Corvus corax) and show that it is more likely to occur after conflicts between partners who share a valuable relationship. Furthermore, former opponents were less likely to engage in renewed aggression following reconciliation, suggesting that reconciliation repairs damage caused to their relationship by the preceding conflict. Our findings suggest not only that primate-like valuable relationships exist outside the pair bond in birds, but that such partners may employ the same mechanisms in birds as in primates to ensure that the benefits afforded by their relationships are maintained even when conflicts of interest escalate into aggression. These results provide further support for a convergent evolution of social strategies in avian and mammalian species.Reconciliation, a post-conflict affiliative interaction between former opponents, is an important mechanism for reducing the costs of aggressive conflict in primates and some other mammals as it may repair the opponents' relationship and reduce post-conflict distress. Opponents who share a valuable relationship are expected to be more likely to reconcile as for such partners the benefits of relationship repair should outweigh the risk of renewed aggression. In birds, however, post-conflict behavior has thus far been marked by an apparent absence of reconciliation, suggested to result either from differing avian and mammalian strategies or because birds may not share valuable relationships with partners with whom they engage in aggressive conflict. Here, we demonstrate the occurrence of reconciliation in a group of captive subadult ravens ( Aggressive conflict features regularly in the lives of group-living animals but may entail significant costs, including loss of time and energy, risk of injury, damage to the opponents' relationship and post-conflict distress Reconciliation has been demonstrated in many primates In this study, we investigated the occurrence of reconciliation in another group of captive subadult ravens. We further examined the influence of conflict intensity and opponent relationship quality on reconciliation, predicting that reconciliation may be more likely to occur after more intense conflicts as a result of increased post-conflict distress and that conflicts between valuable partners would be most likely to be reconciled as the benefits of relationship repair would be higher for such partners. Finally, we investigated the interdependency between reconciliation and renewed aggression between former opponents, predicting that if post-conflict affiliation between former opponents in birds serves the same relationship repair function as has been demonstrated in primates, the likelihood of renewed aggression should be lower following reconciliation than if reconciliation does not occur.2 = 11.299, df = 1, P = 0.001; We demonstrated the occurrence of post-conflict reconciliation in a group of seven captive ravens by showing that the latency to first affiliative contact between former opponents was shorter in post-conflict periods  than during matched control periods   occurred after 37 of 197 conflicts. We investigated the effects of kinship, levels of contact sitting and preening, opponent sex-combination and conflict intensity on the occurrence of reconciliation using generalized linear mixed models , supporting the relationship repair hypothesis for the function of reconciliation in ravens. Moreover, we showed that when reconciliation does not occur, neither kinship  nor levels of contact sitting and preening  influenced the occurrence of renewed aggression. This suggests that the interdependency between reconciliation and renewed aggression is not merely because valuable partners, who are more likely to reconcile, are less likely to engage in renewed aggression.We found that renewed post-conflict aggression between former opponents was less likely to occur after than without reconciliation . Although reconciliation in primates has been suggested to be an artifact of captivity, a detailed analysis of rates of reconciliation across many primate species in the wild and in captivity has found no evidence to support this hypothesis Reconciliation in primates has been shown to repair damage caused to the opponents' relationship by the preceding conflict and reduce post-conflict distress outside the pair bond in ravens and that such partners may employ the same mechanisms in some birds as in primates to ensure that the benefits afforded by their relationships are maintained even when conflicts of interest escalate into aggression.Taken together, our results indicate that despite differences in social structure and evolutionary history, ravens exhibit similar conflict resolution strategies to primates, as former opponents engaged in post-conflict reconciliation to repair valuable relationships and reduce the likelihood of renewed aggression. Primate sociality has been suggested to differ from those of other mammals and birds because it is based on bonded relationships of a type that only exist in pair bonds in other taxa Recent research has unveiled that corvids may be capable of a whole host of cognitively demanding tasks that were previously considered to be the exclusive domain of apes and other primates, such as episodic-like memory All procedures were conducted in accordance with US law on animal research and treatment. Permits for ravens include US Federal Fish and Wildlife Permit Number MB689376-0, State of Maine Department of Inland Fisheries and Wildlife Permit 22077, and Vermont Fish and Wildlife Department Scientific Collecting Permit. Permission was received from the University of Vermont to observe the ravens for this study.2 outdoor aviary at the University of Vermont, USA. Six subjects from two nests  hatched in 2002, the seventh subject was an unrelated adult male hatched in 1999.The study subjects were seven hand-raised ravens housed together in a 100 mData were collected from May 2002 to August 2003 by TB. All occurrences of aggressive conflict  were recorded along with the identities of the aggressor and victim  and the intensity of the conflict . The established post-conflict (PC)- matched control (MC) method Data analysis was based on 197 PC-MC pairs on six subjects . The only adult subject was never recorded as a conflict victim.In order to determine whether reconciliation occurred, the mean proportion of PC-MC pairs per individual in which affiliation between former opponents occurred only in the PC, or earlier in the PC than the MC (‘attracted’ pairs) was compared those in which such affiliation occurred earlier, or only, in the MC (‘dispersed’ pairs) using a paired t-test. The latency to first affiliative contact between former opponents in PCs and MCs was also compared using a Kaplan–Meier survival analysis with a Mantel–Cox test. We did not look for selective attraction between former opponents as ravens engage in frequent post-conflict affiliation with bystanders uninvolved in the preceding conflict We used generalized linear mixed models (GLMMs) to investigate the effects of conflict intensity (high or low), opponent sex combination , kinship (sibling or non-sibling) and proportion of time spent contact sitting or preening on the occurrence of reconciliation (yes/no). An additional GLMM was run investigating the effects of kinship and proportion of time spent contact sitting or preening on the occurrence of renewed aggression (when reconciliation did not occur). For all GLMMs, the identities of both conflict opponents were entered as random factors. We used GLMMs with binomial error structures and a logit-link function. Akaike's information criteria (AIC) values were used to select the best (most parsimonious) model 2 test.To examine the interdependency reconciliation and renewed aggression between former opponents, we compared the probability of renewed aggression occurring after and without reconciliation using a Chiwww.r-project.org). All other analyses were conducted in SPSS v.17. Data conformed to normality whenever parametric tests were used. All tests were two-tailed and the alpha level was set at 0.05.GLMM analyses were conducted using the lme4 package


To review the recent developments and published literature on laparoendoscopic single-site (LESS) surgery in gynaecology.Minimally invasive surgery has become a standard of care for the treatment of many benign and malignant gynaecological conditions. Recent advances in conventional laparoscopy and robotic-assisted surgery have favorably impacted the entire spectrum of gynaecological surgery. With the goal of improving morbidity and cosmesis, continued efforts towards refinement of laparoscopic techniques have lead to minimization of size and number of ports required for these procedures. LESS surgery is a recently proposed surgical term used to describe various techniques that aim at performing laparoscopic surgery through a single, small-skin incision concealed within the umbilicus. In the last 5 years, there has been a surge in the developments in surgical technology and techniques for LESS surgery, which have resulted in a significant increase in utilisation of LESS across many surgical subspecialties. Recently published outcomes data demonstrate feasibility, safety and reproducibility for LESS in gynaecology. The contemporary LESS literature, extent of gynaecological procedures utilising these techniques and limitations of current technology will be reviewed in this manuscript.LESS surgery represents the newest frontier in minimally invasive surgery. Comparative data and prospective trials are necessary in order to determine the clinical impact of LESS in treatment of gynaecological conditions. Laparoscopy has become the standard treatment for many gynaecological conditions. Numerous studies have demonstrated that utilising laparoscopy for various benign and malignant gynaecological diseases results in shorter hospital stays, improved quality of life and improved surgical outcomes when compared with open abdominal surgery.–3 LaparoSingle-incision surgery has been performed anecdotally for decades in gynaecology; however, the first surgery employing LESS techniques was not described in the literature until 2008. Since that time, the interest in this surgical approach has grown exponentially. Several publications in the gynaecology literature have demonstrated preliminary feasibility, safety and reproducibility of LESS in the treatment of both benign and oncological female conditions.–20 The rVarious terminologies and acronyms have been used to describe laparoscopic surgical procedures performed through a single-incision or surgical site . In 2008et al.[Initially, during the 1960s and 1970s, the application of laparoscopic surgery in gynaecology was restricted to diagnostic cases and tubal procedures such as sterilisation.–20 The fet al. performeet al. This metPotential advantages of single-port over conventional multiport laparoscopy include superior cosmesis from a relatively hidden umbilical scar, a possible decrease in morbidity related to visceraland vascular injury during trocar placement, as well as risk reduction of postoperative wound infection, hernia formation and elimination of multiple trocar site closures. Studies have also suggested that women who undergo LESS report improved postoperative pain profiles when compared with those receiving conventional laparoscopic surgery. This mayLESS procedures are typically performed via one of two approaches. The first is single-site surgery, where two or more conventional ports are placed through a single-incision. The second approach utilises a single, multichannel device, through which multiple instruments and optics are passed. The access point for these surgeries is typically the umbilicus, although less cosmetic extra-umbilical incisions may occasionally be necessary to complete the surgery. Improvements in access devices, optics and instrumentation have driven the dissemination of this new format of laparoscopic surgery.LESS surgery can be performed through a variety of access devices. Conventional, low profile ports of different lengths can help to minimize limitation of movement by the surgeon(s) due to the extracorporeal interaction of the instruments and camera (known as “sword fighting”). Technological developments have produced multichannel single-port devices as well.–29 The pAnother port that has also been used successfully for LESS procedures is the Uni-X Single-Port Access Laparoscopic system . This port has three working channels for 5-mm instruments, and it is placed by an open access technique, requiring stitches to secure it to the fascia.® wound retractor with a Gelseal® cap which maintains pneumoperitoneum during multiple instrument exchanges.[The GelPort or newer generation GelPoint  devices consist of a combination of the rigid ring of the Alexisxchanges.28 Unlikexchanges.. This de™ Port Multiple Instrument Access Port  is another multi-instrument access port that allows up to three laparoscopicinstruments (three 5-mm cannulas or two 5-mm and one 12-mm cannula) to be used simultaneously through separate flexiblechannels [2 insufflation. The port must be inserted through an open access technique. Finally, the latest port to be approved is the Single-Site Laparoscopy Access System  which was introduced on the market in 2010 [The SILS channels . This po in 2010 . Two 5-mTwo of the biggest caveats that limit use of the LESS technique are instrument crowding and lack of triangulation. Many surgeons are accustomed to the tenet of triangulation, due to the use of conventional laparoscopy, and this practice can be approximated to some degree by utilising special single-port instrumentation, including flexible and/or articulating instruments. These instruments allow for intracorporeal triangulation, rather than the extracorporeal triangulation utilised in traditional laparoscopy. Those instruments currently available as articulating devices includegraspers, shears, endoshears, needle-drivers, and hook electrocautery. Several companies have designed a comprehensive spectrum of these articulating instruments. At this stage in development, bulk and technical challenge pose major obstacles in using articulating instruments.Instrument crowding may occur due to several instruments being passed though a multichannel, single-port. Instruments may easily clash with one another or with the laparoscope, all of which are passed through the same surgical fulcrum. Conventional laparoscopes have a large extracorporeal profile with a light cable perpendicular to the telescope. Due to this latter feature, if the conventional laparoscope is utilised for LESS instrument clashing may be exacerbated. One method, however, to minimize this problem is by using a lower profile camera system. One system that is currently available is the rotatable 30°Visera EndoEYE laparoscope , do not necessarily preclude the performance of LESS.1315 Howe13et al.[Since the initial reports of clinical successes, there have been a large number LESS surgeries reported in gynaecology, with various new techniques being described. In 2005, Ghezzi et al. describeet al.20et al. included 52 LESS hysterectomies compared with 101 conventional hysterectomies. This study demonstrated improved blood loss, hospital stay and pain scores  in women who underwent the LESS hysterectomy.[Both case reports and prospective studies have also described LESS in adnexal surgery for benign pathologies, including unilateral or bilateral salpingo-oopherectomy, adhesiolysis, excision of endometriosis and ovarian cystectomy.30–33 The17erectomy. Further et al. repoted on a series of 61 patients using a 2-mm miniport with standard trocar and instrumentation for the treatment of benign gynaecological disease. The results demonstrated that a 2-mm miniport is safe and feasible to use, and patient satisfaction was high, as greater than 80% of patients were satisfied with their surgical experience and 94% were satisfied with the cosmetic results.[Recently, exceedingly small single-port devices have been explored in gynaecology. Chong  results.P < 0.0001). Operative times for 31 consecutive LESS TLH/BSO cases showed similar improvements in operating time across all quartiles, with the most significant reductions observed between Quartile 1 cases (mean = 79.3 minutes) and Quartile 2 cases . These preliminary results suggest a similar learning curve for conventional laparoscopy and LESS procedures to that of Hasson trocar placement.There is a learning curve for the techniques utilised in LESS single-port insertion and for total laparoscopic hysterectomy and bilateral salpingo-oophorectomy which was initially described by Fader and Escobar. Studies et al. demonstrated that more complicated procedures, such as pelvic and para-aortic lymphadenectomy were also feasible and safe to perform with LESS techniques. These procedures produced comparable nodal counts to open or conventional laparoscopic surgery.[In examining LESS techniques for gynaecological malignancies, several advantages may be proposed. Many women with breast or gynaecological cancers may perceive a benefit of LESS specific to their body image following surgery. Moreover, fewer incisions may result in faster recovery periods and a more timely administration of adjuvant therapies when required. More data is needed in order to support or refute these theories. There have been several reports from our research group demonstrating feasibility, safety and reproducibility of the LESS approach for treatment of select early-stage endometrial or ovarian cancers, pelvic masses, precancerous conditions and for risk-reducing salpingo-oophorectomy in women at high risk for ovarian cancer.13 Furthe surgery. One limiP < 0.001) and non-staging procedures . This statistic revealed that approximately 20 cases were required to achieve stable decreased operative times, again supporting a learning curve for complex LESS procedures that is similar to that of conventional laparoscopic cases.In a retrospective review of 74 LESS cases performed on a gynaecological oncology service, a variety of procedures were performed . This study showed that perioperative complications were low (3.5%) and pain scores were excellent. A PearsoFinally, LESS surgery may also be done via the da Vinci surgical system robotic platform through a GelPort or other similar single-port device.40 Our grLESS surgery represents the next step forward in minimally invasive techniques; however, many questions must be answered and research must be performed to support the general application of LESS. There is definite patient interest, especially among women, as demonstrated by patients opting for single-port rather than multiport access surgeries; however, further research is need to answer the fundamental question of whether LESS shows any objective, reproducible benefit over conventional laparoscopy. There is agreement that these techniques provide improved cosmesis; however, standardized measures have not yet been employed to scientifically verify these findings. While this apparent benefit is important, the true indicator for the widespread acceptance of LESS will be whether or not these procedures demonstrates reduced pain, perioperative morbidity and convalescence thus justifying the increased technical demands and arguably more costly technology . Preliminary comparative studies indicate that LESS outcomes are at least equivalent to those of conventional laparoscopy, and in several studies LESS has shown improved pain profiles, decreased home oral narcotic requirements and faster return to work. It is likely that as the learning curve is overcome and large prospective studies are completed, that these questions will be addressed and more definitively answered.Laparoendoscopic single-site surgery is the latest innovation in minimally invasive surgery and appears to be feasible and safe to perform for a variety of gynecologic conditions. This approach may result in a “scarless” effect, because the healed incision remains concealed at the base of the navel. While initial series in the urological, general surgery and gynaecological literature have demonstrated the safety, aesthetic superiority and potentially improved pain profile of a single-port approach when compared with conventional laparoscopy, these early findings must be further validated. The routine application of LESS in gynaecology not only requires evaluation of safety but also of cost-effectiveness, and these studies must all be performed in larger, prospective studies to definitively answer questions regarding the clinical and economic impact of this novel surgical approach. More detailed data is also needed to further describe the learning curve and the optimal environment for trainees and surgeons to become skilled in LESS procedures. These additional research initiatives will help to drive advances in minimally invasive surgical techniques and technology, in order to continue to provide better outcomes for our surgical patients.


Cell physiology dynamically affects the nutrient requirements of a culture. It is critical to obtain data over appropriate time intervals to assess the impact of process conditions on the cell population. By optimizing bioreactor operation, feed strategies and media composition, we can limit the number of experiments to obtain the empirical data sets.For this poster, we present an emerging process-development methodology that is based on applying novel and existing bioreactor monitoring technologies, coupled with applied mathematics, to bioreactor processes. This approach employs tools like dielectric spectroscopy, aseptic autosamplers, and cell-based bioreactor models. We will illustrate how information gained from these tools can be coupled through utilization of the proper data integration and applied mathematics techniques.The knowledge gained using this improved process development methodology also supports a less-invasive monitoring and feedback system, and can be implemented using a customized bioreactor control code.


A common feature in biological neuromuscular systems is the redundancy in joint actuation. Understanding how these redundancies are resolved in typical joint movements has been a long-standing problem in biomechanics, neuroscience and prosthetics. Many empirical studies have uncovered neural, mechanical and energetic aspects of how humans resolve these degrees of freedom to actuate leg joints for common tasks like walking. However, a unifying theoretical framework that explains the many independent empirical observations and predicts individual muscle and tendon contributions to joint actuation is yet to be established. Here we develop a computational framework to address how the ankle joint actuation problem is resolved by the neuromuscular system in walking. Our framework is founded upon the proposal that a consideration of both neural control and leg muscle-tendon morphology is critical to obtain predictive, mechanistic insight into individual muscle and tendon contributions to joint actuation. We examine kinetic, kinematic and electromyographic data from healthy walking subjects to find that human leg muscle-tendon morphology and neural activations enable a metabolically optimal realization of biological ankle mechanics in walking. This optimal realization (a) corresponds to independent empirical observations of operation and performance of the soleus and gastrocnemius muscles, (b) gives rise to an efficient load-sharing amongst ankle muscle-tendon units and (c) causes soleus and gastrocnemius muscle fibers to take on distinct mechanical roles of force generation and power production at the end of stance phase in walking. The framework outlined here suggests that the dynamical interplay between leg structure and neural control may be key to the high walking economy of humans, and has implications as a means to obtain insight into empirically inaccessible features of individual muscle and tendons in biomechanical tasks. Biological neuromuscular systems are generally able to perform a specified movement task in several ways – as they have significantly more degrees of freedom than mechanical constraints. Understanding how humans resolve these redundancies to drive individual muscles and tendons in typical joint movements is of interest in the fields of biomechanics, neuroscience and prosthetics. Many experimental studies have uncovered neural, mechanical and energetic features of individual muscle and tendon function in common tasks like walking and running. However, a unifying theoretical framework that explains the many independent empirical observations is yet to be established. In this work, we show that leg muscle-tendon morphology and neural co-ordination, together, enable efficient ankle movements in walking. This finding provides quantitative insight into the operation and performance of posterior-leg muscles and tendons in walking, and motivates the idea that different muscle-tendon units take on different mechanical roles to best actuate the ankle in gait. Results reported have implications both for better understanding neuromuscular co-ordination in gait, and for the design of lower limb prosthetic and orthotic technologies. A common feature in biological neuromuscular systems is the redundancy in joint actuation. Redundancies in actuating a joint with a prescribed force and motion can be classified at three levels. Joints can be actuated by multiple muscle-tendon units (MTUs) working simultaneously. At any instant, energy for MTU work could come from the series elastic tendon or from the active muscle. Each muscle has many sensors and can be controlled by multiple neural pathways acting together. Understanding how these redundancies are resolved in typical joint movements has been a long-standing problem in biomechanics, neuroscience and prosthetics There is a large literature  driving objectives underlying and (b) empirical observations on redundancy resolution is not accompanied by a unifying theoretical framework that relates the two. There is a need to explain the breakdown of joint actuation, possibly driven by one or more of the above driving objectives, into observed individual element contributions.Previous studies a priori for a given joint actuation.An alternative proposal for resolving individual muscle-tendon contributions to joint actuation in walking is found in optimal design. A starting point for such an approach lies in a recent study by Lichtwark & Wilson Thus, existing optimal control and optimal design approaches are limited, albeit in different ways, by the very joint actuation redundancies they seek to address. Extra sources of information are needed to address this problem. EMG data contains information about muscle activity, and could potentially be used as a source of biologically realistic neural control commands to muscles. This promises to circumvent the above-mentioned difficulties in obtaining optimal muscle activations. Further, having muscle activation profiles could also enable a more systematic study of the effects of MTU structure (design) on the breakdown of joint actuation amongst individual elements. In other words, estimating muscle activations from the data allows a consideration of both neural control and muscle-tendon design, in tandem, on the operation of individual muscles and tendons.Motivated by the above ideas, we have developed a theoretical framework to (a) address how the load of actuating a joint is shared amongst the many MTUs, (b) elucidate features of leg design and neuromuscular control enabling the breakdown and (c) clarify functional advantages arising from the load sharing. As a case study, we examine ankle joint actuation in human walking. We model the three primary leg MTUs contributing to ankle action in walking . Each MTOur results are organized into five sections. First we present our estimates of muscle activations from EMGs recorded during human walking. In the second section, we characterize the leg parameter space by ability to produce human-like ankle torques and economy. We show that there is a unique parameter vector that is able to accomplish both, and that this unique vector corresponds to the maximum metabolic economy. Third, we present the optimal leg parameters, compare them with biological values and discuss their influence on metabolic economy. Fourth, we present model plantar flexor muscle and tendon strain predictions, compare them with two sets of independent empirical recordings and use them to evaluate mechanical power breakdown between muscle and tendon within each MTU. In the fifth section, we present metrics regarding the breakdown of ankle actuation amongst the two different plantar flexors.Muscle activation is an indicator of a muscle's force-generation capability, indicated by the proportion of troponin bound to calcium Classic EMG analysis involves rectification and low-pass filtering Propagating the probability densities in a classic recursive Bayesian manner, to estimate the le is on .We attribute this to differences between the modeled jump-diffusion process and the true buildup of muscle active state in normal tasks  the overall L shape, (b) a vertical boundary evidently representing the minimum energy that model muscles have to expend given the inputs, regardless of torque match and (c) an evidently systematic horizontal boundary below the population representing the best match between model and data. Each point along this horizontal boundary corresponds to a different metabolic consumption for the same level of error between model and human dynamics. A published empirical estimate of the range of metabolic consumption for ankle actuation in walking Remarkably, this overall parameter-space characterization reveals that the empirically observed realization is among the most economical of the many ways to produce human-like torque. Thus the human leg and the nervous system controlling it resolve the load-sharing redundancies in actuating the ankle most economically.and optimal human-like metabolics lie near the bottom horizontal and left vertical boundary respectively. Thus points representing a logical intersection of the model's ability to best produce both human-like dynamics and metabolics lie in a small region at the lower-left corner  into a multi-objective problem. Solutions for such problems are generally sets of points that simultaneously realize both objectives as best as possible. These solutions, known as Pareto solutions, typically form a frontier along which the two objectives can be traded off against each other to varying degrees. In the special case that both objectives logically intersect at a mathematically sharp corner, there is a single strong Pareto optimal solution that best fulfils both objectives without any tradeoffs. As demonstrated above, our problem resembles this special case - within systematic limits of experimental precision, data variability and functional relevance. Thus it is possible to interpret our problem within the strong Pareto optimal framework, and simplify standard multi-objective optimization methods  minimize metabolic cost. To solve for Our simplified approach relies on the observation that biologically realistic muscle-tendon morphological parameters  dimensions of the subjects studied, and (b) differences between our lumped element model geometry and the true anatomical geometries, arising possibly from the two-dimensional nature of our analyses (no volume or shape considerations) and from other model simplifications like constant pennation angles. Nevertheless, the overall trends in model muscle and tendon strain predictions are robust to these errors, and empirically realistic.Beyond these qualitative observations, model soleus muscle peak strains , Panel A lengths  and MTU The value of our modeling effort extends well beyond enabling comparisons between our theory and published empirical measurements. Difficulties in directly measuring individual muscle and tendon forces within a muscle-tendon unit have precluded resolution of how the total MTU power output breaks down between the muscle and the tendon. Our analysis provides estimates of individual muscle and tendon forces, and therefore enables calculation of muscle power and tendon power within each MTU - as displayed in The synergistic soleus and gastrocnemius muscles are similar in that they shorten significantly right before toe-off, and move with low velocities, as is expected from their compliant tendons. But there are two easily apparent differences in the movement of these two muscles - during mid and late stance respectively.First, the length estimates of the two plantar flexors are very different in mid-stance . In partMoreover, there are differences in late stance operation of the two muscles, which are apparent from an analysis of muscle velocities , Panel AMotivated by this idea, we compared each muscle's positive mechanical work and metabolic consumption during the positive work phase of late stance. To further elucidate roles of the two plantar flexors, we studied the metabolically optimal breakdown of ankle torque between the two , Panel BFinally, the muscle operation and load-sharing results arise uniquely from the optimal parameter vectors. A point Our results describe how humans resolve redundancies within and between MTUs involved in ankle joint actuation. We have demonstrated that there is a unique leg morphology which (a) most economically relates activations and angles from gait data with torques therein, (b) produces the above data via plantar flexor muscle motions, tendon motions, and metabolic performance that are consistent with experimental observations and (c) resolves empirically inaccessible features ranging from individual muscle forces and metabolic demand to mechanical power and working efficiencies. This morphology  is anatomically realistic, and Pareto optimal for the two objectives of torque match and efficiency.To understand features of the morphology that enable this multi-objective optimality, we make a few observations about the solution. The optimal muscle isometric forces result in the most efficient breakdown of joint torque amongst the different MTUs. The tendon slack lengths balance the capacity for a timely buildup of force in response to the activations against the need to cycle tendon elastic energy for efficient force generation. Finally the optimal tendon material properties make for just the right stiffness values to produce the required joint torque but with just enough compliance to reduce muscle metabolic cost. These features indicate that leg muscles and tendons are designed to enable a metabolically optimal realization of human-like ankle mechanics under neural controls observed in normal walking.Interestingly, the optimal parameters for any one MTU do not arise independently of those for the other MTUs, as both efficiency and torque match are net objectives for all the MTUs operating together. Rather the optimal structural parameters are a solution for the system as a whole to achieve the two objectives. Therefore, unlike the Lichtwark & Wilson study Further, the load-division implied by the optimal leg morphology also reveals a role division amongst the different muscles. The gastrocnemius muscle has a very compliant tendon - allowing it to work isometrically like a clutch in mid-stance, store energy in the tendon slowly and release it rapidly in late stance to produce high mechanical power on a per fiber basis - akin to a catapult  and leg structure (modeled here with MTU morphologies) may in itself be optimal for the overall objective of efficiently generating ankle torque. This idea stands in contrast to previous proposals of the optimality of neural control alone Our framework has implications as a starting point for such an endeavor. Since every reflex pathway is sensitive to specific changes in muscle state , inspecting the dominant trends in our muscle state and activation estimates provides insight on possible pathways contributing to the observed state changes. For instance, a period of muscle stretch and low activation followed by a period of isometric behavior and a coincident rise in activation is likely to correspond to a stretch reflex . A period of similarly shaped force and activation profiles may involve positive force feedback . Such observations generate hypotheses on how impedance is modulated within the neuromuscular system. Forward dynamical simulations with perturbation analyses could used to test such hypotheses and quantify contributions of different reflexes to legged dynamics. Insights gained from such efforts are of interest for applications in the control of assistive devices Finally, the framework described in this study also has implications as an analytical tool to probe empirically inaccessible metrics to understand regulation, roles, operation and performance of individual elements in gait. The first steps would be to extend the theory across muscles and joints for walking. Difficulties in obtaining inputs from gait and EMG data for deeper and more proximal muscles could be overcome via a forward dynamical simulation approach wherein both the timings of muscle activity, along with the muscle-tendon morphological parameters, are evaluated for our two objectives. If feedback control loops linking muscle state to activation are also included, perhaps other objectives of dynamical stability could be considered in tandem - in a similar framework, to quantitatively characterize the interplay between neural control and leg morphology. Accounting for feed-forward contributions to this interplay constitutes an important challenge that needs to be overcome. Another natural extension would be to characterize different tasks with our framework. A question of fundamental interest is to understand whether the same leg morphology is energetically optimal for the neural controls and joint mechanics across tasks. An affirmative answer would suggest that, for any specified task, humans select the joint mechanics that minimizes metabolic cost for the legs they have. A negative outcome would imply that human leg morphology and neuromuscular co-ordination are specifically energetically optimal for self-selected-speed walking.This study was conducted in strict accordance with the principles expressed in the Declaration of Helsinki. The study was approved by the MIT Committee on the Use of Humans as Experimental Subjects (protocol number 0903003157). All subjects provided written informed consent for the collection of data, subsequent analysis and publication of results.Kinematic, kinetic and electromyographic (EMG) data were collected at an instrumented motion analysis facility in the MIT Computer Science and Artificial Intelligence Lab. Five healthy adult males participated in the study. After obtaining informed consent, participants were asked to walk barefoot at a self-selected speed  to measure three-dimensional locations  to obtain joint motion and dynamics. Using biomechanical properties in the SIMM Full Body Dynamic Model, inverse kinematics was performed to calculate joint angles, muscle-tendon lengths and moment arms EMG data was analyzed in MATLAB(R)  to estimate the phase and amplitude of the underlying muscle active state. Raw EMG data for each muscle was pre-processed by removing DC offsets, clipping the signal amplitude to within five standard deviations, full-wave rectifying the clipped signal and then normalizing with respect to the peak value of the rectified signal Plantar flexor muscle EMGs were occasionally corrupted by motion artifacts. The artifacts were prominent in the neural excitation estimates All gait data for a given subject were split into mutually exclusive training and testing sets. Within each set, ensemble averages and standard deviations of temporal profiles of each variable  were used for analysis.To investigate the leg dynamics underlying the data, we modeled the major muscle-tendon units contributing to ankle function in normal walking. Anatomically, this corresponds to the big MTUs responsible for ankle joint rotation in the sagittal plane - the soleus and gastrocnemius plantar flexors with the Achilles tendon split amongst them, and the tibialis anterior dorsiflexor . Both thEach muscle was modeled as a unidirectional actuator with classic Hill-type dynamics, as in Each tendon is a non-linear elastic element in series with the corresponding muscle. Of the several approximations to tendon force-length relations in the literature, we chose a general non-linear form Each MTU comprises a muscle and a tendon connected in series, at pennation angle The overall ankle torque resulting from the three model muscle-tendon units was specified as:The full model dynamics was implemented in MATLAB Simulink, and is defined by For each MTU, we minimized the number of free model parameters by (a) using literature values where they are known to be reliable , (b) fixin vivoThe other twelve parameters each correspond to a key morphological feature  of the three modeled muscle-tendon units. They are known to be difficult to measure The leg muscle-tendon unit dynamics, characterized by Each possible vector Muscle metabolic consumption is known to result from the heats of activation, maintenance, shortening, resting, and other molecular processes involved in muscle force generation At any time To avoid numerical errors in computing cost, metabolic power was only accounted for when In summary, given the data-driven inputs and model dynamics, each set of morphological parameters defining the dynamics specifies a model torque profile, and a model metabolic consumption - as indicated in equation 4.For analysis, two efficiency metrics were calculated for stance phase of the gait cycle:Muscle efficiency - accounting for positive mechanical work from the active muscle (during shortening) only:Muscle-tendon efficiency - accounting for both muscle and tendon contributions to the net ankle joint mechanics:Biologically realistic muscle-tendon parameters Cost is calculated for stance phase only, as swing phase metabolic consumption for ankle function is small and rather flat in the parameter space. Constraint was kept consistent with cost, and imposed point-wise during stance. As numerical errors in starting up the model and splitting up gait cycles make it difficult to satisfy the constraint of matching the steady state biological torque profile during 0–5% GC, the simulation was started at a point in the 0-5%GC range when the model-biological torque matching constraint was fulfilled and ran to completion of one gait cycle from there on out. Constraint violations between Identifying the most economical parameter vector for the best torque match gives the most energetically conservative estimates for The parameter space along the constrained landscape . Panel C shows metabolic power of soleus and gastrocnemius muscles. 100% gait cycle is equivalent to a stridetime of 1.16 seconds for the gait cycle displayed. Both muscles consume significant metabolic energy even when their MTU is doing negative mechanical work (∼15-50%GC). Comparisons between the mechanical and metabolic power trends for the two muscles in late stance are analyzed in (1.88 MB EPS)Click here for additional data file.Text S1Model and Solver Settings. Model parameters motivated from literature, metabolic cost calculation details, bounds and algorithm settings used to identify optimal parameter vectors.(0.45 MB PDF)Click here for additional data file.Text S2Estimating Muscle Activation. Biophysical interpretation of the estimation procedure, along with estimated activation profiles for the 3 ankle muscles across 5 subjects.(0.71 MB PDF)Click here for additional data file.Text S3MTU Parameter Space Exploration. Supplementary notes on the biologically realistic points in the corner region, comparisons between corner region points and other points along the boundaries, tabulation of the optimal parameter values for 5 subjects.(0.54 MB PDF)Click here for additional data file.


Pain is often perceived an unpleasant experience that includes sensory and emotional/motivational responses. Accordingly, pain serves as a powerful teaching signal enabling an organism to avoid injury, and is critical to survival. However, maladaptive pain, such as neuropathic or idiopathic pain, serves no survival function. Genomic studies of individuals with congenital insensitivity to pain or paroxysmal pain syndromes considerable increased our understanding of the function of peripheral nociceptors, and especially of the roles of voltage-gated sodium channels and of nerve growth factor (NGF)/TrkA receptors in nociceptive transduction and transmission. Brain imaging studies revealed a “pain matrix,” consisting of cortical and subcortical regions that respond to noxious inputs and can positively or negatively modulate pain through activation of descending pain modulatory systems. Projections from the periaqueductal grey (PAG) and the rostroventromedial medulla (RVM) to the trigeminal and spinal dorsal horns can inhibit or promote further nociceptive inputs. The “pain matrix” can explain such varied phenomena as stress-induced analgesia, placebo effect and the role of expectation on pain perception. Disruptions in these systems may account for the existence idiopathic pan states such as fibromyalgia. Increased understanding of pain modulatory systems will lead to development of more effective therapeutics for chronic pain. Any complete discussion of pain must include not only its somatosensory parameter that allows us to feel nociception, but must also include its motivational and affective qualities with which we experience pain. Pain is defined as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage,” by the International Society for the Study of Pain (IASP) . The senAn important factor to consider in the evaluation and management of pain is that it is a highly variable experience among individuals. Whereas pain is generally initiated by activation of nociceptors, that function to detect noxious stimuli capable of producing tissue damage, there is no evidence that the experiential perception of pain is directly correlated with the level of nociceptor activation. The variability of the pain experience along with observations that pain can change in the presence of other factors including past memories, stress, anxiety, distraction, or attention suggests the presence of endogenous pain modulatory systems that can either enhance or inhibit the pain experience . Recent δ fibers or unmyelinated C-fibers. The Aδ nociceptors are subdivided into the Type I nociceptors, that respond preferentially to strong mechanical or chemical stimuli, but can also respond to high (>50°C) temperatures, and the Type II nociceptors, that respond preferentially to noxious thermal stimuli over mechanical stimuli -carfentanil revealed activation of μ-opioid receptors in the ACC, anterior insula, and the dorsolateral prefrontal cortex during the placebo response [An example of how these sites may interact to alter pain perception is demonstrated by the phenomenon of placebo analgesia. Early studies showed that approximately 33% of the population is responsive to placebo-induced analgesia . Placeboresponse . Using cresponse . Naloxonresponse . These rresponse .11C] raclopride and fMR were used to image dopamine levels in individuals that received placebo infusion followed by a 20 period of expectation of a painful stimulus, those individuals that reported greater pain relief showed increased dopamine in the NAc [Studies with fMRI showed that the expectation of pain relief reduces pain perception as well as the activity of the ACC and insula . Subject the NAc . These r the NAc . Healthy the NAc . Fear co the NAc .The term “nocebo” describes an effect opposite to placebo; that is, the expectation of a worsening outcome in response to a treatment . VolunteIn addition to modulating placebo and nocebo responses, the overlap between the areas responsive to pain and those that are components of the reward pathway are consistent with observed interactions between emotional state and pain perception . The oppThe interaction between pain and reward circuitries led to the “Motivational-Decision Model,” which is described in terms of negative, aversive and positive, or appetitive, motivational systems . In a coβ and C-fibers. Moreover, DNIC was abolished by systemic naloxone or spinal cord section, indicating the involvement of descending modulation from supraspinal sites [Early observations that the electrophysiologic responses of dorsal horn neurons to somatic noxious stimuli were inhibited when a second noxious stimulus was applied to an extrasegmental site led to formulation of the concept of diffuse noxious inhibitory control (DNIC) , 311. Geal sites –312. Eleal sites –317. Sinal sites , 319.Converging evidence suggests that dysfunctional chronic pain syndromes may be caused, at least in part, by deficiencies in DNIC . DNIC caThe development of chronic tension-type (CTT) headache and migraine headache may also be due to a reduced capacity for DNIC. Patients with CTT receiving conditioning stimuli  did not report reduced pain scores to the experimental noxious stimulus (electrocutaneous noxious stimulus to the arm or temple), whereas DNIC was evident in normal healthy volunteers . SimilarThe discovery that analgesia could be initiated from electrical stimulation of the brain was signal moment in pain research. This discovery precipitated a robust effort that over the years produced a wealth of information to help us understand how pain is initiated, perceived, and modulated. Since that time, we have come to understand that specialized nociceptors, when activated, send inputs into the CNS through the spinal or medullary dorsal horns that are then transmitted to sites in the medulla, midbrain, and cortex. These ascending projections activate descending pain modulatory mechanisms that project through the midbrain PAG and the RVM to either facilitate or inhibit further nociceptive inputs. Because of significant advances in neuroimaging techniques that allow functional analyses with a greater degree of spatial and temporal resolution, our perceptions of how pain is integrated and modulated in the central nervous system have evolved tremendously especially over the past 2 decades. From the early linear system of pain modulation from the PAG through the RVM and descending to the spinal cord, the concept of a complex “pain matrix” that includes somatosensory and limbic cortical regions, subcortical elements of the limbic system, the PAG and RVM, and noradrenergic nuclei. The concept of a “top-down” pain modulation system arising from cortical sites has been invoked to explain seemingly disparate phenomena such placebo analgesia, stress-induced analgesia, or pain augmentation as well as the effects of distraction, attention, and emotional state on pain perception. Increasing our understanding of these systems also provides greater insight into the potential mechanisms of action of analgesic drugs and atypical analgesics that are effective in neuropathic and dysfunctional pain states. Finally, these studies lend insight into the mechanisms that may drive dysfunctional pain states, such as the chronic headaches, fibromyalgia, IBS, and others that appear without any discernible injury or pathology. Converging evidence points to altered functioning of endogenous pain modulation, including loss of DNIC, as a potential mechanism driving dysfunctional pain. A greater understanding of the anatomy, physiology, and pharmacology of pain modulatory systems will lead to more advanced therapies against chronic pain states.


Black meristematic fungi can survive high doses of radiation and are resistant to desiccation. These adaptations help them to colonize harsh oligotrophic habitats, e.g., on the surface and subsurface of rocks. One of their most characteristic stress-resistance mechanisms is the accumulation of melanin in the cell walls. This, production of other protective molecules and a plastic morphology further contribute to ecological flexibility of black fungi. Increased growth rates of some species after exposure to ionizing radiation even suggest yet unknown mechanisms of energy production. Other unusual metabolic strategies may include harvesting UV or visible light or gaining energy by forming facultative lichen-like associations with algae or cyanobacteria. The latter is not entirely surprising, since certain black fungal lineages are phylogenetically related to clades of lichen-forming fungi. Similar to black fungi, lichen-forming fungi are adapted to growth on exposed surfaces with low availability of nutrients. They also efficiently use protective molecules to tolerate frequent periods of extreme stress. Traits shared by both groups of fungi may have been important in facilitating the evolution and radiation of lichen-symbioses. Deinococcus radiodurans. Large scale “omics” studies showed only that extreme radiation resistance of this bacterium is not caused by unusually efficient DNA repair mechanisms as initially presumed. The mechanisms of radiotolerance seemed more enigmatic then ever, until a set of elegant non-“omics” experiments showed that the key adaptation is much simpler: it is based on the accumulation of antioxidant manganese orthophosphate and peptide complexes that protect the cell proteome  accumulation of melanin and other metabolites with different protective roles, (2) growth in oligotrophic conditions by interaction with other microorganisms or by employing unusual metabolic pathways.Many oligotrophic fungi respond to stress conditions by expressing a high degree of phenotypic plasticity  comprise low-molecular-weight , water-soluble molecules composed of either an aminocyclohexenone or an aminocycloheximine ring, carrying nitrogen, or imino alcohol substituents. When substituted with amino acid residues, they are designated MAAs. They act as shields against UV radiation, but some MAAs may also protect the cell by scavenging reactive oxygen species such as singlet oxygen, superoxide anions, hydroperoxyl radicals, and hydroxyl radicals. Additionally, a function of mycosporines as compatible solutes has been suggested in fungi  appear to be especially adept at synthesizing stress protective compounds  were presumably oligotrophic organisms living on rock surface or subsurface  surfaces in Atacama Desert , where they cannot derive substantial amounts of fixed carbon from the substrate.In addition to their cohabitation with algae, the ubiquity of black fungi on rocks in polar and other largely unpolluted areas indicates the possible existence of unpredicted and unconventional ways of carbon acquisition or energy gain. In this context, Palmer and Friedman  suggesteHalobacterium sp., where it functions as a light driven proton pump  resulted in a specific spatial arrangement of both organisms and growth alteration in the photosynthetic cyanobacteria.What other options are available to oligotrophic black fungi growing on surfaces with almost no usable organic-carbon? Some evidence shows that black fungi improve their carbon supply by attaching to microscopic algae Figure . Rock-inAn ancestral proximity of certain lichenized fungal lineages and different lineages of black fungi has been shown by reconstructing their molecular phylogeny. Rock-inhabitants are basal to the large lichenized lineages of Arthoniomycetes and Verrucariales (Gueidan et al., Loose associations of black fungi and algae in nature might be seen as borderline lichens (Kohlmeyer et al., D. radiodurans. These were shown to preserve immunogenicity of epitopes during sterilisation of the pathogen by gamma radiation, opening new possibilities for vaccine development (Gaidamakova et al., Knowledge about stress-protective mechanisms in black fungi and lichenized fungi may lead to unforeseen applications in medicine and industry. This was exemplified recently in the case of protective molecules from the bacterium As rapid progress in sequencing technologies will enable us to look deeper into the genomes of non-conventional, oligotrophic organisms, analyses of previously unimaginable amounts of data will answer many, but not all, questions about their biology. Besides the presence of stress-associated genes and expressed products, other mechanisms appear to play an important role in the linked phenomena of polyextremotolerance and oligotrophism. These include small metabolites and their complexes. Therefore the bioinformatic rush following the “omics” revolution needs to be accompanied by well-designed, hypothesis-driven experimental work to evaluate phenotypic plasticity, production of multi-purpose protective metabolites, and metabolic interactions with other microorganisms as responses to a life in hostile environments.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


CaMKII has been shown to be activated during different cardiac pathological processes, and CaMKII-dependent mechanisms contribute to pathological cardiac remodeling, cardiac arrhythmias, and contractile dysfunction during heart failure. Activation of CaMKII during cardiac stress results in a broad number of biological effects such as, on the one hand, acute effects due to phosphorylation of distinct cellular proteins as ion channels and calcium handling proteins and, on the other hand, integrative mechanisms by changing gene expression. This review focuses on transcriptional and epigenetic effects of CaMKII activation during chronic cardiac remodeling. Multiple mechanisms have been described how CaMKII mediates changes in cardiac gene expression. CaMKII has been shown to directly phosphorylate components of the cardiac gene regulation machinery. CaMKII phosphorylates several transcription factors such as CREB that induces the activation of specific gene programs. CaMKII activates transcriptional regulators also indirectly by phosphorylating histone deacetylases, especially HDAC4, which in turn inhibits transcription factors that drive cardiac hypertrophy, fibrosis, and dysfunction. Recent studies demonstrate that CaMKII also phosphorylate directly histones, which may contribute to changes in gene expression. These findings of CaMKII-dependent gene regulation during cardiac remodeling processes suggest novel strategies for CaMKII-dependent “transcriptional or epigenetic therapies” to control cardiac gene expression and function. Manipulation of CaMKII-dependent signaling pathways in the settings of pathological cardiac growth, remodeling, and heart failure represents an auspicious therapeutic approach. Heart failure is the leading cause of death in developed countries and is characterized by adverse cardiac remodeling upon pathological stress situations such as arterial hypertension, ischemic injuries or due to genetic causes. Adverse left ventricular remodeling is usually described by a combination of myocardial hypertrophy, cell death, interstitial fibrosis and an activation of a so-called fetal gene program , and they described the expression patterns of the Calcium/Calmodulin-dependent kinases CaMKI, CaMKII, and CaMKIV  and resulted in enhanced transcriptional activation of an ANF-luciferase reporter gene , but not CaMKII, was demonstrated to be involved in the development of cardiac hypertrophy  or heterodimers of the Fos and Jun families   leading to cardiomyocyte hypertrophy , a transcription factor responsible for inducible heat shock protein 70 (iHSP70) gene regulation. CaMKII is known to phosphorylate HSF-1 at Ser-230  into the nucleus and thereby promotes DREAM-induced transcriptional repression. In their study, the authors could show that this mechanism is involved in CaMKII-dependent downregulation of the pore-forming α-subunit (Cav1.2) of the L-type calcium channel (LTCC) and postulate this to be a physiological feedback mechanism, which enables cardiomyocytes to adjust calcium influx through the LTCC to calcium-activated CaMKII activity , resulting in nuclear accumulation of NFAT and consequent activation of NFAT-dependent transcriptional programs and severe cardiac hypertrophy  and in particular class II HDACs. These interesting mechanisms were initially identified upon the observation that class II HDACs interact with the transcription factor MEF2. MEF2 was introduced to depend on CaMKI and CaMKIV more than 10 years ago by the group of Eric Olson and has been established as a critical transcription factor in cardiac remodeling processes (Passier et al., We found that CaMKII selectively signals to HDAC4 via binding to a unique docking site and phosphorylation of Ser-467 and Ser-632 (Backs et al., Histones are major components of chromatin and assemble with DNA to form nucleosomes, (Jenuwein and Allis, With regard to epigenetic mechanisms, in cardiac biology most attention so far was paid to histone acetylation and methylation. Histone phosphorylation is thought to be important for cell cycle regulation and was thus not carefully studied in the adult heart (Walter et al., CaMKII regulates not only immediate cellular functions but also chronic processes such as ventricular remodeling leading to heart failure. In particular, CaMKII integrates several cellular pathways by inducing gene programs that are not understood in detail. Here, we reviewed the yet known transcriptional and epigenetic mechanisms by which CaMKII regulates cardiac gene expression. However, the relative importance of the different downstream mechanisms still needs to be clarified. Unbiased gene expression analyses and epigenetic profiling are warranted to define the specific gene programs that contribute to phenotypic changes induced by CaMKII.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Cardiovascular implants must resist thrombosis and intimal hyperplasia to maintain patency. These implants when in contact with blood face a challenge to oppose the natural coagulation process that becomes activated. Surface protein adsorption and their relevant 3D confirmation greatly determine the degree of blood compatibility. A great deal of research efforts are attributed towards realising such a surface, which comprise of a range of methods on surface modification. Surface modification methods can be broadly categorized as physicochemical modifications and biological modifications. These modifications aim to modulate platelet responses directly through modulation of thrombogenic proteins or by inducing antithrombogenic biomolecules that can be biofunctionalised onto surfaces or through inducing an active endothelium. Nanotechnology is recognising a great role in such surface modification of cardiovascular implants through biofunctionalisation of polymers and peptides in nanocomposites and through nanofabrication of polymers which will pave the way for finding a closer blood match through haemostasis when developing cardiovascular implants with a greater degree of patency. Cardiovascular disease accounts for a significant percentage of mortality and morbidity in the ageing population and has an estimated increase in the coming years . There iThe initial events leading to thrombosis surrounding the tissue-implant interface are mediated by surface interactions with adsorbed proteins (intrinsic pathway) or through the release of tissue factor (TF) from damaged cells at the site of injury (extrinsic pathway)  Figure . The intVascular injury and damage to the endothelium releases TF, collagen, and von Willebrand factor (vWF) to initiate the extrinsic pathway. Clotting factors interact with platelet surface receptors and play a fundamental role in the interaction of collagen to initiate thrombosis, release growth factors and cytokines to enhance the coagulation cascade and strengthen the haemostatic plug. The platelets change morphology and agglomerate forming a thrombus layer. It is important to note that both pathways converge during the formation of the prothrombinase complex leading to thrombin generation referred to as the common pathway.2) and nitric oxide (NO) required for the regulation of blood flow soon diminish [Vascular procedures such as arteriovenous graft placement and angioplasty damage the adventitial and medial tissues of the arterial wall with injury to the endothelium lining the intima . For exadiminish . Both modiminish .Almost all materials are considered to be thrombogenic with the exception of the endothelial cell (EC) layer, which lines the vasculature. Large diameter vascular grafts were originally thought to be antithrombogenic in nature. For example, expanded polytetrafluoroethylene (ePTFE) bypass grafts appear nonthrombogenic due to the high flow rates of blood past the luminal surface, but in reality, all are thrombogenic to a certain degree.In healthy individuals the flow of blood is laminar but when compared with diseased or occluded arteries may often be transitional or even turbulent in behaviour. At the blood-biomaterial interface, haemodynamic forces of shear stress at the wall surface play a critical role in blood contacting devices and influence protein adsorption , plateleπ-π) stacking, and electrostatic interactions. Exactly which force governs the interaction of proteins on surfaces depends upon the particular protein and other factors including size, charge, conformation, and unfolding rate described by Vroman [Cardiovascular implants, in the body, are subjected to the “Vroman effect”  which hiy Vroman . Chemicay Vroman . Surfacey Vroman .γ-globulin), and to a lesser degree fibronectin, collagen, vWF, coagulation factors XI and XII, and HMWK play a crucial role in balancing thrombosis and haemostasis [Adsorption of plasma and extracellular matrix (ECM) proteins  on EC growth. It was found that EC cell growth was enhanced by smaller pores (5–20 μm in diameter) and at a lower interpore distances.A range of physical techniques has been applied to modify the surface topography of vascular graft materials. Topography on the micron and nanometre scale is an important physical property, which influences protein adsorption, platelet adhesion, thrombogenicity, and cell behaviour . The incChanging the surface topography on the micron and nanometre scale also lead to localised changes in surface chemistry as both physicochemical cues are intrinsically linked. The primary aim of topographical and chemical surface modification is to encourage desirable protein, cellular, and tissue interactions at the blood-biomaterial interface, thus improving patency and performance of the material, since all are known contributory factors that influence thrombogenicity. Nanocomposite materials are recognisedto offer favourable solutions as biomaterials for cardiovascular implants. Nanocomposite polymers in general have found to be amphiphilic, thermodynamically stable and, when used in vascular bypass graft development, they have shown to exert novel advantageous properties such as favourable blood response , biostabin vitro when compared with controls. This study highlighted that POC-ePTFE grafts maintained EC adhesion and proliferation of porcine cells similar to that of the native tissues, and within 10 days the EC was confluent, while only random patches were evident on ePTFE controls.Nonfouling surfaces have been used to prevent protein adsorption and platelet adhesion. Much effort has focused upon the passivation of materials using polymers to achieve a nonadhesive, nonbiofouling surfaces such as PEG (polyethylene glycol), hydrogels (containing dextran), and PEO (polyethylene oxide). For example, ePTFE grafts have been coated with polypropylene sulphide (PPS)-PEG and evaluated in arteriovenous models. This study included heparinised and nonheparinised graft perfusion and evaluated cell adhesion and thrombus formation. No difference was observed in cell adhesion when compared with controls; however, the surface coating significantly decreased thrombus formation when used in conjunction with heparin. Dextrans (hydrophilic polysaccharides) show a similar effect to PEG with regard to protein adsorption. Dextrans, PEG, and PEO can be further chemically modified along the polymer backbone with cell-selective peptides to promote specific cell adhesion. Spin coating of the luminal surface of ePTFE was recently achieved using a biodegradable elastomer poly (POC). The POC coatings had no effect on graft compliance and delayed thrombosis insitu endothelialisation is considered to be most favourable. This need for insitu endothelialisation has led to a considerable interest in stem cells which have the potential to induce endothelialisation. This interest in endothelial progenitor stem cells inturn has given rise to an exciting area of research on “stem cell technology” for vascular grafts. The endothelium is in intimate contact with the blood flow and consists of a single layer of EC, which functions as a dynamic organ and covers the entire surface of the circulating system from the heart to the smallest capillary. Endothelialisation of cardiovascular implants is considered most favourable as this would protect the vessels by producing natural biochemicals, for example, NO for vasoprotection. There is a great deal of research involved in inducing endothelialisation of cardiovascular implants and Stem cells/EPC are on the threshold of realising their great potential in cardiovascular therapy and stem cell interactions with various biomaterials which have been extensively studied –34. Cellinsitu endothelialisation including: (1) promoting the mobilisation of EPC from the bone marrow, (2) encouraging cell-specific  homing to the vascular graft site, (3) providing cell-specific adhesion motifs (peptides) on the vascular grafts , and (4) directing the behaviour of the cells after adhesion to rapidly form a mature, fully functioning endothelium capable of self-repair.Features of the ECM such as nanoscale topography, optimised mechanical properties, and presentation of bioresponsive motifs have inspired multiple examples of biomaterials design for tissue engineering scaffolds. One strategy in vascular research is to present endothelium-derived macromolecules or their cell interacting domains onto vascular grafts to mimic these features of the ECM and to assist specific cell adhesion. Bioresponsive vascular grafts can target several biological processes to promote Optimal cell attachment, migration, proliferation, and differentiation on a biomaterial require a surface which mimics the natural ECM. Natural ECM proteins range in diameter from 50–500 nm. The significance of mimicking the ECM, which facilitates the interactions with the cell receptors such as integrins, has been discussed. This also recognises the effect of peptides such as RGD , which aThe microtopography of scaffold materials is not entirely ideal for vascular cells, particularly EC as they are naturally placed in a nanometre scale environment. Nanotopography surfaces created by surface roughening of a range of materials including polymers have shown enhanced cellular adhesion –40. ReceIn addition to mimicking an ECM, research has looked into antibody-mediated stem cell recruitment as a rather impressive approach in stem cell technology for applications in vascular graft endothelialisation. EC and EPC have been found to express CD34+, and therefore CD34+ antibodies can be attached onto bypass graft surfaces to facilitate interaction between graft and progenitor cells. Antihuman CD34 monoclonal antibodies  were immobilised to the ePTFE graft material  with a proprietary multistep process.In additional, further studies have shown that superparamagnetic nanoparticles labelled endothelial cells can be used to obtain an endothelial cell lining, for instance, as on the luminal surface PTFE tubular grafts, coated with fibronectin with the aid of a customized electromagnet . The cardiovascular protective role of the endothelium is recognized to be attributed to NO. Therefore, there is a great interest in inducing NO from cardiovascular implants and this has recently been reviewed in depth . Recent Blood contacting materials, which are used to fabricate cardiovascular implants, are expected to preferably promote endothelial adhesion but resist other blood cell adhesion that can give rise to thrombosis and intimal hyperplasia. A greater understanding of the interactions of blood proteins with material surfaces will enable better designing of surfaces for blood contact. Surface modifications of materials will be highly influenced by nanotechnology as this enables to impart favourable properties without influencing the structural and mechanical properties of the base material, which forms the structure of a device of interest. It is also of significance that a particular surface modification should be always tailored to the implant of interest and should be tested for its efficacy in physiological haemodynamic conditions. We believe that a reasonable progress has been made in the search for optimal blood contacting materials, but research into NO eluting polymers, endothelialisation, and nanotechnology associated with surface modification of such materials may promise more sophisticated solutions in the quest for optimal blood compatibility.


LMNA) which encodes for the nuclear lamina scaffold protein, prelamin A. The most common point mutation occurs within exon 11 and results in a silent Gly-to-Gly mutation that causes increased usage of an internal cryptic splice site. This cryptic splice site produces a truncated form of prelamin A known as progerin . Farnesylation then targets prelamin A to the inner nuclear membrane where the last three amino acids are cleaved by zinc metallopeptidase STE24 (ZMPSTE24). This is followed by immediate methylation of the farnesylcysteine by isoprenylcysteine carboxyl methyltransferase (ICMT) and subsequent cleavage by ZMPSTE24 to produce lamin A. Following cleavage from the nuclear membrane, lamin A is capable of migrating to the nucleoplasm. In HGPS, progerin lacks a vital cleavage site utilized by ZMPSTE24. This results in progerin remaining permanently attached to the inner nuclear membrane and is suspected to contribute the HGPS phenotype  is a rare, genetic progeroid disorder that causes premature ageing, nuclear lamina shape abnormalities, growth impairment, and early death at ~13 year of age (Gordon et al., Icmt expression as a means to reverse progeria-like symptoms in a mouse model of HGPS (Ibrahim et al., CAAX protein motifs has been shown to play a role in protein membrane targeting (Bergo et al., CAAX methylation in HGPS, Ibrahim et al. introduced a hypomorphic allele of Icmt into a mouse model of HGPS that utilizes Zmpste24 deficient mice. It was found that the mice hypomorphic for Icmt had increased body weight, normalized grip strength, decreased bone fractures and decreased death compared to non-hypomorphic mice.Although previous studies have been dedicated to treating HGPS by halting farnesylation via FTase inhibitors, Ibrahim et al. targeted Icmt hypomorphic mice fibroblasts. This indicates that misshapen nuclei play a lesser role in the HGPS phenotype than previously thought. Icmt hypomorphic mice fibroblasts also restored cell proliferation to rates similar to wild type fibroblasts. To further elucidate the role of ICMT within cell proliferation, Ibrahim et al. evaluated the impact of ICMT on the on AKT-mTOR cell growth, proliferation and survival pathway. It was found that reduced ICMT activity triggers prelamin A dependent activation of AKT-mTOR, which decreases premature senescence of Zmpste24 deficient fibroblasts. Furthermore, ICMT activates the pathway through AKT and not mTOR. The precise mechanism of interaction was not determined.Analysis of primary mouse embryonic fibroblasts obtained from sacrificed mice indicate that reduced ICMT activity does not affect levels of prelamin A, but instead causes mislocalization of prelamin A away from the nuclear rim. Interestingly, there is not a subsequent reduction in the number of misshapen nuclei in LMNA are capable of utilizing the cryptic spice site seen in HGPS cells. The truncated protein was not found to accumulate with age, but the localization of the protein shifted from the nucleoplasm to the nuclear rim with increasing age (Scaffidi and Misteli, LMNA cryptic splice site have shorter telomeres and high senescence-associated β-gal activity (Cao et al., The findings of the Ibrahim et al. study are interesting not only to the field of progeroid disorders, but to the field of ageing studies at large. Scaffidi and Misteli found that dermal fibroblasts with wild type LMNA splice site plays a critical role not only in HGPS but also in normal ageing and cellular senescence. The Ibrahim et al. study has provided promising results for preventing progerin accumulation at the nuclear rim by reducing ICMT activity. Finding endogenous and exogenous mediators that can control the ICMT activity seen in aging conditions is an important step to discover pharmaceutical intervention and even possible reverse aging. Understanding the influence of ICMT in aging is likely to provide important insights that will not only guide investigation of the molecular and cellular basis of aging, but may also help to identify novel treatment strategies targeting these pathways.Thus, the


Our negative results indicate that, unless the correlation between morphology and diet is very strong, ecological variation among individuals may be largely decoupled from morphological variance. Consequently we should be cautious in our interpretation both of theoretical models that assume perfect correlations between morphology and diet, and of empirical studies that use morphological variation as a proxy for resource use diversity.It has long been known that intraspecific variation impacts evolutionary processes, but only recently have its potential ecological effects received much attention. Theoretical models predict that genetic or phenotypic variance within species can alter interspecific interactions, and experiments have shown that genotypic diversity in clonal species can impact a wide range of ecological processes. To extend these studies to quantitative trait variation within populations, we experimentally manipulated the variance in body size of threespine stickleback in enclosures in a natural lake environment. We found that body size of stickleback in the lake is correlated with prey size and (to a lesser extent) composition, and that stickleback can exert top-down control on their benthic prey in enclosures. However, a six-fold contrast in body size variance had no effect on the degree of diet variation among individuals, or on the abundance or composition of benthic or pelagic prey. Interestingly, post-hoc analyses revealed suggestive correlations between the degree of  A fundamental goal in evolutionary biology is to understand the origin, maintenance, and consequences of variability within populations. The key forces shaping genetic and phenotypic variation within and between populations have been identified, as have many of the consequences of this variation for adaptation and speciation A small but growing set of theoretical models suggests that intraspecific variation can have profound effects on population Experimental manipulations of intraspecific genotypic diversity have supported many of these theoretical predictions. These studies have demonstrated that genotypic diversity can enhance population productivity phenotypic variation, despite its central role in ecological theory pertaining to intraspecific variation Most experimental manipulations have used clonal genetic diversity in asexual species as a measure of intraspecific variation but see . ComparaGasterosteus aculeatus) has undergone recent and dramatic evolutionary divergence among north temperate marine, stream, and lake habitats The threespine stickleback  tend to be more variable in lakes predicted to have a greater diversity of habitats and prey types Animal use protocols in this experiment were approved by the University of Texas Institutional Animal Care and Use Committee (permit # 07100201).In late May, 2009, we established experimental enclosures in Blackwater Lake, on Vancouver Island, British Columbia  to test for effects of our treatments on benthic invertebrate and zooplankton community composition We thawed each stickleback and measured standard length and body depth to 0.1 mm. We also counted gill rakers on the first gill arch, and calculated the average length of the three longest gill rakers, measured to 0.025 mm under an ocular micrometer. We then calculated residuals from linear regressions of body depth, gill raker number and log-transformed gill raker length against SL, yielding three size-corrected traits . Means and variances of these traits did not differ significantly among size variance treatments . We also measured each prey item if possible, and substituted taxon-specific average lengths for the To determine the strength of the diet-morphology relationship, we calculated the correlation between individual fish size and mean prey size among the 75 wild-caught fish. We also conducted a linear regression of prey size against fish size in each enclosure population, and tested whether this slope differed between HV and LV treatments. For analyses of diet variables, we used a linear mixed-effect model with spatial block as a random effect and size variance treatment as a fixed-effect.As diet variation may involve dimensions other than prey size, we evaluated the relationship between prey taxonomic composition and morphology by computing the proportional dissimilarity PDS  between the diets of all pairs of individuals We expected any effects of increased stickleback size variance on prey density and composition to be mediated by increases in the population niche width and/or degree of individual specialization (diet variation). We tested whether size variance did in fact affect measures of diet variation based on both prey size and taxonomic composition. For prey size data, we first calculated the population's total niche width  as fishless enclosures , it would appear reasonable to expect that higher size variation among individuals would confer more among-individual diet variation. In particular, we expected higher size variance to increase between-individual diet variation  within a single population, and testing for effects on ecological interactions. We confirmed previous findings that body size is related to diet within age cohorts in stickleback population The most important and surprising result of our study is that a 6-fold change in size variance in stickleback had no detectable effects on stickleback diet variation or niche width, let alone on the density or composition of lower trophic levels. This compelling lack of a variance effect runs counter to our expectations based on both theory and prior empirical results. It is therefore important that we carefully consider a range of factors that might (1) obscure an effect that actually exists, or (2) explain a genuine lack of relationship between trait variance and the ecological variables investigated here.The absence of effects of size variance is fairly convincing, with no hint of a trend for almost all variables examined  and 4. NA second possibility is that intraspecific size variation typically does affect lower trophic levels, but that our experimental design did not effectively induce this effect. The strength of top-down control can vary over time The stickleback density used in this experiment results in natural levels of intraspecific competition, leading to prey densities and fish growth rates similar to those seen in the lake Geospiza fortis) is correlated with use of large seeds (Anolis sagrei), hindlimb length is positively correlated with endurance running  spanned the entire range of mean prey sizes . Thus, wAnother possibility is that we chose to manipulate the wrong trait, as morphology more directly related to foraging might have a stronger effect on diet than size. Gill raker length and number, jaw structure, fin morphology and body shape influence how fish approach, strike at, and handle various prey types Models might be wrong about the ecological effects of morphological variance (due to its weak correlation with diet), but still be correct that variance in resource use has considerable ecological effects. Our results illustrate this point: although size variance had no effect on benthic prey, stickleback diet variation did show intriguing relationships with benthos density and composition. Within a given spatial block, the enclosure with greater among-individual diet variation (E) tended to have benthos density and composition more similar to those in fishless enclosures. These results were statistically marginal and correlative in nature, meaning we cannot confidently infer causation. However, if the patterns are real, and if diet variation influences the benthic community rather than vice-versa, diet variation may reduce the strength of top-down control of stickleback on their prey. This would be consistent with theory suggesting that predators with nonlinear (i.e. type II) functional responses have lower overall consumption rates when there is among-individual variation in attack rates The disconnect between trait variance and diet variation has a number of important implications. First, existing models of the ecological impact of intraspecific genetic or phenotypic variation should either incorporate noise into the mapping of morphology to resource use, or focus on variation in resource use traits themselves (which may be much more difficult to measure). Second, empiricists should find ways to manipulate ecologically relevant variance if we are to effectively study the ecological impacts of intraspecific variation. Finally, the insights presented here help to explain a classic conflict between theory and data. Van Valen's niche variation hypothesis predicted that populations experiencing ecological release would become more generalized via increased resource use variation among individuals Our intuition, codified in numerous theoretical models, is that morphological variation among individuals in a population can be used as a surrogate for niche variation. Even when morphology is indeed correlated with individual's resource use, this intuition may be wrong. Our analyses show that (1) fish size is correlated with prey size, and (2) stickleback suppress the density and alter the composition of their benthic invertebrate prey. Nevertheless, we found no effect of size variance on any measure of diet variation in experimental stickleback populations, or on the abundance or composition of their prey. However, analyses using diet variation in place of size variance hinted at effects on the prey community consistent with weaker top-down control. Thus, despite our largely negative results, intraspecific variation may still have profound effects on population, food web and ecosystem dynamics. The challenge ahead is to develop experimental approaches that explicitly test for such effects of intraspecific variation in resource use on ecological processes.


This study was performed to investigate the effectiveness of grape seed extract (GSE) compared to butylated hydroxytoluene (BHT) on retarding lipid oxidation of sunflower oil subjected to convection and microwave heating up to 240 min under simulated frying conditions. The progress of lipid oxidation was assessed in terms of peroxide value (PV), p-anisidine value (p-AV), conjugated dienes and trienes , inhibition of oil oxidation (IO) and TOTOX value. In addition, total phenolic content (TP) was evaluated in samples before and after heating in order to assess the changes in these compounds relative to the extent of lipid oxidation. The results of this study highlight that GSE showed a significantly inhibitory effect on lipid oxidation during both treatments, although to a different extent. This ability was dose-dependent; therefore, the extent of lipid oxidation was inversely related to GSE level. Convective heating, respective microwave exposure for 240 min of samples supplemented by GSE to a level of 1000 ppm, resulted in significant decreases of investigated indices relative to the control values as follows: PV , p-AV , CD , CT , TOTOX . GSE to a level of 600–800 ppm inhibited the lipid oxidation in a similar manner to BHT. These results suggested that GSE can be used as a potential natural extract for improving oxidative stability of sunflower oil during thermal applications. Lipid oxidation is the main deterioration process that occurs during thermal processing of vegetable oils containing lipid molecules with polyunsaturation ::The totaThe conjugated dienes (CD) and conjugated trienes hydroperoxides (CT) formed were measured in the lipids, according to the method reported by Kim and Labella [ Labella . Oil samp < 0.05, after analysis of variance (ANOVA one-way). Data were analyzed by ANOVA to ascertain if the GSE levels or BHT were a source of variance related to measured parameters. Computations Tukey post-hoc means comparisons and Levene’s test for equal variance was also included. Statistical processing data was performed using the Statistical Analysis System-SAS .All determinations were carried out in triplicates and values were expressed as means ± standard deviation (SD). Significant statistical differences of investigated parameters were determined by Fisher’s least significant differences (LSD) test at The analysis of convective and microwave heating of sunflower oil, supplemented by various levels of GSE in terms of standard chemical indices, appears to be a valuable tool to assess the ability of this natural extract to inhibit lipid oxidation. Exposing the oil samples to convective and microwave heating caused the formation of hydroperoxides and secondary oxidation products resulting in significant alterations to sunflower oil quality. Supplementation with GSE and BHT prior to heating significantly improved oxidative stability of sunflower oil. The efficiency of GSE to enhance the oxidative stability of sunflower oil during investigated thermal applications increased with increasing antioxidant concentration in the studied range (200–1000 ppm). Oil supplementation with GSE to a level in the range 600–800 ppm inhibited the lipid oxidation in a similar manner to BHT, while a level over 800 ppm limits thermo-oxidative degradation of sunflower oil more than BHT. Also, these results highlight that TP content of samples could be correlated to oxidative deterioration strengthening the concept that total antioxidant capacity is inversely related to the extent of lipid oxidation in the heating time range. These data prove that GSE is a very effective inhibitor of lipid oxidation in applications which require oil heated at high temperatures and can be recommended as a potential natural antioxidant for the edible oil industry.