Is Desmin Propensity to Aggregate Part of its Protective Function?

Desmin is the major protein component of the intermediate filaments (IFs) cytoskeleton in muscle cells, including cardiac. The accumulation of cleaved and misfolded desmin is a cellular hallmark of heart failure (HF). These desmin alterations are reversed by therapy, suggesting a causal role for the IFs in the development of HF. Though IFs are known to play a role in the protection from stress, a mechanistic model of how that occurs is currently lacking. On the other hand, the heart is uniquely suited to study the function of the IFs, due to its inherent, cyclic contraction. That is, HF can be used as a model to address how IFs afford protection from mechanical, and possibly redox, stress. In this review we provide a brief summary of the current views on the function of the IFs, focusing on desmin. We also propose a new model according to which the propensity of desmin to aggregate may have been selected during evolution as a way to dissipate excessive mechanical and possibly redox stress. According to this model, though desmin misfolding may afford protection from acute injury, the sustained or excessive accumulation of desmin aggregates could impair proteostasis and contribute to disease

Optical pumping of a single hole spin in a p-doped quantum dot coupled to a metallic nanoparticle

The preparation of quantum states with a defined spin is analyzed in a hybrid system consisting of a p-doped semiconductor quantum dot (QD) coupled to a metallic nanoparticle. The quantum dot is described as a four-level atom-like system using the density matrix formalism. The lower levels are Zeeman-split hole spin states and the upper levels correspond to positively charged excitons containing a spin-up, spin-down hole pair and a spin electron. A metallic nanoparticle with spheroidal geometry is placed in close proximity to the quantum dot, and its effects are considered in the quasistatic approximation. A linearly polarized laser field drives two of the optical transitions of the QD and produces localized surface plasmons in the nanoparticle which act back upon the QD. The frequencies of these localized plasmons are very different along the two principal axes of the nanoparticle, thus producing an anisotropic modification of the spontaneous emission rates of the allowed optical transitions which is accompanied by local-field corrections. This effect translates into a preferential acceleration of some of the optical pathways and therefore into a fast initialization of the QD by excitation with a short optical pulse. The population transfer between the lower levels of the QD and the fidelity is analyzed as a function of the nanoparticle's aspect ratio, the external magnetic field, and the Rabi frequency of the driving field. It is also shown that the main effect of the local-field corrections is a lengthening of the time elapsed to reach the steady-state. The hole spin is predicted to be successfully cooled from 5 to 0.04 K at a magnetic field of 4.6 T applied in the Voigt geometry

Plasmonic effects in excitonic population transfer in a driven semiconductor–metal nanoparticle hybrid system

We have investigated the coherent transfer of excitonic populations in a semiconductor quantum dot (SQD) modulated by the surface plasmon of a metallic nanoparticle (MNP). The SQD is considered as a three-level V-type atomic system. We applied a transform-limited laser pulse field resonant with the upper atomic levels of the SQD. When the SQD is close enough to the MNP, the otherwise equally populated atomic levels can be selectively excited. Selectivity population can be achieved by two physical mechanisms: an enhancement of the Rabi frequencies that drive the optical transitions, which depends on the polarization arrangement, and a frequency shift of the optical transitions that leads to a dynamical detuning

The impact of motivation on employees productivity in the retail sector: the mediating effect of compensation benefits

All companies aspire to compete against their rivals, retain a strategic edge in the industry, gain the largest market share and be inspired to bring out their utmost to achieve their desired goals at work. Few businesses think they will gain growth and wealth by important assets for their workers. Unfortunately, most companies appear to exploit the dismissal of their workers and talented applicants. Recognizing the critical position of workers appears to have a major effect on operational performance as most companies aim to maintain staff by empowering and enhancing the working standards of their employees. Therefore, it is necessary to enforce certain techniques to retain high quality and ensure performance and efficiency. The research examined the influence of organizational participation and encouragement in banks' work results. A study of 100 participants was tested, and findings were evaluated using the chi-square analysis. The findings revealed a substantial level below 5% which indicates that the study variables are closely linked. The quantitative approach and qualitative framework have been used to analyze their perception of the effects of job retention on the success of workers. Approach a single case study for various branches by implementing a similar case study and addressing a larger number of samples. This allows the researcher to remove the survey challenge and hold evidence from a larger community with a deeper comprehension of the idea of encouragement and how it influences workers' output

Plasmon-enhanced terahertz emission in self-assembled quantum dots by femtosecond pulses

A scheme for terahertz (THz) generation from intraband transition in a self-assembled quantum dot (QD) molecule coupled to a metallic nanoparticle (MNP) is analyzed. The QD structure is described as a three-level atom-like system using the density matrix formalism. The MNP with spherical geometry is considered in the quasistatic approximation. A femtosecond laser pulse creates a coherent superposition of two subbands in the quantum dots and produces localized surface plasmons in the nanoparticle which act back upon the QD molecule via dipole-dipole interaction. As a result, coherent THz radiation with a frequency corresponding to the interlevel spacing can be obtained, which is strongly modified by the presence of the MNP. The peak value of the terahertz signal is analyzed as a function of nanoparticle's size, the MNP to QD distance, and the area of the applied laser field. In addition, we theoretically demonstrate that the terahertz pulse generation can be effectively controlled by making use of a train of femtosecond laser pulses. We show that by a proper choice of the parameters characterizing the pulse train a huge enhancement of the terahertz signal is obtained

Penrose limits of Lie Branes and a Nappi--Witten braneworld

Departing from the observation that the Penrose limit of AdS_3 x S^3 is a group contraction in the sense of Inonu and Wigner, we explore the relation between the symmetric D-branes of AdS_3 x S^3 and those of its Penrose limit, a six-dimensional symmetric plane wave analogous to the four-dimensional Nappi--Witten spacetime. Both backgrounds are Lie groups admitting bi-invariant lorentzian metrics and symmetric D-branes wrap their (twisted) conjugacy classes. We determine the (twisted and untwisted) symmetric D-branes in the plane wave background and we prove the existence of a space-filling D5-brane and, separately, of a foliation by D3-branes with the geometry of the Nappi--Witten spacetime which can be understood as the Penrose limit of the AdS_2 x S^2 D3-brane in AdS_3 x S^3. Parenthetically we also derive a simple criterion for a symmetric plane wave to be isometric to a lorentzian Lie group. In particular we observe that the maximally supersymmetric plane wave in IIB string theory is isometric to a lorentzian Lie group, whereas the one in M-theory is not.Comment: 21 pages (v2: references added

Vocational rehabilitation via social firms : a qualitative investigation of the views and experiences of employees with mental health problems, social firm managers and clinicians

Background Employment within social firms in the UK is under-developed and under-researched, but a potentially beneficial route to vocational rehabilitation for people with mental health problems. This study explores the views and experiences of employees with mental ill-health, managers of social firms and mental health clinicians, in order to understand the potential value of social firms for the vocational rehabilitation, employment and well-being of people with mental health problems. Methods Semi-structured interviews were conducted with 23 employees with mental health problems in 11 social firms in England. A focus group and individual interviews were conducted with 12 managers of social firms. Two focus groups were held with 16 mental health clinicians. Data were analysed using thematic analysis. Results Most employees expressed very positive views about working in a social firm. In responses from both employees and social firm managers, an overarching theme regarding the supportive ethos of social firms encompassed several related features: openness about mental health issues; peer, team and management support; flexibility; and support to progress and develop skills over time. Managers identified benefits of employing people with mental health problems who were sufficiently recovered. Knowledge of social firms within clinician focus groups was very limited, although clinicians thought they could be a welcome additional vocational resource. Conclusions High levels of job satisfaction among social firm employees may be explained by the supportive ethos of these working environments. Social firms have potential to be a helpful addition to the range of vocational pathways available for people with mental ill-health. Further mixed methods investigations of experiences and outcomes in order to understand who engages with and benefits from this form of vocational rehabilitation would be valuable in informing decisions about scaling up the model

Article number 270

Abstract Background: Employment is associated with better quality of life and wellbeing in people with mental illness

First insights into the phylogenetic diversity of Mycobacterium tuberculosis in Nepal

BACKGROUND: Tuberculosis (TB) is a major public health problem in Nepal. Strain variation in Mycobacterium tuberculosis may influence the outcome of TB infection and disease. To date, the phylogenetic diversity of M. tuberculosis in Nepal is unknown. METHODS AND FINDINGS: We analyzed 261 M. tuberculosis isolates recovered from pulmonary TB patients recruited between August 2009 and August 2010 in Nepal. M. tuberculosis lineages were determined by single nucleotide polymorphisms (SNP) typing and spoligotyping. Drug resistance was determined by sequencing the hot spot regions of the relevant target genes. Overall, 164 (62.8%) TB patients were new, and 97 (37.2%) were previously treated. Any drug resistance was detected in 50 (19.2%) isolates, and 16 (6.1%) were multidrug-resistant. The most frequent M. tuberculosis lineage was Lineage 3 (CAS/Delhi) with 106 isolates (40.6%), followed by Lineage 2 (East-Asian lineage, includes Beijing genotype) with 84 isolates (32.2%), Lineage 4 (Euro-American lineage) with 41 (15.7%) isolates, and Lineage 1 (Indo-Oceanic lineage) with 30 isolates (11.5%). Based on spoligotyping, we found 45 different spoligotyping patterns that were previously described. The Beijing (83 isolates, 31.8%) and CAS spoligotype (52, 19.9%) were the dominant spoligotypes. A total of 36 (13.8%) isolates could not be assigned to any known spoligotyping pattern. Lineage 2 was associated with female sex (adjusted odds ratio [aOR] 2.58, 95% confidence interval [95% CI] 1.42-4.67, p = 0.002), and any drug resistance (aOR 2.79; 95% CI 1.43-5.45; p = 0.002). We found no evidence for an association of Lineage 2 with age or BCG vaccination status. CONCLUSIONS: We found a large genetic diversity of M. tuberculosis in Nepal with representation of all four major lineages. Lineages 3 and 2 were dominating. Lineage 2 was associated with clinical characteristics. This study fills an important gap on the map of the M. tuberculosis genetic diversity in the Asian reg