Nonlinear network model analysis of vibrational energy transfer and localisation in the Fenna-Matthews-Olson complex

Collective protein modes are expected to be important for facilitating energy transfer in the Fenna-Matthews-Olson (FMO) complex of photosynthetic green sulphur bacteria, however to date little work has focussed on the microscopic details of these vibrations. The nonlinear network model (NNM) provides a computationally inexpensive approach to studying vibrational modes at the microscopic level in large protein structures, whilst incorporating anharmonicity in the inter-residue interactions which can influence protein dynamics. We apply the NNM to the entire trimeric FMO complex and find evidence for the existence of nonlinear discrete breather modes. These modes tend to transfer energy to the highly connected core pigments, potentially opening up alternative excitation energy transfer routes through their influence on pigment properties. Incorporating localised modes based on these discrete breathers in the optical spectra calculations for FMO using ab initio site energies and excitonic couplings can substantially improve their agreement with experimental results.A.W.C. and S.E.M. acknowledge support from the Winton Programme for the Physics of Sustainability. S.E.M. is also supported by an EPSRC doctoral training award. D.J.C. is supported by a Marie Curie International Outgoing Fellowship within the seventh European Community Framework Programme

A Quantum Scattering Interferometer

The collision of two ultra-cold atoms results in a quantum-mechanical superposition of two outcomes: each atom continues without scattering and each atom scatters as a spherically outgoing wave with an s-wave phase shift. The magnitude of the s-wave phase shift depends very sensitively on the interaction between the atoms. Quantum scattering and the underlying phase shifts are vitally important in many areas of contemporary atomic physics, including Bose-Einstein condensates, degenerate Fermi gases, frequency shifts in atomic clocks, and magnetically-tuned Feshbach resonances. Precise measurements of quantum scattering phase shifts have not been possible until now because, in scattering experiments, the number of scattered atoms depends on the s-wave phase shifts as well as the atomic density, which cannot be measured precisely. Here we demonstrate a fundamentally new type of scattering experiment that interferometrically detects the quantum scattering phase shifts of individual atoms. By performing an atomic clock measurement using only the scattered part of each atom, we directly and precisely measure the difference of the s-wave phase shifts for the two clock states in a density independent manner. Our method will give the most direct and precise measurements of ultracold atom-atom interactions and will place stringent limits on the time variations of fundamental constants.Comment: Corrected formatting and typo

Kinematic aspects of trunk motion and gender effect in normal adults

<p>Abstract</p> <p>Background</p> <p>The purpose of this study was to analyze kinematic trunk motion data in normal adults and to investigate gender effect.</p> <p>Methods</p> <p>Kinematic trunk motion data were obtained for 20 healthy subjects (11 men and 9 women; age from 21 to 40 years) during walking a 9 m long lane at a self selected speed, namely, motions in the sagittal (tilt), coronal (obliquity), and transverse (rotation) planes, which were all expressed as motions in global (relative to the ground) and those in pelvic reference frame (relative to pelvis), i.e., tilt (G), obliquity (G), rotation (G), tilt (P), obliquity (P), rotation (P).</p> <p>Results</p> <p>Range of tilt (G), obliquity (G) and rotation (G) showed smaller motion than that of tilt (P), obliquity (P) and rotation (P), respectively. When genders were compared, female trunks showed a 5 degree more extended posture during gait than male trunks (p = 0.002), which appeared to be caused by different lumbar lordosis. Ranges of coronal and transverse plane motion appeared to be correlated. In gait cycle, the trunk motion appeared to counterbalance the lower extremity during swing phase in sagittal plane, and to reduce the angular velocity toward the contralateral side immediate before the contralateral heel strike in the coronal plane.</p> <p>Conclusions</p> <p>Men and women showed different lumbar lordosis during normal gait, which might be partly responsible for the different prevalence of lumbar diseases between genders. However, this needs further investigation.</p

An in vivo platform to select and evolve aggregation-resistant proteins

Protein biopharmaceuticals are highly successful, but their utility is compromised by their propensity to aggregate during manufacture and storage. As aggregation can be triggered by non-native states, whose population is not necessarily related to thermodynamic stability, prediction of poorly-behaving biologics is difficult, and searching for sequences with desired properties is labour-intensive and time-consuming. Here we show that an assay in the periplasm of E. coli linking aggregation directly to antibiotic resistance acts as a sensor for the innate (un-accelerated) aggregation of antibody fragments. Using this assay as a directed evolution screen, we demonstrate the generation of aggregation resistant scFv sequences when reformatted as IgGs. This powerful tool can thus screen and evolve ‘manufacturable’ biopharmaceuticals early in industrial development. By comparing the mutational profiles of three different immunoglobulin scaffolds, we show the applicability of this method to investigate protein aggregation mechanisms important to both industrial manufacture and amyloid disease

Isolated left ventricular non-compaction as an unusual cause of heart failure: a case report

<p>Abstract</p> <p>Introduction</p> <p>Isolated left ventricular non-compaction is a recently described form of cardiomyopathy that is associated with a significant risk of life-threatening arrhythmia and thromboembolic complications.</p> <p>Case presentation</p> <p>We report the presentation, diagnosis and management of isolated left ventricular non-compaction in a 54-year-old Caucasian woman presenting with progressive symptoms of heart failure.</p> <p>Conclusion</p> <p>Advances in diagnostic imaging have undoubtedly led to an increase in the detection of isolated left ventricular non-compaction. Diagnosing and differentiating this uncommon condition from other forms of cardiomyopathy are important as treatment and prognosis may differ significantly. Our current understanding of isolated left ventricular non-compaction, including diagnostic criteria, management and prognosis, is discussed.</p

Effect of RAAS Inhibition on the Incidence of Cancer and Cancer Mortality in Patients with Glomerulonephritis

Angiotensin II type 1 receptor blocker (ARB), which is frequently prescribed in patients with glomerulonephritis (GN), is suggested to increase the risk of cancer. We registered 3,288 patients with renal biopsy and analyzed the relationship between the use of renin-angiotensin-aldosterone system (RAAS) blockade and the incidence of cancer or cancer mortality. After renal biopsy, cancer developed in 33 patients with an incidence rate of 1.0% (95% of CI for incidence: 0.7%-1.3%). There was no difference in the cancer incidence among the groups according to the use of angiotensin-converting enzyme inhibitors (ACEI) or ARB: 1.2% in the None (23/1960), 0.7% in the ARB-only (5/748), 0.4% in the ACEI-only (1/247), and 1.2% in the ACEI-ARB (4/333) (P = 0.487) groups. The cancer mortality was 2.1%, 0.4%, 0.0%, and 0.3% in None, ACEI-only, ARB-only, and ACEI-ARB group, respectively (P < 0.001). The risk of cancer mortality in patients with ARB was only 0.124 (0.034-0.445) compared to that of non-users of ARB by Cox's hazard proportional analysis. In conclusion, prescription of ACEI or ARB in patients with GN does not increase cancer incidence and recipients of ARB show rather lower rates of all-cause mortality and cancer mortality

Left ventricular non-compaction: clinical features and cardiovascular magnetic resonance imaging

Background: It is apparent that despite lack of family history, patients with the morphological characteristics of left ventricular non-compaction develop arrhythmias, thrombo-embolism and left ventricular dysfunction. METHODS: Forty two patients, aged 48.7 +/- 2.3 yrs (mean +/- SEM) underwent cardiovascular magnetic resonance (CMR) for the quantification of left ventricular volumes and extent of non-compacted (NC) myocardium. The latter was quantified using planimetry on the two-chamber long axis LV view (NC area). The patients included those referred specifically for CMR to investigate suspected cardiomyopathy, and as such is represents a selected group of patients. RESULTS: At presentation, 50% had dyspnoea, 19% chest pain, 14% palpitations and 5% stroke. Pulmonary embolism had occurred in 7% and brachial artery embolism in 2%. The ECG was abnormal in 81% and atrial fibrillation occurred in 29%. Transthoracic echocardiograms showed features of NC in only 10%. On CMR, patients who presented with dyspnoea had greater left ventricular volumes (both p < 0.0001) and a lower left ventricular ejection fraction (LVEF) (p < 0.0001) than age-matched, healthy controls. In patients without dyspnoea (n = 21), NC area correlated positively with end-diastolic volume (r = 0.52, p = 0.0184) and end-systolic volume (r = 0.56, p = 0.0095), and negatively with EF (r = -0.72, p = 0.0001). CONCLUSION: Left ventricular non-compaction is associated with dysrrhythmias, thromboembolic events, chest pain and LV dysfunction. The inverse correlation between NC area and EF suggests that NC contributes to left ventricular dysfunction

Porokeratotic Eccrine Ostial and Dermal Duct Nevus Showing Partial Remission by Topical Photodynamic Therapy

Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is an uncommon, benign dermatosis and is characterized by asymptomatic grouped keratotic papules and plaques with a linear pattern on the extremities. Various treatments, including topical steroids, topical calcipotriol, topical 5-fluorouracil, retinoid, cryotherapy, and carbon dioxide laser ablation have been tried for PEODDN, but the results were unsatisfactory. Recently, topical photodynamic therapy (PDT) has been shown to be effective for various cutaneous disorders. We report a case of PEODDN showing partial remission with PDT using topical 5-aminolevulanic acid in a 4-year-old girl

Fabrication of light-weighted acoustic absorbers made of natural fiber composites via additive manufacturing

Synthetic fiber is still considered the best sound absorptive material. However, due to the health concern of synthetic fiber usage, researchers are trying to find another viable alternative. A microperforated panel (MPP) is a promising alternative that relies on the concept of a Helmholtz resonator for sound absorption. MPP possessed excellent acoustic resistance and a considerable range of absorption bandwidth. In this paper, MPP made of natural fiber composite was fabricated and its acoustic absorption was measured using a two-microphone impedance tube method as per ISO 10534-2 standard. Later, the tensile strength of the fabricated acoustic absorbers was measured using an Instron Universal Testing Machine as per ASTM D638. The idea of employing additive manufacturing, better known as the 3D printing technique, is proposed to produce lightweight MPP. The 3D printing technique provides design freedom and is less tedious in creating complex and light structures. The 3D printing technique has various important parameters, and infill density is one of the parameters. It was found that the reduction of infill density leads to a decrease of the MPP’s mass and thus, slightly affects the resonance frequency of the MPP, still within the mid-frequency spectrum. It was also noted that the increment of air gap thickness leads to the shifting of MPP’s resonance frequency to a lower frequency range. The tensile strength of the 3D printed samples decreases with a decrease in infill density. A sample with an infill density of 100% has the highest tensile strength of 22 MPa, and a sample with an infill density of 20% has the lowest tensile strength of 12 MPa