Extreme Asymmetry Research Articles

LOWER QUARTER- AND UPPER QUARTER Y BALANCE TESTS AS PREDICTORS OF RUNNING-RELATED INJURIES IN HIGH SCHOOL CROSS-COUNTRY RUNNERS

While cross-country running is a popular interscholastic sport, it also has a high incidence of running-related injuries (RRIs). Recent literature suggests that functional tests may identify athletes at increased risk of injury. The Y-Balance Test (YBT) is an objective measure used to assess functional muscle strength, balance, and expose asymmetries between tested limbs. The purpose of this study was to determine if the YBT could predict RRI in high school cross-country runners. It was hypothesized that an asymmetric right (R)/left (L) YBT reach distance for the lower or upper extremities would be associated with an increased risk of RRI. Prospective observational cohort. One hundred forty-eight athletes (80 girls, 68 boys) who competed in interscholastic cross-country in Southern California during the 2015 season participated in the study. Prior to the cross-country season, the runners completed Lower-Quarter YBT (LQ-YBT) and Upper-Quarter YBT (UQ-YBT) testing to assess lower and upper extremity asymmetry, respectively. The runners were prospectively monitored for RRI occurrence throughout the season using the Daily Injury Report form. Forty-nine runners (33.1%) incurred a RRI during the 2015 season, with the lower leg (shin/calf) and knee the most common RRI sites. Girls had a higher RRI occurrence (38.8%) than boys (26.5%) (p = 0.12). Boys had greater raw scores for LQ-YBT R and L anterior (ANT), posteromedial (PM), posterolateral (PM) and composite reach distances than girls (p<0.05). With the exception of normalized superolateral reach distance, boys had significantly greater scores for raw and normalized R and L UQ-YBT reach distances and raw composite scores than girls (p<0.05). After adjusting for prior RRI, while boy runners with a LQ-YBT PM reach difference ≥4.0 cm were five times more likely to incur a RRI (Adjusted odds ratio [AOR] = 5.05, 95% CI: 1.3-19.8; p = 0.02), girl runners with a UQ-YBT inferolateral (IL) reach difference ≥ 4.0 cm were 75% less likely to incur a RRI (AOR = 0.25, 95% CI: 0.1-0.7; p = 0.005). By lower extremity body region, boy runners with a UQ-YBT superolateral (SL) reach difference ≥ 4.0 cm were seven times more likely to incur a hip/thigh/knee RRI [AOR] = 7.20, 95% CI: 1.1-45.6; p = 0.002). Greater lower extremity (PM) or upper extremity (SL) reach distance asymmetry, as measured by the LQ-YBT or UQ-YBT, respectively, were associated with RRI in boy high school cross-country runners. 2b.

PAIN AND PHYSICAL PERFORMANCE AMONG RECREATIONAL RUNNERS WHO RECEIVE A CORRECTION FOR AN ILIAC CREST HEIGHT DIFFERENCE: A CASE SERIES

Leg-length inequality (LLI) is a musculoskeletal condition where one lower extremity is longer than the other. There is conflicting evidence on the relevance of LLI and conservative treatment options. Iliac crest height difference (ICHD) is a good estimate of LLI. To observe changes in pain and performance among recreational runners with running-induced lower extremity pain who received ICHD correction. A 12-week case series with multiple baseline and intervention (A-B-A-B) phases was used to observe the effects of ICHD correction on pain and performance among three symptomatic recreational runners. Primary outcome measures included the Lower Extremity Functional Scale (LEFS), the Visual Analog Scale -Worst Pain (VAS-W), symptom-free running distance, and average running speed. A standardized procedure for fabricating an in-shoe shim was utilized for ICHD correction. There were no clinically important differences in functional capacity for any subject between any phases. Also, two subjects demonstrated trends towards increased pain over the 12-week experimental period, whereas one subject demonstrated a decrease. One subject demonstrated a statistically significant increase in running distance during intervention phases, but the others demonstrated reductions. All subjects demonstrated trends towards increased running speed, but none were statistically significant. The correction of small ICHD < 9mm did not improve pain or performance among recreational runners. Individuals with small ICHD may be able to effectively compensate for lower extremity asymmetries; therefore, correction seems to be unnecessary and potentially harmful in short-term. Therapy, level 4.

Stability of the A15 phase in diblock copolymer melts

The self-assembly of block polymers into well-ordered nanostructures underpins their utility across fundamental and applied polymer science, yet only a handful of equilibrium morphologies are known with the simplest AB-type materials. Here, we report the discovery of the A15 sphere phase in single-component diblock copolymer melts comprising poly(dodecyl acrylate)-block-poly(lactide). A systematic exploration of phase space revealed that A15 forms across a substantial range of minority lactide block volume fractions (fL = 0.25 - 0.33) situated between the σ-sphere phase and hexagonally close-packed cylinders. Self-consistent field theory rationalizes the thermodynamic stability of A15 as a consequence of extreme conformational asymmetry. The experimentally observed A15-disorder phase transition is not captured using mean-field approximations but instead arises due to composition fluctuations as evidenced by fully fluctuating field-theoretic simulations. This combination of experiments and field-theoretic simulations provides rational design rules that can be used to generate unique, polymer-based mesophases through self-assembly.

Asymmetric hot-carrier thermalization and broadband photoresponse in graphene-2D semiconductor lateral heterojunctions.

The massless Dirac electron transport in graphene has led to a variety of unique light-matter interaction phenomena, which promise many novel optoelectronic applications. Most of the effects are only accessible by breaking the spatial symmetry, through introducing edges, p-n junctions, or heterogeneous interfaces. The recent development of direct synthesis of lateral heterostructures offers new opportunities to achieve the desired asymmetry. As a proof of concept, we study the photothermoelectric effect in an asymmetric lateral heterojunction between the Dirac semimetallic monolayer graphene and the parabolic semiconducting monolayer MoS2. Very different hot-carrier cooling mechanisms on the graphene and the MoS2 sides allow us to resolve the asymmetric thermalization pathways of photoinduced hot carriers spatially with electrostatic gate tunability. We also demonstrate the potential of graphene-2D semiconductor lateral heterojunctions as broadband infrared photodetectors. The proposed structure shows an extreme in-plane asymmetry and provides a new platform to study light-matter interactions in low-dimensional systems.

Women’s Collegiate Volleyball Players Exhibit Kinetic Asymmetries during Sport-Specific Tasks

Women’s volleyball demands frequent lateral movements and vertical jumps. Repetitive lateral movements in the same direction could lead to biomechanical asymmetries and a potential increased risk of lower extremity injury. PURPOSE:To identify and analyze biomechanical asymmetries in collegiate women’s volleyball players during sport-specific lateral and vertical jumping tasks. METHODS: Nineteen female collegiate volleyball players were analyzed using standard 3D motion capture techniques during a drop vertical jump (DVJ) from a 30-cm box and a reactive jump (REACT) task. For the REACT, participants began in an athletic stance awaiting a directional cue on a screen placed in front of them. Once directed, participants were instructed to jump laterally and then vertically as high and fast as possible to mimic a volleyball block. Repeated measures MANOVA models were used to identify asymmetries in kinematic and kinetic measures in the DVJ and REACT task (α=0.05). Paired t-tests identified asymmetries in reaction time during the REACT task. Limb symmetry indices (LSI) were calculated for significant findings. RESULTS:Significant kinetic asymmetries were identified for both the DVJ (p=0.01) and REACT (p=0.003) tasks, but no kinematic asymmetries were found in either task (p>0.05). During the DVJ, participants exhibited asymmetrical knee abduction (LSI=81%, p=0.03), ankle dorsiflexion (LSI=94%, p=0.03), and ankle inversion (LSI=30%, p=0.001) external joint moments and vertical ground reaction forces (LSI=93%, p=0.04). During the REACT task, participants exhibited asymmetrical ankle dorsiflexion (LSI=85%, p=0.03), and ankle inversion (LSI=73%, p=0.001) external joint moments. There were no differences in reaction times between the two limbs (p>0.05). CONCLUSIONS:Collegiate women’s volleyball players exhibit significant asymmetry in the knee and ankle during jumping and landing tasks. Interestingly, asymmetries were identified in kinetic variables but not kinematic variables. These findings indicate that screening, injury prevention and rehabilitation practices cannot solely rely on visual observation to identify lower extremity asymmetry in this athletic population.

A new Arietellidae (Copepoda: Calanoida) from the Red Sea

ABSTRACTA new species of the calanoid copepod genus Paramisophria T. Scott, 1897 is described from the Egyptian sublittoral zone of the Red Sea. Paramisophria aegypti sp. nov. appears to be closely related to the species Paramisophria ammophila and Paramisophria platysoma. Paramisophria aegypti differs from P. ammophila in having two unequal lateral setae plus one long terminal process and two tiny equal lateral setae plus one long terminal process on the third exopodal segment on the male right and left fifth legs (vs three terminal processes increasing in size inward on both male fifth legs). Paramisophria aegypti can be distinguished from P. platysoma in the following characters: prosome symmetrical (vs extreme asymmetry); third exopod segment of the right leg completely separated from the second segment and bears two unequal lateral setae plus one long terminal process (vs partially fused to the second segment and bears four terminal processes increasing in size inward); third exopod segment of the left leg with two lateral setules and one long terminal process (vs two lateral setules, one short outer medial process and one long terminal process); endopodal lobes of the female legs 5 bear one long plumose seta (vs setae are lacking).http://www.zoobank.org/urn:lsid:zoobank.org:pub:C0A92BF9-2306-4A35-AA39-CE3B5865A396

Time-dependent analysis of electroosmotic fluid flow in a microchannel

The present work models electroosmotic induced fluid flow in a microfluidic device. For theoretical analysis, the geometry of this device is considered as an asymmetric, narrow, wavy channel with charged surface. It is assumed that the length of the channel is finite and the characteristic wavelength is very large compared to the half width of the channel. The flow is assumed to be governed by Navier–Stokes equations augmented with electric body force. A transient two-dimensional flow analysis is presented by employing lubrication theory. Debye–Huckel linearization is adopted to obtain a general solution of Poisson–Boltzmann equation. The flow rate, velocity profile, pressure distribution, and wall shear stress are analyzed as functions of various parameters involved like zeta-potential ratio, Debye–Huckel parameter, etc. It is noted that the fluctuations in pressure and shear stress increase with the increasing zeta-potential ratio when the Helmholtz–Smoluchowski velocity is positive. The streamline pattern and the particle trajectories are analyzed to understand the trapping phenomenon and the retrograde motion. It is observed that the electroosmosis phenomenon drastically modulates the fluid flow in microchannels. Although the asymmetric nature of the wavy channel does not support active particle transport, the applied electric field enhances the particle motion favoring optimal conditions. It is observed that the extreme asymmetry of the wall motility reduces the net flow rate. Further, it is noticed that the asymmetry reduces the amplitudes of the pressure. This model can help toward designing artificial organs based on microfluidic devices which can also be applicable to analyze lumenal flow inside arteries and flow inside intrauterine system, and to implant the embryo at the best location in the uterus for human-assisted reproduction.

Primary and Secondary Central Nervous System Involvement in Acute Myeloid Leukemia

Introduction: Central Nervous System involvement (CNSi) in patients with Acute Myeloid Leukemia (AML) rarely occurs. It is not well characterized clinically and lacks standardized treatments. Patients and methods: A retrospective analysis of 77 consecutive AML patients with primary and secondary CNSi during 2004-2016 was performed in eight Polish haematological centres. Results: 77 patients (38 with primary CNSi-AML) were included. Median age was 44 years in both groups. Elevated lactate dehydrogenase activity was found in the majority of subjects. Patients in primary CNSi-AML group more often had myelomonocytic and monoblastic AML subtypes (68.4%) compared to secondary CNSi AML (43.5%) (p=0.039). There were no differences between both groups in the number of leukocytes or the proportion of blast cells rates in peripheral blood or bone marrow at AML diagnosis. There were also no statistically significant differences between both groups in the incidence of cytogenetic or molecular abnormalities. In both groups, CNSi was most frequently found in the cerebrospinal fluid and the most common neurological symptom was headache. The following manifestations were more frequent in secondary than in primary CNSi-AML: lower extremity weakness (38.46% vs. 13.16%; p=0.023), paraesthesia (38.46% vs. 13.16%; p=0.023), motor deficits (31.58% vs. 10.53%; p=0.047), and asymmetry of reflexes (26.32% vs. 2.7%; p=0.007). Median pleocytosis was also significantly higher in secondary than in primary CNSi-AML: 27 (IQR 2-146) vs. 2 (IQR: 1-12; p=0.004). Both groups had rather short Overall Survival (OS), with a median of 16.6 months (9.9-NA) for patients with primary CNSi-AML and 15.4 months (10.1-21.1) for patients with secondary CNSi. Conclusion: Patients with CNSi AML were relatively young, having high lactate dehydrogenase activity and high rates of the myelomonocytic and monoblastic/monocytic AML subtypes. The advisability of undertaking CNS examination and prophylaxis in patients with such characteristics thus merits further reassessment.

On the Intensity of the Magnetic Superstorm of September 1909

AbstractAnalysis is made of solar observations and ground‐based magnetometer data recording space weather before and during the magnetic superstorm of 25 September 1909. From these data, it is inferred that the storm was initiated by an interplanetary coronal‐mass ejection having a mean Sun‐to‐Earth velocity of ~1,679 km/s. The commencement pressure on the magnetopause was ~32.4 nPa, sufficient to compress the subsolar magnetopause radius to ~5.9 Earth radii. Early on in the evolution of the storm, low‐latitude geomagnetic disturbance exhibited extreme longitudinal asymmetry, something that can be attributed to substorm activity extending to low latitudes. For this storm,Dstattained a minimum of −595 nT, comparable to that of the great magnetic storm of March 1989 (−589 nT; the most intense storm in terms ofDstof the space age). These results inform projects focused on understanding and mitigating the deleterious effects of extreme space‐weather events.

Comparison of topographic indices and corneal higher order aberrations in eyes with an extreme asymmetry of keratoconus with control eyes

Purpose: To compare topographic indices and anterior corneal higher order aberrations (HOAs) of forme fruste keratoconus (KC) (fellow eyes) with clinical KC and control eyes. Setting: Tertiary Eye Hospital, India. Materials and Methods: This study retrospectively reviewed 298 patients with KC. Patients were evaluated with placido-based topographer. KC was diagnosed according to Rabinowitz and McDonnell criteria and clinical sign. Twenty-one patients with clinical KC in one eye (Group A), fellow eye (Group B) with normal topography with no clinical sign, and 21 control eyes (Group C) were included in the study. Topographic indices (keratometry, inferior superior ratio, irregularity, shape factor, and eccentricity) and HOAs (trefoil, coma, spherical aberration, total root mean square [RMS], HOAs RMS of third to seventh order for 6 mm diameter) were obtained. Group B was compared with Groups A and C. Results: The prevalence of an extreme asymmetry of KC in our study population is 7.04% with mean age of 21.98 ± 7.39 years. All topographic indices were higher in Group A compared to Group B (P

Extreme asymmetry of Néel domain walls in multilayered films of the dilute magnetic semiconductor (Ga,Mn)(As,P)

We report on unconventional perfectly shaped, fully asymmetric $\ensuremath{\sim}{90}^{\ensuremath{\circ}}$ N\'eel domain walls in multilayered films of the diluted ferromagnetic semiconductor (Ga,Mn)(As,P) with a stepwise variation of P doping. Our results contradict micromagnetic calculations, which favor symmetric domain walls due to crystallographic anisotropy and stray field energy. We demonstrate that both the puzzling uniaxial in-plane anisotropy in the tetragonal multilayered film and the asymmetry of the domain walls could result from Dzyaloshinskii-Moriya interactions that are enhanced by the multiple sharp interfaces between the layers and from anisotropic nonrelativistic exchange coupling. Our finding shows that digital variations of composition during the molecular beam epitaxy can be used to tune the anisotropy and chirality of magnetic multilayers.

Cdk1 inactivation induces post-anaphase-onset spindle migration and membrane protrusion required for extreme asymmetry in mouse oocytes

Female meiotic divisions are extremely asymmetric, producing large oocytes and small polar bodies (PBs). In mouse oocytes, the spindle relocates to the cortex before anaphase of meiosis I (MI). It is presumed that by displacing the future midzone, pre-anaphase spindle repositioning alone ensures asymmetry. But how subsequent anaphase events might contribute to asymmetric PB extrusion (PBE) is unknown. Here, we find that inactivation of cyclin-dependent kinase 1 (Cdk1) induces anaphase and simultaneously triggers cytoplasmic formin-mediated F-actin polymerisation that propels the spindle into the cortex causing it to protrude while anaphase progresses. Significantly, if post-anaphase-onset spindle migration fails, protrusion and asymmetry are severely threatened even with intact pre-anaphase migration. Conversely, post-anaphase migration can completely compensate for failed pre-anaphase migration. These data identify a cell-cycle-triggered phase of spindle displacement occurring after anaphase-onset, which, by inducing protrusion, is necessary for extreme asymmetry in mouse oocytes and uncover a pathway for maximising unequal division.

Asymmetries Identified in Sit-to-Stand Task Explain Physical Function After Hip Fracture.

Several known demographic and functional characteristics combine to predict physical function after hip fracture. Long-term weight-bearing asymmetries, evident during functional movements after hip fracture, contribute to limited mobility and large asymmetries in muscle function are linked to a high rate of injurious falls. Although postfracture mobility is commonly measured as whole body movement, a force-plate imbedded chair can identify individual limb contributions to an important task like moving from a sitting to standing position. The modified Physical Performance Test (mPPT) and stair climb test (SCT) are reliable, valid measures of function that predict independence after hip fracture. The purpose of this study was to determine to what extent asymmetry during a sit-to-stand task (STST) predicts function (mPPT, 12-step SCT), above and beyond other known predictors. Thirty-one independent community-dwelling older adults, recently discharged from usual care physical therapy (mean [standard deviation], 77.7 [10.5] years, 10 male), within 2 to 8 months postfracture, volunteered for this study. Participants performed an STST on a force-plate-imbedded chair designed to identify individual limb contributions during an STST. Asymmetry magnitude during the STST was determined for each individual. In addition, mPPT and SCT were assessed and regression analyses were performed to determine the contribution of asymmetry to the variance in these physical function scores beyond other factors predicting function. Demographic factors (sex, time since fracture, repair type, and body mass index) were not significantly related to function in this sample. Age, gait speed, knee extension strength, balance confidence, and functional self-report were each significantly related to both mPPT (r = 0.43-0.86) and SCT (r = 0.40-0.83), and were retained in the regression model. Included variables accounted for 83.4% of the variance in mPPT score, and asymmetry during the STST did not significantly contribute to explaining variability in mPPT (P = .23). Variables in the regression model accounted for 78.0% of the variance in SCT score, and STST asymmetry explained 7.1% (P < .005) of the variance in SCT score. In this small sample, asymmetry contributed significantly to explaining the variability in SCT performance, but not mPPT score. The SCT requires greater unilateral strength and control than the battery of items that comprise the mPPT. This contributes to the disproportionate number of falls occurring during stair ambulation (>10% of all fall-related deaths), relative to the minimal time typically involved in stair negotiation. Our results indicate potential benefit to identifying injured limb asymmetries as they predict function in challenging, high-risk functional tasks after hip fracture. Although gait speed is the best explanator of physical function in older adults after hip fracture, lower extremity asymmetry during an STST provides a unique contribution to explaining high-level ambulatory performance after hip fracture. Efforts to reduce weight-bearing asymmetry during rehabilitation following hip fracture may improve function and recovery.

Comparison of drop jump landing biomechanics and asymmetry among adolescents with hamstring, patellar and quadriceps tendon autografts for anterior cruciate ligament reconstruction

BackgroundAdolescent anterior cruciate ligament reconstruction (ACLR) commonly utilizes hamstring (HT), patellar (PT) or quadriceps (QT) tendon autografts, but consensus is lacking regarding optimal graft choice. This study compared landing biomechanics and asymmetries among ACLR patients with HT, PT and QT grafts and uninjured controls. MethodsThis retrospective study included 61 adolescents with unilateral ACLR (27 HT, 20 PT, 14 QT; four to 12 months post-surgery, mean 6.4; age 15.4, SD 1.4 years) and 27 controls (14.6, SD 0.9 years) who were evaluated during drop jump landings. Lower extremity 3D biomechanics and asymmetries were compared. ResultsCompared to controls, all operative limbs exhibited 1) greater hip flexion and lower dorsiflexion angles; 2) higher hip and lower knee and ankle flexion moments; 3) higher energy absorption at the hip (HT and QT only) and lower at the knee and ankle; and 4) higher knee abduction moments. Asymmetries observed in all ACLR groups included 1) lower knee and ankle flexion angles; 2) lower knee and ankle flexion moments; 3) lower energy absorption at the knee and ankle; and 4) higher hip and knee abduction moments on the operative side. The PT and QT groups demonstrated greater asymmetry in hip and knee flexion moments compared to HT. ConclusionsWhile adolescent ACLR limbs offloaded the knee and ankle, patients with PT or QT grafts demonstrated greater deficiencies during rehabilitation than those reconstructed with HT. Graft choice in ACLR should remain patient-specific and aim to optimize biomechanics with the ultimate goal of minimizing graft re-tear and donor site morbidity.

P 052 – Detection of lower extremity asymmetries in slow and dynamic bilateral tasks. Inertial Sensor system vs Optical Motion Capture System

P 052 – Detection of lower extremity asymmetries in slow and dynamic bilateral tasks. Inertial Sensor system vs Optical Motion Capture System

Study of Temperature and Heat Flux on the EAST Divertor Target Plate in LHW+ NBI/ICRH H-Mode

The heat fluxes on the lower outer divertor plate were calculated using the DFLUX code with the surface temperature measured by the IR camera on the experimental advanced superconducting tokamak. The analyzed discharges were lower single-null divertor configuration discharges with different auxiliary heating: lower hybrid wave current drive (LHCD) combined with neutral beam injection (NBI) and LHCD combined with ion cyclotron resonant heating (ICRH). The surface temperature of the lower outer divertor target plate was about 170 °C in the LHCD + NBI H-mode, with the high temperature mostly distributed in the location near the joint of the dome and the outer target plate. The temperature increased as the NBI was turned on and fluctuated due to edge localized modes (ELMs). The heat flux reached nearly 4 MW/m2 when ELMs appeared and declined to less than 1 MW/m2 when the NBI was turned off. Temperature distribution with extreme toroidal asymmetry was observed in the selected LHCD + ICRH H-mode discharge. The surface temperature on the lower outer divertor target plate was up to 220 °C in one region with broader temperature distribution. During the LHCD + ICRH H-mode, the peak heat flux was not seen during the period of ICRH injection, though a brief spike in heat flux was observed at the beginning of the ICRH injection. The full-width at half-maximum of the heat flux profile as a function of divertor target plate location of the LHCD + ICRH H-mode is three times that of the LHCD + NBI H-mode.

Dynamic vacuum pressure tracking control with high-speed on-off valves

A vacuum pressure tracking system with high-speed on-off valves is a discontinuous system due to the discrete nature of high-speed on-off valves. Chamber pressure changes in the system are determined by the mass flow rates during the processes of charging and discharging. Here, a sliding mode controller with an asymmetric compensator based on average mass flow rate is designed for accurate vacuum pressure tracking. The controller output signal is converted into the duty cycles of the high-speed on-off valves via a pulse width modulation pulsing scheme. Owing to the extreme asymmetry of the processes, an asymmetric structure comprising one high-speed on-off valve in the charging unit and three high-speed on-off valves in the discharging unit is applied to weaken the impact of asymmetry. In addition, an asymmetric compensator is also designed to modify the pulse width modulation pulsing scheme to further eliminate the asymmetry. Experimental results indicate that the proposed controller achieves better performance in pressure tracking with the asymmetric compensator overcoming process asymmetry and enhancing system robustness.

The Cognition of Severe Moral Failure: A Novel Approach to the Perception of Evil.

I describe the perception of evil as a categorization judgment, based on a prototype, with extensive feedback loops and top-down influences. Based on the attachment approach to moral judgment (Govrin, 2014, 2018), I suggest that the perception of evil consists of four salient features: Extreme asymmetry between victim and perpetrator; a specific perceived attitude of the perpetrator toward the victim's vulnerability; the observer's inability to understand the perpetrator's perspective; and insuperable differences between the observer and perpetrator's judgment following the incident which shake the observer no less than the event itself. I then show that the perception of evil involves a cognitive bias: The observer is almost always mistaken in his attributions of a certain state of mind to the perpetrator. The philosophical and evolutionary significance of this bias is discussed as well as suggestions for future testing of the prototype model of evil.

Invited commentary

Abdominal aortic aneurysm diameter is the primary factor that has been used to direct aneurysm therapy. Aortic morphologic characteristics have failed to have a demonstrable impact on clinical decision-making for several reasons. Foremost, the morphologic assessments must be readily available to clinicians, inexpensive, and easy to measure and have clinically defined thresholds that direct care. However, defining aneurysm morphologic features does have additional value beyond directing therapy. Clinicians, researchers, and engineers alike are constantly exploring the boundary conditions on which to base new medical treatments; these morphologic features can help direct new therapies. Advent and adoption of endovascular aneurysm repair have limited the opportunity to examine aortic wall tissue. In the current manuscript, Barrett et al monopolize the opportunity to subject harvested aortic aneurysm wall to mechanical stretch forces that parallel physiologic conditions. It is intuitive that degraded aortic wall will demonstrate varying degrees of stiffness and response to stress. However, it is uncertain which morphologic features affect those features. The authors reinforce the assumption that the aortic wall is subjected to extreme asymmetry when uniform stress is applied. Regions of high stiffness, marked by calcium deposition, are surrounded by vulnerable regions of low stiffness. The regions surrounding calcium are subjected to greater degrees of deformation, which translates to increased strains; in some regions surrounding calcium, the wall demonstrated two to four times the strain compared with reference regions. In addition, the authors demonstrated that stiff intraluminal thrombus also alters surrounding aortic wall mechanical properties similar to that of calcium. Regions of high strain also correlated with wall thinning and stretching visualized on electron microscopy. Interestingly, aortic diameter did not correlate with changes in aortic wall mechanics. Routine clinical imaging readily detects calcium burden within the aortic wall, and each patient demonstrates varying degrees of calcium within the aneurysm. The localized variation in aortic wall mechanics may provide additional information to identify patients at risk for rupture. In the future, this information may be used to adjust surveillance or to offer therapy, but for now, it will provide another boundary condition to better explain aneurysm wall mechanics and resultant aneurysm behavior. The opinions or views expressed in this commentary are those of the authors and do not necessarily reflect the opinions or recommendations of the Journal of Vascular Surgery or the Society for Vascular Surgery. On the influence of wall calcification and intraluminal thrombus on prediction of abdominal aortic aneurysm ruptureJournal of Vascular SurgeryVol. 67Issue 4PreviewParameters other than maximum diameter that predict rupture of abdominal aortic aneurysms (AAAs) may be helpful for risk-benefit analysis in individual patients. The aim of this study was to characterize the biomechanical-structural characteristics associated with AAA walls to better identify the related mechanistic variables required for an accurate prediction of rupture risk. Full-Text PDF Open Archive

Solar Activity Changes During Prolonged Sunspot Minima as Inferred from Indian Monsoon Rainfall Variations

AbstractWe could find a new 5 year periodicity in the occurrences of peaks in sunspot activity and inferred deviations of annual Indian monsoon rainfall variations from the normal during the Maunder minimum (MM) period. This result is explained in terms of solar dynamo functioning in a different mode from normal during the MM where quadrupole field (first harmonic, 5-5.5 years) dominate over dipole field (fundamental, 11 years) causing extreme north south asymmetry in sunspot activity.