Associations of region-specific foot pain and foot biomechanics: the framingham foot study

BACKGROUND. Specific regions of the foot are responsible for the gait tasks of weight acceptance, single-limb support, and forward propulsion. With region foot pain, gait abnormalities may arise and affect the plantar pressure and force pattern utilized. Therefore, this study’s purpose was to evaluate plantar pressure and force pattern differences between adults with and without region-specific foot pain. METHODS. Plantar pressure and force data were collected on Framingham Foot Study members while walking barefoot at a self-selected pace. Foot pain was evaluated by self-report and grouped by foot region (toe, forefoot, midfoot, or rearfoot) or regions (two or three or more regions) of pain. Unadjusted and adjusted linear regression with generalized estimating equations was used to determine associations between feet with and without foot pain. RESULTS. Individuals with distal foot (forefoot or toes) pain had similar maximum vertical forces under the pain region, while those with proximal foot (rearfoot or midfoot) pain had different maximum vertical forces compared to those without regional foot pain (referent). During walking, there were significant differences in plantar loading and propulsion ranging from 2% to 4% between those with and without regional foot pain. Significant differences in normalized maximum vertical force and plantar pressure ranged from 5.3% to 12.4% and 3.4% to 24.1%, respectively, between those with and without regional foot pain. CONCLUSIONS. Associations of regional foot pain with plantar pressure and force were different by regions of pain. Region-specific foot pain was not uniformly associated with an increase or decrease in loading and pressure patterns regions of pain

The Hagedorn spectrum and large NcN_c QCD in 2+1 and 3+1 dimensions

We show that a Hagedorn spectrum (i.e., spectrum where the number of hadrons grows exponentially with the mass) emerges automatically in large $N_c$ QCD in 2+1 and 3+1 dimensions. The approach is based on the study of Euclidean space correlation functions for composite operators constructed from quark and gluon fields and exploits the fact that the short time behavior of the correlators is known in QCD. The demonstration relies on one critical assumption: that perturbation theory accurately describes the trace of the logarithm of a matrix of point-to-point correlation functions in the regime where the perturbative corrections to the asymptotically free value are small.Comment: 18 pages, 5 figure

Hallux valgus and plantar pressure loading: the Framingham foot study

Background: Hallux valgus (HV), a common structural foot deformity, can cause foot pain and lead to limited mobility. The purpose of this study was to evaluate differences in plantar pressure and force during gait by HV status in a large population-based cohort of men and women. Methods: A trained examiner performed a validated physical examination on participants’ feet and recorded the presence of hallux valgus and other specific foot disorders. Each foot was classified into one of four mutually exclusive groups based on the foot examination. Foot groups were: (i) HV only, (ii) HV and at least one additional foot disorder (FD), (iii) no HV but at least one other FD, and (iv) neither HV nor FD (referent). Biomechanical data for both feet were collected using Tekscan Matscan. Foot posture during quiet standing, using modified arch index (MAI), and foot function during gait, using center of pressure excursion index (CPEI), were calculated per foot. Further, walking scans were masked into eight sub-regions using Novel Automask, and peak pressure and maximum force exerted in each region were calculated. Results: There were 3205 participants, contributing 6393 feet with complete foot exam data and valid biomechanical measurements. Participants with HV had lower hallucal loading and higher forces at lesser toes as well as higher MAI and lower CPEI values compared to the referent. Participants with HV and other FDs were also noted to have aberrant rearfoot forces and pressures. Conclusions: These results suggest that HV alters foot loading patterns and pressure profiles. Future work should investigate how these changes affect the risk of other foot and lower extremity ailments

Factors affecting center of pressure in older adults: the Framingham Foot Study

Background: Although aberrant foot movement during gait has been associated with adverse outcomes in the lower extremities in clinical patients, few studies have analyzed population differences in foot function. The purpose of this study was to assess demographic differences in foot function in a large population-based study of community-dwelling adults. Methods: Participants in this study were from the Framingham Foot Study. Walking data were collected from both feet using a Tekscan Matscan pressure mat. Foot function was characterized using the center of pressure excursion index (CPEI). T-tests were used to assess differences between population subsets based on sex, and in men and women separately, age, body mass index (BMI), physical activity and in women, past high heel use. Results: There were 2111 participants included in this analysis. Significant differences in CPEI were noted by sex (p< 0.0001), by age in women (p = 0.04), and by past high heel use in women (p = 0.04). Conclusions: Foot function during gait was affected by sex, as well as by age and shoe-wear in women, but not by BMI or physical activity. Future work will evaluate possible relations between CPEI and outcomes such as falls, sarcopenia, and lower extremity function

The associations of leg lean mass with foot pain, posture and function in the Framingham foot study

Background: Foot disorders are common in older adults and associated with impaired lower extremity function. Reduced muscle mass may play a role in the etiology of foot disorders and consequent poor function. Methods: We examined the association of leg lean mass with foot pain, posture and function among 1,795 individuals (mean age 67 years) from the population-based Framingham Foot Study (2002–2008). Pain was assessed via questionnaire, and a pressure mat classified foot posture (arch: high, low, referent) during standing and function (pronation, supination, referent) during gait. Leg lean mass was measured by whole body dual energy x-ray absorptiometry. Results: In age- and body mass index-adjusted logistic (pain) and multinomial logistic (posture, function) regression models, a 1-standard deviation increase in leg lean mass was associated with lower odds of foot pain (OR = 0.76, 95% CI: 0.68, 0.86) and pronation (OR = 0.76, 95% CI: 0.67, 0.85), and higher odds of supination (OR = 1.17, 95% CI: 1.04, 1.31). Adjustment for sex attenuated these associations. Higher leg lean mass was associated with lower odds of high arch, even after adjustment for sex (OR = 0.73, 95% CI: 0.60, 0.89). Conclusions: Though not related to foot pain or function, reduced leg lean mass was associated with extreme foot posture in older adults. Loss of muscle mass with aging may thus play a role in the etiology of functional impairment due to foot disorders

Foot Disorders, Foot Posture, and Foot Function: The Framingham Foot Study

Introduction: Foot disorders are common among older adults and may lead to outcomes such as falls and functional limitation. However, the associations of foot posture and foot function to specific foot disorders at the population level remain poorly understood. The purpose of this study was to assess the relation between specific foot disorders, foot posture, and foot function. Methods: Participants were from the population-based Framingham Foot Study. Quintiles of the modified arch index and center of pressure excursion index from plantar pressure scans were used to create foot posture and function subgroups. Adjusted odds ratios of having each specific disorder were calculated for foot posture and function subgroups relative to a referent 3 quintiles. Results: Pes planus foot posture was associated with increased odds of hammer toes and overlapping toes. Cavus foot posture was not associated with the foot disorders evaluated. Odds of having hallux valgus and overlapping toes were significantly increased in those with pronated foot function, while odds of hallux valgus and hallux rigidus were significantly decreased in those with supinated function. Conclusions: Foot posture and foot function were associated with the presence of specific foot disorders

The Minimal Phantom Sector of the Standard Model: Higgs Phenomenology and Dirac Leptogenesis

We propose the minimal, lepton-number conserving, SU(3)xSU(2)xU(1) gauge-singlet, or phantom, extension of the Standard Model. The extension is natural in the sense that all couplings are of O(1) or forbidden due to a phantom sector global U(1)_D symmetry, and basically imitates the standard Majorana see-saw mechanism. Spontaneous breaking of the U(1)_D symmetry triggers consistent electroweak gauge symmetry breaking only if it occurs at a scale compatible with small Dirac neutrino masses and baryogenesis through Dirac leptogenesis. Dirac leptogenesis proceeds through the usual out-of-equilibrium decay scenario, leading to left and right-handed neutrino asymmetries that do not fully equilibrate after they are produced. The model contains two physical Higgs bosons and a massless Goldstone boson. The existence of the Goldstone boson suppresses the Higgs to bb branching ratio and instead the Higgs bosons will mainly decay to invisible Goldstone and/or to visible vector boson pairs. In a representative scenario, we estimate that with 30 fb^-1 integrated luminosity, the LHC could discover this invisibly decaying Higgs, with mass ~120 GeV. At the same time a significantly heavier, partner Higgs boson with mass ~210 GeV could be found through its vector boson decays. Electroweak constraints as well as astrophysical and cosmological implications are analysed and discussed.Comment: 21 pages, 4 figures. Corrected typos and added references. To appear in JHE

Factors affecting center of pressure in older adults: the Framingham Foot Study

Abstract Background Although aberrant foot movement during gait has been associated with adverse outcomes in the lower extremities in clinical patients, few studies have analyzed population differences in foot function. The purpose of this study was to assess demographic differences in foot function in a large population-based study of community-dwelling adults. Methods Participants in this study were from the Framingham Foot Study. Walking data were collected from both feet using a Tekscan Matscan pressure mat. Foot function was characterized using the center of pressure excursion index (CPEI). T-tests were used to assess differences between population subsets based on sex, and in men and women separately, age, body mass index (BMI), physical activity and in women, past high heel use. Results There were 2111 participants included in this analysis. Significant differences in CPEI were noted by sex (p< 0.0001), by age in women (p = 0.04), and by past high heel use in women (p = 0.04). Conclusions Foot function during gait was affected by sex, as well as by age and shoe-wear in women, but not by BMI or physical activity. Future work will evaluate possible relations between CPEI and outcomes such as falls, sarcopenia, and lower extremity function

QCD and the Hagedorn spectrum

It is shown that large Nc QCD must have a Hagedorn spectrum (i.e. a spectrum of hadron which grows exponentially with the hadrons mass) provided that certain technical assumptions concerning the applicability of perturbation theory to a certain class of correlation functions apply. The basic argument exploits the interplay of confinement and asymptotic freedom.Comment: 16 pages, 1 figure. This version is expanded from the original version. Additional discussion has been added to clarify the central issues. Typos have been fixed. The appendix has been updated and greatly expanded

The interaction between a sexually transferred steroid hormone and a female protein regulates oogenesis in the malaria mosquito anopheles gambiae

Molecular interactions between male and female factors during mating profoundly affect the reproductive behavior and physiology of female insects. In natural populations of the malaria mosquito Anopheles gambiae, blood-fed females direct nutritional resources towards oogenesis only when inseminated. Here we show that the mating-dependent pathway of egg development in these mosquitoes is regulated by the interaction between the steroid hormone 20-hydroxy-ecdysone (20E) transferred by males during copulation and a female Mating-Induced Stimulator of Oogenesis (MISO) protein. RNAi silencing of MISO abolishes the increase in oogenesis caused by mating in blood-fed females, causes a delay in oocyte development, and impairs the function of male-transferred 20E. Co-immunoprecipitation experiments show that MISO and 20E interact in the female reproductive tract. Moreover MISO expression after mating is induced by 20E via the Ecdysone Receptor, demonstrating a close cooperation between the two factors. Male-transferred 20E therefore acts as a mating signal that females translate into an increased investment in egg development via a MISO-dependent pathway. The identification of this male–female reproductive interaction offers novel opportunities for the control of mosquito populations that transmit malaria