Tomonaga-Luttinger parameters for quantum wires

The low-energy properties of a homogeneous one-dimensional electron system are completely specified by two Tomonaga-Luttinger parameters $K_{\rho}$ and $v_{\sigma}$. In this paper we discuss microscopic estimates of the values of these parameters in semiconductor quantum wires that exploit their relationship to thermodynamic properties. Motivated by the recognized similarity between correlations in the ground state of a one-dimensional electron liquid and correlations in a Wigner crystal, we evaluate these thermodynamic quantities in a self-consistent Hartree-Fock approximation. According to our calculations, the Hartree-Fock approximation ground state is a Wigner crystal at all electron densities and has antiferromagnetic order that gradually evolves from spin-density-wave to localized in character as the density is lowered. Our results for $K_{\rho}$ are in good agreement with weak-coupling perturbative estimates $K_{\rho}^{pert}$ at high densities, but deviate strongly at low densities, especially when the electron-electron interaction is screened at long distances. $K_{\rho}^{pert}\sim n^{1/2}$ vanishes at small carrier density $n$ whereas we conjecture that $K_{\rho}\to 1/2$ when $n\to 0$, implying that $K_{\rho}$ should pass through a minimum at an intermediate density. Observation of such a non-monotonic dependence on particle density would allow to measure the range of the microscopic interaction. In the spin sector we find that the spin velocity decreases with increasing interaction strength or decreasing $n$. Strong correlation effects make it difficult to obtain fully consistent estimates of $v_{\sigma}$ from Hartree-Fock calculations. We conjecture that v_{\sigma}/\vf\propto n/V_0 in the limit $n\to 0$ where $V_0$ is the interaction strength.Comment: RevTeX, 23 pages, 8 figures include

iPSC-derived reactive astrocytes from patients with multiple-sclerosis protect cocultured neurons in inflammatory conditions

Multiple sclerosis (MS) is the most common chronic inflammatory disease of the central nervous system (CNS). The individual course is highly variable with complete remission in some patients and relentless courses in others. We generated induced pluripotent stem cells (iPSCs) to investigate possible mechanisms in benign MS (BMS), compared to progressive MS (PMS). We differentiated neurons and astrocytes that were then stressed with inflammatory cytokines typically associated with MS. TNFα/IL-17A treatment increased neurite damage in MS neurons irrespective of clinical phenotypes. In contrast, TNFα/IL-17A-reactive BMS astrocytes cultured with healthy control (HC) neurons exhibited significantly decreased axonal damage, compared to PMS astrocytes. Accordingly, single cell transcriptomic analysis of BMS-astrocyte co-cultured neurons demonstrated upregulated pathways of neuronal resilience, namely these astrocytes revealed differential growth factor expression. Moreover, supernatants from BMS astrocyte-neuron co-cultures rescued TNFα/IL-17-induced neurite damage. This process was associated with the unique expression of the growth factors, LIF and TGF-β1, as induced by TNFα/IL-17 and JAK-STAT activation. Our findings highlight a potential therapeutic role of modulating astrocyte phenotypes that generate a neuroprotective milieu preventing permanent neuronal damage

Nursing Home Revenue Source and Information Availability During the Emergency Department Evaluation of Nursing Home Residents

Lack of access to medical information for nursing home residents during Emergency Department (ED) evaluation is a barrier to quality care. We hypothesized that the quantity of information available in the ED differs based on the funding source of the resident’s nursing home

Computer-facilitated Review of Electronic Medical Records Reliably Identifies Emergency Department Interventions in Older Adults

An estimated 14% to 25% of all scientific studies in peer-reviewed emergency medicine (EM) journals are medical records reviews. The majority of the chart reviews in these studies are performed manually, a process that is both time-consuming and error-prone. Computer-based text search engines have the potential to enhance chart reviews of electronic emergency department (ED) medical records. The authors compared the efficiency and accuracy of a computer-facilitated medical record review of ED clinical records of geriatric patients with a traditional manual review of the same data and describe the process by which this computer-facilitated review was completed. Clinical data from consecutive ED patients age 65 years or older were collected retrospectively by manual and computer-facilitated medical record review. The frequency of three significant ED interventions in older adults was determined using each method. Performance characteristics of each search method, including sensitivity and positive predictive value, were determined, and the overall sensitivities of the two search methods were compared using McNemar's test. For 665 patient visits, there were 49 (7.4%) Foley catheters placed, 36 (5.4%) sedative medications administered, and 15 (2.3%) patients who received positive pressure ventilation. The computer-facilitated review identified more of the targeted procedures (99 of 100, 99%), compared to manual review (74 of 100 procedures, 74%; p < 0.0001). A practical, non-resource-intensive, computer-facilitated free-text medical record review was completed and was more efficient and accurate than manually reviewing ED records

MHC-II dynamics are maintained in HLA-DR allotypes to ensure catalyzed peptide exchange.

Presentation of antigenic peptides by major histocompatibility complex class II (MHC-II) proteins determines T helper cell reactivity. The MHC-II genetic locus displays a large degree of allelic polymorphism influencing the peptide repertoire presented by the resulting MHC-II protein allotypes. During antigen processing, the human leukocyte antigen (HLA) molecule HLA-DM (DM) encounters these distinct allotypes and catalyzes exchange of the placeholder peptide CLIP by exploiting dynamic features of MHC-II. Here, we investigate 12 highly abundant CLIP-bound HLA-DRB1 allotypes and correlate dynamics to catalysis by DM. Despite large differences in thermodynamic stability, peptide exchange rates fall into a target range that maintains DM responsiveness. A DM-susceptible conformation is conserved in MHC-II molecules, and allosteric coupling between polymorphic sites affects dynamic states that influence DM catalysis. As exemplified for rheumatoid arthritis, we postulate that intrinsic dynamic features of peptide-MHC-II complexes contribute to the association of individual MHC-II allotypes with autoimmune disease

What is the evidence for the management of patients along the pathway from the emergency department to acute admission to reduce unplanned attendance and admission? An evidence synthesis

Background Globally, the rate of emergency hospital admissions is increasing. However, little evidence exists to inform the development of interventions to reduce unplanned Emergency Department (ED) attendances and hospital admissions. The objective of this evidence synthesis was to review the evidence for interventions, conducted during the patient’s journey through the ED or acute care setting, to manage people with an exacerbation of a medical condition to reduce unplanned emergency hospital attendance and admissions. Methods A rapid evidence synthesis, using a systematic literature search, was undertaken in the electronic data bases of MEDLINE, EMBASE, CINAHL, the Cochrane Library and Web of Science, for the years 2000–2014. Evidence included in this review was restricted to Randomised Controlled Trials (RCTs) and observational studies (with a control arm) reported in peer-reviewed journals. Studies evaluating interventions for patients with an acute exacerbation of a medical condition in the ED or acute care setting which reported at least one outcome related to ED attendance or unplanned admission were included. Results Thirty papers met our inclusion criteria: 19 intervention studies (14 RCTs) and 11 controlled observational studies. Sixteen studies were set in the ED and 14 were conducted in an acute setting. Two studies (one RCT), set in the ED were effective in reducing ED attendance and hospital admission. Both of these interventions were initiated in the ED and included a post-discharge community component. Paradoxically 3 ED initiated interventions showed an increase in ED re-attendance. Six studies (1 RCT) set in acute care settings were effective in reducing: hospital admission, ED re-attendance or re-admission (two in an observation ward, one in an ED assessment unit and three in which the intervention was conducted within 72 h of admission). Conclusions There is no clear evidence that specific interventions along the patient journey from ED arrival to 72 h after admission benefit ED re-attendance or readmission. Interventions targeted at high-risk patients, particularly the elderly, may reduce ED utilization and warrant future research. Some interventions showing effectiveness in reducing unplanned ED attendances and admissions are delivered by appropriately trained personnel in an environment that allows sufficient time to assess and manage patients

Suspension packaging cell lines for the simplified generation of T-cell receptor encoding retrovirus vector particles

The transfer of T-cell receptor (TCR) genes into primary human T-cells to endow their specificity toward virus-infected and tumor cells is becoming an interesting tool for immunotherapy. TCR-modified T cells are mainly generated by retrovirus-mediated gene transfer. To produce TCR-retrovirus particles, fibroblast packaging cell lines are the most common tool. We constructed two packaging cell lines based on the human suspension T-cell lymphoma line Deltabeta-Jurkat, which lacks endogenous TCRbeta-chains and is therefore unable to express CD3 complexes on the cell surface. After supply of gag-pol (murine leukemia virus (Mo-MLV)) and env (GALV or MLV-10A1) genes, a green fluorescent protein (GFP)-encoding retrovirus vector was transduced into both packaging cell clones, which then stably produced GFP-retroviruses with titers of up to 4 x 10(5) infectious particles (IP)/ml. After transfer of a TCRalpha/beta-encoding retrovirus vector, Deltabeta-Jurkat/GALV and Deltabeta-Jurkat/10A1 cells expressed CD3 molecules on the cell surface. CD3-high expressing packaging cells were enriched by fluorescence-activated cell sorter sorting. In these cells, the CD3 expression level directly correlated with the titer of vector particles. TCR-retroviruses efficiently transduced human T-cell lines and primary T cells. In conclusion, the method allowed the fast and easy generation of high virus titer supernatants for TCR gene transfer