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Angioleiomyomas are benign neoplasms, which usually present as solitary, slow-growing nodules on the skin of lower extremities, but acral location on the hands or feet is unusual. Yet, microscopically, they may show many histopathological variants, focal calcification is uncommon. Extensive calcification masquerading the real nature of the tumor has been rarely reported, the term acral calcified leiomyoma having been proposed for this entity. This change is more often in distal locations and has been interpreted as degenerative in nature, probably related to repetitive minor trauma. We report 3 examples of this unusual condition on the feet of 2 male and one female subjects (aged, 68, 69, and 80 years) and make a review of the 31 cases available in the literature. Two of our cases are associated with highly uncommon features, such as transepidermal calcium elimination and concomitant calcaneal spur.

The initiation and propagation of the action potential (AP) along an axon allows neurons to convey information rapidly and across distant sites. Although AP properties have typically been characterized at the soma and proximal axon, knowledge of the propagation of APs toward distal axonal domains of mammalian CNS neurons remains limited. We used genetically encoded voltage indicators (GEVIs) to image APs with submillisecond temporal resolution simultaneously at different locations along the long axons of dissociated hippocampal neurons from rat embryos of either sex. We found that APs became sharper and showed remarkable fidelity as they traveled toward distal axons, even during a high-frequency train. Blocking voltage-gated potassium channels (Kv) with 4-AP resulted in an increase in AP width in all compartments, which was stronger at distal locations and exacerbated during AP trains. We conclude that the higher levels of Kv channel activity in distal axons serve to sustain AP fidelity, conveying a reliable digital signal to presynaptic boutons. SIGNIFICANCE STATEMENT The AP represents the electrical signal carried along axons toward distant presynaptic boutons where it culminates in the release of neurotransmitters. The nonlinearities involved in this process are such that small changes in AP shape can result in large changes in neurotransmitter release. Since axons are remarkably long structures, any distortions that APs suffer along the way have the potential to translate into a significant modulation of synaptic transmission, particularly in distal domains. To avoid these issues, distal axons have ensured that signals are kept remarkably constant and insensitive to modulation during a train, despite the long distances traveled. Here, we uncover the mechanisms that allow distal axonal domains to provide a reliable and faithful digital signal to presynaptic terminals.

Introduction Evaluation of nerve mechanical properties has the potential to improve assessment of nerve impairment. Shear wave velocity, as measured by using shear wave (SW) ultrasound elastography, is a promising indicator of nerve mechanical properties such as stiffness. However, elucidation of external factors that influence SW velocity, particularly nerve tension, is required for accurate interpretations. Methods Median and ulnar nerve SW velocities were measured at proximal and distal locations with limb positions that indirectly altered nerve tension. Results Shear wave velocity was greater at proximal and distal locations for limb positions that induced greater tension in the median (mean increase proximal 89.3%, distal 64%) and ulnar (mean increase proximal 91.1%, distal 37.4%) nerves. Discussion Due to the influence of nerve tension when SW ultrasound elastography is used, careful consideration must be given to limb positioning.

Recent developments in the SARS-CoV-2 pandemic point to its inevitable transformation into an endemic disease, urging both refinement of diagnostics for emerging variants of concern (VOCs) and design of variant-specific drugs in addition to vaccine adjustments. Exploring the structure and dynamics of the SARS-CoV-2 Spike protein, we argue that the high-mutability characteristic of RNA viruses coupled with the remarkable flexibility and dynamics of viral proteins result in a substantial involvement of allosteric mechanisms. While allosteric effects of mutations should be considered in predictions and diagnostics of new VOCs, allosteric drugs advantageously avoid escape mutations via non-competitive inhibition originating from alternative distal locations. The exhaustive allosteric signaling and probing maps presented herein provide a comprehensive picture of allostery in the spike protein, making it possible to locate potential mutations that could work as new VOC “drivers” and to determine binding patches that may be targeted by newly developed allosteric drugs., Graphical abstract, Tan et al. characterize the dynamics of the SARS-CoV-2 Spike protein and derive allosteric signaling maps for the spike protein, which is of interest for drug development. The analysis of allosteric effects of spike protein mutations allows the prediction of potential drivers in emerging variants of concern.

Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background The ideal location for single-injection adductor canal block that maximizes analgesia while minimizing quadriceps weakness after painful knee surgery is unclear. This triple-blind trial compares ultrasound-guided adductor canal block injection locations with the femoral artery positioned medial (proximal adductor canal), inferior (mid-adductor canal), and lateral (distal adductor canal) to the sartorius muscle to determine the location that optimizes postoperative analgesia and motor function. The hypothesis was that distal adductor block has (1) a superior opioid-sparing effect and (2) preserved quadriceps strength, compared with proximal and mid-locations for anterior cruciate ligament reconstruction. Methods For the study, 108 patients were randomized to proximal, mid-, or distal adductor canal injection locations for adductor canal block. Cumulative 24-h oral morphine equivalent consumption and percentage quadriceps strength decrease (maximum voluntary isometric contraction) at 30 min postinjection were coprimary outcomes. The time to first analgesic request, pain scores, postoperative nausea/vomiting at least once within the first 24 h, and block-related complications at 2 weeks were also evaluated. Results All patients completed the study. Contrary to the hypothesis, proximal adductor canal block decreased 24-h morphine consumption to a mean ± SD of 34.3 ± 19.1 mg, (P < 0.0001) compared to 64.0 ± 33.6 and 65.7 ± 22.9 mg for the mid- and distal locations, respectively, with differences [95% CI] of 29.7 mg [17.2, 42.2] and 31.4 mg [21.5, 41.3], respectively, mostly in the postanesthesia care unit. Quadriceps strength was similar, with 16.7%:13.4%:15.3% decreases for proximal:mid:distal adductor canal blocks. The nausea/vomiting risk was also lower with proximal adductor canal block (10 of 34, 29.4%) compared to distal location (23 of 36, 63.9%; P = 0.005). The time to first analgesic request was longer, and postoperative pain was improved up to 6 h for proximal adductor canal block, compared to mid- and distal locations. Conclusions A proximal adductor canal injection location decreases opioid consumption and opioid-related side effects without compromising quadriceps strength compared to mid- and distal locations for adductor canal block in patients undergoing anterior cruciate ligament reconstruction.

Purpose Intraoperatively implanted Cesium-131 (131Cs) permanent seed brachytherapy is used to deliver highly localized re-irradiation in recurrent head and neck cancers. A single planar implant of uniform air kerma strength (AKS) seeds and 10 mm seed-to-seed spacing is used to deliver the prescribed dose to a point 5 mm or 10 mm perpendicular to the center of the implant plane. Nomogram tables to quickly determine the required AKS for rectangular and irregularly shaped implants were created and dosimetrically verified. By eliminating the need for a full treatment planning system plan, nomogram tables allow for fast dose calculation for intraoperative re-planning and for a second check method. Material and methods TG-43U1 recommended parameters were used to create a point-source model in MATLAB. The dose delivered to the prescription point from a single 1 U seed at each possible location in the implant plane was calculated. Implant tables were verified using an independent seed model in MIM Symphony LDR™. Implant tables were used to retrospectively determine seed AKS for previous cases: three rectangular and three irregular. Results For rectangular implants, the percent difference between required seed AKS calculated using MATLAB and MIM was at most 0.6%. For irregular implants, the percent difference between MATLAB and MIM calculations for individual seed locations was within 1.5% with outliers of less than 3.1% at two distal locations (10.6 cm and 8.8 cm), which have minimal dose contribution to the prescription point. The retrospectively determined AKS for patient implants using nomogram tables agreed with previous calculations within 5% for all six cases. Conclusions Nomogram tables were created to determine required AKS per seed for planar uniform AKS 131Cs implants. Comparison with the treatment planning system confirms dosimetric accuracy that is acceptable for use as a second check or for dose calculation in cases of intraoperative re-planning.

Simple Summary One of the most complicated problems during rectal cancer surgery is to determine what part of intestine to remove along with tumor. If the excised fragment will be too small, it could increase the risk of tumor recurrence. On the contrary, the removal of extra tissues could be completely unnecessary and complicate patient life a lot, especially when the region is close to sphincter. To determine the length of fragments to remove, it was necessary to reveal areas without changes in molecule functioning, specific for tumor. We investigated functioning the proteasomes, important cellular components, in patient rectal cancer and different intestine locations and did not reveal tumor-specific characteristics of proteasomes at sphincter side of intestine even at a distance of 2–4 cm from the tumor. This result supports the idea of preserving the sphincter under surgery. Besides, we discovered proteasome subtype that may be a promising target for anti-cancer therapy. Abstract A special problem in the surgery of rectal cancer is connected with a need for appropriate removal of intestine parts, along with the tumor, including the fragment close to the sphincter. To determine the length of fragments to remove, it is necessary to reveal areas without changes in molecule functioning, specific for tumor. The purpose of the present study was to investigate functioning the proteasomes, the main actors in protein hydrolysis, in patient rectal adenocarcinoma and different intestine locations. Chymotrypsin-like and caspase-like activities, open to complex influence of different factors, were analyzed in 43–54 samples by Suc-LLVY-AMC- and Z-LLE-AMC-hydrolysis correspondingly. Both activities may be arranged by the decrease in the location row: cancer→adjacent tissue→proximal (8–20 cm from tumor) and distal (2 and 4 cm from tumor) sides. These activities did not differ noticeably in proximal and distal locations. Similar patterns were detected for the activities and expression of immune subunits LMP2 and LMP7 and expression of 19S and PA28αβ activators. The largest changes in tumor were related to proteasome subtype containing LMP2 and PA28αβ that was demonstrated by native electrophoresis. Thus, the results indicate a significance of subtype LMP2-PA28αβ for tumor and absence of changes in proteasome pool in distal fragments of 2–4 cm from tumor.

Coronary calcification is one of the features that characterize atherosclerosis. The location of a calcific plaque may vary from case to case [1]. Some distal locations may affect procedural outcomes of coronary angioplasty, resulting in impaired device deliverability. In these cases, guiding extension catheters have been widely introduced into practice to overcome the problem of poor deliverability and guiding catheter support. In some patients, calcified lesions are located distally and rotational burr deliverability is also impaired. The aim of this study was to test the commercially available guiding extension catheters in terms of compatibility of these devices with rotational atherectomy burrs outside the patient’s body.

Chimpanzees gesture to one another regularly. Although some of their gestures are relatively inflexible displays invariably elicited by particular environmental events, an important subset are learned by individuals and used flexibly—such things as ―arm raise‖ to elicit play or ―touch side‖ to request nursing. We know that such gestures are learned because in many cases only some individuals use them, and indeed several observers have noted the existence of idiosyncratic gestures used by only single individuals (Goodall 1986). And their flexible use has been repeatedly documented in the sense of a single gesture being used for multiple communicative ends, and the same communicative end being served by multiple gestures (Tomasello et al. 1985, 1989). Flexible use is also evident in the fact that apes only use their visually based gestures such as ―arm raise‖ when the recipient is already visually oriented toward them—so-called audience effects (Kaminski et al. 2004; Tomasello et al. 1994, 1997). Chimpanzees and other great apes also know quite a bit about what other individuals do and do not see. They follow the gaze direction of conspecifics to relatively distal locations (Tomasello et al. 1998), and they even follow another’s gaze direction around and behind barriers to locate specific targets (Tomasello et al. 1999). This gaze following is not an inflexible response to a stimulus, as from a certain age chimpanzees look where another individual is looking and, if they find nothing interesting on that line of sight, check back a second time and try again (Call et al. 2000). Indeed if a chimpanzee follows another’s line of sight and repeatedly finds nothing there, they will quit following that individual’s gaze altogether (Tomasello et al.

AIMTo analyze the increase in the cross-sectional area (CSA) of the median nerve during early childhood.METHODThis prospective, cross-sectional study used high-resolution ultrasound images of the median nerve from three locations (wrist, forearm and upper arm). A total of 43 participants (32 of whom were children younger than 2 years) were included in the study.RESULTSA strong and highly significant correlation was found between age and CSA (r = 0.8, p < 0.0001). The growth rate of CSA decreases with age. The increase in CSA follows a logarithmic growth curve (p < 0.0001). Based on the regression analysis, an age-synchronous increase in CSA for all three locations was found. The nerve reaches 70% of its final CSA by 2 years of age.INTERPRETATIONSimilar to the nerve conduction speed, the increase in CSA is greatest during the first 2 years of life. Then, the rate gradually and synchronously slows at the proximal and distal locations.What this paper adds-Normative values for increased cross-sectional area (CSA) of the median nerve.-Standardized locations and image procedures outlined for the clinical setting.-Growth dynamic of the CSA of the median nerve in children.-Normative data for development of the median nerve in children.-High resolution ultrasound images of the maturating median nerve in neonates, infants and children.

To analyze age dependencies in the cross-sectional area (CSA) of the median nerve during early childhood.A total of 43 participants (32 of whom were children younger than 2 years) were included in this cross-sectional study to analyze the age dependency of the CSA of the median nerve at three locations (wrist, forearm and upper arm) using high-resolution ultrasound images.A strong and highly significant correlation was found between age and CSA (p 0.001). When plotted, the relationship followed a logarithmic curve (p 0.001) with a growth rate that decreases with age. Based on the regression analysis, a temporally similar increase in CSA for all three locations was found. The nerve reaches 70% of its final CSA by 2 years of age at all three locations.Similar to the nerve conduction speed, the increase in CSA is greatest during the first 2 years of life. Then, the rate gradually and synchronously slows at the proximal and distal locations. Measurement of the CSA in the clinical setting might offer a new method to assess the maturation of the nervous system in infants with minimal interference.

Objectives To characterize 3D electroanatomical mapping (EAM) of the His bundle (HB) region. Background Visualization of selective (S) and nonselective (NS) HB capture areas by EAM has not been described and may help guide HB pacing (HBP). Methods EAM was performed via NavX system in 17 patients (pts) undergoing HBP. HB cloud, S-HB, NS-HB, and right bundle (RB) capture areas were mapped. Results S-HBP areas were identified in 11, NS-HBP in 14, and RB in 11 pts. Two NS-HBP areas (upper and lower) either separated by S-HBP (8 pts) or almost contiguous (5 pts) were observed. S-HBP area measured: 1.1 ± 0.9 cm2 , NS upper: -1.2 ± 0.9 cm2 , NS lower: -1.2 ± 0.9 cm2 , RB: -1.7 ± 1.3 cm2 , total His cloud: -4.1 ± 2.7 cm2 . Electrocardiogram (ECG) pacemaps were different between upper and lower NS-HBP areas in 13/14 pts (p = .006). ECG differences between NS clouds were present in inferior leads in 9 pts (more negative QRS complex from lower NS area) and in precordial leads in 5 pts. There was no correlation between HBP lead location and capture threshold. R-wave amplitude was higher at more distal locations on HB cloud (p = .02). Conclusion (1) Pacemapping identifies distinct regions that may correspond to HB anatomy. (2) A linear S-HBP area is typically surrounded by two separate NS areas. (3) Pace-map ECGs from upper and lower NS-HBP areas have different morphologies. (4) These EAM features and pace-mapping may be helpful to the implanter.

Neurons are incredibly reliant on their cytoskeletal transport machinery. During development the cytoskeleton is the primary driver of growth and remodelling. In mature neurons the cytoskeleton keeps all components in a constant state of movement, allowing both supply of newly synthesized proteins to distal locations as well as the removal of aging proteins and organelles for recycling or degradation. This process is most challenging within axons as large distances need to be covered between synthesis and degradation, but it is essential as the lifetime of any single protein is much shorter than the lifetime of the neuron and its synapses. However, the transport machinery itself also has to be actively transported, recycled and degraded in order to localise properly and perform within neurons. This review provides an overview of the lifecycle of cytoskeletal components in neurons, focusing on its spatial organisation over time in the axon.

Ileocolic intussusception occurs when the terminal ileum “telescopes” into the colon. We observed that ileocolic intussusception lengths are similar regardless of location in the colon. To examine the uniformity of ileocolic intussusception length and its relationship to colon location, symptom duration and reducibility. We retrospectively reviewed ultrasound-diagnosed pediatric ileocolic intussusceptions initially treated with pneumatic reduction at the Mayo Clinic or Texas Children’s Hospital. We recorded demographic, imaging and surgical findings including age, gender, symptom duration, location of the ileocolic intussusception, reducibility with air enema and, if fluoroscopically irreducible, surgical findings. We identified 119 ileocolic intussusceptions (64% boys), with 81% in the right colon. There was no significant relationship between ileocolic intussusception length and colon location (P=0.15), nor ileocolic intussusception length and symptom duration (P=0.36). Ileocolic intussusceptions were more distal with increasing symptom duration (P=0.016). Successful reductions were unrelated to symptom duration (P=0.84) but were more likely with proximal versus distal locations (P=0.02). Ileocolic intussusception lengths are relatively uniform regardless of location along the course of the colon where they present. Our findings suggest that most of the apparent distal propagation of ileocolic intussusceptions is not caused by increasing telescoping of small bowel across the ileocecal valve but rather by foreshortening of the right colon. This implies poor cecal fixation and confirms fluoroscopic and surgical observations of cecal displacement from the right lower quadrant with ileocolic intussusceptions. The movement of the leading edge of the ileocolic intussusception during reduction is first due to “relocating” the cecum into the right lower quadrant after which the reduction of small bowel back across the ileocecal valve then occurs.

BackgroundIntracranial aneurysms represent a significant health concern and are poorly understood despite decades of research. Our study focused on understanding temporal patterns of endothelial cell distribution in different spatial locations within the aneurysm early after creation in a rabbit model.MethodsElastase induced saccular aneurysms were created in rabbits and harvested on day 1 (n=3) and after 2 (n=5), 4 (n=4), 8 (n=5), and 12 (n=6) weeks. Sham operated controls (n=3) were harvested on the same day. Aneurysm and control tissue samples were subjected to en face whole mount CD31 staining for endothelial cells. Semiquantitative scoring was performed on the basis of endothelial coverage of the vessel wall (proximal, middle, and distal portions of the aneurysm dome). Mixed effects models were used to assess the effect of time and aneurysm section on endothelial coverage.ResultsAneurysmal segments were near completely de-endothelialized at 4 and 8 weeks but had re-endothelialized by 12 weeks. Compared with controls, aneurysms at all time points showed decreased endothelialization, but the difference was only significant compared with the 4 and 8 week groups. Both time (P=0.03) and aneurysm section (P=0.07) were significantly associated with the degree of endothelialization. Proximal locations showed increased endothelialization compared with distal locations (P=0.03).ConclusionIn experimental aneurysms of rabbits, endothelial cells regress during the first month after creation, followed by ascending re-endothelialization that stays incomplete. These findings suggest that re-population of endothelial cells comes from resident cells in the adjacent parent artery and that deranged hemodynamics may affect full reconstitution of endothelial cells long term.

Measurements made on routine A-P radiographs can predict strength/quality of the proximal humerus, as shown in terms of two easy-to-measure parameters: cortical index (CI) and mean-combined cortical thickness (MCCT). Because of high variability inherent when using established methods to measure these parameters, we describe a new orientation system. Using digitized radiographs of 33 adult proximal humeri, five observers measured anatomical reference locations in accordance with: (1) Tingart et al. (2003) method, (2) Mather et al. (2013) method, and (3) our new humeral head Circle-Fit method (CFM). The Tingart and Mather methods measure CI and MCCT with respect to upper and lower edges of 20 mm tall rectangles fit to a proximal diaphyseal location where endosteal (Tingart) or periosteal (Mather) cortical margins become parallel. But high intra- and inter-observer variability occurs when placing the rectangles because of uncertainty in identifying cortical parallelism. With the CFM an adjustable circle is fit to the humeral head articular surface, which reliably and easily establishes a proximal metaphyseal landmark (M1) at the surgical neck. Distal locations are then designated at successive 10 mm increments below M1, including a second metaphyseal landmark (M2) followed by diaphyseal (D) locations (D1, D2 …D6). D1 corresponds most closely to the proximal edges of the rectangles used in the other methods. Results showed minimal inter-observer variations (mean error, 1.5 ± 1.1mm) when the CFM is used to establish diaphyseal locations for making CI and MCCT measurements when compared to each of the other methods (mean error range, 10.7 ± 5.9 to 13.3 ± 6.7 mm) (p

Intracranial aneurysms in distal locations are sometimes difficult to treat due to their branching locations and the presence of blister-like or very wide-necked aneurysms. Braided intracranial stents, including flow diverters (FDs) and low-profile braided intracranial stents (LPBSs) may provide additional advantages, due to their flow-diverting properties.The use of FDs in off-label, distal intracranial locations has been increasing with promising outcomes and has given rise to the LPBS, which has less flow-diverting properties, allowing for easier use in distal branching sites through 0.017' microcatheters. These devices have shifted the interest from the aneurysm's sac filling to the regional remodeling through the effect of flow diversion. The purpose of this article is to discuss their functionality, safety, performance, and perspectives through a critical review of important publications of the last 11.5 years (January 2007 to July 2018) on the use of these devices at and beyond the circle of Willis.FDs modify the regional anatomy thus careful pre-procedural consideration of the regional hemodynamic equilibrium is mandatory, as well as effective antiplatelet regimen. LPBSs provide moderate flow-diversion effect, which may be an advantage, especially for very distal and small aneurysms.

Background From 18% to 30% of infantile hemangiomas (IH) are located on the extremities (IHE). They can be divided into localized, segmental, and minimal or arrested growth (IH-MAG) subtypes. Objective We sought to correlate localization of IHE with the anatomy of the arterial vascular supply. Methods All children with segmental IHE and IH-MAG presenting to our department of pediatric dermatology from 2002 to 2015 were evaluated. Hemangiomas were mapped and their patterns were analyzed. Results Most IHE were unilateral (105/109). Two thirds (68/109) were located on the upper, and one third (41/109) on the lower extremities. Distal locations were more frequently affected. Segmental IHE were more common (upper extremities 83.8%; lower extremities 56.1%) than IH-MAG (16.2% and 43.9%, respectively). Ulceration occurred in 5.5%. Localization of IHE was found to correspond to supply areas of embryonic arterial variants. Limitations This was a retrospective study. Only segmental IHE and IH-MAG were evaluated. Angiographic studies were not performed. Conclusion The location of IHE may be related to variant anatomy of arterial supply during embryo fetal development. We hypothesize that this contributes to temporary regional tissue hypoxia during early fetal development, which is a known stimulus for the proliferation of hemangioma stem cells.

Minimally invasive and robotic coronary revascularization strategies offer less pain, fewer adverse events, better cosmesis, and speedier recovery. These procedures are vulnerable to left internal mammary artery (LIMA) injury that may require a full sternotomy, which eliminates the benefits of minimally invasive procedures. We present a management protocol to avoid conversion to sternotomy in minimally invasive cases based on the location of the LIMA injury at proximal, mid, and distal locations. By applying axillary bypass, LIMA extension, and repair over a shunt approaches, our protocol can be used as a successful bailout to LIMA damage in minimally invasive coronary cases.

BACKGROUND: This study examines spatial relationships between alcohol outlet density and the incidence of alcohol-related crashes. The few prior studies conducted in this area used relatively large spatial units; here we use highly resolved units from Melbourne, Australia (Statistical Area level 1 [SA1] units: mean land area=0.5 km(2); SD=2.2km(2)), in order to assess different micro-scale spatial relationships for on- and off-premise outlets. METHODS: Bayesian conditional autoregressive Poisson models were used to assess cross-sectional relationships of three-year counts of alcohol-related crashes (2010-2012) attended by Ambulance Victoria paramedics to densities of bars, restaurants, and off-premise outlets controlling for other land use, demographic and roadway characteristics. RESULTS: Alcohol-related crashes were not related to bar density within local SA1 units, but were positively related to bar density in adjacent SA1 units. Alcohol-related crashes were negatively related to off-premise outlet density in local SA1 units. CONCLUSIONS: Examined in one metropolitan area using small spatial units, bar density is related to greater crash risk in surrounding areas. Observed negative relationships for off-premise outlets may be because the origins and destinations of alcohol-affected journeys are in distal locations relative to outlets.Copyright © 2016 Elsevier Ireland Ltd. All rights reserved. Language: en

Objective This study aimed to investigate the characteristics of A1 aneurysms according to their locations and to compare their imaging appearances so as to identify factors associated with their rupture. Methods We retrospectively reviewed the medical records of 31 patients harboring 32 A1 aneurysms diagnosed and treated between March 2009 and September 2018 at our institute. Results Thirteen (41.9%) of the patients had vascular abnormalities, and multiple aneurysms were found in 13 (41.9%) patients. A total of 16 (53.3%) aneurysms were located on the proximal A1 segment, whereas the middle segments were affected in 7 (23.3%) and the distal segments in 7 (23.3%). Altogether, 93.8% of proximal A1 aneurysms projected posteriorly, 85.7% of middle aneurysms projected superiorly, and 85.7% of distal aneurysms projected inferiorly (P = 0.000). Four (33.3%) of the 12 total ruptured aneurysms were located on the distal A1 segment. Nine (69.2%) ruptured aneurysms were elongated or irregular in shape (P = 0.004). The aspect and height-width ratios of the ruptured aneurysms were higher than those of the unruptured aneurysms (P = 0.001, P = 0.018, respectively). Conclusions Most A1 aneurysms showed a directional predilection according to the location of the A1 segment. Additionally, A1 aneurysms with elongated or irregular shapes, high aspect or height-width ratios, and distal locations of the A1 segment showed high risks of rupture. Therefore, a thorough assessment of the characteristics of A1 aneurysms can enhance the selection of proper treatment strategies.

Nephrocalcinosis often begins on a calcium phosphate deposit, at the tip of the medullo-papillary complex (MPC) known as Randall’s plaque (RP). Contextualizing proximally observed biominerals within the MPC has led us to postulate a mechanobiological switch that can trigger interstitial biomineralization at the MPC tip, remote from the intratubular biominerals. Micro X-ray computed tomography scans of human MPCs correlated with transmission and scanning electron micrographs, and X-ray energy dispersive spectrometry demonstrated novel findings about anatomically-specific biominerals. An abundance of proximal intratubular biominerals were associated with emergence of distal interstitial RP. The fundamental architecture of the MPC and mineral densities at the proximal and distal locations of the MPC differed markedly. A predominance of plate-like minerals or radially oriented plate-like crystallites within spheroidal minerals in the proximal intratubular locations, and core-shell type crystallites within spheroidal minerals in distal interstitial locations were observed. Based on the MPC anatomic location of structure-specific biominerals, a biological switch within the mineral-free zone occurring between the proximal and distal locations is postulated. The “on” and “off” switch is dependent on changes in the pressure differential resulting from changes in tubule diameters; the “Venturi effect” changes the “circumferential strain” and culminates in interstitial crystal deposits in the distal tubule wall in response to proximal tubular obstruction. These distal interstitial mineralizations can emerge into the collecting system of the kidney linking nephrocalcinosis with nephrolithiasis.

Periodontal probing is a useful diagnostic tool to estimate the periodontal pocket depth and assess the status of periodontal disease, but is limited by systematic and random errors. Here, we used photoacoustic imaging in tandem with a food grade cuttlefish ink contrast agent to specifically measure pocket depths in swine models (n=27 teeth) and then compared this to Williams probe. Photoacoustic imaging used a Vevo LAZR imaging system (Visualsonics) at 40 MHz. Spectral data was collected at both 680 and 800 nm to discriminate between the photoacoustic signal from stains and contrast agent. The pocket depths were measured on the sagittal view of the 3D images as well as with a Williams probe before photoacoustic imaging. The Bland-Altman plots show that 97% of our samples fell within ± 1.96 standard deviations of the differences between the depths measured by photoacoustic imaging and the probe (95% confidence interval) at mesial, lingual and buccal, and distal locations. Small bias values of -0.04, +0.17, and -0.2 mm were identified at mesial, lingual and buccal, and distal locations, respectively; the 95% confidence intervals are plotted as well and all are < 1.0 mm. The photoacoustic imaging approach also offered 0.01 mm precision and could cover the entire pocket versus the probe-based approach that is limited to only a few sites.

For small animal vascular disease models and for the development of small-diameter vascular prosthesis, biomechanical data is important. However, these tiny structures with low diameter (

Traveling waves of cortical activity, in which local stimulation triggers lateral spread of activity to distal locations, have been hypothesized to play an important role in cortical function. However, there is conflicting physiological evidence for the existence of spreading traveling waves of neural activity triggered locally. Dichoptic stimulation, in which the two eyes view dissimilar monocular patterns, can lead to dynamic wave-like fluctuations in visual perception and therefore, provides a promising means for identifying and studying cortical traveling waves. Here, we used voltage-sensitive dye imaging to test for the existence of traveling waves of activity in the primary visual cortex of awake, fixating monkeys viewing dichoptic stimuli. We find clear traveling waves that are initiated by brief, localized contrast increments in one of the monocular patterns and then, propagate at speeds of ∼30 mm/s. These results demonstrate that under an appropriate visual context, circuitry in visual cortex in alert animals is capable of supporting long-range traveling waves triggered by local stimulation.

Thoracic aortic dissections involving the ascending aorta represent one of the most dramatic and lethal emergencies in cardiovascular surgery. It is therefore critical to identify the mechanisms driving them and biomechanical analyses hold great clinical promise, since rupture/dissection occur when aortic wall strength is unable to withstand hemodynamic stresses. Although several studies have been done on the biomechanical properties of thoracic aortic aneurysms, few data are available about thoracic aortic dissections. Detailed mechanical tests with measurement of tissue thickness and failure properties were performed with a tensile-testing device on 445 standardized specimens, corresponding to 19 measurement sites per inner (intima with most of media)/outer layer (leftover media with adventitia); harvested from twelve patients undergoing emergent surgical repair for type A dissection. Our data suggested inherent differences in tissue properties between the origin of dissection and distal locations, i.e. thinner and stiffer inner layers that might render them more vulnerable to tearing despite their increased strength. The strength of tissue circumferentially was greater than that longitudinally, likely determining the direction of tear. The relative strengths of the inner: ∼{65,40}N/cm2 and outer layer: ∼{350,270}N/cm2 in the two principal directions of dissected tissue were differentiated from the intima: ∼{100,75}N/cm2, media: ∼{150,55}N/cm2, and adventitia: ∼{270,190}N/cm2 of non-dissected ascending aortic aneurysms (Sokolis et al., 2012), in favor of weaker inner and stronger outer layers, allowing an explanation as to why the presently-studied tissue suffered dissection, i.e. tear of the inner layers, and not rupture, i.e. full tearing across the entire wall thickness.

Despite the economic importance of soybean [Glycine max (L.) Merr.], knowledge on the contributionof entomological pollination on seed yield is scarce. This study estimates the production of soybean resulting frompollination by honeybees (Apis mellifera L.) in two consecutive growing seasons in Paraná (Argentina). Experimentshad two treatments: excluded flower-visiting insects (EV) and non-excluded flower-visiting insects (NEV).The abundance of honeybees was similar in both years, although soybean production differed significantly(P < 0.05) between years. The NEV treatment out-yielded (P < 0.001) the EV treatment by 18% (5224 vs.4415 kg ha−1) in year 1, which was associated with an increase in the seeds per unit area but not with individual seedweight. In contrast, seed yield (on average 3830 kg ha−1) and seeds per unit area did not differ between treatments inyear 2. Individual seed weight was 3?5% (P < 0.05) higher in EV than in NEV in both years. The mechanismsinvolved in the seed yield increase could be related with pollen sterility in relegated flowers in secondary racemes orin distal locations of primary racemes under favorable conditions, as recorded in year 1. Thus, the action ofhoneybees carrying pollen from fertile flowers to relegated flowers may have increased the pod and seed set intreatment NEV in year 1. Fil: Blettler, Diego César. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina Fil: Fagundez, Guillermina Andrea. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina Fil: Caviglia, Octavio Pedro. Instituto Nacional de Tecnología Agropecuaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Entre Ríos. Facultad de Ciencias Agropecuarias; Argentina

Objective The present study aimed to test the effect of the electrode position and inter-electrode distance on the evoked force by neuromuscular electrical stimulation (NMES) with a low current intensity and a single pair of electrodes. Knee extensor forces during NMES to quadriceps femoris muscles were compared among four different electrode configurations in seven healthy men. Electrodes were located at 10 cm proximal and 15 cm distal (P10-D15), 10 cm proximal and 10 cm distal (P10-D10), 5 cm proximal and 15 cm distal, and 5 cm proximal and 10 cm distal (P5-D10) to the center of the longitudinal axis of the quadriceps femoris muscles. Results The evoked force–time area for P5-D10 was significantly higher than those for P10-D15 and P10-D10 (p

Large vessels can be reliably sealed with radio frequency current. High apposition pressures are necessary to ensure a high probability of a successful seal. However, the complex architecture of the vessels, particularly arteries, means that results can vary substantially even with similar thermal histories. The relative volume fractions and spatial distributions of collagen, elastin, and smooth muscle dominate the vessel function in vivo and can even vary from proximal to distal locations in the same vessel. We begin by reviewing the architectural features characteristic of porcine and canine large vessels and conclude with an experimental and numerical modeling demonstration of the reasons why cylindrical electrodes are a sub-optimal choice.

Allostery is a ubiquitous process for protein regulatory activity in which a binding event can change a protein's function carried out at a distal site. Despite intensive theoretical and experimental investigation of protein allostery in the past five decades, effective methods have yet to be developed that can systematically identify key residues involved in allosteric mechanisms. In this study, we propose the rigid residue scan as a systematic approach to identify important allosteric residues. The third PDZ domain (PDZ3) in the postsynaptic density 95 protein (PSD-95) is used as a model system, and each amino acid residue is treated as a single rigid body during independent molecular dynamics simulations. Various indices based on cross-correlation matrices are used, which allow for two groups of residues with different functions to be identified. The first group is proposed as "switches" that are needed to "turn on" the binding effect of protein allostery. The second group is proposed as "wire residues" that are needed to propagate energy or information from the binding site to distal locations within the same protein. Among the nine residues suggested as important for PDZ3 intramolecular communication in this study, eight have been reported as critical for allostery in PDZ3. Therefore, the rigid residue scan approach is demonstrated to be an effective method for systemically identifying key residues in protein intramolecular communication and allosteric mechanisms.

Preliminary studies suggest that intracranial arteries are capable of accommodating plaque formation by remodeling. We sought to study the ability and extent of intracranial arteries to remodel using 3-dimensional high-resolution black blood magnetic resonance imaging and investigate its relation to ischemic events.Forty-two patients with cerebrovascular ischemic events underwent 3-dimensional time-of-flight magnetic resonance angiography and contrast-enhanced black blood magnetic resonance imaging examinations at 3 T for intracranial atherosclerotic disease. Each plaque was classified by location (eg, posterior versus anterior circulation) and its likelihood to have caused a stroke identified on magnetic resonance imaging (culprit, indeterminate, or nonculprit). Lumen area, outer wall area, and wall area were measured at the lesion and reference sites. Plaque burden was calculated as wall area divided by outer wall area. The arterial remodeling ratio (RR) was calculated as outer wall area at the lesion site divided by outer wall area at the reference site after adjusting for vessel tapering. Arterial remodeling was categorized as positive if RR1.05, intermediate if 0.95≤RR≤1.05, and negative if RR0.95.One hundred and thirty-seven plaques were identified in 42 patients (37% [50] posterior and 63% [87] anterior). Compared with anterior circulation plaques, posterior circulation plaques had a larger plaque burden (77.7±15.7 versus 69.0±14.0; P=0.008), higher RR (1.14±0.38 versus 0.95±0.32; P=0.002), and more often exhibited positive remodeling (54.0% versus29.9%; P=0.011). Positive remodeling was marginally associated with downstream stroke presence when adjusted for plaque burden (odds ratio 1.34, 95% confidence interval: 0.99-1.81).Intracranial arteries remodel in response to plaque formation, and posterior circulation arteries have a greater capacity for positive remodeling and, consequently, may more likely elude angiographic detection. Arterial remodeling may provide insight into stroke risk.

Evaluation of the heart work is starting to emerge as a new diagnostic tool for arterial diseases. The aim of this study is to develop a mathematical model for the estimation of heart work utilizing the pulse waves between two points of a vessel. In order to calculate heart work, medical data such as blood pressure waveforms (which are measured using a cuff) are utilized. The heart work is calculated by employing the modified Windkessel model together with the viscosity models of Casson or Herschel-Bulkely (H-B). The results indicate that the compliance values at the proximal and distal locations differ for the Casson and H-B models.

Summary Recent study in rabbits demonstrated that vasectomy via the inguinal canal did not result in any spermatogenic damage 3 months postoperation; this study aimed to determine whether the damage would occur in a longer term. The left or right vas deferens was ligated near the epididymal head (unilateral proximal vasectomy, 12 animals) or via the inguinal canal (unilateral distal vasectomy, 11 animals) in adult male rabbits, with a sham operation being performed on the contralateral side. Six months postoperation, testes, epididymides and vasa deferentia were removed and methacrylate resin-embedded sections prepared to evaluate spermatogenesis by histological (qualitative) and stereological (quantitative) studies. The juxta-epididymal segment of the occluded vas deferens was severely distended (filled with sperm) in 10 of the 11 animals with distal vasectomy and moderately or slightly distended in nine of the 12 animals with proximal vasectomy. Severe spermatogenic damage occurred in seven animals with proximal vasectomy (the juxta-epididymal vas moderately or slightly distended), in only one animal with distal vasectomy (the vas not severely distended). In conclusion, spermatogenic damage occurred at 6 months postvasectomy in some animals, especially those with proximal vasectomy and therefore shorter occluded reproductive tract for sperm storage; the damage was probably intra-tract pressure mediated.

Frequently, we learn of the locations of things and events in our environment by means of hearing. Hearing, I argue, is a locational mode of perceiving with a robustly spatial phenomenology. I defend three proposals. First, audition furnishes one with information about the locations of things and happenings in one’s environment because auditory experience itself has spatial content—auditory experience involves awareness of space. Second, we hear the locations of things and events by or in hearing the locations of their sounds. Third, we auditorily experience sounds themselves as having relatively stable distal locations. I reject skepticism about spatial audition and auditory experience tracing to Strawson’s Individuals, and suggest that spatial auditory experience grounds a form of perceptual access to objects and events that is critical to negotiating one’s environment.

In strongly weathered tephras, it is commonly the case that only quartz and opaque minerals remain unaltered. For example, the K-Tz tephra is distinguished by abundant quartz crystals. The identification of strongly weathered tephras is difficult because major-element analyses of volcanic glass are affected by weathering. Here, we propose a method of identifying weathered tephras based on major-element analyses of pristine glass inclusions preserved in quartz phenocrysts, and apply the method to identifying the K-Tz, Nr-N, and Kt-1 tephras.We used energy-dispersive X-ray (EDX) techniques to analyze samples of the K-Tz tephra collected from a proximal location (Tanegashima, near Kikai caldera) and from three distal locations. The major-element compositions of glass inclusions are similar in all the K-Tz samples, but are distinct from those of the Nr-N and Kt-1 tephras.Major-element analysis of quartz-hosted glass inclusions is a promising method in investigations of strongly weathered Quaternary tephras in Japan, such as K-Tz.

In this study, the effect of feeding differ- ent types and amounts of dietary fiber (DF) on luminal environment and morphology in the small and large intestine of sows was studied. Three diets, a low-fiber diet (LF) and 2 high-fiber diets (high fiber 1, HF1, and high fiber 2, HF2) were used. Diet LF (DF, 17%; soluble DF 4.6%) was based on wheat and barley, whereas the 2 high-fiber diets (HF1: DF, 43%; soluble DF, 11.0%; and HF2: DF, 45%; soluble DF, 7.6%) were based on wheat and barley supplemented with different coprod- ucts from the vegetable food and agroindustry (HF1 and HF2: sugar beet pulp, potato pulp, and pectin resi- due; HF2: brewers spent grain, seed residue, and pea hull). The diets were fed for a 4-wk period to 12 sows (4 receiving each diet). Thereafter, the sows were killed 4 h postfeeding, and digesta and tissue samples were collected from various parts of the small and large in- testine. The carbohydrates in the LF diet were well di- gested in the small intestine, resulting in less digesta in all segments of the intestinal tract. The fermenta- tion of nonstarch polysaccharides in the large intestine was affected by the chemical composition and physico- chemical properties. The digesta from pigs fed the LF diet provided low levels of fermentable carbohydrates that were depleted in proximal colon, whereas for pigs fed the 2 high-DF diets, the digesta was depleted of fermentable carbohydrates at more distal locations of the colon. The consequence was an increased retention time, greater DM percentage, decreased amount of ma- terial, and a decreased tissue weight after feeding the LF diet compared with the HF diets. The concentration of short-chain fatty acids was consistent with the fer- mentability of carbohydrates in the large intestine, but there was no effect of the dietary composition on the molar short-chain fatty acid proportions. It was fur- ther shown that feeding the diet providing the great- est amount of fermentable carbohydrates (diet HF1, which was high in soluble DF) resulted in significant morphological changes in the colon compared with the LF diet.

Many vascular disorders, including aortic aneurysmsand dissections, are characterized by localized changes in wall composition and structure. Notwithstanding the importance of histopathologic changes that occur at the microstructural level, macroscopic manifestations ultimately dictate the mechanical functionality and structural integrity of the aortic wall. Understanding structure–function relationships locally is thus critical for gaining increased insight into conditions that render a vessel susceptible to disease or failure.Given the scarcity of human data, mouse models are increasingly useful in this regard. In this paper, we present a novel inverse characterization of regional, nonlinear, anisotropic properties of the murine aorta. Full-field biaxial data are collected using a panoramic-digital image correlation system. An inverse method, based on the principle of virtual power, is used to estimate values of material parameters regionallyfora microstructurally motivated constitutive relation. We validate our experimental-computational approach by comparing results to those from standard biaxial testing. Results for the non-diseased suprarenal abdominal aorta from apolipoprotein-E null mice reveal material heterogeneities, with significant differences between dorsal and ventral as well as between proximal and distal locations, which may arise in part due to differential perivascular support and localized branches.Overall results were validated for both a membrane and a thick-wall model that delineated medial and adventitial properties. Whereas full-field characterization can be useful in the study of normal arteries, we submit that it will be particularly useful for studying complex lesions such as aneurysms, which can now be pursued with confidence given the present validation.

It is now over 30 years since Bodo Christ first demonstrated that the musculature of the limb originated from the somites and overturned the then prevailing view that limb muscle develops from a local source. Subsequently, using electron microscopy and histological procedures, Bodo Christ identified that cells of the somites undergo an epithelial to mesenchymal transition which enabled them to move from their paraxial point of origin to distal locations. These studies defined this translocation as one of the major mechanisms allowing myogenic cells to translocate around the body. The other means used to translocate muscle involves the movement of cells as a sheet. The deployment of one of these two mechanisms has been postulated to be involved in the formation of all the hypaxial musculature of the vertebrate body. In this paper we describe the formation of muscles both in the head and in the body, which use a translocatory mechanism during their development. We highlight recent data showing that muscle translocation is a far more complex process than first thought but which in itself can be used as a valuable tool to address questions regarding tissue patterning and development.

Learning-associated cellular modifications were previously studied experimentally in the rat piriform cortex after operand conditioning. The results showed a 19% reduction in the level of the action potential after-hyperpolarization (AHP) in trained rats, while the spike trains indicated decreased adaptation during long depolarization. Paradoxically, this reduced AHP amplitude was associated with a level of depression in the EPSP amplitude, which was significantly higher in trained rats than in the control groups, the pseudo-trained and naive rats. Our goal in the present study is to analyze and explain through computational techniques the effect of increased EPSP depression after learning. We apply three different models to simulate the exact reduction in the AHP amplitude: (1) ''Conductance change:'' Controlled by decreasing g"k"C"a by 40 %. (2) ''Moving:'' Shifting the location of the dendritic segment that exhibits active conductances, including AHP conductance, distally from the soma, while decreasing g"k"C"a by only 15%. (3) ''Shrinkage:'' Decreasing the length of the AHP dendritic segment, while increasing g"k"C"a by 9%. Moving the synaptic input distally from the soma enhances EPSP depression by the AHP conductance. Hence, the learning process could be simulated by a ''jump'' from the control curve to any other curve, representing decreased AHP amplitude. At the same time, the enhanced EPSP depression requires an additional shift of the EPSP input to more distal locations.

Ambient sound pressure levels (SPLs) created with intense blasts were compared with SPLs recorded in the abdomen of euthanized sheep. Hydrophones were placed in the abdominal cavity at locations referred to as proximal, medial, and distal with respect to a shock tube that created 169-dB peak SPL (pSPL). No differences in pSPL, duration, or rise time were found between recordings in air and at the intra-abdominal proximal position. Significant differences were noted in these variables when recordings in air were compared with recordings made at the medial and distal locations. Intra-abdominal pSPL varied by 20 dB depending on recording location.

Reverse flaps lend themselves to transposition from proximal to distal locations in the extremities. This series comprised 18 radial forearm flaps, 17 digital artery flaps, 13 posterior interosseous flaps, 3 lateral arm flaps, 2 dorsal digital flaps, and 1 dorsal metacarpal flap, all of which were utilized in a reverse pattern. The radial forearm flap was mainly chosen for defects involving part of the palm and the palmar aspect of the first web space. The posterior interosseous flap was more commonly utilized for resurfacing the dorsum, dorsal aspect of the first web space, and especially the hypothenar aspect of the hand. The lateral arm flap was used to reconstruct antecubital fossa and proximal forearm defects. All posterior interosseous and lateral arm donor areas were closed primarily. Sensate digital artery flaps yielded 5 mm on average static two-point discrimination in 6 to 18 months of follow-up. Functional and cosmetic results concerning the recipient and donor areas were found to be satisfactory. It was concluded that reverse flaps are versatile tools in the coverage of all kind of defects in the upper limb and should be thought of in the first place.

Functional recovery after oculomotor nerve injury is very poor. Electrical stimulation has been shown to promote regeneration of injured nerves. We hypothesized that electrical stimulation would improve the functional recovery of injured oculomotor nerves. Oculomotor nerve injury models were created by crushing the right oculomotor nerves of adult dogs. Stimulating electrodes were positioned in both proximal and distal locations of the lesion, and non-continuous rectangular, biphasic current pulses (0.7 V, 5 Hz) were administered 1 hour daily for 2 consecutive weeks. Analysis of the results showed that electrophysiological and morphological recovery of the injured oculomotor nerve was enhanced, indicating that electrical stimulation improved neural regeneration. Thus, this therapy has the potential to promote the recovery of oculomotor nerve dysfunction.

Temporal parameters such as stage transition duration, bolus location at swallow onset, and pharyngeal transit time are often measured during videofluoroscopy, but these parameters may vary depending on assessment instructions. Specifically, “command” (cued) swallows have been observed to alter timing compared to spontaneous (noncued) situations in healthy older adults. The aim of our study was to confirm whether healthy young people show timing differences for thin liquid swallows between cued and noncued conditions. Twenty healthy young adults swallowed 10-cc boluses of ultrathin barium in videofluoroscopy. The cued condition was to hold the bolus in the mouth for 5 s before swallowing. Three noncued swallows were also recorded. In the cued condition, bolus advancement to the pyriform sinuses prior to swallow initiation was seen significantly less frequently. Stage transition durations showed a nonsignificant trend toward being shorter. Pharyngeal transit times and pharyngeal response time (a measure capturing the interval between hyoid movement onset and bolus clearance through the upper esophageal sphincter) were both significantly longer in the cued condition. Our study in healthy young adults confirms findings previously observed in older adults, namely, that swallow onset patterns and timing differ between cued and noncued conditions. In particular, bolus advancement to more distal locations in the pharynx at the time of swallow onset is seen more frequently in noncued conditions. This pattern should not be mistaken for impairment in swallow onset timing during swallowing assessment.

This paper presents a study into the use of mobile phones as private tactile displays for interactions with tabletop computers. Text entry performance on tabletop computers is often poor due to the soft keyboards that are normally used. We propose using the vibration motor in the user's mobile phone to provide tactile feedback to improve the experience and performance of typing on tabletop computers. We ran an experiment to compare the effects of two different sets of tactile feedback when delivered at two different distal locations on the body (wrist and trouser pocket) using a high quality actuator. The results showed that both sets of feedback improved the text entry rates at the two locations, and that providing more complex feedback produces greater benefits than simplified feedback. We also establish a baseline for standard text entry performance by novice users on tabletop computers using MacKenzie's phrase set.

The present study focusses on the determination, comparison and constitutive modelling of the passive mechanical properties of the swine carotid artery over very long stretches in both proximal and distal regions. Special attention is paid to the histological and mechanical variations of these properties depending on the proximity to the heart. The results can have clinical relevance, especially in the research field of intravascular device design. Before the final clinical trials on humans, research in the vascular area is conducted on animal models, swine being the most common due to the similarities between the human and swine cardiovascular systems as well as the fact that the swine size is suitable for testing devices, in this case endovascular carotid systems. The design of devices usually involves numerical techniques, and an important feature is the appropriate modelling of the mechanical properties of the vessel. Fourteen carotid swine arteries were harvested just after sacrifice and cyclic uniaxial tension tests in longitudinal and circumferential directions were performed for distal and proximal samples. The stress-stretch curves obtained were fitted with a hyperelastic anisotropic model. Stress-free configuration states were also analyzed. Finally, human and swine samples were processed in a histological laboratory and images were used to quantify their microconstituents. The statistical analysis revealed significant differences between the mechanical behavior of proximal and distal locations in the circumferential but not in the longitudinal direction. Circumferential direction samples show clear differences both in residual stretches and tensile curves between the two locations, while the features of longitudinal specimens are independent of the axial position. The statistical analysis provides significant evidence of changes depending on the position of the sample, mainly in elastin and SMC quantification.

Purpose: To examine the feasibility of flow-independent T2-prepared inversion recovery (T2IR) black-blood (BB) magnetization preparation for three-dimensional (3D) balanced steady-state free precession (SSFP) vessel wall MRI of the popliteal artery, and to evaluate its performance relative to flow-dependent double inversion recovery (DIR), spatial presaturation (SPSAT), and motion-sensitizing magnetization preparation (MSPREP) BB techniques in healthy volunteers. Materials and Methods: Eleven subjects underwent 3D MRI at 1.5 Tesla with four techniques performed in a randomized order. Wall and lumen signal-to-noise ratio (SNR), wall-to-lumen contrast-to-noise ratio (CNR), vessel wall area, and lumen area were measured at proximal, middle, and distal locations of the imaged popliteal artery. Image quality scores based on wall visualization and degree of intraluminal artifacts were also obtained. Results: In the proximal region, DIR and SPSAT had higher wall SNR and wall-to-lumen CNR than both MSPREP and T2IR. In the middle and distal regions, DIR and SPSAT failed to provide effective blood suppression, whereas MSPREP and T2IR provided adequate black blood contrast with comparable wall-to-lumen CNR and image quality. Conclusion: The feasibility of 3D SSFP imaging of the popliteal vessel wall using flow-independent T2IR was demonstrated with effective blood suppression and good vessel wall visualization. Although DIR and SPSAT are effective for thin slab imaging, MSPREP and T2IR are better suited for 3D thick slab imaging. J. Magn. Reson. Imaging 2011;. © 2011 Wiley-Liss, Inc.

This paper presents an extension of a recently developed low-dimensional modeling approach for normal human gait to the modeling of asymmetric gait. The asymmetric model is applied to analyze the gait dynamics of a transtibial prosthesis user, specifically the changes in joint torque and joint power costs that occur with variations in sagittalplane alignment of the prosthesis, mass distribution of the prosthesis, and roll-over shape of the prosthetic foot being used. The model predicts an increase in cost with addition of mass and a more distal location of the mass, as well as the existence of an alignment at which the costs are minimized. The model's predictions also suggest guidelines for the selection of prosthetic feet and suitable alignments. The results agree with clinical observations and results of other gait studies reported in the literature. The model can be a useful analytical tool for more informed design and selection of prosthetic components, and provides a basis for making the alignment process systematic. Copyright � 2009 by ASME.

Background Cells are not mixed bags of signaling molecules. As a consequence, signals must travel from their origin to distal locations. Much is understood about the purely diffusive propagation of signals through space. Many signals, however, propagate via signaling cascades. Here, we show that, depending on their kinetics, cascades speed up or slow down the propagation of signals through space, relative to pure diffusion. Methodology/Principal Findings We modeled simple cascades operating under different limits of Michaelis-Menten kinetics using deterministic reaction-diffusion equations. Cascades operating far from enzyme saturation speed up signal propagation; the second mobile species moves more quickly than the first through space, on average. The enhanced speed is due to more efficient serial activation of a downstream signaling module (by the signaling molecule immediately upstream in the cascade) at points distal from the signaling origin, compared to locations closer to the source. Conversely, cascades operating under saturated kinetics, which exhibit zero-order ultrasensitivity, can slow down signals, ultimately localizing them to regions around the origin. Conclusions/Significance Signal speed modulation may be a fundamental function of cascades, affecting the ability of signals to penetrate within a cell, to cross-react with other signals, and to activate distant targets. In particular, enhanced speeds provide a way to increase signal penetration into a cell without needing to flood the cell with large numbers of active signaling molecules; conversely, diminished speeds in zero-order ultrasensitive cascades facilitate strong, but localized, signaling., National Institutes of Health, Director's Pioneer Award

One-year-old shoots from stooling beds of Populus × deltoides ‘Walker’ and Populus jackii ‘Northwest’ were collected in late fall to determine the effect of cutting position on rooting and growth of hardwood poplar cuttings. Cuttings with a minimum diameter of 9.0 mm were obtained from basal, middle and distal locations on the poplar shoot. Rooting and shoot growth were assessed in the greenhouse and under field conditions. ‘Walker’ poplar cuttings collected from basal portions of the shoot and planted in the field had 87.6% rooting and 103.8 cm growth compared to 78.8% and 103.4 cm and 67.6% and 88.8 cm for middle and distal locations respectively. For ‘Northwest’ rooting and growth under field conditions was 84.4% and 94.7 cm for basal, 78.4% and 90.5 cm for mid and 64.4% and 84.3 cm for distal locations. Rooting in the greenhouse was superior to the field. ‘Walker’ cuttings had fewer roots and buds per cutting than ‘Northwest’, however, growth of ‘Walker’ in the field was superior.

Unstable clavicular fractures can be treated surgically with pins and wires or with plates. The migration of metallic devices such as Kirschner wires (K-wires) from the shoulder to a variety of anatomical proximal and distal locations is well documented. Spinal migration, however, is rare and is normally associated with severe spinal injury. This article presents the case of a man who presented with cervicothoracic migration of a K-wire after treatment of a clavicular fracture sustained during a sports accident. The distinctive feature in this case, when compared to the existing literature, is its fortuitous detection by imaging studies and its surgical removal without neurological sequelae.