Restored floodplains enhance denitrification compared to naturalized floodplains in agricultural streams

Predicted changes in the timing and magnitude of storms have the potential to amplify water quality challenges associated with agricultural runoff. In agricultural streams of the Midwestern US, floodplain restoration has the potential to enhance inorganic nitrogen (N) removal by increasing the bioreactive surface area for microbially-mediated denitrification. The restoration of inset floodplains via construction of the two-stage ditch increases denitrification compared to channelized systems, however, little is known about how denitrification on restored floodplains compares to those formed naturally when stream channel management lapses. We used sacrificial microcosm incubations and membrane-inlet mass spectrometry (MIMS) to compare denitrification rates in floodplain soils collected along transects in both naturalized and restored floodplains; longitudinal transects spanned two zones in the active floodplain (near-stream, NS vs. middle, MID) and a third zone that reflected upland conditions in the riparian buffer strip (UP). Denitrification rates were 35–49% higher in the restored, inset floodplains compared to naturalized floodplains. Variation in denitrification rates were primarily explained by soil organic matter (OM) and OM was > 20% higher in restored floodplains than naturalized, highlighting the contrasts between stable, constructed floodplains with heterogeneous, depositional bars typical of naturalizing channels. Consequently, restored inset floodplains could remove > 70% more N than the naturalized floodplains during similar storm inundation events.     

Knowledge and power in the clinical setting

In this paper we consider the three categories offered by Howard Brody for understanding power in medicine. In his book, The Healer's Power Brody separates out power in medicine into the categories of Aesculapian, Social, and Charismatic power. We examine these three categories and then apply them to a case. In this case set in an Obstetric ward, a junior member of the medical staff makes a clinical decision about a patient. This clinical decision is overruled by a senior medical staff member who then carries out his plan with disastrous consequences for the woman and her baby. This case challenges the three categories of power offered by Brody and highlights the need for a further category of Hierarchical power to be added to Brody's framework. We conclude by suggesting that there is a need to recognise the discrepancy in power not only between physician and patient but also between senior and junior staff in a clinical setting.     

The isolation and biochemical characterization of three subfractions of myelin from central nervous tissue of the adult rat

Abstract— By techniques of isosmotic density gradient ultracentrifugation three subfractions of myelin were isolated from homogenates of whole rat brain at densities of 1.054 g/ml (myelin I), 1.060 g/ml (myelin II) and 1.066 g/ml (myelin III). The stability of these fractions was demonstrated by the zonal centrifuge profile analysis of recycled fractions. Examination of the three myelin subfractions by techniques of electron microscopy and thin layer chromatography detected no obvious morphological or chemical differences. However, analysis for protein, cholesterol, phospholipids and cerebrosides did reveal differences among myelin I, myelin II and myelin III. Myelin I contained relatively more cholesterol than II or III. Myelin III contained relatively more phospholipids than I or II. The cerebroside-to-protein ratios were the same in all three fractions. Quantitative differences in fatty acid composition (as detected by gas-liquid chromatography) were also observed.     

A comparison of five methods for obtaining the intrinsic viscosity of bovine serum albumin

Intrinsic viscosity [η] is a characteristic of proteins and other molecules related directly to their ability to disturb flow and indirectly to their size and shape. It is usually determined by extrapolating reduced viscosity to zero concentration. Four other methods for deriving [η] have been utilized by previous investigators. Studies of the intrinsic viscosity of bovine serum albumin had been carried out two years apart as a test of viscometry technique; the data obtained were used to compare the five methods. Four of the five produced [η] values ranging from 3.92 to 4.21 ml/g. Agreement was good between the two studies. The five methods were compared to each other using linearity of regression, statistical error of determination, effect of varying solvent time, and result obtained in different concentration ranges. By these four criteria, use of the regression of specific fluidity (1 ? 1/η_rel) with concentration was found superior to other methods. Its only deficiency was a requirement that solution density be corrected for at each concentration studied rather than applying a single correction for density after using kinematic viscosity data. All methods for deriving intrinsic viscosity are based on one of three equations; flow is expressed either in terms of reduced viscosity (Huggins), inherent viscosity (Kraemer), or specific fluidity. Of these three equations, specific fluidity is the most closely related both to theoretical analyses and to experimental studies of rigid spheres. There is abundant evidence in past reports that in contrast to rigid spheres, flexible polymers do not produce a linear rise in specific fluidity as their concentration increases, strongly suggesting that their molecular conformation is changing with concentration. A linear relation between fluidity and concentration has been observed for almost all proteins and protein mixtures studied. When this linear relation is present it indicates both that molecular conformation during flow is independent of concentration in the range studied and that the specific fluidity method for deriving intrinsic viscosity is the most appropriate.     

Zonal centrifuge profiles of rat brain homogenates: Instability in sucrose,stability in iso-osmotic Ficoll-sucrose

By substituting iso-osmotic Ficoll-sucrose for hyperosmotic sucrose between the densities of 1.043 and 1.088 in sucrose density gradients in the B-XV rotor of an Anderson-NIH-AEC zonal centrifuge system, it was possible to stabilize the zonal centrifuge absorbancy profiles of adult rat brain homogenates. The reason for the instability in ordinary sucrose gradients was found to be the interaction of myelin with other brain structures in hyperosmotic sucrose. No such interaction occurred in isoosmotic sucrose (0.32 M) with or without Ficoll. In Ficoll-sucrose, myelin was separated at three reproducible densities of 1.054, 1.060, and 1.066 gm/ml. No myelin appeared at a density if 1.094 gm/ml, which represented the main collection point in ordinary sucrose. Synaptosomes were separated at peak densities of 1.072 and 1.152 gm/ml. Mitochondria were obtained at a density of 1.176 gm/ml. Areas under zonal centrifuge absorbancy profiles of rat brain homogenates were found to be constant regardless of the values of ω²t that were reached.     

Remobilizing <Emphasis Type="Italic">netukulimk</Emphasis>: indigenous cultural and spiritual connections with resource stewardship and fisheries management in Atlantic Canada

Recent global initiatives such as the United Nations Declaration on the Rights of Indigenous Peoples have brought the issues facing and needs of Indigenous peoples to the forefront of international attention. While underscoring respect for traditional practices, these initiatives have yet to appreciate fully the extent to which Indigenous peoples’ practices engage ways of being, living and believing that encompass a holistic understanding of the relations between humans and all facets of their ecosystems. The Mi’kmaw, a nation of Indigenous peoples in Atlantic Canada, work to recapture and express ancient holistic understandings through their contemporary natural resource management aspirations and practices. In this paper we review key colonial events that have impacted Indigenous relations with settlers and resulted in historical marginalization of the Mi’kmaw from fishery policy and management processes. We provide an overview and discussion of recent developments wherein the Mi’kmaw are working to revitalize the place of netukulimk, a concept that embraces cultural and spiritual connections with resource stewardship, in the exercise of treaty-based rights, particularly within self-governing fisheries management initiatives. We conclude with the core attributes of Two-Eyed Seeing, a methodological framework for collaborative, decolonizing research practices and Indigenous knowledge mobilization strategies. The Mi’kmaw experiences provide insights regarding the challenges and requirements for achieving respect for Indigenous traditional practices and point a way forward for more effective and inclusive stewardship of natural aquatic resources into the future.     

Semi-Automated Digital Image Analysis of Pick’s Disease and TDP-43 Proteinopathy

Digital image analysis of histology sections provides reliable, high-throughput methods for neuropathological studies but data is scant in frontotemporal lobar degeneration (FTLD), which has an added challenge of study due to morphologically diverse pathologies. Here, we describe a novel method of semi-automated digital image analysis in FTLD subtypes including: Pick’s disease (PiD, n=11) with tau-positive intracellular inclusions and neuropil threads, and TDP-43 pathology type C (FTLD-TDPC, n=10), defined by TDP-43-positive aggregates predominantly in large dystrophic neurites. To do this, we examined three FTLD-associated cortical regions: mid-frontal gyrus (MFG), superior temporal gyrus (STG) and anterior cingulate gyrus (ACG) by immunohistochemistry. We used a color deconvolution process to isolate signal from the chromogen and applied both object detection and intensity thresholding algorithms to quantify pathological burden. We found object-detection algorithms had good agreement with gold-standard manual quantification of tau- and TDP-43-positive inclusions. Our sampling method was reliable across three separate investigators and we obtained similar results in a pilot analysis using open-source software. Regional comparisons using these algorithms finds differences in regional anatomic disease burden between PiD and FTLD-TDP not detected using traditional ordinal scale data, suggesting digital image analysis is a powerful tool for clinicopathological studies in morphologically diverse FTLD syndromes.     

Macrophage trafficking in the uterus and cervix precedes parturition in the mouse.

Immune activation is implicated in the etiology of preterm labor, but little is known about macrophage number or distribution in the uterus or cervix at term. This study tested the hypothesis that macrophages migrate into the reproductive tract before the onset of parturition. Paraffin-embedded sections from the mid-uterine horn and cervix of C3/HeN mice on Days 15 and 18 of pregnancy, the day of birth (Day 19), and 1 day postpartum were stained with a pan-macrophage marker to analyze cell numbers and distribution. During pregnancy, uterine macrophages were dispersed in endometrium, usually associated with vasculature and subluminal epithelium. In myometrium, macrophages were clustered in stromal connective tissue; near term and postpartum, cells appeared to surround the muscle bundles. Total macrophage numbers were increased on Day 15 relative to those in nonpregnant controls, declined before birth, and increased postpartum. In the cervix, macrophages congregated in subepithelium, often perivascular or near ganglia. Macrophage numbers in the cervix peaked on Day 18, then declined to nonpregnant levels by the day after birth. Thus, macrophage numbers in the uterus were inversely related to those in the cervix. These findings raise the possibility that macrophages and their products may be involved in uterine contractility and cervical remodeling during the processes of parturition.