Motor units as tools to evaluate profile of human Renshaw inhibition

Although Renshaw inhibition (RI) has been extensively studied for decades, its precise role in motor control is yet to be discovered. One of the main handicaps is a lack of reliable methods for studying RI in conscious human subjects. We stimulated the lowest electrical threshold motor axons (thickest axons) in the tibial nerve and analysed the stimulus‐correlated changes in discharge of voluntarily recruited low‐threshold single motor units (SMUs) from the soleus muscle. In total, 54 distinct SMUs from 12 subjects were analysed. Stimuli that generated only the direct motor response (M‐only) on surface electromyography induced an inhibitory response in the low‐threshold SMUs. Because the properties of RI had to be estimated indirectly using the background discharge rate of SMUs, its profile varied with the discharge rate of the SMU. The duration of RI was found to be inversely proportional to the discharge rate of SMUs. Using this important finding, we have developed a method of extrapolation for estimating RI as it develops on motoneurons in the spinal cord. The frequency methods indicated that the duration of RI was between 30 and 40 ms depending on the background firing rate of the units, and the extrapolation indicated that RI on silent motoneurons was ∼55 ms. The present study establishes a novel methodology for studying RI in human subjects and hence may serve as a tool for improving our understanding of the involvement of RI in human motor control

Long-term effects of neoadjuvant chemoradiotherapy followed by sphincter-preserving resection on anal sphincter function in relation to quality of life among locally advanced rectal cancer patients: a cross-sectional analysis

BACKGROUND: There is growing recognition for the consequences of rectal cancer treatment to maintain an adequate functional sphincter in the long-term rather than preserving the anal sphincter itself. This study aims to evaluate long-term effects of neoadjuvant chemoradiotherapy (nCRT) followed by sphincter-preserving resection on anal sphincter function in relation to quality of life (QoL) among locally advanced rectal cancer patients. METHODS: Twenty-nine patients treated with nCRT followed by low anterior resection surgery were included in this study. Data on patient demographics, tumor location and symptoms of urgency and fecal soiling were recorded and evaluated with respect to Wexner Fecal Incontinence Scoring Scale, European Organization for Research and Cancer (EORTC) cancer-specific (EORTC QLQ-C30) and colorectal cancer-specific (EORTC QLQ-CR38) questionnaires and anorectal manometrical findings. Correlation of manometrical findings with Wexner Scale, EORTC QLQ-CR38 scores and EORTC QLQ-C30 scores was also evaluated. RESULTS: Median follow-up was 45.6 months (ranged 7.5–98 months. Higher scores for incontinence for gas (p = 0.001), liquid (p = 0.048) and solid (p = 0.019) stool, need to wear pad (p = 0.001) and alteration in life style (p = 0.004) in Wexner scale, while lower scores for future perspective (p = 0.010) and higher scores for defecation problems (p = 0.001) in EORTC QLQ-CR38 were noted in patients with than without urgency. Manometrical findings of resting pressure (mmHg) was positively correlated with body image (r = 0.435, p = 0.030) and sexual functioning (r = 0.479, p = 0.011) items of functional scale, while rectal sensory threshold (RST) volume (mL) was positively correlated with defecation problems (r = 0.424, p = 0.031) items of symptom scale in EORTC QLQ-CR38 and negatively correlated with social function domain (r = −0.479, p = 0.024) in EORTC QLQ-C30. RST volume was also positively correlated with Wexner scores including incontinence for liquid stool (r = 0.459, p = 0.024), need to wear pad (r = 0.466, p = 0.022) and alteration in lifestyle (r = 0.425, p = 0.038). CONCLUSION: The high risk of developing functional anal impairment as well as the systematic registration of not only oncological but also functional and QoL related outcomes seem important in rectal cancer patients in the long-term disease follow-up

Submarine and coastal karstic groundwater discharges along the Southwestern Mediterranean coast of Turkey

A 120 km-long part of the southwestern coast of Turkey, with well-developed karst terrain in contact with the sea, has been investigated by systematic diving surveys to determine the submarine groundwater discharges (SGDs). The physical, chemical and isotopic data have been used to determine the rate of the fresh groundwater end member (FEM) and its temporal dynamics. About 150 SGDs have been detected by diving surveys employed mostly up to a depth of 30 m below sea level (bsl). Among those, 15 SGDs are in the form of coastal or submarine caves with entrances ranging between sea surface and 40 m bsl. The FEM contribution in SGDs ranges from a few percent to more than 80%. Stable isotope data suggest a range of mean recharge area elevations extending from the coast to more than 1,000 m inland. In many of the SGDs, the FEMs are characterized by tritium-based residence times ranging from recent to several decades. Hypothetical geochemical calculations of mixing between freshwater and seawater end members reveal that more than 45% of freshwater contribution is required for karst development in the SGDs. Models suggest a threshold pH of 7.6 or lower for the carbonate rock dissolution. © 2010 Springer-Verlag

Blind competition on the numerical simulation of continuous shallow steel‐fiber reinforced concrete beams failing in bending

This article describes the second blind simulation competition (BSC) organized by the fib WG 2.4.1, which aims to assess the predictive performance of models based on the finite element method (FEM) for the analysis and design of fiber reinforced concrete (FRC) structures. Slabs supported on columns or piles have becoming competitive applications for FRC due to the technical and economic benefits may be obtained by combining properly the fiber reinforcement mechanisms to those provided by conventional reinforcement placed, as a strip, in the alignment of columns/piles. Therefore, a representative zone of this structural system, namely a hybrid fiber reinforced concrete (R/FRC) shallow beam, is chosen in this BSC to show the potentialities of FRC in these types of applications, as well as to assess the predictive performance of FEM-based computational models on the design verification at serviceability and at ultimate limit state conditions (SLS and ULS, respectively). Two statically indeterminateshallow beams of two equal spans were tested up to their failure, by recording the applied loads, the strains in the conventional reinforcements and in the FRC of the critical zones of the structure. By using digital image correlation, the average crack width at the level of the flexural reinforcements was recorded. The participants had to predict these results by receiving information about the mechanical properties of the materials, the geometry of the prototypes and their loading and support conditions. In this article, the rules and the results of this 2nd BSC competition are presented, and the data obtained experimentally is thoroughly analyzed.PID2021-125553NB-I00; PTDC/ECI-EST/6300/202

The Function Biomedical Informatics Research Network Data Repository

The Function Biomedical Informatics Research Network (FBIRN) developed methods and tools for conducting multi-scanner functional magnetic resonance imaging (fMRI) studies. Method and tool development were based on two major goals: 1) to assess the major sources of variation in fMRI studies conducted across scanners, including instrumentation, acquisition protocols, challenge tasks, and analysis methods, and 2) to provide a distributed network infrastructure and an associated federated database to host and query large, multi-site, fMRI and clinical datasets. In the process of achieving these goals the FBIRN test bed generated several multi-scanner brain imaging data sets to be shared with the wider scientific community via the BIRN Data Repository (BDR). The FBIRN Phase 1 dataset consists of a traveling subject study of 5 healthy subjects, each scanned on 10 different 1.5 to 4 Tesla scanners. The FBIRN Phase 2 and Phase 3 datasets consist of subjects with schizophrenia or schizoaffective disorder along with healthy comparison subjects scanned at multiple sites. In this paper, we provide concise descriptions of FBIRN’s multi-scanner brain imaging data sets and details about the BIRN Data Repository instance of the Human Imaging Database (HID) used to publicly share the data

On the distribution of spinal premotor interneurons

The activity of flexor and extensor motor neurons is tightly regulated by a network of interneurons in the spinal cord. The introduction of rabies retrograde monosynaptic tracing has provided a powerful method to map interneurons directly connected to motor neurons so as to visualize premotor circuits. Previous strategies have used AAV for complementing rabies glycoprotein expression in motor neurons to obtain selectivity in transsynaptic transfer to identify premotor interneurons innervating specific motor neuron pools These studies revealed differences in the location of flexor and extensor premotor interneurons. Here, we report that by using a genetic approach to complement rabies glycoprotein expression in motor neurons, we did not observe any differences in the distribution of flexor and extensor premotor interneurons. In order to identify possible causes for these paradoxical findings, we discuss advantages and caveats of the experimental designs and suggest ways forward to resolve possible ambiguities. Furthermore, to obtain a complete picture of existing approaches and results we ask for contributions from the scientific community describing the use of additional mouse models, viral constructs, and complementation methods. The aim is to generate an open, comprehensive database to understand the specific organisation of premotor circuits

Using Weighted Goal Programming Model for Planning Regional Sustainable Development to Optimal Workforce Allocation:An Application for Provinces of Iran

Due to the urbanization and economic growth, planning of regional sustainable development has become one of the major challenges in the world. The key indicators such as gross domestic product (GDP), electricity and energy consumption and greenhouse gas emission (GHG) are considered in sustainable development planning. This paper determines number of required workforce in diferent sectors of each province in Iran considering targets/goals for sustainable development indicators in the 2030 macroeconomic and regional planning. First, the relative goals are designed for GDP, electricity, energy and GHG emission and then, two weighted goal programming models are applied to allocate the optimal workforce among four sectors: agriculture, industry, services and transportation. The frst model minimizes recruitment of new workforce and allows current workforce exchange among the four sectors in each province in order to achieve the goals, while the second model indicates equitable distribution of new workforce recruitment in diferent sectors within each province. In both models, the workforce changes have been investigated based on achieving the desirable growth rates of GDP, GHG, electricity and energy consumption as planned by the government. Based on the results of this paper, policy makers can manage workforce and the government can make optimized decisions to macroeconomic and regional planning

Stereotaxical Infusion of Rotenone: A Reliable Rodent Model for Parkinson's Disease

A clinically-related animal model of Parkinson's disease (PD) may enable the elucidation of the etiology of the disease and assist the development of medications. However, none of the current neurotoxin-based models recapitulates the main clinical features of the disease or the pathological hallmarks, such as dopamine (DA) neuron specificity of degeneration and Lewy body formation, which limits the use of these models in PD research. To overcome these limitations, we developed a rat model by stereotaxically (ST) infusing small doses of the mitochondrial complex-I inhibitor, rotenone, into two brain sites: the right ventral tegmental area and the substantia nigra. Four weeks after ST rotenone administration, tyrosine hydroxylase (TH) immunoreactivity in the infusion side decreased by 43.7%, in contrast to a 75.8% decrease observed in rats treated systemically with rotenone (SYS). The rotenone infusion also reduced the DA content, the glutathione and superoxide dismutase activities, and induced alpha-synuclein expression, when compared to the contralateral side. This ST model displays neither peripheral toxicity or mortality and has a high success rate. This rotenone-based ST model thus recapitulates the slow and specific loss of DA neurons and better mimics the clinical features of idiopathic PD, representing a reliable and more clinically-related model for PD research