Microstructural damage of the posterior corpus callosum contributes to the clinical severity of neglect

One theory to account for neglect symptoms in patients with right focal damage invokes a release of inhibition of the right parietal cortex over the left parieto-frontal circuits, by disconnection mechanism. This theory is supported by transcranial magnetic stimulation studies showing the existence of asymmetric inhibitory interactions between the left and right posterior parietal cortex, with a right hemispheric advantage. These inhibitory mechanisms are mediated by direct transcallosal projections located in the posterior portions of the corpus callosum. The current study, using diffusion imaging and tract-based spatial statistics (TBSS), aims at assessing, in a data-driven fashion, the contribution of structural disconnection between hemispheres in determining the presence and severity of neglect. Eleven patients with right acute stroke and 11 healthy matched controls underwent MRI at 3T, including diffusion imaging, and T1-weighted volumes. TBSS was modified to account for the presence of the lesion and used to assess the presence and extension of changes in diffusion indices of microscopic white matter integrity in the left hemisphere of patients compared to controls, and to investigate, by correlation analysis, whether this damage might account for the presence and severity of patients' neglect, as assessed by the Behavioural Inattention Test (BIT). None of the patients had any macroscopic abnormality in the left hemisphere; however, 3 cases were discarded due to image artefacts in the MRI data. Conversely, TBSS analysis revealed widespread changes in diffusion indices in most of their left hemisphere tracts, with a predominant involvement of the corpus callosum and its projections on the parietal white matter. A region of association between patients' scores at BIT and brain FA values was found in the posterior part of the corpus callosum. This study strongly supports the hypothesis of a major role of structural disconnection between the right and left parietal cortex in determining 'neglect'

A review of the surgical options for the correction of presbyopia

Presbyopia is an age-related eye condition where one of the signs is the reduction in the amplitude of accommodation, resulting in the loss of ability to change the eye's focus from far to near. It is the most common age-related ailments affecting everyone around their mid-40s. Methods for the correction of presbyopia include contact lens and spectacle options but the surgical correction of presbyopia still remains a significant challenge for refractive surgeons. Surgical strategies for dealing with presbyopia may be extraocular (corneal or scleral) or intraocular (removal and replacement of the crystalline lens or some type of treatment on the crystalline lens itself). There are however a number of limitations and considerations that have limited the widespread acceptance of surgical correction of presbyopia. Each surgical strategy presents its own unique set of advantages and disadvantages. For example, lens removal and replacement with an intraocular lens may not be preferable in a young patient with presbyopia without a refractive error. Similarly treatment on the crystalline lens may not be a suitable choice for a patient with early signs of cataract. This article is a review of the options available and those that are in development stages and are likely to be available in the near future for the surgical correction of presbyopia

Assessment of finite volume modeling approaches for intermediate temperature Solid Oxide Fuel Cells working with CO-rich syngas fuels

The application of Solid Oxide Fuel Cells (SOFCs) to a wide variety of syngas fuels, as those generated from coal or biomass gasification, may represent an important opportunity for the improvement of electric efficiency and for emission reduction in the electric sector. The paper presents an assessment of the impact on SOFC performance prediction of the effect of the combined electrochemical oxidation of CO and H2, proposing additional analyses to delve into the effects of different SMR and WGS kinetics models, along with the risk of carbon deposition. The work is based on a finite-volume model for SOFC simulation, updated to examine two different electrochemical reaction approaches where (i) the first considers only the electrochemical conversion of H2 and neglects the possibility of a direct CO oxidation at electrode surface; (ii) the second calculates the current contribution of both H2 and CO oxidation. The two models are compared against different test cases with low and high-CO syngas, representative of different primary fuels, discussing the relative proportion of H2 and CO-related current densities depending on the inlet fuel composition. A sensitivity analysis is carried out on the electrochemical model, focusing on the activation overpotentials. We show that the resulting enhanced H2–CO electrochemical model allows a better understanding of the fuel composition and H2/CO ratios effect on the cell performances

Growth of Pseudomonas aeruginosa in zinc poor environments is promoted by a nicotianamine-related metallophore

Previous studies have suggested that P. aeruginosa possesses redundant zinc uptake systems. To identify uncharacterized zinc transporters, we analyzed the genome-wide transcriptional responses of P. aeruginosa PA14 to zinc restriction. This approach led to the identification of an operon (zrmABCD) regulated by the zinc uptake regulator Zur, that encodes for a metallophore-mediated zinc import system. This operon includes the genes for an uncharacterized TonB-dependent Outer Membrane Protein (ZrmA) and for a putative nicotianamine synthase (ZrmB). The simultaneous inactivation of the ZnuABC transporter and of one of these two genes markedly decreases the ability of P. aeruginosa to grow in zinc-poor media and compromises intracellular zinc accumulation. Our data demonstrate that ZrmB is involved in the synthesis of a metallophore which is released outside the cell and mediates zinc uptake through the ZrmA receptor. We also show that alterations in zinc homeostasis severely affect the ability of P. aeruginosa to cause acute lung and systemic infections in C57BL/6 mice, likely due to the involvement of zinc in the expression of several virulence traits. These findings disclose a hitherto unappreciated role of zinc in P. aeruginosa pathogenicity and reveal that this microorganism can obtain zinc through a strategy resembling siderophore-mediated iron uptake

LOCOREGIONAL RECURRENCE AFTER CONSERVATIVE SURGERY FOR DUCTAL BREAST CANCER: ROLE OF SURGICAL MARGIN

Non

Classical Cyclophosphamide, Methotrexate, and Fluorouracil Chemotherapy Is More Effective in Triple-Negative, Node-Negative Breast Cancer: Results From Two Randomized Trials of Adjuvant Chemoendocrine Therapy for Node-Negative Breast Cancer

Purpose Retrospective studies suggest that primary breast cancers lacking estrogen receptor (ER) and progesterone receptor (PR) and not overexpressing human epidermal growth factor receptor 2 (HER2; triple-negative tumors) are particularly sensitive to DNA-damaging chemotherapy with alkylating agents. Patients and Methods Patients enrolled in International Breast Cancer Study Group Trials VIII and IX with node-negative, operable breast cancer and centrally assessed ER, PR, and HER2 were included (n 2,257). The trials compared three or six courses of adjuvant classical cyclophosphamide, methotrexate, and fluorouracil (CMF) with or without endocrine therapy versus endocrine therapy alone. We explored patterns of recurrence by treatment according to three immunohistochemically defined tumor subtypes: triple negative, HER2 positive and endocrine receptor absent, and endocrine receptor present. Results Patients with triple-negative tumors (303 patients; 13%) were significantly more likely to have tumors 2 cm and grade 3 compared with those in the HER2-positive, endocrine receptor– absent, and endocrine receptor–present subtypes. No clear chemotherapy benefit was observed in endocrine receptor–present disease (hazard ratio [HR], 0.90; 95% CI, 0.74 to 1.11). A statistically significantly greater benefit for chemotherapy versus no chemotherapy was observed in triplenegative breast cancer (HR, 0.46; 95% CI, 0.29 to 0.73; interaction P .009 v endocrine receptor–present disease). The magnitude of the chemotherapy effect was lower in HER2-positive endocrine receptor–absent disease (HR, 0.58; 95% CI, 0.29 to 1.17; interaction P .24 v endocrine receptor–present disease). Conclusion The magnitude of benefit of CMF chemotherapy is largest in patients with triple-negative, node-negative breast cancer