Universality in Bacterial Colonies

The emergent spatial patterns generated by growing bacterial colonies have been the focus of intense study in physics during the last twenty years. Both experimental and theoretical investigations have made possible a clear qualitative picture of the different structures that such colonies can exhibit, depending on the medium on which they are growing. However, there are relatively few quantitative descriptions of these patterns. In this paper, we use a mechanistically detailed simulation framework to measure the scaling exponents associated with the advancing fronts of bacterial colonies on hard agar substrata, aiming to discern the universality class to which the system belongs. We show that the universal behavior exhibited by the colonies can be much richer than previously reported, and we propose the possibility of up to four different sub-phases within the medium-to-high nutrient concentration regime. We hypothesize that the quenched disorder that characterizes one of these sub-phases is an emergent property of the growth and division of bacteria competing for limited space and nutrients.Comment: 12 pages, 5 figure

Non-aqueous Isorefractive Pickering Emulsions

Non-aqueous Pickering emulsions of 16–240 μm diameter have been prepared using diblock copolymer worms with ethylene glycol as the droplet phase and an n-alkane as the continuous phase. Initial studies using n-dodecane resulted in stable emulsions that were significantly less turbid than conventional water-in-oil emulsions. This is attributed to the rather similar refractive indices of the latter two phases. By utilizing n-tetradecane as an alternative oil that almost precisely matches the refractive index of ethylene glycol, almost isorefractive ethylene glycol-in-n-tetradecane Pickering emulsions can be prepared. The droplet diameter and transparency of such emulsions can be systematically varied by adjusting the worm copolymer concentration

Heart Transplantation Survival and the Use of Traumatically Brain-Injured Donors: UNOS Registry Propensity-Matched Analysis

Background-The transplantation of hearts from traumatically brain-injured (TBI) donors has been associated with inferior long-term survival in single-center analyses. However, in a more recent analysis, death caused by cerebrovascular accident was associated with worse posttransplant survival in recipients. The purpose of this study was to explore the outcomes of heart transplantation in recipients receiving donor hearts from TBI and non-TBI donors in a large national registry. Methods and Results-We performed a retrospective cohort analysis of the UNOS (United Network of Organ Sharing) Registry Organ Procurement and Transplantation Network between 2006 and 2018 for adult candidates wait-listed for isolated heart transplantation. Recipients were stratified into 2 groups, TBI and non-TBI donors. Propensity score matching was performed. Kaplan-Meier analysis was used to estimate survival posttransplant. A total of 24 894 candidates met inclusion criteria. TBI was the leading cause of death in the donor population. Recipients of TBI donor hearts (N=13 07) were younger (median age, 55 versus 57 years; P<0.001) and less likely women (21.6% versus 29.8%; P<0.001). At 10 years, the TBI group had better long-term survival compared with the non-TBI group (62.8% versus 59.9%; P<0.001). After propensity group matching, the 10-year survival was similar between groups. Conclusions-In the largest analysis of heart transplants and their survival, according to the type of donor injury (TBI versus non-TBI), we found similar survival in heart transplant recipients. Future studies should address specific subpopulations (eg, hemorrhagic stroke) in the non-TBI group to address concerns about reduced posttransplant survival.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Thoracic metastasectomy for adoptive immunotherapy of melanoma: A single-institution experience

Although refractory to chemotherapy, metastatic melanoma may respond to adoptive immunotherapy. As novel treatments evolve, surgeons may be asked to perform metastasectomy not only for palliation or potential cure but also for isolation of tumor-infiltrating lymphocytes. This study was undertaken to examine outcomes of patients with melanoma undergoing thoracic metastasectomy in preparation for investigational immunotherapy. A retrospective review identified 107 consecutive patients who underwent 116 thoracic metastasectomy procedures from April 1998 to July 2009. Indications for surgical intervention included procurement of tumor-infiltrating lymphocytes, rendering of patients to no evaluable disease status, palliation, and diagnosis. Response Evaluation Criteria in Solid Tumors criteria were used to assess tumor response. Thoracotomy, lobectomy, and video-assisted thoracoscopic surgery with nonanatomic resection were the most common procedures. Major complications included 1 death and 1 coagulopathy-induced hemothorax. Seventeen patients were rendered to no evaluable disease status. Virtually all patients with residual disease had tumor specimens cultured for tumor-infiltrating lymphocytes; approximately 70% of tumor-infiltrating lymphocyte cultures exhibited antitumor reactivity. Of the 91 patients with residual or recurrent disease, 24 (26%) underwent adoptive cell transfer of tumor-infiltrating lymphocytes, of whom 7 exhibited objective responses (29% response rate and 8% based on intent to treat). Rapid disease progression precluded tumor-infiltrating lymphocyte therapy in most cases. Actuarial 1- and 5-year survival rates for patients rendered to no evaluable disease status or receiving or not receiving tumor-infiltrating lymphocytes were 93% and 76%, 64% and 33%, and 43% and 0%, respectively. Relatively few patients currently having thoracic metastasectomy undergo adoptive cell transfer. Continued refinement of tumor-infiltrating lymphocyte expansion protocols and improved patient selection might increase the number of patients with melanoma benefiting from these interventions