Scalable Production of Ambient Stable Hybrid Bismuth-Based Materials: AACVD of Phenethylammonium Bismuth Iodide Films*.

Large homogeneous and adherent coatings of phenethylammonium bismuth iodide were produced using the cost-effective and scalable aerosol-assisted chemical vapor deposition (AACVD) methodology. The film morphology was found to depend on the deposition conditions and substrates, resulting in different optical properties to those reported from their spin-coated counterparts. Optoelectronic characterization revealed band bending effects occurring between the hybrid material and semiconducting substrates (TiO2 and FTO) due to heterojunction formation, and the optical bandgap of the hybrid material was calculated from UV-visible and PL spectrometry to be 2.05 eV. Maximum values for hydrophobicity and crystallographic preferential orientation were observed for films deposited on FTO/glass substrates, closely followed by values from films deposited on TiO2 /glass substrates.

Model-free classification of X-ray scattering signals applied to image segmentation.

In most cases, the analysis of small-angle and wide-angle X-ray scattering (SAXS and WAXS, respectively) requires a theoretical model to describe the sample's scattering, complicating the interpretation of the scattering resulting from complex heterogeneous samples. This is the reason why, in general, the analysis of a large number of scattering patterns, such as are generated by time-resolved and scanning methods, remains challenging. Here, a model-free classification method to separate SAXS/WAXS signals on the basis of their inflection points is introduced and demonstrated. This article focuses on the segmentation of scanning SAXS/WAXS maps for which each pixel corresponds to an azimuthally integrated scattering curve. In such a way, the sample composition distribution can be segmented through signal classification without applying a model or previous sample knowledge. Dimensionality reduction and clustering algorithms are employed to classify SAXS/WAXS signals according to their similarity. The number of clusters, i.e. the main sample regions detected by SAXS/WAXS signal similarity, is automatically estimated. From each cluster, a main representative SAXS/WAXS signal is extracted to uncover the spatial distribution of the mixtures of phases that form the sample. As examples of applications, a mudrock sample and two breast tissue lesions are segmented.

The SF3B1 inhibitor spliceostatin A (SSA) elicits apoptosis in chronic lymphocytic leukaemia cells through downregulation of Mcl-1.

The pro-survival Bcl-2 family member Mcl-1 is expressed in chronic lymphocytic leukaemia (CLL), with high expression correlated with progressive disease. The spliceosome inhibitor spliceostatin A (SSA) is known to regulate Mcl-1 and so here we assessed the ability of SSA to elicit apoptosis in CLL. SSA induced apoptosis of CLL cells at low nanomolar concentrations in a dose- and time-dependent manner, but independently of SF3B1 mutational status, IGHV status and CD38 or ZAP70 expression. However, normal B and T cells were less sensitive than CLL cells (P=0.006 and P<0.001, respectively). SSA altered the splicing of anti-apoptotic MCL-1(L) to MCL-1(s) in CLL cells coincident with induction of apoptosis. Overexpression studies in Ramos cells suggested that Mcl-1 was important for SSA-induced killing since its expression inversely correlated with apoptosis (P=0.001). IL4 and CD40L, present in patient lymph nodes, are known to protect tumour cells from apoptosis and significantly inhibited SSA, ABT-263 and ABT-199 induced killing following administration to CLL cells (P=0.008). However, by combining SSA with the Bcl-2/Bcl-x(L) antagonists ABT-263 or ABT-199, we were able to overcome this pro-survival effect. We conclude that SSA combined with Bcl-2/Bcl-x(L) antagonists may have therapeutic utility for CLL.

A retrospective comparison of VLBW outcomes before and after implementing new delivery room guidelines at a regional tertiary care center.

OBJECTIVE: To evaluate the impact of implemented protocol changes on delivery room interventions and very low birth weight (VLBW) health outcomes. STUDY DESIGN: Retrospective study comparing birth characteristics, interventions and health outcomes of VLBW infants born in a tertiary care center before (calendar years 2008 to 2009) and after (calendar years 2012 to 2013) implementing new protocols using Chi-square analyses. RESULT: Four hundred and nine were born before and 303 after changes were implemented. Postimplementation infants had more use of antenatal steroids (P=0.02), gestational age ⩽24 weeks (P=0.03) and birth weights between 501 and 750 g (P=0.04) and less oxygen administration (P=0.002), face mask ventilation (P=0.0001), surfactant use (P=0.0001), chest compressions (P=0.0001), intubation (P=0.002), epinephrine use (P=0.011), hypothermia (P=0.0001) and discharges home on supplemental oxygen (P=0.05). CONCLUSION: Changes creating a new delivery team, adopting new delivery practice guidelines and updating delivery room equipment resulted in positive outcomes for delivery room practices and patient outcomes.

Predictions of dynamic changes in reaction rates as a consequence of incomplete mixing using pore scale reactive transport modeling on images of porous media.

We present a pore scale model capable of simulating fluid/fluid reactive transport on images of porous media from first principles. We use a streamline-based particle tracking method for simulating flow and transport, while for reaction to occur, both reactants must be within a diffusive distance of each other during a time-step. We assign a probability of reaction (Pr), as a function of the reaction rate constant (kr) and the diffusion length. Firstly, we validate our model for reaction against analytical solutions for the bimolecular reaction (A+B→C) in a free fluid. Then, we simulate transport and reaction in a beadpack to validate the model through predicting the fluid/fluid reaction experimental results provided by Gramling et al. (2002). Our model accurately predicts the experimental data, as it takes into account the degree of incomplete mixing present at the sub-pore (image voxel) level, in contrast to advection-dispersion-reaction equation (ADRE) model that over-predicts pore scale mixing. Finally, we show how our model can predict dynamic changes in the reaction rate accurately accounting for the local geometry, topology and flow field at the pore scale. We demonstrate the substantial difference between the predicted early-time reaction rate in comparison to the ADRE model.

Statistical scaling of pore-scale Lagrangian velocities in natural porous media.

We investigate the scaling behavior of sample statistics of pore-scale Lagrangian velocities in two different rock samples, Bentheimer sandstone and Estaillades limestone. The samples are imaged using x-ray computer tomography with micron-scale resolution. The scaling analysis relies on the study of the way qth-order sample structure functions (statistical moments of order q of absolute increments) of Lagrangian velocities depend on separation distances, or lags, traveled along the mean flow direction. In the sandstone block, sample structure functions of all orders exhibit a power-law scaling within a clearly identifiable intermediate range of lags. Sample structure functions associated with the limestone block display two diverse power-law regimes, which we infer to be related to two overlapping spatially correlated structures. In both rocks and for all orders q, we observe linear relationships between logarithmic structure functions of successive orders at all lags (a phenomenon that is typically known as extended power scaling, or extended self-similarity). The scaling behavior of Lagrangian velocities is compared with the one exhibited by porosity and specific surface area, which constitute two key pore-scale geometric observables. The statistical scaling of the local velocity field reflects the behavior of these geometric observables, with the occurrence of power-law-scaling regimes within the same range of lags for sample structure functions of Lagrangian velocity, porosity, and specific surface area.

Disinfecting the iPad: evaluating effective methods.

BACKGROUND: Tablet computers are increasingly used in healthcare, but they may carry nosocomial pathogens. There are few data available on how to clean an iPad effectively for use in the clinical setting. AIM: We aimed to identify the most effective method of decontaminating the Apple iPad, without causing damage, and establish the duration of any residual effect. METHODS: Following contamination with a microbial broth (meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus (VRE) and Clostridium difficile), we examined efficacy of iPad disinfection in the laboratory using six different disinfectant wipes: Sani-Cloth CHG 2% (chlorhexidine 2%/alcohol 70%), Clorox, Tristel, Trigene, soap and water, and plain cloth. Following cleaning, iPads were recontaminated to examine residual activity. After 480 Sani-Cloth CHG 2% disinfecting episodes, functional and visual analysis of iPads was performed by blinded subjects. FINDINGS: With the exception of Clostridium difficile, Sani-Cloth CHG 2% and Clorox wipes were most effective against MRSA and VRE, and they were significantly better than the Apple-recommended plain cloth (P ≤ 0.001). A substantial residual antimicrobial effect was seen for >6h after wiping the iPad with Sani-Cloth CHG 2% despite repeated recontamination and without further disinfection. The functionality or visual appearance of the iPad was not damaged by repeated use of Sani-Cloth CHG 2% wipes. CONCLUSIONS: Sani-Cloth CHG 2% wipes effectively disinfect the iPad against MRSA and VRE, with a residual antibacterial effect and without causing damage.

Chlorhexidine cleaning of re-usable bougies.

Bougies are susceptible to becoming contaminated before or during use. Chlorhexidine wipes may have a residual antibacterial effect, potentially minimising bacterial transmission after bougie use or storage. We evaluated the decontaminant and antibacterial effectiveness of 70% alcohol/2% chlorhexidine wipes in laboratory, clinical and accelerated ageing studies, and conducted a telephone survey of normal practice. In the laboratory tests, chlorhexidine wipes were completely effective against Escherichia coli and methicillin-resistant Staphylococcus aureus, and prevented recontamination for 24 h. Clinical introduction of chlorhexidine wipes reduced bougie contamination from 33% to 0%. Following 150 cleaning episodes, there was no physical or functional damage to the bougies. Eight out of nine hospitals in the East of England Health Region use re-usable bougies. We recommend that following decontamination, bougies should be wiped with 70% alcohol/2% chlorhexidine wipes, to retain antimicrobial activity during handling.

Emergency capnography monitoring: comparing ergonomic design of intensive care unit ventilator interfaces and specific training of staff in reducing time to activation.

Modern ventilators provide capnography monitoring in patients with tracheal tubes, in compliance with national and international recommendations. This technology is often not used when patients' lungs are non-invasively ventilated; however, it should be accessed immediately following tracheal intubation to confirm tube placement. This study assessed the effect of ventilation interface design on the speed with which capnography can be activated by comparing the Dräger Evita 4 and Dräger V500 before and after a specific training episode. We configured the V500 to have a capnography activation button on the front screen in contrast to the Evita 4 which requires a sequence of actions to access capnography monitoring. We used a randomised crossover design, measuring time to monitoring activation, and repeated the study after 3 months. Survival analysis showed significantly quicker activation associated with ventilator choice (V500, p < 0.0001) and training (p = 0.0058). The training improved activation speed with both machines, though this was only significant for the Evita 4 (p = 0.0097).

Comparison of residual oil cluster size distribution, morphology and saturation in oil-wet and water-wet sandstone.

We imaged an oil-wet sandstone at residual oil saturation (S(or)) conditions using X-ray micro-tomography with a nominal voxel size of (9 µm)(3) and monochromatic light from a synchrotron source. The sandstone was rendered oil-wet by ageing with a North Sea crude oil to represent a typical wettability encountered in hydrocarbon reservoirs. We measured a significantly lower S(or) for the oil-wet core (18.8%) than for an analogue water-wet core (35%). We analysed the residual oil cluster size distribution and find consistency with percolation theory that predicts a power-law cluster size distribution. We measure a power-law exponent τ=2.12 for the oil-wet core which is higher than τ for the water-wet system (τ=2.05), indicating fewer large clusters in the oil-wet case. The clusters are rough and sheet-like consistent with connectivity established through layers in the pore space and occupancy of the smaller pores; in contrast the clusters for water-wet media occupy the centres of the larger pores. These results imply less trapping of oil, but with a greater surface area for dissolution. In carbon storage applications, this suggests that in CO(2)-wet systems, capillary trapping is less significant, but that there is a large surface area for dissolution and reaction.

Role of geomechanically grown fractures on dispersive transport in heterogeneous geological formations.

A second order in space accurate implicit scheme for time-dependent advection-dispersion equations and a discrete fracture propagation model are employed to model solute transport in porous media. We study the impact of the fractures on mass transport and dispersion. To model flow and transport, pressure and transport equations are integrated using a finite-element, node-centered finite-volume approach. Fracture geometries are incrementally developed from a random distributions of material flaws using an adoptive geomechanical finite-element model that also produces fracture aperture distributions. This quasistatic propagation assumes a linear elastic rock matrix, and crack propagation is governed by a subcritical crack growth failure criterion. Fracture propagation, intersection, and closure are handled geometrically. The flow and transport simulations are separately conducted for a range of fracture densities that are generated by the geomechanical finite-element model. These computations show that the most influential parameters for solute transport in fractured porous media are as follows: fracture density and fracture-matrix flux ratio that is influenced by matrix permeability. Using an equivalent fracture aperture size, computed on the basis of equivalent permeability of the system, we also obtain an acceptable prediction of the macrodispersion of poorly interconnected fracture networks. The results hold for fractures at relatively low density.

Modelling approaches to the dewetting of evaporating thin films of nanoparticle suspensions.

We review recent experiments on dewetting thin films of evaporating colloidal nanoparticle suspensions (nanofluids) and discuss several theoretical approaches to describe the ongoing processes including coupled transport and phase changes. These approaches range from microscopic discrete stochastic theories to mesoscopic continuous deterministic descriptions. In particular, we describe (i) a microscopic kinetic Monte Carlo model, (ii) a dynamical density functional theory and (iii) a hydrodynamic thin film model. Models (i) and (ii) are employed to discuss the formation of polygonal networks, spinodal and branched structures resulting from the dewetting of an ultrathin 'postcursor film' that remains behind a mesoscopic dewetting front. We highlight, in particular, the presence of a transverse instability in the evaporative dewetting front, which results in highly branched fingering structures. The subtle interplay of decomposition in the film and contact line motion is discussed. Finally, we discuss a simple thin film model (iii) of the hydrodynamics on the mesoscale. We employ coupled evolution equations for the film thickness profile and mean particle concentration. The model is used to discuss the self-pinning and depinning of a contact line related to the 'coffee-stain' effect. In the course of the review we discuss the advantages and limitations of the different theories, as well as possible future developments and extensions.

Front instabilities in evaporatively dewetting nanofluids.

Various experimental settings that involve drying solutions or suspensions of nanoparticles-often called nanofluids-have recently been used to produce structured nanoparticle layers. In addition to the formation of polygonal networks and spinodal-like patterns, the occurrence of branched structures has been reported. After reviewing the experimental results we use a modified version of the Monte Carlo model first introduced by Rabani [Nature 426, 271 (2003)] to study structure formation in evaporating films of nanoparticle solutions for the case that all structuring is driven by the interplay of evaporating solvent and diffusing nanoparticles. After introducing the model and its general behavior we focus on receding dewetting fronts which are initially straight but develop a transverse fingering instability. We analyze the dependence of the characteristics of the resulting branching patterns on the driving effective chemical potential, the mobility and concentration of the nanoparticles, and the interaction strength between liquid and nanoparticles. This allows us to understand the underlying instability mechanism.

Modification in prescribing practices for third-generation cephalosporins and ciprofloxacin is associated with a reduction in meticillin-resistant Staphylococcus aureus bacteraemia rate.

To decrease the incidence of hospital infections caused by meticillin-resistant Staphylococcus aureus (MRSA), an educational intervention study was performed in which the use of intravenous ciprofloxacin and third-generation cephalosporins was discouraged. The effect was assessed by observing the MRSA bacteraemia rate both within the hospital and the intensive care unit for 18 months before, and 16 months after, the two-month intervention programme. MRSA bacteraemia rate throughout the hospital was reduced by 62.9% (P<0.001) by the end of the study and MRSA colonisation rate was reduced by 38.4% (not significant). There was no concomitant decrease in episodes of bacteraemia caused by meticillin-susceptible Staphylococcus aureus (MSSA) during the study period. There was a fall in hospital dispensing of both ciprofloxacin (80.4%) and third-generation cephalosporins (75.2%). The overall incidence of MRSA bloodstream infections within critical care was reduced (4.200 vs 0.272 per 1000 occupied bed-days) but this was not significant.

Fingering instabilities in dewetting nanofluids.

The growth of fingering patterns in dewetting nanofluids (colloidal solutions of thiol-passivated gold nanoparticles) has been followed in real time using contrast-enhanced video microscopy. The fingering instability on which we focus here arises from evaporatively driven nucleation and growth in a nanoscopically thin precursor solvent film behind the macroscopic contact line. We find that well-developed isotropic fingering structures only form for a narrow range of experimental parameters. Numerical simulations, based on a modification of the Monte Carlo approach introduced by Rabani et al. [Nature (London) 426, 271 (2003)10.1038/nature02087], reproduce the patterns we observe experimentally.

Coerced mechanical coarsening of nanoparticle assemblies.

Coarsening is a ubiquitous phenomenon that underpins countless processes in nature, including epitaxial growth, the phase separation of alloys, polymers and binary fluids, the growth of bubbles in foams, and pattern formation in biomembranes. Here we show, in the first real-time experimental study of the evolution of an adsorbed colloidal nanoparticle array, that tapping-mode atomic force microscopy (TM-AFM) can drive the coarsening of Au nanoparticle assemblies on silicon surfaces. Although the growth exponent has a strong dependence on the initial sample morphology, our observations are largely consistent with modified Ostwald ripening processes. To date, ripening processes have been exclusively considered to be thermally activated, but we show that nanoparticle assemblies can be mechanically coerced towards equilibrium, representing a new approach to directed coarsening. This strategy enables precise control over the evolution of micro- and nanostructures.

Postoperative stay following colorectal surgery: a study of factors associated with prolonged hospital stay.

AIM: To study the factors that contribute to postoperative stay following colorectal surgery. DESIGN: A prospective observational study. SETTING: Three colorectal surgical units - a teaching hospital, a large district general hospital and a district general hospital. PARTICIPANTS: 350 patients undergoing colorectal surgery. MAIN OUTCOME MEASURES: 28 pre-, peri- and postoperative patient- and treatment-related factors. RESULTS: Stepwise regression analysis suggests that the factors that significantly lengthen postoperative stay include a low albumin on admission, stoma formation, operative blood loss, urinary and respiratory complications, wound infections, postoperative ventilation and social delay at the time of discharge. The postoperative stay was not affected by patient age or by the seniority of the surgical team. CONCLUSIONS: Factors have been identified that determine the postoperative length of stay. These data may allow better planning and treatment of patients undergoing colorectal surgery.

Seasonal variation in admission rates to intensive care units.

Intensive care physicians perceive that there is seasonal variation in the number of admissions to critical care services. There is, however, little published evidence to support this belief. Data were therefore collected from five adjacent critical care units in the eastern region over a period of 8 years, in order to quantify any seasonal variation that may exist. Data on 16 355 critically ill patients were obtained between 1992 and 2000. Analysis showed clear winter peaks; December had a 30% higher admission rate than the quietest month, February. There was a small, but increasing, summer peak. The admission rate also exhibits an increasing linear trend, equivalent to a 6.6% annual increase in admissions per critical care bed. We conclude that there is significant seasonal variation in critical care activity, and that this is important to consider when planning services.