166 research outputs found
Application of Biotechnology to Solve Relevant Biological Problems Promotes Understanding of Underlying Concepts
Although some efforts have been made to modify the curriculum of the Introductory Biology laboratories from a passive to a more experimental form, the use of modern biotechnology had not been implemented at our institution. The need to understand the applications of modern technology to real-life situations seems imperative at the turn of the century [1,2]. Because several studies have shown that the study of biotechnology by itself does not increase conceptual understanding, the objective of this research was to determine if the use of biotechnology to solve relevant biological problems increased conceptual understanding among our students. We designed two complex problems: one on the conservation of an endangered Puerto Rican frog, and the other on tropical plant evolution. Two students majoring in Biology-Education participated as research assistants in the design and implementation of the laboratory activities. Graduate biology students who worked as teaching assistants in the laboratories were trained to use equipment and teach the activities. Assessment evidence indicated that students exposed to these experiences: (1) increased biological literacy by understanding the use and application of cutting-edge biotechnology; (2) were able to make connections between organismal and molecular biology; (3) decreased levels of anxiety and insecurity associated with the use of laboratory equipment; and, (4) were motivated to conduct research within and beyond the classroom setting
Systems Medicine: from molecular features and models to the clinic in COPD
BACKGROUND AND HYPOTHESIS: Chronic Obstructive Pulmonary Disease (COPD) patients are characterized by heterogeneous clinical manifestations and patterns of disease progression. Two major factors that can be used to identify COPD subtypes are muscle dysfunction/wasting and co-morbidity patterns. We hypothesized that COPD heterogeneity is in part the result of complex interactions between several genes and pathways. We explored the possibility of using a Systems Medicine approach to identify such pathways, as well as to generate predictive computational models that may be used in clinic practice. OBJECTIVE AND METHOD: Our overarching goal is to generate clinically applicable predictive models that characterize COPD heterogeneity through a Systems Medicine approach. To this end we have developed a general framework, consisting of three steps/objectives: (1) feature identification, (2) model generation and statistical validation, and (3) application and validation of the predictive models in the clinical scenario. We used muscle dysfunction and co-morbidity as test cases for this framework. RESULTS: In the study of muscle wasting we identified relevant features (genes) by a network analysis and generated predictive models that integrate mechanistic and probabilistic models. This allowed us to characterize muscle wasting as a general de-regulation of pathway interactions. In the co-morbidity analysis we identified relevant features (genes/pathways) by the integration of gene-disease and disease-disease associations. We further present a detailed characterization of co-morbidities in COPD patients that was implemented into a predictive model. In both use cases we were able to achieve predictive modeling but we also identified several key challenges, the most pressing being the validation and implementation into actual clinical practice. CONCLUSIONS: The results confirm the potential of the Systems Medicine approach to study complex diseases and generate clinically relevant predictive models. Our study also highlights important obstacles and bottlenecks for such approaches (e.g. data availability and normalization of frameworks among others) and suggests specific proposals to overcome them
Disentangling host, pathogen, and environmental determinants of a recently emerged wildlife disease: lessons from the first 15Â years of amphibian chytridiomycosis research
The amphibian fungal disease chytridiomycosis, which affects species across all continents, recently emerged as one of the greatest threats to biodiversity. Yet, many aspects of the basic biology and epidemiology of the pathogen, Batrachochytrium dendrobatidis (Bd), are still unknown, such as when and from where did Bd emerge and what is its true ecological niche? Here, we review the ecology and evolution of Bd in the Americas and highlight controversies that make this disease so enigmatic. We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment. Reevaluating the causes of the panzootic is timely given the wealth of data on Bd prevalence across hosts and communities and the recent discoveries suggesting coâevolutionary potential of hosts and Bd. We generate a new species distribution model for Bd in the Americas based on over 30,000 records and suggest a novel future research agenda. Instead of focusing on pathogen âhot spots,â we need to identify pathogen âcold spotsâ so that we can better understand what limits the pathogen's distribution. Finally, we introduce the concept of âthe Ghost of Epizootics Pastâ to discuss expected patterns in postepizootic host communities.We review the ecology and evolution of amphibian fungal disease chytridiomycosis in the Americas, where it has recently emerged as one of the greatest threats to biodiversity and highlight controversies that make this disease so enigmatic. We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment. We generate a new species distribution model for Bd in the Americas based on over 30,000 records, which suggests emphasis needs to be placed on studying pathogen âcold spotsâ so that we can better understand what biotic and abiotic factors limit the pathogen's distribution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113682/1/ece31672_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/113682/2/ece31672.pd
Spin Caloritronics
This is a brief overview of the state of the art of spin caloritronics, the
science and technology of controlling heat currents by the electron spin degree
of freedom (and vice versa).Comment: To be published in "Spin Current", edited by S. Maekawa, E. Saitoh,
S. Valenzuela and Y. Kimura, Oxford University Pres
Adaptive remodeling of the bacterial proteome by specific ribosomal modification regulates Pseudomonas infection and niche colonisation
Post-transcriptional control of protein abundance is a highly important, underexplored regulatory process by which organisms respond to their environments. Here we describe an important and previously unidentified regulatory pathway involving the ribosomal modification protein RimK, its regulator proteins RimA and RimB, and the widespread bacterial second messenger cyclic-di-GMP (cdG). Disruption of rimK affects motility and surface attachment in pathogenic and commensal Pseudomonas species, with rimK deletion significantly compromising rhizosphere colonisation by the commensal soil bacterium P. fluorescens, and plant infection by the pathogens P. syringae and P. aeruginosa. RimK functions as an ATP-dependent glutamyl ligase, adding glutamate residues to the C-terminus of ribosomal protein RpsF and inducing specific effects on both ribosome protein complement and function. Deletion of rimK in P. fluorescens leads to markedly reduced levels of multiple ribosomal proteins, and also of the key translational regulator Hfq. In turn, reduced Hfq levels induce specific downstream proteomic changes, with significant increases in multiple ABC transporters, stress response proteins and non-ribosomal peptide synthetases seen for both ÎrimK and Îhfq mutants. The activity of RimK is itself controlled by interactions with RimA, RimB and cdG. We propose that control of RimK activity represents a novel regulatory mechanism that dynamically influences interactions between bacteria and their hosts; translating environmental pressures into dynamic ribosomal changes, and consequently to an adaptive remodeling of the bacterial proteome
Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity
Anthropogenic trade and development have broken down dispersal barriers, facilitating the spread of diseases that threaten Earth's biodiversity. We present a global, quantitative assessment of the amphibian chytridiomycosis panzootic, one of the most impactful examples of disease spread, and demonstrate its role in the decline of at least 501 amphibian species over the past half-century, including 90 presumed extinctions. The effects of chytridiomycosis have been greatest in large-bodied, range-restricted anurans in wet climates in the Americas and Australia. Declines peaked in the 1980s, and only 12% of declined species show signs of recovery, whereas 39% are experiencing ongoing decline. There is risk of further chytridiomycosis outbreaks in new areas. The chytridiomycosis panzootic represents the greatest recorded loss of biodiversity attributable to a disease
Bone mineral density in Jamaican men on androgen deprivation therapy for prostate cancer
<p>Abstract</p> <p>Background</p> <p>Androgen deprivation therapy (ADT) has been reported to reduce the bone mineral density (BMD) in men with prostate cancer (CaP). However, Afro-Caribbeans are under-represented in most studies. The aim was to determine the effect of androgen deprivation therapy (ADT) on the bone mineral density (BMD) of men with prostate cancer in Jamaica.</p> <p>Methods</p> <p>The study consisted of 346 Jamaican men, over 40 years of age: 133 ADT treated CaP cases (group 1), 43 hormone-naïve CaP controls (group 2) and 170 hormone naïve controls without CaP (group 3). Exclusion criteria included metastatic disease, bisphosphonate therapy or metabolic disease affecting BMD. BMD was measured with a calcaneal ultrasound and expressed in S.D. units relative to young adult men (T score), according to the World Health Organization definition. Patient weight, height and BMI were assessed.</p> <p>Results</p> <p>Mean ± sd, age of patients in group 1 (75± 7.4 yrs) was significantly greater than groups 2 and 3 (67 ± 8.1 yrs; 65±12.0 yrs). There was no significant difference in weight and BMI between the 3 groups. . The types of ADT (% of cases, median duration in months with IQR) included LHRH (Luteinizing hormone releasing hormone) analogues (28.6%, 17.9, IQR 20.4), oestrogens (9.8%, 60.5, IQR 45.6) anti-androgens (11.3%, 3.3, IQR 15.2) and orchiectomy (15.7%, 43.4, IQR 63.9). Unadjusted t score of group 1, mean ± sd, (-1.6± 1.5) was significantly less than group 2 (-0.9±1.1) and group 3 (-0.7±1.4), p <0.001. Ninety three (69.9%), 20 (45%) and 75 (42%) of patients in groups 1, 2 and 3 respectively were classified as either osteopenic or osteoporotic (p<0.001). Adjusting for age, there was a significant difference in t scores between groups 1 and 2 as well as between groups 1 and 3 (p<0.001). Compared with oestrogen therapy and adjusting for duration of therapy, the odds of low bone mineral density (osteopenia or osteoporosis) with LHRH analogue was 4.5 (95%CI, 14.3 to 3.4); with anti-androgens was 5.9 (95%CI, 32.7 to 5); with orchiectomy was 7.3 (95%CI, 30 to 5.8) and multiple drugs was 9.2 ((95%CI, 31 to 7.1).</p> <p>Conclusions</p> <p>ADT is associated with lower BMD in Jamaican men on hormonal therapy for prostate cancer.</p
A systemic framework based on Soft OR approaches to support teamwork strategy: an aviation manufacturer Brazilian company case
The paper reports on the application of a combination of Operational Research (OR) approaches to a real-world case of re-designing the strategy of a department management team, in an aircraft manufacturing organization in Brazil. We combine approaches from âSoftâ OR Problem Structuring Methods in a multi-methodological framework arguing that this helps to discuss, develop and implement a new departmental strategy. The proposed framework uses elements of Soft Systems Methodology; Strategic Options Development and Analysis to understand and structure the situation; Value-Focused Thinking to define the means and objectives; and Value-Focused Brainstorming to highlight the potential solutions. We conceptualize a four-phased systemic framework linking elements of the above four âSoftâ OR approaches and apply it to a real-world case in a department where a new team leader was appointed with the specific brief to improve the departmental strategy and its performance in general. Findings suggest that combining the approaches into a framework encourages trust and participation from stakeholders which, in practice, is translated into an improved strategy for the organization. A reflection on the multi-methodological approach is proposed. Conclusions and points for further research are suggested
Consumersâ values and behaviour in the Brazilian coffee-in-capsules market: Promoting circular economy
Coffee consumption is changing. Monodose, flavoured coffee capsules provide new experiences beyond the traditional custom of brewing coffee. While these pods mean access to a selection of premium coffee worldwide, they create huge quantities of plastic-aluminium packaging waste. This paper examines the novelty of coffee capsule consumption in Brazil in terms of consumersâ perspectives about ethical enterprise and environmental stewardship. We argue for âwaste to resourceâ management and applying reverse logistics to the coffee production supply chain. Based on Circular Economy principles and fuelled by the âgreenâ awareness of Brazilian coffee consumers themselves, we propose a conceptual framework to support business decision-making by adopting a systemic intervention from the consumer viewpoint. To structure and scope the problematic situation, we conducted over 40 interviews, using purposive sampling. Analytic Hierarchy Process (AHP), Value Focused Thinking (VFT) and Rich Picture Technique also informed our problem structuring approach. Findings illustrate that the ambition for a reverse supply chain in coffee capsule manufacturing presents real challenges to achieving circular practice. Yet, the eco-values of Brazilian coffee enthusiasts may be partly considered a âwealth of information flowâ and a potential driving force for change. This paper should be of interest to researchers and practitioners exploring how consumers may contribute to behavioural change, towards more circular business
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