Comparative Power Of The Anova, Randomization Anova, And Kruskal-Wallis Test

The t test has been suggested to be robust to departures from normality as long as group sizes are equal and samples approach 30 or more. The F statistic has also been proposed to have the same robust qualities as the t, though researchers have suggested that because a test is robust to departures from normality, that does not necessarily make it the best test for every situation. With the increase in computing capabilities, the permutation ANOVA has been explored as an alternative to the ANOVA under non-normal conditions to rehabilitate the loss of statistical power. Since the permutation ANOVA does not operate under the assumption of normality and uses actual scores, many researchers suggest that the permutation ANOVA is superior to rank tests such as the Kruskal-Wallis because ranking data disposes of valuable information. To compare the power of the ANOVA, randomization ANOVA, and the Kruskal-Wallis test, the researcher performed a Monte Carlo analysis on group sizes of n=10 to n=30 and groups of k=3 and k=5 using Fortran program language and the IMSL subroutine library. In 12 different treatment conditions, the researcher implemented equal treatment effect sizes of small (0.1 sd) to huge (1.0 sd) on each treatment group in graduated increments, until all but one group had received a treatment. Data were drawn from three theoretical distributions: the normal (Gaussian) distribution, the uniform distribution, and the chi-square (df=2) distribution. Results indicated that regardless of the number of treatment groups, the ANOVA and randomization ANOVA exhibited almost equal power under every distribution and effect size. The power of the Kruskal-Wallis was slightly less than the ANOVA and randomization ANOVA under the normal and uniform condition, and was significantly more powerful under the chi-square (df=2) distribution. The sample size and treatment effect had little to do with the relationship between the performances of the three tests but did affect the rate of power increase and maximum power achieved. Implications of the findings as well the contribution to existing literature is discussed

Effects of Carpal Tunnel Syndrome on Dexterous Manipulation Are Grip Type-Dependent

Carpal tunnel syndrome (CTS) impairs sensation of a subset of digits. Although the effects of CTS on manipulation performed with CTS-affected digits have been studied using precision grip tasks, the extent to which CTS affects multi-digit force coordination has only recently been studied. Whole-hand manipulation studies have shown that CTS patients retain the ability to modulate multi-digit forces to object mass, mass distribution, and texture. However, CTS results in sensorimotor deficits relative to healthy controls, including significantly larger grip force and lower ability to balance the torques generated by the digits. Here we investigated the effects of CTS on multi-digit force modulation to object weight when manipulating an object with a variable number of fingers. We hypothesized that CTS patients would be able to modulate digit forces to object weight. However, as different grip types involve the exclusive use of CTS-affected digits (‘uniform’ grips) or a combination of CTS-affected and non-affected digits (‘mixed’ grips), we addressed the question of whether ‘mixed’ grips would reduce or worsen CTS-induced force coordination deficits. The former scenario would be due to adding digits with intact tactile feedback, whereas the latter scenario might occur due to a potentially greater challenge for the central nervous system of integrating ‘noisy’ and intact tactile feedback. CTS patients learned multi-digit force modulation to object weight regardless of grip type. Although controls exerted the same total grip force across all grip types, patients exerted significantly larger grip force than controls but only for manipulations with four and five digits. Importantly, this effect was due to CTS patients’ inability to change the finger force distribution when adding the ring and little fingers. These findings suggest that CTS primarily challenges sensorimotor integration processes for dexterous manipulation underlying the coordination of CTS-affected and non-affected digits

Effects of Carpal Tunnel Syndrome on adaptation of multi-digit forces to object mass distribution for whole-hand manipulation

Background Carpal tunnel syndrome (CTS) is a compression neuropathy of the median nerve that results in sensorimotor deficits in the hand. Until recently, the effects of CTS on hand function have been studied using mostly two-digit grip tasks. The purpose of this study was to investigate the coordination of multi-digit forces as a function of object center of mass (CM) during whole-hand grasping. Methods Fourteen CTS patients and age- and gender-matched controls were instructed to grasp, lift, hold, and release a grip device with five digits for seven consecutive lifts while maintaining its vertical orientation. The object CM was changed by adding a mass at different locations at the base of the object. We measured forces and torques exerted by each digit and object kinematics and analyzed modulation of these variables to object CM at object lift onset and during object hold. Our task requires a modulation of digit forces at and after object lift onset to generate a compensatory moment to counteract the external moment caused by the added mass and to minimize object tilt. Results We found that CTS patients learned to generate a compensatory moment and minimized object roll to the same extent as controls. However, controls fully exploited the available degrees of freedom (DoF) in coordinating their multi-digit forces to generate a compensatory moment, i.e., digit normal forces, tangential forces, and the net center of pressure on the finger side of the device at object lift onset and during object hold. In contrast, patients modulated only one of these DoFs (the net center of pressure) to object CM by modulating individual normal forces at object lift onset. During object hold, however, CTS patients were able to modulate digit tangential force distribution to object CM. Conclusions Our findings suggest that, although CTS did not affect patients’ ability to perform our manipulation task, it interfered with the modulation of specific grasp control variables. This phenomenon might be indicative of a lower degree of flexibility of the sensorimotor system in CTS to adapt to grasp task conditions

Effects of Carpal Tunnel Syndrome on Adaptation of Multi-Digit Forces to Object Weight for Whole-Hand Manipulation

The delicate tuning of digit forces to object properties can be disrupted by a number of neurological and musculoskeletal diseases. One such condition is Carpal Tunnel Syndrome (CTS), a compression neuropathy of the median nerve that causes sensory and motor deficits in a subset of digits in the hand. Whereas the effects of CTS on median nerve physiology are well understood, the extent to which it affects whole-hand manipulation remains to be addressed. CTS affects only the lateral three and a half digits, which raises the question of how the central nervous system integrates sensory feedback from affected and unaffected digits to plan and execute whole-hand object manipulation. We addressed this question by asking CTS patients and healthy controls to grasp, lift, and hold a grip device (445, 545, or 745 g) for several consecutive trials. We found that CTS patients were able to successfully adapt grip force to object weight. However, multi-digit force coordination in patients was characterized by lower discrimination of force modulation to lighter object weights, higher across-trial digit force variability, the consistent use of excessively large digit forces across consecutive trials, and a lower ability to minimize net moments on the object. Importantly, the mechanical requirement of attaining equilibrium of forces and torques caused CTS patients to exert excessive forces at both CTS-affected digits and digits with intact sensorimotor capabilities. These findings suggest that CTS-induced deficits in tactile sensitivity interfere with the formation of accurate sensorimotor memories of previous manipulations. Consequently, CTS patients use compensatory strategies to maximize grasp stability at the expense of exerting consistently larger multi-digit forces than controls. These behavioral deficits might be particularly detrimental for tasks that require fine regulation of fingertip forces for manipulating light or fragile objects

The impact of patterns in linkage disequilibrium and sequencing quality on the imprint of balancing selection

Regions under balancing selection are characterized by dense polymorphisms and multiple persistent haplotypes, along with other sequence complexities. Successful identification of these patterns depends on both the statistical approach and the quality of sequencing. To address this challenge, at first, a new statistical method called LD-ABF was developed, employing efficient Bayesian techniques to effectively test for balancing selection. LD-ABF demonstrated the most robust detection of selection in a variety of simulation scenarios, compared against a range of existing tests/tools (Tajima\u27s D, HKA, Dng, BetaScan, and BalLerMix). Furthermore, the impact of the quality of sequencing on detection of balancing selection was explored, as well, using: (i) SNP genotyping and exome data, (ii) targeted high-resolution HLA genotyping (IHIW), and (iii) whole-genome long-read sequencing data (Pangenome). In the analysis of SNP genotyping and exome data, we identified known targets and 38 new selection signatures in genes not previously linked to balancing selection. To further investigate the impact of sequencing quality on detection of balancing selection, a detailed investigation of the MHC was performed with high-resolution HLA typing data. Higher quality sequencing revealed the HLA-DQ genes consistently demonstrated strong selection signatures otherwise not observed from the sparser SNP array and exome data. The HLA-DQ selection signature was also replicated in the Pangenome samples using considerably less samples but, with high-quality long-read sequence data. The improved statistical method, coupled with higher quality sequencing, leads to more consistent identification of selection and enhanced localization of variants under selection, particularly in complex regions

Genetic Engineering of Amphiphilic Intrinsically Disordered Proteins

Due to the widespread use of surfactants, there have been renewed efforts to develop bio-derived and bio-degradable alternatives. However, the large-scale production of designer bio-surfactants for medical or environmental purposes remains a challenge regarding economic viability compared to their synthetic counterparts. This work shows that the previously studied and characterized intrinsically disordered protein (IDP) that was genetically modified to self-assemble into micelles (IDP-2Yx2A) has promise to be used as a vehicle for traditionally unusable hydrophobic drugs for\textit{ in vivo }delivery to mice. Additionally, this work created a scalable and versatile production method for these amphiphilic proteins and has allowed for the development of different iterations and mutant sequences that were easily attained. The protein sequence was separated and explored by its two opposing hydrophilic and hydrophobic domains. Variants with increased overall charges and systematically decreased hydrophilic domain lengths were produced and examined for their sizes, morphologies, and critical micelle concentrations (CMCs). Additionally, to explore the role of the hydrophobic domain on self-assembly properties, we developed a bioconjugation method to attach N-terminal cysteine peptides of varying hydrophobicities to the C-terminal tyrosine residue of the hydrophilic domain. This represents a facile method for creating a large number of hydrophobic library members to be screened as IDP-based bio-surfactants

Preparation of Bioderived and Biodegradable Surfactants Based on an Intrinsically Disordered Protein Sequence

Surfactants, block-copolymers, and other types of micellar systems are used in a wide variety of biomedical and industrial processes. However, most commonly used surfactants are synthetically derived and pose environmental and toxicological concerns throughout their product life cycle. Because of this, bio-derived and bio-degradable surfactants are promising alternatives. For bio-surfactants to be implemented industrially, they need to be produced on a large scale and also have tailorable properties that match those afforded by the polymerization of synthetic surfactants. In this paper, a scalable and versatile production method for bio-surfactants based on a hydrophilic intrinsically disordered protein (IDP) sequence with a genetically engineered hydrophobic domain is used to study variables that impact their physicochemical and self-assembling properties. These amphiphilic sequences were found to self-assemble into micelles over a broad range of temperatures, pH values, and ionic strengths. To investigate the role of the IDP hydrophilic domain on self-assembly, variants with increased overall charges and systematically decreased IDP domain lengths were produced and examined for their sizes, morphologies, and critical micelle concentrations (CMCs). The results of these studies indicate that decreasing the length of the IDP domain and, consequently, the molecular weight and hydrophilic fraction, leads to smaller micelles. Additionally, significantly increasing the amount of charged residues in the hydrophilic IDP domain results in micelles of similar sizes, but with higher CMC values. This represents an initial step in developing a quantitative model for the future engineering of bio-surfactants based on this IDP sequence

Dismissing chronic illness: a qualitative analysis of negative healthcare experiences

In the US, medical training is inadequate regarding the symptomatology, prognosis, and treatment for myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). As a result, many physicians lack the appropriate level of knowledge about effective methods for ME and CFS symptom reduction and often suggest inappropriate treatments, such as increased exercise or psychiatric services. The authors’ purpose in this study was to analyze negative patient experiences with health care professionals. Patients with ME and CFS who reported experiencing a dismissive physician attitude were asked to detail the encounter via open-ended response on an international, online survey. Participant responses were thematically coded and analyzed using processes outlined by Patton. Emergent themes related to perceived physician attitudes and how they impact patient wellbeing are described and their implications discussed. Additionally, we highlight suggestions for how the health care system can effectively approach this often marginalized patient group