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Current Biology : CB Aug 2023Statistical inference, the ability to use limited information to draw conclusions about the likelihood of an event, is critical for decision-making during uncertainty....
Statistical inference, the ability to use limited information to draw conclusions about the likelihood of an event, is critical for decision-making during uncertainty. The ability to make statistical inferences was thought to be a uniquely human skill requiring verbal instruction and mathematical reasoning. However, basic inferences have been demonstrated in both preliterate and pre-numerate individuals, as well as non-human primates. More recently, the ability to make statistical inferences has been extended to members outside of the primate lineage in birds. True statistical inference requires subjects use relative rather than absolute frequency of previously experienced events. Here, we show that crows can relate memorized reward probabilities to infer reward-maximizing decisions. Two crows were trained to associate multiple reward probabilities ranging from 10% to 90% to arbitrary stimuli. When later faced with the choice between various stimulus combinations, crows retrieved the reward probabilities associated with individual stimuli from memory and used them to gain maximum reward. The crows showed behavioral distance and size effects when judging reward values, indicating that the crows represented probabilities as abstract magnitudes. When controlling for absolute reward frequency, crows still made reward-maximizing choices, which is the signature of true statistical inference. Our study provides compelling evidence of decision-making by relative reward frequency in a statistical inference task.
Topics: Animals; Humans; Crows; Problem Solving; Behavior, Animal; Uncertainty
PubMed: 37369211
DOI: 10.1016/j.cub.2023.06.023 -
Life Sciences Oct 2023Pregnancy hypertension-induced endothelial dysfunction associated with impairment of nitric oxide (NO) bioavailability and hemodynamic derangements is a challenging for...
AIMS
Pregnancy hypertension-induced endothelial dysfunction associated with impairment of nitric oxide (NO) bioavailability and hemodynamic derangements is a challenging for urgent procedures requiring maternal anesthesia. The volatile anesthetic isoflurane has demonstrated NO-associated protective effects. However, this isoflurane-induced effect is still unclear in pregnancy hypertension. Therefore, the present study examined the potential protective effects of isoflurane anesthesia on endothelial dysfunction and hemodynamic changes induced by hypertensive pregnancy associated with fetal and placental growth restrictions.
MATERIALS AND METHODS
Animals were distributed into four groups: normotensive pregnant rats (Preg), anesthetized pregnant rats (Preg+Iso), hypertensive pregnant rats (HTN-Preg), and anesthetized hypertensive pregnant rats (HTN-Preg+Iso). Systolic and diastolic pressures, mean arterial pressure (MAP), heart rate, fetal and placental weights, vascular contraction, endothelium-derived NO-dependent vasodilation, and NO levels were assessed. The vascular endothelial growth factor (VEGF) levels and endothelial NO synthase (eNOS) Serine (1177) phosphorylation (p-eNOS) expression were also examined.
KEY FINDINGS
Isoflurane produced more expressive hypotensive effects in the HTN-Preg+Iso versus Preg+Iso group, with respective reductions in MAP by 50 ± 13 versus 25 ± 4 mmHg (P < 0.05). Also, HTN-Preg+Iso compared to the HTN-Preg group showed (respectively) preventions against the weight loss of the fetuses (4.0 ± 0.6 versus 2.8 ± 0.6 g, P < 0.05) and placentas (0.37 ± 0.06 versus 0.30 ± 0.06 mg, P < 0.05), hyper-reactive vasocontraction response (1.8 ± 0.4 versus 2.8 ± 0.6 g, P < 0.05), impaired endothelium-derived NO-dependent vasodilation (84 ± 8 versus 50 ± 17 %, P < 0.05), reduced VEGF levels (147 ± 46 versus 25 ± 13 pg/mL, P < 0.05), and decreased p-eNOS expression (0.24 ± 0.07 versus 0.09 ± 0.05 arbitrary units, P < 0.05).
SIGNIFICANCE
Isoflurane anesthesia protects maternal endothelial function in pregnancy hypertension, and possibly endothelium-derived NO is involved.
Topics: Female; Pregnancy; Animals; Rats; Vascular Endothelial Growth Factor A; Isoflurane; Nitric Oxide; Placenta; Anesthesia; Hypertension
PubMed: 37648198
DOI: 10.1016/j.lfs.2023.122039 -
Scientific Reports Nov 2023Our goal was to investigate the effects of head-thorax elevation (HUP) during chest compressions (CC) on lung ventilation. A prospective study was performed on seven...
Our goal was to investigate the effects of head-thorax elevation (HUP) during chest compressions (CC) on lung ventilation. A prospective study was performed on seven human cadavers. Chest was automatically compressed-decompressed in flat position and during progressive HUP from 18 to 35°. Lung ventilation was measured with electrical impedance tomography. In each cadaver, 5 sequences were randomly performed: one without CC at positive end-expiratory pressure (PEEP) 0cmHO, 3 s with CC at PEEP0, 5 or 10cmHO and 1 with CC and an impedance threshold device at PEEP0cmHO. The minimal-to-maximal change in impedance (VT in arbitrary unit a.u.) and the minimal impedance in every breathing cycle (EELI) the) were compared between flat, 18°, and 35° in each sequence by a mixed-effects model. Values are expressed as median (1st-3rd quartiles). With CC, between flat, 18° and 35° VT decreased at each level of PEEP. It was 12416a.u. (10,689; 14,442), 11,239 (7667; 13,292), and 6457 (4631; 9516), respectively, at PEEP0. The same was true with the impedance threshold device. EELI/VT significantly decreased from - 0.30 (- 0.40; - 0.15) before to - 1.13 (- 1.70; - 0.61) after the CC (P = 0.009). With HUP lung ventilation decreased with CC as compared to flat position. CC are associated with decreased in EELI.
Topics: Humans; Prospective Studies; Respiration, Artificial; Positive-Pressure Respiration; Thorax; Electric Impedance; Cadaver; Lung
PubMed: 37989865
DOI: 10.1038/s41598-023-47727-z -
International Journal of Infectious... Oct 2023SARS-CoV-2 remains a global health concern 3 years after its emergence. Safe and effective vaccines mitigate the pandemic impact, but the optimal schedule remains...
Vaccine-induced and hybrid immunity to SARS-CoV-2 after three or four doses of BNT162b2 - results from 22 months follow-up of a healthcare workers cohort, Israel, 2020-2022.
OBJECTIVES
SARS-CoV-2 remains a global health concern 3 years after its emergence. Safe and effective vaccines mitigate the pandemic impact, but the optimal schedule remains unclear, especially in a context where a high proportion of the population is infected.
METHODS
We periodically measured anti-spike SARS-CoV-2 immunoglobulin (Ig)G titers using a quantitative assay in an Israeli healthcare worker cohort who all received at least two BNT162b2 doses and either received further doses and/or were subsequently infected up to 22 months after dose two, and compared geometric mean concentrations according to number of doses received and infection status using analysis of variance.
RESULTS
Among the 993 included participants, infection after dose two led to higher geometric mean concentration IgG titers than a third dose (4285 vs 2845 arbitrary unit/ml 1-2 months after infection/vaccination, P = 0.03). In 16-18 months after dose two, those infected and those who received three or four vaccine doses all had IgG geometric mean concentration levels above 500 arbitrary unit/ml with no significant differences among groups (P = 0.6). IgG levels plateaued 16-22 months after dose two.
CONCLUSION
Three BNT162b2 doses provide long-term immunogenicity comparable to breakthrough infection after dose two. Dose four transiently increases IgG levels and may be especially important for providing additional protection to vulnerable individuals during periods of increased transmission risk.
Topics: Humans; Israel; SARS-CoV-2; BNT162 Vaccine; Follow-Up Studies; COVID-19; Vaccines; Health Personnel; Adaptive Immunity; Immunoglobulin G; Antibodies, Viral
PubMed: 37572957
DOI: 10.1016/j.ijid.2023.08.009 -
Optics Express Nov 2023Metasurfaces have enabled precise electromagnetic (EM) wave manipulation with strong potential to obtain unprecedented functionalities and multifunctional behavior in...
Metasurfaces have enabled precise electromagnetic (EM) wave manipulation with strong potential to obtain unprecedented functionalities and multifunctional behavior in flat optical devices. One promising aspect to achieve multifunction is polarization-dependent metadevices enabled by simultaneous phase control over orthogonally polarized waves. Among these, metasurfaces with geometric phase shows their natural and robust phase control ability over different circularly polarized waves. However, the phase responses under the circularly polarized incidence are locked to be opposite with each other, resulting in limited multifunctionality. In this study, we propose what we believe to be a novel transmission-type microwave metadevice constructed by linear-to-circular metasurface and spin-decoupled metasurface. By endowing independent phase adjustment capability to each unit structure in a spin-decoupled metasurface, the metadevice can reconfigure arbitrary phase wavefronts under orthogonal polarization state incidence, thereby achieving flexible multifunctionality. As a proof-of-concept, the feasibility and reliability of proposed metasurfaces were verified by simulating multifunctional directional deflection, off-axis focusing, and focused vortex beam generation. Finally, the multifunctional manipulation capability of the metadevice is successfully demonstrated by actually measuring the generation of orbital angular momentum modes. This work is expected to drive the application development of metasurface devices in wireless communication.
PubMed: 38041360
DOI: 10.1364/OE.505555 -
Journal, Genetic Engineering &... Nov 2023Factorial design is a simple, yet elegant method to investigate the effect of multiple factors and their interaction on a specific response simultaneously. Hence, this...
BACKGROUND
Factorial design is a simple, yet elegant method to investigate the effect of multiple factors and their interaction on a specific response simultaneously. Hence, this type of study design reaches the best optimization conditions of a process. Although the interaction between the variables is widely prevalent in cell culture procedures, factorial design per se is infrequently utilized in improving cell culture output. Therefore, we aim to optimize the experimental conditions for generating mature bone marrow-derived dendritic cells (BMDCs). Two different variables were investigated, including the concentrations of the inducing factors and the starting density of the bone marrow mononuclear cells. In the current study, we utilized the design of experiments (DoE), a statistical approach, to systematically assess the impact of factors with varying levels on cell culture outcomes. Herein, we apply a two-factor, two-level (2) factorial experiment resulting in four conditions that are run in triplicate. The two variables investigated here are cytokines combinations with two levels, granulocyte-macrophage colony-stimulating factor (GM-CSF) alone or with interleukin-4 (IL4). The other parameter is cell density with two different concentrations, 2 × 10 and 4 × 10 cells/mL. Then, we measured cell viability using the trypan blue exclusion method, and a flow cytometer was used to detect the BMDCs expressing the markers FITC-CD80, CD86, CD83, and CD14. BMDC marker expression levels were calculated using arbitrary units (AU) of the mean fluorescence intensity (MFI).
RESULTS
The current study showed that the highest total viable cells and cells yield obtained were in cell group seeded at 2 × 10 cells/mL and treated with GM-CSF and IL-4. Importantly, the expression of the co-stimulatory molecules CD83 and CD80/CD86 were statistically significant for cell density of 2 × 10 cells/mL (P < 0.01, two-way ANOVA). Bone marrow mononuclear cells seeded at 4 × 10 in the presence of the cytokine mix less efficiently differentiated and matured into BMDCs. Statistical analysis via two-way ANOVA revealed an interaction between cell density and cytokine combinations.
CONCLUSION
The analysis of this study indicates a substantial interaction between cytokines combinations and cell densities on BMDC maturation. However, higher cell density is not associated with optimizing DC maturation. Notably, applying DoE in bioprocess designs increases experimental efficacy and reliability while minimizing experiments, time, and process costs.
PubMed: 38017248
DOI: 10.1186/s43141-023-00597-4 -
BMC Sports Science, Medicine &... Oct 2023Practical blood flow restriction (pBFR) during exercise is a cost-saving alternative to traditional blood flow restriction using pneumatic cuffs, particularly when...
Influence of cuff stiffness on hemodynamics and perceived cuff pressure in the upper extremities in males and females: implications for practical blood flow restriction training.
BACKGROUND
Practical blood flow restriction (pBFR) during exercise is a cost-saving alternative to traditional blood flow restriction using pneumatic cuffs, particularly when exercising in a group setting. Depending on the pBFR technique, several factors (e.g., cuff width, limb circumference) have already been shown to be of importance when applying the pBFR pressure. Given that elastic cuffs are often used for pBFR, the cuff stiffness might be an additional influencing factor. Therefore, the present study compared the acute effects of three elastic cuffs with identical width but different stiffness (high stiffness (HS), medium stiffness (MS), and low stiffness (LS)) on hemodynamic measures and perceived cuff pressure at rest.
METHODS
In a randomized, counter-balanced cross-over study, 36 young and normotensive participants completed three experimental trials. After a 10-min rest period in supine position, the cuff was loosely and proximally applied to the right upper arm. Following baseline data recording, the cuff was successively tightened in 10%-increments with respect to the limb circumference (%overlap) until arterial blood flow was occluded. At baseline and during each %overlap, systolic peak blood flow velocity of the brachial artery, rating of perceived cuff pressure, as well as muscle oxygen saturation and total hemoglobin concentration of the biceps brachii muscle were recorded.
RESULTS
The %overlap required to occlude arterial blood flow was different between the three cuffs (HS: 30.9 ± 3.8%, MS: 43.9 ± 6.1%, LS: 54.5 ± 8.3%). Furthermore, at 30% overlap, systolic peak blood flow velocity was lower when applying the HS (9.0 ± 10.9 cm∙s) compared to MS (48.9 ± 21.9 cm∙s) and LS cuff (62.9 ± 19.1 cm∙s). Rating of perceived cuff pressure at 30% overlap was higher when using the HS (6.5 ± 1.5 arbitrary unit (a.u.)) compared to MS (5.1 ± 1.4 a.u.) and LS cuff (4.9 ± 1.5 a.u.) with no difference between the MS and LS cuff. However, muscle oxygen saturation and total hemoglobin concentration were not different between the three cuffs.
CONCLUSIONS
The present study revealed that the cuff stiffness influenced blood flow velocity and arterial occlusion pressure. Therefore, cuff stiffness seems an important factor for the application of pBFR.
PubMed: 37858237
DOI: 10.1186/s13102-023-00745-w -
Sensors and Actuators. B, Chemical Jul 2023The COVID-19 pandemic has highlighted the need to monitor important correlates of immunity on a population-wide level. To this end, we have developed a competitive assay...
The COVID-19 pandemic has highlighted the need to monitor important correlates of immunity on a population-wide level. To this end, we have developed a competitive assay to assess neutralizing antibody (NAb) titer on the giant magnetoresistive (GMR) biosensor platform. We compared the clinical performance of our biosensor with established techniques such as Ortho's VITROS Anti-SARS-CoV-2 IgG Quantitative Antibody test. Results obtained between the VITROS test and the GMR assay showed correlation ( = -0.93). We then validated the assay with patient plasma samples that had been tested using focus reduction neutralization testing (FRNT). The results obtained from our GMR assay exhibit a previously identified trend of increased NAb titers 2 weeks post-vaccination. We further evaluated NAb titers 6 months post-vaccination and observed waning neutralizing antibody titers over that time in vaccinated patients. In addition, we calibrated our assay to an arbitrary unit (IU/mL) using World Health Organization (WHO) reference plasma provided by the National Institute of Biological Standards and Control (NIBSC). Our biosensor provides highly specific and sensitive results in serum and plasma with analytical, clinical, and point-of-care (POC) applications due to quick turnaround times on samples and the cost-effectiveness of the platform.
PubMed: 37056483
DOI: 10.1016/j.snb.2023.133773 -
Experimental and Clinical... Mar 2024Management of potential organ donors is crucial in the donation process, considering that hemodynamic instability is quite common. (Observational Study)
Observational Study
OBJECTIVES
Management of potential organ donors is crucial in the donation process, considering that hemodynamic instability is quite common.
MATERIALS AND METHODS
In the this single-center retrospective observational study, we analyzed 87 utilized brain death donors consecutively admitted to our intensive care unit from January 1, 2019, to December 31, 2022. We assessed the achievement of donor management goals during the observation period, and we also evaluated whether the achieve-ment of donor goals differed between younger and older donors (arbitrary age cutoff of 65 years).
RESULTS
In our series, mean age of donors was 67 ± 18 y, and organ-per-donor ratio was 2.3. The number of donor goals significantly increased during the 6-hour observation period (P < .001) and all donor goals were achieved in most donors (84/87) at the end of the observation period with no changes in the use and dose of vasoactive drugs. With respect to age, the number of donor goals was significantly higher in older donors at first evaluation, but goals significantly increased in both age subgroups of donors at the end of the 6-hour observation period.
CONCLUSIONS
Our data strongly suggested that a strict hemodynamic monitoring schedule allows the achievement of donor goals both in older and in younger brain death donors. We confirmed our previous findings that hemodynamic management in brain death donors is influenced by age. A strict hemodynamic monitoring schedule of brain death donors is useful to consistently achieve donor goals.
Topics: Humans; Brain Death; Retrospective Studies; Middle Aged; Male; Female; Tissue Donors; Aged; Time Factors; Age Factors; Hemodynamics; Adult; Aged, 80 and over; Donor Selection; Risk Factors
PubMed: 38695586
DOI: 10.6002/ect.2024.0030 -
Sports Medicine (Auckland, N.Z.) Feb 2024Publication bias refers to a systematic deviation from the truth in the results of a meta-analysis due to the higher likelihood for published studies to be included in... (Meta-Analysis)
Meta-Analysis Review
Publication bias refers to a systematic deviation from the truth in the results of a meta-analysis due to the higher likelihood for published studies to be included in meta-analyses than unpublished studies. Publication bias can lead to misleading recommendations for decision and policy making. In this education review, we introduce, explain, and provide solutions to the pervasive misuses and misinterpretations of publication bias that afflict evidence syntheses in sport and exercise medicine, with a focus on the commonly used funnel-plot based methods. Publication bias is more routinely assessed by visually inspecting funnel plot asymmetry, although it has been consistently deemed unreliable, leading to the development of statistical tests to assess publication bias. However, most statistical tests of publication bias (i) cannot rule out alternative explanations for funnel plot asymmetry (e.g., between-study heterogeneity, choice of metric, chance) and (ii) are grossly underpowered, even when using an arbitrary minimum threshold of ten or more studies. We performed a cross-sectional meta-research investigation of how publication bias was assessed in systematic reviews with meta-analyses published in the top two sport and exercise medicine journals throughout 2021. This analysis highlights that publication bias is frequently misused and misinterpreted, even in top tier journals. Because of conceptual and methodological problems when assessing and interpreting publication bias, preventive strategies (e.g., pre-registration, registered reports, disclosing protocol deviations, and reporting all study findings regardless of direction or magnitude) offer the best and most efficient solution to mitigate the misuse and misinterpretation of publication bias. Because true publication bias is very difficult to determine, we recommend that future publications use the term "risk of publication bias".
Topics: Humans; Publication Bias; Cross-Sectional Studies; Systematic Reviews as Topic; Bias
PubMed: 37684502
DOI: 10.1007/s40279-023-01927-9