Characterization of posture and comfort in laptop users in non-desk settings

Laptop computers may be used in a variety of postures not coupled to the office workstation. Using passive motion analysis, this study examined mean joint angles during a short typing/editing task in college students (n=20), in up to seven positions. Comfort was assessed after task execution through a body map. For three required postures, joint angles in a prone posture were different than those while seated at a couch with feet either on floor or on ottoman. Specifically, the prone posture was characterized by comparatively non-neutral shoulders, elbows and wrists, and pronounced neck extension. Significantly greater intensity and more regions of discomfort were marked for the prone posture than for the seated postures. It is recommended that the prone posture only be assumed briefly during laptop use. Exposure to laptops outside of the office setting should be assessed in future epidemiologic studies of musculoskeletal complaints and computer use.     

Simultaneous eigenvalue lower bounds for the Riccati matrixequation

The author derives n simultaneous lower bounds on the sums of the eigenvalues of the solution of the algebraic Riccati equation and of the Lyapunov matrix equation. These bounds extend the single inequalities shown in the literature for the trace and for the maximum eigenvalue. Two inequality versions are derived and evaluated for application purposes, and a comparison to relevant bounds in the literature is given     

Upper summation and product bounds for solution eigenvalues of theLyapunov matrix equation

Upper bounds for summations including the trace, and for products including the determinant, of the eigenvalues of the solution of the continuous algebraic Lyapunov matrix equation are presented. The majority of the bounds are tighter than those in the literature, and some are new     

Upper bounds for the eigenvalues of the solution of the Lyapunovmatrix equation

Eigenvalue upper bounds for the solution of the Lyapunov matrix equation are presented for single eigenvalues, summations of eigenvalues including the trace, and products of eigenvalues including the determinant. These bounds are compared to those for the trace and the extreme eigenvalues     

Simultaneous eigenvalue lower bounds for the Lyapunov matrixequation

Simultaneous eigenvalue lower bounds for the solution of the Lyapunov equation are presented. The n-summation and the n -product bounds generalize existing bounds such as those for the trace and the determinant. These bounds are stronger than the majority of the relevant bounds shown in the literature     

Metabolomic Evidence for Peroxisomal Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic and debilitating disease characterized by unexplained physical fatigue, cognitive and sensory dysfunction, sleeping disturbances, orthostatic intolerance, and gastrointestinal problems. People with ME/CFS often report a prodrome consistent with infections. Using regression, Bayesian and enrichment analyses, we conducted targeted and untargeted metabolomic analysis of plasma from 106 ME/CFS cases and 91 frequency-matched healthy controls. Subjects in the ME/CFS group had significantly decreased levels of plasmalogens and phospholipid ethers (p < 0.001), phosphatidylcholines (p < 0.001) and sphingomyelins (p < 0.001), and elevated levels of dicarboxylic acids (p = 0.013). Using machine learning algorithms, we were able to differentiate ME/CFS or subgroups of ME/CFS from controls with area under the receiver operating characteristic curve (AUC) values up to 0.873. Our findings provide the first metabolomic evidence of peroxisomal dysfunction, and are consistent with dysregulation of lipid remodeling and the tricarboxylic acid cycle. These findings, if validated in other cohorts, could provide new insights into the pathogenesis of ME/CFS and highlight the potential use of the plasma metabolome as a source of biomarkers for the disease.     

A 56-year-old woman with chronic fatigue syndrome

The IgG and secretory IgA (S-IgA) responses to the HIV-1 envelope (gp160 antigen) were analyzed in the colostrum (Col) and in the cervicovaginal fluid (CVF) of HIV-l-infected women. We show IgG antibodies (Abs) to the recombinant gp160 to be predominant as compared with the corresponding S-IgA isotype. The low level of the S-IgA response cannot be related to a general disturbance of the mucosal-associated Iymphoid tissue (MALT) because the level of a current Ab to a caries-associated antigen from Streptococcus sobrinus was in the normal range in these secretions. The major subclass of IgA to gp160 was of the alpha1 isotype both in Col and in CVF. However, the specific activities of S-IgA1 and S-IgA2 were different when expressed as the ratio of the anti-gp160 related to total Ig of each subclass. Indeed, the specific activity of the S-IgA2 was predominant over S-IgA1 in the Col, whereas the reciprocal results were found in CVF, showing a subcompartmentalization of these secretions. The ability of S-IgA and IgG to block one of the pathways involved in the HIV-1 penetration across mucosa, i.e., transcytosis through epithelial cells, was evaluated using a functional in vitro assay. Both S-IgA and IgG Abs impaired virus transcytosis, irrespective of the level of antigp160 specific activities. However, specific S-IgA was more efficient than IgG. These features suggest that mucosal specific S-IgA to HIV-1 could be relevant in decreasing infectivity of HIV-1 in corporal fluids.     

Aids to the Delivery of Ambulatory Medical Care

A large fraction of medical care is delivered in ambulatory settings. It is a hypothesis of this program that a significant fraction of physician-patient encounters can be safely managed by paramedics with no past medical experience and with a minimum of training (about four weeks), operating under well-defined guidance protocols. The paramedic using the protocols can either substitute for the physician on any given visit, or can perform a substantial prephysician workup, thus saving physician time and enhancing the thoroughness of the patient evaluation.     

Diverse bounds for the eigenvalues of the continuous algebraicRiccati equation

Summation bounds for the eigenvalues of A'P+PA are presented. Here matrices A,P∈R^n×n, P is positive definite and A'=transpose of A. These bounds are employed to derive new upper bounds for summations of eigenvalues of the solution of the continuous algebraic Riccati equation