Real time imaging of two-dimensional iron oxide spherulite nanostructure formation

The formation of complex hierarchical nanostructures has attracted a lot of attention from both the fundamental science and potential applications point of view. Spherulite structures with radial fibrillar branches have been found in various solids; however, their growth mechanisms remain poorly understood. Here, we report real time imaging of the formation of two-dimensional (2D) iron oxide spherulite nanostructures in a liquid cell using transmission electron microscopy (TEM). By tracking the growth trajectories, we show the characteristics of the reaction front and growth kinetics. Our observations reveal that the tip of a growing branch splits as the width exceeds certain sizes (5.5–8.5 nm). The radius of a spherulite nanostructure increases linearly with time at the early stage, transitioning to nonlinear growth at the later stage. Furthermore, a thin layer of solid is accumulated at the tip and nanoparticles from secondary nucleation also appear at the growing front which later develop into fibrillar branches. The spherulite nanostructure is polycrystalline with the co-existence of ferrihydrite and Fe3O4 through-out the growth. A growth model is further established, which provides rational explanations on the linear growth at the early stage and the nonlinearity at the later stage of growth. [Figure not available: see fulltext.]

Evaluation of energy and indoor environmental performance of a UK passive house dwelling

The preliminary findings of the energy and indoor environmental performance of a Passive House dwelling in North East of England is presented in this paper. This dwelling is designed to comply with the Passive House Standard (certified by the International Passive House Association) which aims to reduce energy consumption and carbon emissions. The property benefits from advanced building fabric design and materials, PV array, mechanical ventilation with heat recovery system (MVHR) and high efficiency domestic hot water storage vessel to minimise operational carbon emissions. Power generated by the PV panel, imported grid electricity and mains gas consumption of this house are monitored by a proprietary monitoring package; and data of indoor temperature, relative humidity and resident occupancy at several different locations in the dwelling are also recorded. A computational model of this property was developed using DesignBuilder software. The model was validated using the data monitored on site; and is used to predict and evaluate the performance of the house. The initial findings of this study shows the advantages of Passive House in achieving high thermal comfort and good indoor air quality with much lower energy consumption compares to the national averag

Criticality in correlated quantum matter

At quantum critical points (QCP) \cite{Pfeuty:1971,Young:1975,Hertz:1976,Chakravarty:1989,Millis:1993,Chubukov:1 994,Coleman:2005} there are quantum fluctuations on all length scales, from microscopic to macroscopic lengths, which, remarkably, can be observed at finite temperatures, the regime to which all experiments are necessarily confined. A fundamental question is how high in temperature can the effects of quantum criticality persist? That is, can physical observables be described in terms of universal scaling functions originating from the QCPs? Here we answer these questions by examining exact solutions of models of correlated systems and find that the temperature can be surprisingly high. As a powerful illustration of quantum criticality, we predict that the zero temperature superfluid density, $\rho_{s}(0)$, and the transition temperature, $T_{c}$, of the cuprates are related by $T_{c}\propto\rho_{s}(0)^y$, where the exponent $y$ is different at the two edges of the superconducting dome, signifying the respective QCPs. This relationship can be tested in high quality crystals.Comment: Final accepted version not including minor stylistic correction

A cross-sectional survey of water and clean faces in trachoma endemic communities in Tanzania

<p>Abstract</p> <p>Background</p> <p>Face washing is important to interrupt the transmission of trachoma, the leading infectious cause of blindness worldwide. We aimed to assess the household and personal factors that affected water use and face washing practices in Kongwa, Tanzania.</p> <p>Methods</p> <p>We conducted a household water use survey in 173 households (329 children) in January, 2010. Self reported data on water use practices, observed water in the household, and observed clean faces in children were collected. Contingency table analyses and logistic regression analyses were used to measure associations between unclean faces and risk factors.</p> <p>Results</p> <p>We found that women are recognized as primary decision makers on water use in a household, and respondents who reported laziness as a reason that others do not wash children's faces were significantly more likely to have children with clean faces. Washing was reported as a priority for water use in most households. Sixty four percent (95% Confidence Interval = 59%-70%) of children had clean faces.</p> <p>Conclusions</p> <p>Attitudes toward face washing and household water use appear to have changed dramatically from 20 years ago when clean faces were rare and men made decisions on water use in households. The sources of these attitudinal changes are not clear, but are positive changes that will assist the trachoma control program in strengthening its hygiene efforts.</p

Comparison of Newtonian and Special-Relativistic Trajectories with the General-Relativistic Trajectory for a Low-Speed Weak-Gravity System

We show, contrary to expectation, that the trajectory predicted by general-relativistic mechanics for a low-speed weak-gravity system is not always well-approximated by the trajectories predicted by special-relativistic and Newtonian mechanics for the same parameters and initial conditions. If the system is dissipative, the breakdown of agreement occurs for chaotic trajectories only. If the system is non-dissipative, the breakdown of agreement occurs for chaotic trajectories and non-chaotic trajectories. The agreement breaks down slowly for non-chaotic trajectories but rapidly for chaotic trajectories. When the predictions are different, general-relativistic mechanics must therefore be used, instead of special-relativistic mechanics (Newtonian mechanics), to correctly study the dynamics of a weak-gravity system (a low-speed weak-gravity system)

Clinical assessment of a low-cost, hand-held, smartphone-attached intraoral imaging probe for ALA PDT monitoring and guidance

India has one of the highest rates of oral squamous cell carcinoma (OSCC) in the world, with an incidence of 15 per 100,000 and more than 70,000 deaths per year. The problem is exacerbated by lack of medical infrastructure and routine screening, especially in rural areas. This collaboration recently developed, and clinically validated, a low-cost, portable and easy-to-use platform for intraoral photodynamic therapy (PDT) specifically engineered for use in global health settings. Here, we explore the implementation of our low-cost PDT system in conjunction with a small, handheld smartphone-coupled, multichannel fluorescence and white-light oral cancer imaging probe, which was also developed for global health settings. Our study aimed to use this mobile intraoral imaging device for treatment guidance and monitoring PDT using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PS; PpIX) fluorescence. A total of 12 patients with 14 lesions having moderately/well-differentiated micro-invasive OSCC lesions (<2 cm diameter, depth <5 mm) were systemically administered with three doses of 20mg/kg ALA (total 60mg/kg). Lesion site PpIX and auto fluorescence was analyzed before/after ALA administration, and again after light delivery (fractionated, total 100 J/cm^{2} of 630nm red LED light). Quantification of relative PpIX fluorescence enables lesion area segmentation to improve guidance of light delivery and reports extent of photobleaching. These results indicate the utility of this approach for image-guided PDT and treatment monitoring while also laying groundwork for an integrated approach, combining cancer screening and treatment with the same hardware

Imperfect interface of Beclin1 coiled-coil domain regulates homodimer and heterodimer formation with Atg14L and UVRAG

Beclin 1 is a core component of the Class III Phosphatidylinositol 3-Kinase VPS34 complex. The coiled coil domain of Beclin 1 serves as an interaction platform for assembly of distinct Atg14L- and UVRAG-containing complexes to modulate VPS34 activity. Here we report the crystal structure of the coiled coil domain that forms an antiparallel dimer and is rendered metastable by a series of 'imperfect' a-d' pairings at its coiled coil interface. Atg14L and UVRAG promote the transition of metastable homodimeric Beclin 1 to heterodimeric Beclin1-Atg14L/UVRAG assembly. Beclin 1 mutants with their 'imperfect' a-d' pairings modified to enhance self-interaction, show distinctively altered interactions with Atg14L or UVRAG. These results suggest that specific utilization of the dimer interface and modulation of the homodimer–heterodimer transition by Beclin 1-interacting partners may underlie the molecular mechanism that controls the formation of various Beclin1–VPS34 subcomplexes to exert their effect on an array of VPS34-related activities, including autophagy

A patient with metastatic melanoma presenting with gastrointestinal perforation after dacarbazine infusion: a case report

<p>Abstract</p> <p>Introduction</p> <p>We report a rare case of gastrointestinal perforation following dacarbazine infusion for metastatic melanoma. The condition is attributed to a responding malignant melanoma in the gastrointestinal tract.</p> <p>Case presentation</p> <p>A 52-year-old Caucasian man presented with abdominal pain and distension, malaise, night sweats, dysphagia and early satiety. A computed tomography scan showed massive ascites, lymphadenopathy and liver lesions suspect for metastases. An upper gastrointestinal endoscopy was performed and revealed multiple dark lesions of 5 mm to 10 mm in his stomach and duodenum.</p> <p>When his skin was re-examined, an irregular pigmented lesion over the left clavicle measuring 15 mm × 8 mm with partial depigmentation was found. Histological examination of a duodenal lesion was consistent with a diagnosis of metastatic melanoma. The patient deteriorated and his level of lactate dehydrogenase rapidly increased. The patient was started on systemic treatment with dacarbazine 800 mg/m²every three weeks and he was discharged one day after the first dose. On the sixth day he was readmitted with severe abdominal pain. A chest X-ray showed the presence of free intraperitoneal air that was consistent with gastrointestinal perforation. His lactate dehydrogenase level had fallen from 6969U/L to 1827U/L, supporting the conclusion that the response of gastrointestinal metastases to dacarbazine had resulted in the perforation of the patient's bowel wall. A laparotomy was discussed with the patient and his family but he decided to go home with symptomatic treatment. He died 11 days later.</p> <p>Conclusion</p> <p>Melanoma can originate in, as well as metastasize to, the gastrointestinal tract. Gastrointestinal perforations due to responding tumors are a well-known complication of systemic treatment of gastrointestinal lymphomas. However, as the response rate of metastatic melanoma to dacarbazine is only 10% to 20%, and responses are usually only partial, perforation due to treatment response in metastatic melanoma is rare.</p> <p>Medical oncologists should be aware of the risk of bowel perforation after starting cytotoxic chemotherapy on patients with gastrointestinal metastases.</p