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1.
Phys Eng Sci Med ; 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38954381

RESUMO

A fundamental parameter to evaluate the beam delivery precision and stability on a clinical linear accelerator (linac) is the focal spot position (FSP) measured relative to the collimator axis of the radiation head. The aims of this work were to evaluate comprehensive data on FSP acquired on linacs in clinical use and to establish the ability of alternative phantoms to detect effects on patient plan delivery related to FSP. FSP measurements were conducted using a rigid phantom holding two ball-bearings at two different distances from the radiation source. Images of these ball-bearings were acquired using the electronic portal imaging device (EPID) integrated with each linac. Machine QA was assessed using a radiation head-mounted PTW STARCHECK phantom. Patient plan QA was investigated using the SNC ArcCHECK phantom positioned on the treatment couch, irradiated with VMAT plans across a complete 360° gantry rotation and three X-ray energies. This study covered eight Elekta linacs, including those with 6 MV, 18 MV, and 6 MV flattening-filter-free (FFF) beams. The largest range in the FSP was found for 6 MV FFF. The FSP of one linac, retrofitted with 6 MV FFF, displayed substantial differences in FSP compared to 6 MV FFF beams on other linacs, which all had FSP ranges less than 0.50 mm and 0.25 mm in the lateral and longitudinal directions, respectively. The PTW STARCHECK phantom proved effective in characterising the FSP, while the SNC ArcCHECK measurements could not discern FSP-related features. Minor variations in FSP may be attributed to adjustments in linac parameters, component replacements necessary for beam delivery, and the wear and tear of various linac components, including the magnetron and gun filament. Consideration should be given to the ability of any particular phantom to detect a subsequent impact on the accuracy of patient plan delivery.

2.
Neurosurgery ; 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38954601

RESUMO

BACKGROUND AND OBJECTIVES: Laser interstitial thermal therapy (LITT) has demonstrated promise in surgical neuro-oncology because of its effectiveness in delivering precise thermal energy to lesions. The extent of ablation (EOA) is a prognostic factor in improving patient outcomes but is often affected by perilesional heatsink structures, which can lead to asymmetric ablations. The purpose of this study was to quantitatively evaluate the impact of various perilesional heatsink structures on the EOA in LITT for brain metastases. METHODS: Twenty-seven procedures for 22 unique patients with brain metastases fit the inclusion criteria. Intracranial heatsink structures were identified: sulci, meninges, cerebrospinal fluid (CSF) spaces, and vasculature. Asymmetric ablation was determined by measuring 3 pairs of orthogonal distances from the proximal, midpoint, and distal locations along the laser catheter to the farthest edge of the ablation zone bilaterally. Distances from the same points on the laser catheter to the nearest heatsink were also recorded. The Heatsink Effect Index was created to serve as a proxy for asymmetric ablation. Pearson correlations, t-tests, and analysis of variance were the statistical analyses performed. RESULTS: From the midpoint of the catheter, the 27 heatsinks were meninges (40.7%), sulci (22.2%), vasculature (22.2%), and CSF spaces (14.8%). Across all points along the catheter track, there was a significant generalized heatsink effect on asymmetric ablations (P < .0001). There was a negative correlation observed between asymmetric ablations and EOA from the midpoint of the laser catheter (r = -0.445, P = .020). Compared with sulci, CSF spaces trended toward a greater effect on asymmetric ablation volumes (P = .069). CONCLUSION: This novel quantitative analysis shows that perilesional heatsinks contribute to asymmetric ablations. CSF spaces trended toward higher degrees of asymmetric ablations. Importantly, neurosurgeons may anticipate asymmetric ablations preoperatively if heatsinks are located within 13.3 mm of the laser probe midpoint. These preliminary results may guide surgical decision-making in LITT for metastatic brain lesions.

3.
Int J Infect Dis ; : 107157, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38971556

RESUMO

BACKGROUND: With the dominance of different SARS-CoV-2 variants, the severity of COVID-19 has evolved. We aimed to investigate the difference in symptom prevalence and the association between symptoms and adverse pregnancy outcomes during the dominance of Wild-type/Alpha, Delta, and Omicron. METHODS: COVID-19 related symptom prevalence, maternal and specific neonatal outcomes of 5431 pregnant women registered in this prospective study were compared considering the dominant virus variant. Logistic regression models analyzed the association between specific symptoms and intensive care unit (ICU) admission or preterm birth. RESULTS: Infection with the Delta variant led to an increase in the symptom burden compared to the Wild-type/Alpha variant and the highest risk for respiratory tract symptoms, feeling of sickness, headache, and dizziness/drowsiness. An infection with the Omicron variant was associated with the lowest risk of dyspnea and changes in smell/taste but the highest risk for nasal obstruction, expectoration, headaches, myalgia, and fatigue compared to the Wild-type/Alpha and Delta variant dominant periods. With the progression of the Wild-type/Alpha to the Delta variant neonatal outcomes worsened. Dyspnea and fever were strong predictors for maternal ICU admission and preterm birth independent of vaccination status or trimester of infection onset. CONCLUSION: The symptom burden increased during the Delta period and was associated with worse pregnancy outcomes than in the Wild-type/Alpha area. During the Omicron dominance there still was a high prevalence of less severe symptoms. Dyspnea and fever can predict a severe maternal illness.

4.
Cureus ; 16(6): e61790, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38975458

RESUMO

Recently, a new category of heart failure with improved ejection fraction (HFimpEF) has emerged in the classification system. This is defined as the subgroup of patients with heart failure with reduced ejection fraction (HFrEF) whose left ventricular ejection fraction has recovered partially or completely, with no specific cut-off values established yet in the guidelines. In our review, we aim to provide an overview of prevalence, predictors, mechanism of remodeling, and management strategies regarding HFimpEF. These patients constitute a sizeable cohort among patients with reduced ejection fraction. Certain patient characteristics including younger age and female gender, absence of comorbid conditions, low levels of biomarkers, and non-ischemic etiology were identified as positive predictors. The heart undergoes significant maladaptive changes post failure leading to adverse remodeling influenced etiology and duration. Goal-directed medical therapy including beta-blockers, angiotensin-converting enzyme inhibitors (ACEIs), and angiotensin II receptor blockers (ARBs) have notably improved cardiac function by inducing reverse remodeling. Despite a more favorable prognosis compared to HFrEF, patients with improved ejection fraction (EF) still face clinical events and reduced quality of life, and remain at risk of adverse outcomes. Although the evidence is scarce, it is advisable to continue treatment modalities despite improvement in EF, including device therapies, to prevent relapse and clinical deterioration. It is imperative to conduct further research to understand the mechanism leading to EF amelioration and establish guidelines to identify and direct management strategies.

5.
Toxicol Sci ; 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38976647

RESUMO

Quinoline-related antimalarial drugs have been associated with cardiotoxicity risk, in particular QT prolongation and QRS complex widening. In collaboration with Medicines for Malaria Venture (MMV), we discovered novel plasmepsin X (PMX) inhibitors for malaria treatment. The first lead compounds tested in anesthetized guinea pigs (GP) induced profound QRS widening, although exhibiting weak inhibition of NaV1.5-mediated currents in standard patch clamp assays. To understand the mechanism(s) underlying QRS widening to identify further compounds devoid of such liability, we established a set of in vitro models including CaV1.2, NaV1.5 rate-dependence and NaV1.8 patch clamp assays, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM), and Langendorff-perfused isolated GP hearts. Six compounds were tested in all models including anesthetized GP, and 8 additional compounds were tested in vitro only. All compounds tested in anesthetized GP and isolated hearts showed a similar cardiovascular profile, consisting of QRS widening, bradycardia, negative inotropy, hypotension, and for some, QT prolongation. However, a left shift of the concentration-response curves was noted from in vitro to in vivo GP data. When comparing in vitro models, there was a good consistency between decrease in sodium spike amplitude in hiPSC-CM and QRS widening in isolated hearts. Patch clamp assay results showed that the QRS widening observed with PMX inhibitors is likely multifactorial, primarily due to NaV1.8 and NaV1.5 rate-dependent sodium blockade and/or calcium channel-mediated mechanisms. In conclusion, early de-risking of QRS widening using a set of different in vitro assays allowed to identify novel PMX inhibitors with improved cardiac safety profile.

6.
Toxicol Sci ; 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38976649

RESUMO

Within drug development, high off-target promiscuity as well as potent cytotoxicity, are associated with a high attrition rate. We investigated the safety profile of novel plasmepsin X (PMX) inhibitors for the treatment of malaria. In our screening cascade, a total of 249 PMX compounds were profiled in a panel of in vitro secondary pharmacology assays containing 44 targets (SafetyScreen44™ panel) and in a cytotoxicity assay in HepG2 cells using ATP as an endpoint. Six of the lead compounds were subsequently tested in a 7-day rat toxicology study, and/or in a cardiovascular study in guinea pigs. Overall, compounds with high cytotoxicity in HepG2 cells correlated with high promiscuity (off-target hit rate >20%) in the SafetyScreen44™ panel and were associated with poor tolerability in vivo (decedents, morbidity, adverse clinical signs, or severe cardiovascular effects). Some side effects observed in rats or guinea pigs could putatively be linked with hits in the secondary pharmacological profiling, such as the M1 or M2 muscarinic acetylcholine receptor, opioid µ and/or κreceptors or hERG/CaV1.2/Na+ channels, which were common to > 50% the compounds tested in vivo. In summary, compounds showing high cytotoxicity and high promiscuity are likely to be poorly tolerated in vivo. However, such associations do not necessarily imply a causal relationship. Identifying the targets that cause these undesirable effects is key for early safety risk assessment. A tiered approach, based on a set of in vitro assays, helps selecting the compounds with highest likelihood of success to proceed to in vivo toxicology studies.

7.
bioRxiv ; 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38979212

RESUMO

Cognitive neuroscience has advanced significantly due to the availability of openly shared datasets. Large sample sizes, large amounts of data per person, and diversity in tasks and data types are all desirable, but are difficult to achieve in a single dataset. Here, we present an open dataset with N = 101 participants and 6 hours of scanning per participant, with 6 multifaceted cognitive tasks including 2 hours of naturalistic movie viewing. This datasets' combination of ample sample size, extensive data per participant, more than 600 hours worth of data, and a wide range of experimental conditions - including cognitive, affective, social, and somatic/interoceptive tasks - positions it uniquely for probing important questions in cognitive neuroscience.

8.
Cell Commun Signal ; 22(1): 360, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-38992657

RESUMO

Inhibitory phosphatases, such as the inositol-5-phosphatase SHIP1 could potentially contribute to B-cell acute lymphoblastic leukemia (B-ALL) by raising the threshold for activation of the autoimmunity checkpoint, allowing malignant cells with strong oncogenic B-cell receptor signaling to escape negative selection. Here, we show that SHIP1 is differentially expressed across B-ALL subtypes and that high versus low SHIP1 expression is associated with specific B-ALL subgroups. In particular, we found high SHIP1 expression in both, Philadelphia chromosome (Ph)-positive and ETV6-RUNX1-rearranged B-ALL cells. As demonstrated by targeted knockdown of SHIP1 by RNA interference, proliferation of B-ALL cells in vitro and their tumorigenic spread in vivo depended in part on SHIP1 expression. We investigated the regulation of SHIP1, as an important antagonist of the AKT signaling pathway, by the B-cell-specific transcription factor Ikaros. Targeted restoration of Ikaros and pharmacological inhibition of the antagonistic casein kinase 2, led to a strong reduction in SHIP1 expression and at the same time to a significant inhibition of AKT activation and cell growth. Importantly, the tumor suppressive function of Ikaros was enhanced by a SHIP1-dependent additive effect. Furthermore, our study shows that all three AKT isoforms contribute to the pro-mitogenic and anti-apoptotic signaling in B-ALL cells. Conversely, hyperactivation of a single AKT isoform is sufficient to induce negative selection by increased oxidative stress. In summary, our study demonstrates the regulatory function of Ikaros on SHIP1 expression in B-ALL and highlights the relevance of sustained SHIP1 expression to prevent cells with hyperactivated PI3K/AKT/mTOR signaling from undergoing negative selection.


Assuntos
Linfócitos B , Fator de Transcrição Ikaros , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais , Fator de Transcrição Ikaros/genética , Fator de Transcrição Ikaros/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases/genética , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases/metabolismo , Humanos , Linfócitos B/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Animais , Camundongos
9.
Cells ; 13(13)2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38994986

RESUMO

Biogenic polyamines are ubiquitous compounds. Dysregulation of their metabolism is associated with the development of various pathologies, including cancer, hyperproliferative diseases, and infections. The canonical pathway of polyamine catabolism includes acetylation of spermine and spermidine and subsequent acetylpolyamine oxidase (PAOX)-mediated oxidation of acetylpolyamines (back-conversion) or their direct efflux from the cell. PAOX is considered to catalyze a non-rate-limiting catabolic step. Here, we show that PAOX transcription levels are extremely low in various tumor- and non-tumor cell lines and, in most cases, do not change in response to altered polyamine metabolism. Its enzymatic activity is undetectable in the majority of cell lines except for neuroblastoma and low passage glioblastoma cell lines. Treatment of A549 cells with N1,N11-diethylnorspermine leads to PAOX induction, but its contribution to polyamine catabolism remains moderate. We also describe two alternative enzyme isoforms and show that isoform 4 has diminished oxidase activity and isoform 2 is inactive. PAOX overexpression correlates with the resistance of cancer cells to genotoxic antitumor drugs, indicating that PAOX may be a useful therapeutic target. Finally, PAOX is dispensable for the replication of various viruses. These data suggest that a decrease in polyamine levels is achieved predominantly by the secretion of acetylated spermine and spermidine rather than by back-conversion.


Assuntos
Oxirredutases atuantes sobre Doadores de Grupo CH-NH , Poliaminas , Humanos , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética , Poliaminas/metabolismo , Linhagem Celular Tumoral , Espermina/metabolismo , Espermina/análogos & derivados , Acetilação , Células A549
10.
Artigo em Inglês | MEDLINE | ID: mdl-38996415

RESUMO

ABSTRACT: Battlefield lessons learned are forgotten; the current name for this is the Walker Dip. Blood transfusion and the need for a Department of Defense Blood Program are lessons that have cycled through being learned during wartime, forgotten, and then relearned during the next war. The military will always need a blood program to support combat and contingency operations. Also, blood supply to the battlefield has planning factors that have been consistent over a century. In 2024, it is imperative that we codify these lessons learned. The linchpins of modern combat casualty care are optimal prehospital care, early whole blood transfusion, and forward surgical care. This current opinion comprised of authors from all three military Services, the Joint Trauma System, the Armed Services Blood Program, blood SMEs and the CCC Research Program discuss two vital necessities for a successful military trauma system: (1) the need for an Armed Services Blood Program and (2) Planning factors for current and future deployed military ere is no effective care for wounded soldiers, and by extension there is no effective military medicine.

11.
Aging Cell ; : e14273, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-39001573

RESUMO

The kidney undergoes structural and physiological changes with age, predominantly studied in glomeruli and proximal tubules. However, limited knowledge is available about the impact of aging and anti-aging interventions on distal tubules. In this study, we investigated the effects of cytochrome b5 reductase 3 (CYB5R3) overexpression and/or dietary nicotinamide riboside (NR) supplementation on distal tubule mitochondria. Initially, transcriptomic data were analyzed to evaluate key genes related with distal tubules, CYB5R3, and NAD+ metabolism, showing significant differences between males and females in adult and old mice. Subsequently, our emphasis focused on assessing how these interventions, that have demonstrated the anti-aging potential, influenced structural parameters of distal tubule mitochondria, such as morphology and mass, as well as abundance, distance, and length of mitochondria-endoplasmic reticulum contact sites, employing an electron microscopy approach. Our findings indicate that both interventions have differential effects depending on the age and sex of the mice. Aging resulted in an increase in mitochondrial size and a decrease in mitochondrial abundance in males, while a reduction in abundance, size, and mitochondrial mass was observed in old females when compared with their adult counterparts. Combining both the interventions, CYB5R3 overexpression and dietary NR supplementation mitigated age-related changes; however, these effects were mainly accounted by NR in males and by transgenesis in females. In conclusion, the influence of CYB5R3 overexpression and dietary NR supplementation on distal tubule mitochondria depends on sex, genotype, and diet. This underscores the importance of incorporating these variables in subsequent studies to comprehensively address the multifaceted aspects of aging.

12.
Front Cell Dev Biol ; 12: 1389077, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38946799

RESUMO

The molecular mechanisms that govern the metabolic commitment to reproduction, which often occurs at the expense of somatic reserves, remain poorly understood. We identified the Caenorhabditis elegans F-box protein FBXL-5 as a negative regulator of maternal provisioning of vitellogenin lipoproteins, which mediate the transfer of intestinal lipids to the germline. Mutations in fbxl-5 partially suppress the vitellogenesis defects observed in the heterochronic mutants lin-4 and lin-29, both of which ectopically express fbxl-5 at the adult developmental stage. FBXL-5 functions in the intestine to negatively regulate expression of the vitellogenin genes; and consistently, intestine-specific over-expression of FBXL-5 is sufficient to inhibit vitellogenesis, restrict lipid accumulation, and shorten lifespan. Our epistasis analyses suggest that fbxl-5 functions in concert with cul-6, a cullin gene, and the Skp1-related gene skr-3 to regulate vitellogenesis. Additionally, fbxl-5 acts genetically upstream of rict-1, which encodes the core mTORC2 protein Rictor, to govern vitellogenesis. Together, our results reveal an unexpected role for a SCF ubiquitin-ligase complex in controlling intestinal lipid homeostasis by engaging mTORC2 signaling.

13.
J Environ Health ; 86(6): 8-13, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-39040872

RESUMO

After the hurricanes in 2017 in the U.S. Caribbean, it was essential to rebuild, strengthen, and sustain essential environmental health (EH) services and systems. The National Environmental Health Association, in partnership with the Centers for Disease Control and Prevention, developed an online mentorship program for newly hired and existing EH staff and health department leadership in Caribbean health departments. Participants were provided with both practical and didactic learning and were allowed to evaluate the program. Both mentors and mentees were highly satisfied with the knowledge and skills acquired, and mentees expressed it was relevant to their daily work. Based on the findings, we recommend both an online and a hybrid mentorship program for leadership- and inspector-level workforces in EH and potentially in other fields.

14.
Arch Insect Biochem Physiol ; 116(3): e22135, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39038196

RESUMO

The larvae of Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), the swede midge, targets the meristem of brassica crops where they induce the formation of galls and disrupt seed and vegetable production. Previously, we examined the salivary gland transcriptome of newly-hatched first instar larvae as they penetrated the host and initiated gall formation. Here we examine the salivary gland and midgut transcriptome of third instar larvae and provide evidence for cooperative nutrient acquisition beginning with secretion of enzymes and feeding facilitators followed by gastrointestinal digestion. Sucrose, presumably obtained from the phloem, appeared to be a major nutrient source as several α-glucosidases (sucrases, maltases) and ß-fructofuranosidases (invertases) were identified. Genes encoding ß-fructofuranosidases/invertases were among the most highly expressed in both tissues and represented two distinct gene families that may have originated via horizontal gene transfer from bacteria. The importance of the phloem as a nutrient source is underscored by the expression of genes encoding regucalcin and ARMET (arginine-rich mutated in early stages of tumor) which interfere with calcium signalling and prevent sieve tube occlusion. Lipids, proteins, and starch appear to serve as a secondary nutrient sources. Genes encoding enzymes involved in the detoxification of glucosinolates (myrosinases, arylsulfatases, and glutathione-S-transferases) were expressed indicative of Brassicaceae host specialization. The midgut expressed simple peritrophins and mucins typical of those found in Type II peritrophic matrices, the first such description for a gall midge.


Assuntos
Dípteros , Larva , Glândulas Salivares , Animais , Glândulas Salivares/metabolismo , Glândulas Salivares/enzimologia , Larva/genética , Larva/metabolismo , Larva/crescimento & desenvolvimento , Dípteros/genética , Dípteros/enzimologia , Dípteros/metabolismo , Transcriptoma , Digestão , Genômica , Trato Gastrointestinal/metabolismo , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genética
15.
Int J Clin Pharm ; 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39042353

RESUMO

BACKGROUND: Comprehensive medication management (CMM) programs optimize the effectiveness and safety of patients' medication regimens, but CMM may be underutilized. Whether healthcare claims data can identify patients appropriate for CMM is not well-studied. AIM: Determine the face validity of a claims-based algorithm to prioritize patients who likely need CMM. METHOD: We used claims data to construct patient-level markers of "regimen complexity" and "high-risk for adverse effects," which were combined to define four categories of claims-based CMM-need (very likely, likely, unlikely, very unlikely) among 180 patient records. Three clinicians independently reviewed each record to assess CMM need. We assessed concordance between the claims-based and clinician-review CMM need by calculating percent agreement as well as kappa statistic. RESULTS: Most records identified as 'very likely' (90%) by claims-based markers were identified by clinician-reviewers as needing CMM. Few records within the 'very unlikely' group (5%) were identified by clinician-reviewers as needing CMM. Interrater agreement between CMM-based algorithm and clinician review was moderate in strength (kappa = 0.6, p < 0.001). CONCLUSION: Claims-based pharmacy measures may offer a valid approach to prioritize patients into CMM-need groups. Further testing of this algorithm is needed prior to implementation in clinic settings.

16.
Int J Mol Sci ; 25(13)2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-39000078

RESUMO

The immunogenicity of allogeneic skin fibroblasts in transplantation has been controversial. Whether this controversy comes from a natural heterogeneity among fibroblast subsets or species-specific differences between human and mouse remains to be addressed. In this study, we sought to investigate whether fibroblasts derived from either adult or neonatal human skin tissues could induce different immune responses toward phagocytosis and T cell activation using in vitro co-culture models. Our results indicate that both phagocytosis and T cell proliferation are reduced in the presence of neonatal skin fibroblasts compared to adult skin fibroblasts. We also show that neonatal skin fibroblasts secrete paracrine factors that are responsible for reduced T cell proliferation. In addition, we show that neonatal skin fibroblasts express less class II human leukocyte antigen (HLA) molecules than adult skin fibroblasts after interferon gamma priming, which might also contribute to reduced T cell proliferation. In conclusion, this study supports the use of allogeneic neonatal skin fibroblasts as a readily available cell source for tissue production and transplantation to treat patients with severe injuries.


Assuntos
Proliferação de Células , Fibroblastos , Pele , Linfócitos T , Humanos , Fibroblastos/metabolismo , Fibroblastos/imunologia , Pele/imunologia , Pele/metabolismo , Pele/citologia , Recém-Nascido , Linfócitos T/imunologia , Linfócitos T/metabolismo , Ativação Linfocitária/imunologia , Técnicas de Cocultura , Células Cultivadas , Fagocitose , Adulto , Interferon gama/metabolismo
17.
IEEE Trans Haptics ; PP2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38968017

RESUMO

Restoring tactile feedback in virtual reality can improve user experience and facilitate the feeling of embodiment. Electrotactile stimulation can be an attractive technology in this context as it is compact and allows for high-resolution spatially distributed stimulation. In the present study, a 32-channel tactile glove worn on the fingertips was used to provide tactile sensations during a virtual version of a rubber hand illusion experiment. To assess the benefits of multichannel stimulation, we modulated the spatial extent of feedback and its fidelity. Thirty-six participants performed the experiment in two conditions, in which stimulation was delivered to a single finger or all fingers, and three tactile stimulation types within each condition: no tactile feedback, simple single-point stimulation, and complex sliding stimulation mimicking the movements of the brush. Following each trial, the participants answered a multi-item embodiment questionnaire and reported the proprioceptive drift. The results confirmed that modulating the spatial extent of stimulation, from a single finger to all fingers, was indeed a successful strategy. When stimulating all fingers, tactile stimulation significantly improved all subjective measures compared to receiving no tactile stimulation. However, unexpectedly, the second strategy, that of modulating the fidelity of feedback, was not successful since there was no difference between the simple and complex tactile feedback in any of the measures. The results, therefore, imply that the effects of tactile feedback are better expressed in a more dynamic scenario (i.e., making/breaking contact and delivering stimulation to different body locations), while it still needs to be investigated if further improvements of the complex feedback can make it more effective compared to the simple approach.

18.
bioRxiv ; 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-39005462

RESUMO

Subcortical volumes are a promising source of biomarkers and features in biosignatures, and automated methods facilitate extracting them in large, phenotypically rich datasets. However, while extensive research has verified that the automated methods produce volumes that are similar to those generated by expert annotation, the consistency of methods with each other is understudied. Using data from the UK Biobank, we compare the estimates of subcortical volumes produced by two popular software suites: FSL and FreeSurfer. Although most subcortical volumes exhibit good to excellent consistency across the methods, the tools produce diverging estimates of amygdalar volume. Through simulation, we show that this poor consistency can lead to conflicting results, where one but not the other tool suggests statistical significance, or where both tools suggest a significant relationship but in opposite directions. Considering these issues, we discuss several ways in which care should be taken when reporting on relationships involving amygdalar volume.

20.
Nanoscale ; 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39028306

RESUMO

Macromolecule branching upon polyhedral oligomeric silsesquioxanes (POSS) via "click" chemistry has previously been reported for promoting natural biological responses in vitro, particularly when regarding their demonstrated biocompatibility and structural robustness as potential macromolecule anchoring points. However, "clicking" of large molecules around POSS structures uncovers two main challenges: (1) a synthetic challenge encompassing multi-covalent attachment of macromolecules to a single nanoscale-central position, and (2) purification and separation of fully adorned nanocages from those that are incomplete due to their similar physical characteristics. Here we present peptide decoration to a T8POSS nanocage through the attachment of azido-modified trimers. Triglycine- and trialanine-methyl esters "clicked" to 97% and 92% completion, respectively, resulting in 84% and 68% yields of the fully-adorned octamers. The "clicks" halt within 27-h of the reaction time, and efforts to further increase the octamer yield were of negligible benefit. Exploration of reaction conditions reveals multiple factors preventing full octa-arm modification to all available POSS nanocages, and offers insights into macromolecule attachment between both peptides and small inorganic-organic structures, all of which require consideration for future work of this nature.

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