Real-time analysis of T cell receptors in naive cells in vitro and in vivo reveals flexibility in synapse and signaling dynamics

Real-time imaging defines the dynamics of TCR and T cell motility during early T cell activation in lymph nodes

Electronic Structure of Atoms in Magnetic Quadrupole Traps

We investigate the electronic structure and properties of atoms exposed to a magnetic quadrupole field. The spin-spatial as well as generalized time reversal symmetries are established and shown to lead to a two-fold degeneracy of the electronic states in the presence of the field. Low-lying as well as highly excited Rydberg states are computed and analyzed for a broad regime of field gradients. The delicate interplay between the Coulomb and various magnetic interactions leads to complex patterns of the spatial spin polarization of individual excited states. Electromagnetic transitions in the quadrupole field are studied in detail thereby providing the selection rules and in particular the transition wavelengths and corresponding dipole strengths. The peculiar property that the quadrupole magnetic field induces permanent electric dipole moments of the atoms is derived and discussed.Comment: 17 pages, 13 figures, accepted for publication in PR

The effect of assessing genetic risk of prostate cancer on the use of PSA tests in primary care: a cluster randomized controlled trial

Background Assessing genetic lifetime risk for prostate cancer has been proposed as a means of risk stratification to identify those for whom prostate-specific antigen (PSA) testing is likely to be most valuable. This project aimed to test the effect of introducing a genetic test for lifetime risk of prostate cancer in general practice on future PSA testing. Methods and findings We performed a cluster randomized controlled trial with randomization at the level of general practices (73 in each of two arms) in the Central Region (Region Midtjylland) of Denmark. In intervention practices, men were offered a genetic test (based on genotyping of 33 risk-associated single nucleotide polymorphisms) in addition to the standard PSA test that informed them about lifetime genetic risk of prostate cancer and distinguished between “normal” and “high” risk. The primary outcome was the proportion of men having a repeated PSA test within 2 years. A multilevel logistic regression model was used to test the association. After applying the exclusion criteria, 3,558 men were recruited in intervention practices, with 1,235 (34.7%) receiving the genetic test, and 4,242 men were recruited in control practices. Men with high genetic risk had a higher propensity for repeated PSA testing within 2 years than men with normal genetic risk (odds ratio [OR] = 8.94, p < 0.01). The study was conducted in routine practice and had some selection bias, which is evidenced by the relatively large proportion of younger and higher income participants taking the genetic test. Conclusions Providing general practitioners (GPs) with access to a genetic test to assess lifetime risk of prostate cancer did not reduce the overall number of future PSA tests. However, among men who had a genetic test, knowledge of genetic risk significantly influenced future PSA testing

X-Ray Scattering Study of the Smectic−A1Smectic-A_1 to Smectic−A2Smectic-A_2 Transition

X-ray scattering measurements are reported for critical $smectic-A_2$ fluctuations along a line of second-order transitions between the $smectic-A_1$ and $smectic-A_2$ phases in mixtures of hexylphenyl cyanobenzoyloxy benzoate $(DB_6)$ and terephthal-bis-butylaniline (TBBA). The measured exponents $\gamma = 1.46 \pm 0.05$ and $\nu_{\parallel} = \nu_{\perp}= 0.74 \pm 0.03$ are constant along the second-order line and agree with recent heat-capacity measurements and the scaling law, $3\nu + \alpha =2$. They disagree with current theoretical expectations.Engineering and Applied Science

X-Ray Studies of Transitions between Nematic, Smectic−A1,−A2,and−AdSmectic-A_1, -A_2, and -A_d Phases

We report high-resolution x-ray scattering measurements of the critical fluctuations in mixtures of hexylphenyl cyanobenzoyloxy benzoate $(DB_6)$ and terephtal-bis-butylaniline (TBBA). The phase sequence exhibited on cooling pure $DB_6$ (or mixtures with a low concentration of TBBA), is nematic (N) to $smectic-A_d (A_d)$ to $smectic-A_2 (A_2)$. Mixtures with $\gtrsim 12$ molar percent (mol %) of TBBA have a $smectic-A_1 (A_1)$ phase between the nematic and $smectic-A_2$ phases. For each of the second-order transitions the critical-temperature dependence of the susceptibility and correlation lengths are fit to power laws of the form $t^x$ where $t=(T-T_c)/T_c$. For the $N-A_d$ transition in pure $DB_6$ the susceptibility exponent $\beta=1.29 \pm 0.05$ and the parallel and perpendicular correlation-length exponents are $\nu_{\parallel} 0.67 \pm 0.03$ and $\nu_{\perp} =0.52 \pm 0.03$, respectively. Close to the multicritical point (12 mol% TBBA) where the second-order $N-A_1$ line meets the first-order portion of the $A_1-A_2$ line, the $N-A_1$ exponents are $\beta =1.09 \pm 0.05, \mu_{\parallel} 0.57 \pm 0.03, and \nu_{\perp} =0.43 \pm 0.03$. The correlation length anisotropy $(\nu_{\parallel} \neq \nu_{\perp})$ persists along the entire $N-A_1$ line, with the observed exponents decreasing as the concentration approaches the multicritical point. The $A_1-A_2$ line has both first-order and second-order regions. All the measured exponents $(\beta, \nu_{\parallel}, \nu_{\perp})$ were invariant along the second-order portion of the $A_1-A_2$ line and the correlation-length exponents were isotropic $(\nu_{\parallel} = \nu_{\perp})$. The measured exponents were $\beta = 1.46 \pm 0.05$, and $\nu_{\parallel} = \nu_1 = 0.74 \pm 0.03$. These numbers also held close to the tricritical point where the $A_1-A_2$ transition became first order.Engineering and Applied Science

Development of a decision support tool to facilitate primary care management of patients with abnormal liver function tests without clinically apparent liver disease [HTA03/38/02]. Abnormal Liver Function Investigations Evaluation (ALFIE)

Liver function tests (LFTs) are routinely performed in primary care, and are often the gateway to further invasive and/or expensive investigations. Little is known of the consequences in people with an initial abnormal liver function (ALF) test in primary care and with no obvious liver disease. Further investigations may be dangerous for the patient and expensive for Health Services. The aims of this study are to determine the natural history of abnormalities in LFTs before overt liver disease presents in the population and identify those who require minimal further investigations with the potential for reduction in NHS costs