The mechanical and electrical properties of direct-spun carbon nanotube mats

The mechanical and electrical properties of a direct-spun carbon nanotube mat are measured. The mat comprises an interlinked random network of nanotube bundles, with approximately 40 nanotubes in a bundle. A small degree of in-plane anisotropy is observed. The bundles occasionally branch, and the mesh topology resembles a 2D lattice of nodal connectivity slightly below 4. The macroscopic in-plane tensile response is elasto-plastic in nature, with significant orientation hardening. In-situ microscopy reveals that the nanotube bundles do not slide past each other at their junctions under macroscopic strain. A micromechanical model is developed to relate the macroscopic modulus and flow strength to the longitudinal shear response of the nanotube bundles. The mechanical and electrical properties of the mat are compared with those of other nanotube arrangements over a wide range of density

Fracture testing of lithium‐ion battery cathode secondary particles in‐situ inside the scanning electron microscope

Fracture of cathode secondary particles is a critical degradation mechanism in lithium-ion batteries. The microindentation strength of LiNi0.8Mn0.1Co0.1O2 secondary particles is measured in situ in the scanning electron microscope (SEM), enabling dynamical imaging of fracture. Crack propagation is intergranular between primary particles when induced by compressing between flat platens (analogous to calendaring), and with a cono-spherical indenter (representing particle-particle contact). Fracture occurs directly beneath the cono-spherical tip and at the centre of secondary particles when compressed between flat platens. Finite element modelling of stress states provides insight into the dependence of fracture load upon cohesive strength and particle toughness. Secondary particle indentation strength decreases with increasing secondary particle size, with cycling, and with increasing state of charge. The indentation strength decrease is greatest in earlier stages of delithiation. The novel microindentation technique allows assessment of strength and toughness of different cathode morphologies, aiding prediction of optimal particle structure and processing conditions

The BioWipe: a non-invasive method to detect intestinal carriage of multi-drug resistant GRAM-negative bacteria

Colonization precedes infection and facilitates spread of several clinically important multidrug resistant organisms (MDRO). Reliable detection of carriage is important to improve our understanding of risk factors and spread of MDRO. Bacterial culture of stool samples obtained from peri-rectal swabs or whole stool is often used for this purpose. The previously described BioWipe method is a non-invasive stool collection method that resembles the use of toilet paper, and can be self-administered. The BioWipe consists of a 100×160 mm square of soft, absorbent synthetic fiber material attached to a plastic backing layer (Fisher Scientific, USA). It is used prior to using toilet paper after a bowel movement. The wipe with collected stool sample is placed onto the surface of an absorbent pad (3M™ Petroleum Sorbent Pads, Fisher Scientific, USA) containing modified Cary Blair transport media. The two parts are then folded together and placed inside a plastic bag. Prior to use, both components are treated with ultraviolet light irradiation in a biological safety cabinet for 30 minutes. After sample collection, the BioWipe is eluted with 20 mL mix of Phosphate Buffer Saline solution (PBS, pH=7.2) and 0.1% Tween 80 (vol/vol) directly in its original bag in a biosafety cabinet, until the stool sample is completely eluted. The resulting suspended stool sample is used for further processing

Use of boost radiotherapy in oncoplastic breast-conserving surgery – a systematic review

Background: The use of local boost radiotherapy to the tumour bed has been demonstrated in randomised-controlled trials to reduce local recurrence rates following breast-conserving surgery (BCS) and is the standard of care. Oncoplastic BCS techniques with parenchymal rearrangement present new challenges to the localisation of the tumour bed and therefore delivery of local boost radiotherapy. The aim of this review was to evaluate the reporting of boost radiotherapy in the oncoplastic BCS literature.<p></p> Methods: Pubmed, Ovid MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews were searched for studies reporting oncoplastic BCS using volume displacement techniques.<p></p> Results: 24 studies met the inclusion criteria (n = 1933 patients). Use of boost radiotherapy was reported in 11 studies, in 2 of which it was for the treatment of incomplete or close margins, and marking of the tumour bed was only reported in 8 studies. None of the studies reported the number of patients where the tumour bed could not be localised.<p></p> Conclusions: The use of local boost radiotherapy and tumour bed marking was not reported in the majority of studies of oncoplastic BCS. Future studies need to provide detailed information regarding the use of boost radiotherapy and difficulties determining the target volume so that current radiotherapy approaches can be reviewed and improved for these advanced techniques.<p></p&gt

Oncoplastic breast conservation surgery is oncologically safe when compared to wide local excision and mastectomy

Background: Support for the oncological safety of oncoplastic breast conservation surgery (OBCS) is mostly based on evidence comparing recurrence rates after OBCS to wide local excision (WLE). However, OBCS is often indicated for larger cancers and oncological results should also be compared to patients treated with mastectomy. In this study we compared recurrence and survival following OBCS, mastectomy and WLE. Methods: Patients treated with OBCS between 2009 and 2012 were identified from a prospectively maintained database. For comparison, consecutive patients treated with WLE or mastectomy with or without immediate reconstruction (Ms ± IR) over the same time period were identified. Histological variables of patients were compared using Fisher Exact or Chi squared tests, and recurrence and survival were compared using Kaplan-Meier and Cox regression survival analysis. Results: 980 patients' data were analysed (OBCS: n = 104; WLE: n = 558; Ms ± IR: n = 318). Tumour size, grade, nodal status, ER, and PR expression of patients treated with OBCS were all significantly more adverse compared with patients treated with WLE (p < 0.001). These histological variables were similar in patients treated with Ms ± IR and OBCS. 5-year local recurrence rates were similar in all three groups (WLE: 3.4 per cent, OBCS: 2 per cent, Ms ± IR: 2.6 per cent; log rank = 0.973), while distant recurrence rates were higher after Ms ± IR and OBCS (Ms ± IR:13.1 per cent, OBCS:7.5 per cent, WLE:3.3 per cent; log rank: p < 0.001). Conclusion: OBCS is oncologically safe in patients even when histological results are similar to patients treated with Ms ± IR

Mechanical properties of cathode materials for lithium-ion batteries

Mechanochemical degradation processes such as the fracture of cathode particles play a major role in limiting the service life of advanced lithium-ion batteries (LIBs). In order to help alleviate the degradation of battery performance, it is necessary to measure the relationship between the degradation of the mechanical properties of cathodes and their concomitant degradation of electrochemical performance. In this review, measurements of the mechanical properties of LIB cathode materials are summarized from the literature, along with the range of experimental methods used in their determination. Dimensional changes that accompany charge and discharge are compared for active materials of olivine, spinel, and layered atomic structures. The sensitivity of indentation hardness, Young's modulus and fracture strength to grain size, porosity, state of charge and charge/discharge history are critically reviewed and discussed with reference to the behavior of conventional, electrically inactive solids. This approach allows for the identification of microstructural properties that dictate the mechanical properties of LIB cathode materials

Geomorphology and earth system science

Earth system science is an approach to obtain a scientific understanding of the entire Earth system on a global scale by describing how its component parts and their interactions have evolved, how they function, and how they may be expected to continue to evolve on all time-scales. The aim of this review is to introduce some key examples showing the role of earth surface processes, the traditional subject of geomorphology, within the interacting Earth system. The paper considers three examples of environmental systems in which geomorphology plays a key role: (i) links between topography, tectonics, and atmospheric circulation; (ii) links between geomorphic processes and biogeochemical cycles; and (iii) links between biological processes and the earth’s surface. Key research needs are discussed, including the requirement for better opportunities for interdisciplinary collaboration, clearer mathematical frameworks for earth system models, and more sophisticated interaction between natural and social scientists