies to address the crisis.

Biosorption of Technologically Valuable Metal Ions on Algae Wastes: Laboratory Studies and Applicability

In the context of a circular economy that recommends the most efficient use of wastes, algae wastes have a huge potential for valorization. In this study, algae wastes obtained after the alkaline extraction of active compounds from two types of marine algae (green algae—Ulva sp. and red algae—Callithamnion sp.) were used as biosorbents to remove metal ions from aqueous effluents. The efficiency of these biosorbents was tested for Zn(II), Cu(II), and Co(II) ions, considered technologically valuable metal ions. The batch monocomponent experiments performed under optimal conditions (pH = 5.0; 4.0 g biosorbent/L; 22 ± 1 °C) showed that more than 75% of the metal ions were removed when their initial concentration was less than 1.25 mmol/L. The experimental data were well described by the pseudo-second-order kinetic model and Langmuir isotherm model. The high values obtained for the maximum biosorption capacity (qmax: Cu(II) (0.52 mmol/g) > Zn(II) (0.41 mmol/g) > Co(II) (0.39 mmol/g) for G-AWB, and qmax: Cu(II) (1.78 mmol/g) > Zn(II) (1.72 mmol/g) > Co(II) (1.66 mmol/g) for R-AWB) show the potential use of these biosorbents to remove such technologically valuable metal ions from industrial wastewater. This possibility was tested using industrial wastewater samples obtained from the metal coating industry. The quantitative removal (>91%) of Zn(II), Cu(II), and Co(II) ions was obtained when their initial concentration was adjusted to 50 mg/L. In addition, the rapid and efficient desorption of these metal ions from loaded biosorbents by simple treatment with small volumes of HNO3 (10−1 mol/L) further emphasizes the possibility of their recovery and reuse in the technological circuit. The results included in this study indicate that algae wastes have the potential to be used in industrial effluent decontamination processes and open new perspectives for the implementation of circular economy principles.

Revolutionizing HIV-1 Viral Load Monitoring in India: The Potential of Dried Blood Spot Analysis for Expanding Access and Improving Care.

India continues to grapple with a significant burden of HIV infections. Despite notable progress in prevention and treatment efforts, multiple challenges, such as high-risk populations, inadequate testing facilities, and limited access to healthcare in remote areas, persist. Though the Government of India offers HIV-1 plasma viral load testing at various medical centers, aiding treatment decisions and monitoring antiretroviral therapy effectiveness, enhancing care for individuals living with HIV under the National AIDS Control Program (NACP), the nation's large population and diverse demographics further complicate its outreach and response. Hence, strategic interventions and alternative methods of testing remain crucial to curbing HIV transmission and improving the quality of life for those affected. Dried blood spot (DBS) sampling has emerged as a convenient and cost-effective alternative for HIV-1 viral load testing, revolutionizing the landscape of diagnostic and monitoring strategies for HIV infection. Though the plasma-based viral load remains the gold standard for monitoring HIV-1, DBS-based HIV-1 viral load testing holds immense promise for improving access to care, particularly in resource-limited settings where traditional plasma-based methods may be logistically challenging. DBS entails the collection of a small volume of blood onto filter paper, followed by drying and storage. This approach offers numerous advantages, including simplified sample collection, transportation, and storage, reducing the need for cold-chain logistics. Recent studies have demonstrated the feasibility and accuracy of DBS-based HIV-1 viral load testing, revealing a strong correlation between DBS and plasma measurements. Its implementation can enhance the early detection of treatment failure, guide therapeutic decisions, and ultimately contribute to better clinical outcomes for HIV-infected individuals. Hence, this review explores the principles, advancements, feasibility, and implications of DBS-based HIV-1 viral load testing.

Breakdown of Langmuir Adsorption Isotherm in Small Closed Systems.

For more than a century, monolayer adsorptions in which adsorbate molecules and adsorbing sites behave ideally have been successfully described by Langmuir's adsorption isotherm. For example, the amount of adsorbed material, as a function of concentration of the material which is not adsorbed, obeys Langmuir's equation. In this paper, we argue that this relation is valid only for macroscopic systems. However, when particle numbers of adsorbate molecules and/or adsorbing sites are small, Langmuir's model fails to describe the chemical equilibrium of the system. This is because the kinetics of forming, or the probability of observing, occupied sites arises from two-body interactions, and as such, ought to include cross-correlations between particle numbers of the adsorbate and adsorbing sites. The effect of these correlations, as reflected by deviations in predicting composition when correlations are ignored, increases with decreasing particle numbers and becomes substantial when only few adsorbate molecules, or adsorbing sites, are present in the system. In addition, any change that augments the fraction of occupied sites at equilibrium (e.g., smaller volume, lower temperature, or stronger adsorption energy) further increases the discrepancy between observed properties of small systems and those predicted by Langmuir's theory. In contrast, for large systems, these cross-correlations become negligible, and therefore when expressing properties involving two-body processes, it is possible to consider independently the concentration of each component. By applying statistical mechanics concepts, we derive a general expression of the equilibrium constant for adsorption. It is also demonstrated that in ensembles in which total numbers of particles are fixed, the magnitudes of fluctuations in particle numbers alone can predict the average chemical composition of the system. Moreover, an alternative adsorption equation, predicting the average fraction of occupied sites from the value of the equilibrium constant, is proposed. All derived relations were tested against results obtained by Monte Carlo simulations.

Mechanisms underlying the laxative effect of lactulose: A randomized placebo-controlled trial showing increased small bowel water and motility unaltered by the 5-HT3 receptor antagonist, ondansetron.

Lactulose is a laxative which accelerates transit and softens stool. Our aim was to investigate its mechanism of action and use this model of diarrhea to investigate the anti-diarrheal actions of ondansetron. A double-blind, randomized, placebo-controlled crossover study of the effect of ondansetron 8 mg in 16 healthy volunteers. Serial MRI scans were performed fasted and 6 h after a meal. Participants then received lactulose 13.6 g twice daily and study drug for a further 36 h. On Day 3, they had further serial MRI scans for 4 h. Measurements included small bowel water content (SBWC), colonic volume, colonic gas, small bowel motility, whole gut transit, and ascending colon relaxation time (T1AC), a measure of colonic water content. Lactulose increased area under the curve (AUC) of SBWC from 0 to 240 min, mean difference 14.2 L · min (95% CI 4.1, 24.3), p = 0.009, and substantially increased small bowel motility after 4 h (mean (95% CI) 523 (457-646) a.u. to 852 (771-1178) a.u., p = 0.007). There were no changes in T1AC after 36 h treatment. Ondansetron did not significantly alter SBWC, small bowel motility, transit, colonic volumes, colonic gas nor T1AC, with or without lactulose. Lactulose increases SBWC and stimulates small bowel motility; however, unexpectedly it did not significantly alter colonic water content, suggesting its laxative effect is not osmotic but due to stimulation of motility. Ondansetron's lack of effect on intestinal water suggests its anti-diarrheal effect is not due to inhibition of secretion but more likely altered colonic motility.

Separation of Lipoproteins for Quantitative Analysis of 14C-Labeled Lipid-Soluble Compounds by Accelerator Mass Spectrometry.

To date, 14C tracer studies using accelerator mass spectrometry (AMS) have not yet resolved lipid-soluble analytes into individual lipoprotein density subclasses. The objective of this work was to develop a reliable method for lipoprotein separation and quantitative recovery for biokinetic modeling purposes. The novel method developed provides the means for use of small volumes (10-200 µL) of frozen plasma as a starting material for continuous isopycnic lipoprotein separation within a carbon- and pH-stable analyte matrix, which, following post-separation fraction clean up, created samples suitable for highly accurate 14C/12C isotope ratio determinations by AMS. Manual aspiration achieved 99.2 ± 0.41% recovery of [5-14CH3]-(2R, 4'R, 8'R)-α-tocopherol contained within 25 µL plasma recovered in triacylglycerol rich lipoproteins (TRL = Chylomicrons + VLDL), LDL, HDL, and infranatant (INF) from each of 10 different sampling times for one male and one female subject, n = 20 total samples. Small sample volumes of previously frozen plasma and high analyte recoveries make this an attractive method for AMS studies using newer, smaller footprint AMS equipment to develop genuine tracer analyses of lipophilic nutrients or compounds in all human age ranges.

Quantitation of circulating short-chain fatty acids in small volume blood samples from animals and humans

BackgroundThe role of gut microbiota in human health has been intensively studied and more recently shifted from emphasis on composition towards function. Function is partly mediated through formed metabolites. Short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate as well as their branched analogues represent major products from gut fermentation of dietary fibre and proteins, respectively. Robust and high-throughput analysis of SCFAs in small volume blood samples have proven difficult. Major obstacles come from the ubiquitous presence of SCFAs that leads to contaminations and unstable analytical results because of the high volatility of these small molecules. Comprehensive and comparable data on the variation of SCFAs in blood samples from different blood matrices and mammal species including humans is lacking. Therefore, our aim was to develop and evaluate a stable and robust method for quantitation of 8 SCFAs and related fermentation products in small volume blood plasma samples and to investigate their variation in humans and different animal species. ResultsDerivatization was a successful approach for measurement of SCFAs in biological samples but quenching of the derivatization reaction was crucial to obtain long-term stability of the derivatized analytes. In total 9 compounds (including succinic acid) were separated in 5 min. The method was linear over the range 0.6–3200 nM formic (FA), acetic (AA), 0.3–1600 nM propionic (PA), and 0.16–800 nM for butyric (BA)-, isobutyric (IBA)-, valeric (VA)-, isovaleric (IVA)-, succinic (SA) and caproic acid (CA). The precision ranged ≤12 % within days and ≤28 % between days (except for CA and VA) in three different plasma quality control (QC) samples (29 batches analyzed over 3 months). The extraction recovery was on average 94 % for the different SCFAs. Typical interquartile range (IQR) concentrations (μM) of SCFAs in human plasma samples were 168 μM (FA), 64 μM (AA), 2.2 μM (PA), 0.54 μM (BA), 0.66 μM (IBA), 0.18 μM (VA), 0.40 μM (IVA), and 0.34 μM (CA). In total, 55 samples per batch/day were successfully analyzed and in total 5380 human plasma samples measured over a 3-year timespan. SignificanceThe developed UHPLC-MS based method was suitable for measuring SCFAs in small blood volume samples and enabled robust quantitative data.

Enhancement of Radiative Power Using a Divergent Splitter Plate Design in H2–Air Non-Premixed Micro-Combustor

Abstract Micro-combustion based power generation devices can be considered as future alternatives to batteries in miniature electronic devices. Micro-combustors operating in non-premixed mode are free from flashback but face the challenge of properly mixing fuel and air within a small volume. In this work, the effect of a divergent fuel–air splitter design on the mixing performance and combustion characteristics of H2–air fueled diffusion micro-combustor is studied. The laminar reacting flow is simulated using the finite volume method and a detailed hydrogen kinetic mechanism. Three divergent splitter designs are compared with the commonly used rectangular splitter to study the effect on radiation power, an essential parameter for thermophotovoltaic power generation. The best-performing divergent and base rectangular splitter designs are investigated in detail. The study shows that the micro-combustor with divergent splitter design reduces mixing distance (Lmix) by 5–23% depending on inlet velocity and channel height. With the divergent splitter, the peak value of the heat release rate also increases slightly, implying enhanced combustion. The divergent splitter increases the high-temperature surface area of the outer wall as compared to the rectangular splitter. This leads to the micro-combustor with divergent splitter producing significantly higher radiation power (>10%) than the rectangular splitter for larger channel heights and higher inlet velocities.

Snapping of a viscoelastic cylindrical panel under loading with small volume compressed gas

The paper considers the dynamics of the process of a flat rectangular elastic panel having an initial deflection equal to the critical deflection of the static problem of panel stability. The panel is loaded with compressed gas enclosed in a small volume container. Using this value, the load acting on the panel during the snapping process will depend on the deflection of the panel as a result of the adiabatic expansion of the compressed gas. The main goal of the work is to investigate the stability region of a cylindrical panel when loaded with compressed gas. The problem is solved using a developed methodology based on the method of separating variable equations of mathematical physics. Based on calculations, it was found that when the panel is loaded with compressed gas enclosed in a small-volume container, a stabilizing effect appears, i.e. a certain deflection interval appears where the panel does not lose stability. The presence of external pressure makes it possible to expand this area, i.e. the external environment increases the “stabilizing” effect. Also, taking into account the viscoelastic properties of the material expands this area to 10%.

An improved equalization circuit with bidirectional CUK converter for series-connected battery strings

This paper proposed an improved equalization circuit based on a bidirectional CUK converter. Compared with traditional bus equalization circuits based on CUK converter, it owns a simpler structure with fewer inductors, resulting in a smaller volume and higher energy density of the proposed equalization circuit. The operation principle and steady-state characteristic of the equalizer are analysed. The equalizer is applied to the energy balance of the series-connected battery strings, and the balance principle is designed. The proposed equalization system achieves a fast energy balance of the battery pack. Simulation results verify the effectiveness of the designed equalization circuit and balance strategy.

Research on the Law of Affecting the Quality of forging Metallurgy Quality on the Quality of Wedge Horizontal Rolling Mold

Drawing on the traditional and mature cross wedge rolling forming technology for stepped shaft parts, it is innovatively applied to the high-efficiency and low-cost manufacturing of blade preforms with special-shaped sections. Under the action of the rollers, the material undergoes radial compression deformation and axial extension deformation, and the blank changes from a uniform cross-section to a variable cross-section, which is in the shape of a stepped shaft. Forming, to prepare a blade preform with deformed cross-section characteristics. Then, the cooled blade preform is heated again and placed in a precision forging die. Under the action of the unidirectional compressive stress of the upper and lower dies, the blade preform is compressed and deformed, filling the die cavity with the smallest volume, thereby realizing precision forming of blade forgings. In the process parameters of the horizontal wedge rolling mold, the effect of forming angle has the greatest impact on center damage.

Abstract TMP52: Modern Thin-Slice CT Perfusion Has High Sensitivity for Supratentorial Lacunar Stroke

Background: Lacunar stroke is a common form of ischaemic stroke with mechanisms poorly understood compared to large vessel stroke. Access to gold standard MRI is often limited in the acute setting. Acute diagnosis of lacunar stroke is difficult with conventional CT, as non-contrast CT and CT angiography have poor sensitivity. Previous studies have demonstrated only low to moderate sensitivity of CT perfusion (CTP). Aims: To test the accuracy of thin-slice CTP to detect lacunar stroke and compare the clinical and radiological characteristics to better understand the limitations of CTP for diagnosis of lacunar stroke. Methods: We reviewed thin-slice CTP (slice thickness <=3mm) of cases presenting with an acute lacunar syndrome without large/medium vessel occlusion, or perfusion lesion detected by automated analysis. Cases presented to two comprehensive stroke centres in Sydney and Newcastle, NSW, Australia, between 2019 and 2022. CTP was reviewed by two independent reviewers, blinded to follow-up MRI but not the clinical syndrome. CTP and DWI were registered to a standard template and DWI lesions were manually segmented. CTP was further reviewed adjacent to DWI, and raw CTP values within the lesion was calculated. Results: We reviewed 394 cases of acute lacunar syndrome including 82 stroke mimics, 48 infratentorial and 250 supratentorial infarcts. Overall sensitivity was 76% and varied by infarct location. Sensitivity was lowest for brainstem (46%), moderate for thalamic (69%) and high for infarcts within the lenticulostriate perforator territory (84%). Factors associated with reduced sensitivity include small infarct volume, increased noise, or artefact, and infratentorial location. Conclusion: Thin-slice CTP has high sensitivity for detection of supratentorial lacunar infarcts however is more susceptible to noise and imaging artefact than larger infarcts. Advanced processing techniques show promise to improve overall diagnosis of lacunar stroke.

Analysis of fibrocalcific aortic valve stenosis: computational pre-and-post TAVR haemodynamics behaviours.

Fibro-calcific aortic valve (AV) diseases are characterized by calcium growth or accumulation of fibrosis in the AV tissues. Fibrocalcific aortic stenosis (FAS) rises specifically in females, like calcification-induced aortic stenosis (CAS), may eventually necessitate valve replacement. Fluid-structure-interaction (FSI) computational models for severe CAS and FAS patients were developed using lattice Boltzmann method and multi-scale finite elements (FE). Three parametric AV models were introduced: pathology-free of non-calcified tri-and-bicuspid AVs with healthy collagen fibre network (CFN), a FAS model incorporated a thickened CFN with embedded small calcification volumes, and a CAS model employs healthy CFN with embedded high calcification volumes. The results indicate that the interaction between calcium deposits, adjacent tissue and fibres crucially influences haemodynamics and structural reactions. A fourth model of transcatheter aortic valve replacement (TAVR) post-procedure outcomes was created to study both CAS and FAS. TAVR-CAS had a higher maximum contact pressure and lower anchoring area than TAVR-FAS, making it prone to aortic tissue damage and migration. Finally, although the TAVR-CAS offered a larger opening area, its paravalvular leakage was higher. This may be attributed to a similar thrombogenicity potential characterizing both models. The computational framework emphasizes the significance of mechanobiology in FAS and underscores the requirement for tissue modelling at multiple scales.

Small pretreatment lesion size and high sphericity as favorable prognostic factors after laser interstitial thermal therapy in brain metastases.

The objective of this study was to identify baseline clinical and radiological characteristics of brain metastases (BMs) associated with a higher probability of lesion-specific progression-free survival (PFS-L) after laser interstitial thermal therapy (LITT). A total of 47 lesions in 42 patients with BMs treated with LITT were retrospectively examined, including newly diagnosed BM, suspected recurrent BM, and suspected radiation necrosis. The association of baseline clinical and radiological features with PFS-L was assessed using survival analyses. Radiological features included lesion size measurements, diffusion and perfusion metrics, and sphericity, which is a radiomic feature ranging from 1 (perfect sphere) to 0. The probability of PFS-L for the entire cohort was 88.0% at 3 months, 70.6% at 6 months, 67.4% at 1 and 2 years, and 62.2% at 3 years. For lesions progressing after LITT (n = 13), the median time to progression was 3.9 months, and most lesions (n = 11) progressed within 6 months after LITT. In lesions showing response to LITT (n = 17), the median time to response was 12.1 months. All 3 newly diagnosed BMs showed a long-term response. The mean (± SD) follow-up duration for all censored lesions (n = 34) was 20.7 ± 19.4 months (range 12 days to 6.1 years). The mean pretreatment enhancing volume was 2.68 cm3 and the mean sphericity was 0.70. Pretreatment small enhancing volume (p = 0.003) and high sphericity (p = 0.024) computed from lesion segmentation predicted a longer PFS-L after LITT. Lesions meeting optimal cutoffs of either enhancing volume < 2.5 cm3 (adjusted p = 0.004) or sphericity ≥ 0.705 (adjusted p = 0.019) had longer PFS-L, and their probability of PFS-L was 86.8% at 3 years. Lesions meeting both cutoffs showed a cumulative benefit (p < 0.0001), with a 100% probability of PFS-L at 3 years, which was unchanged at the end of follow-up (4.1 years). Manually computed estimates of lesion size (maximal axial diameter, p = 0.011) and sphericity (p = 0.043) were also predictors of PFS-L. Optimal cutoffs of diameter < 2 cm (adjusted p = 0.035) or manual sphericity ≥ 0.91 (adjusted p = 0.092) identified lesions with longer PFS-L, and lesions meeting both cutoffs showed a cumulative benefit (p = 0.0023). Baseline diffusion imaging did not predict PFS-L. A subset of lesions (n = 7) with highly perfused hotspots had worse PFS-L (adjusted p = 0.010), but perfusion signal contamination from vessels and cortex and underlying size differences were possible confounders. Small size and high sphericity are ideal baseline features for lesions considered for LITT treatment, with a cumulative PFS-L benefit when both features are present, that could aid patient selection.

A Review on High Performance Thin Layer Chromatography

A common excellent replacement for GC and HPLC is High-Performance Thin Layer Chromatography (HPTLC), an improved and automated technique of thin-layer chromatography (TLC) that provides better separation performance and detection limits. Applications of HPTLC include the study of biological materials and phytochemicals, the measurement of herbal medications and active components, formulation fingerprinting, and the identification of adulterants in formulations. Using HPTLC, chemicals of forensic importance can be located. It is more sensitive and feasible to run many samples in a little period of time by using a small volume of solvent. It is one of the more intricate instrumental procedures, utilizing every feature available in thin-layer chromatography.