Compensation Pattern Research Articles

Stumbling reactions during perturbed walking: Neuromuscular reflex activity and 3-D kinematics of the trunk – A pilot study

Reflex activity of the lower leg muscles involved when compensating for falls has already been thoroughly investigated. However, the trunk׳s role in this compensation strategy remains unclear. The purpose of this study, therefore, was to analyze the kinematics and muscle activity of the trunk during perturbed walking. Ten subjects (29±3yr;79±11cm;74±14kg) walked (1m/s) on a split-belt treadmill, while 5 randomly timed, right-sided perturbations (treadmill belt deceleration: 40m/s2) were applied. Trunk muscle activity was assessed with a 12-lead-EMG. Trunk kinematics were measured with a 3D-motion analysis system (12 markers framing 3 segments: upper thoracic area (UTA), lower thoracic area (LTA), lumbar area (LA)). The EMG–RMS [%] (0–200ms after perturbation) was analyzed and then normalized to the RMS of normal walking. The total range of motion (ROM;[°]) for the extension/flexion, lateral flexion and rotation of each segment were calculated. Individual kinematic differences between walking and stumbling [%; ROM] were also computed. Data analysis was conducted descriptively, followed by one- and two-way ANOVAs (α=0.05).Stumbling led to an increase in ROM, compared to unperturbed gait, in all segments and planes. These increases ranged between 107±26% (UTA/rotation) and 262±132% (UTS/lateral flexion), significant only in lateral flexion. EMG activity of the trunk was increased during stumbling (abdominal: 665±283%; back: 501±215%), without significant differences between muscles.Provoked stumbling leads to a measurable effect on the trunk, quantifiable by an increase in ROM and EMG activity, compared to normal walking. Greater abdominal muscle activity and ROM of lateral flexion may indicate a specific compensation pattern occurring during stumbling.

Simulated Ankle Equinus Affects Knee Kinematics During Gait.

It is critical to distinguish gait compensations from true abnormalities when planning interventions to improve gait in individuals with neuromuscular disorders. The aim of this study was to determine the effect of isolated ankle equinus on knee kinematics during the initial contact phase of gait. Ten healthy subjects (29 + 4.3years) participated, and testing occurred in a motion analysis laboratory. This cross-sectional study investigated five gait conditions in each subject: shoe alone, shoe with unilateral ankle foot orthosis locked at neutral, 10°, 20°, and 30° of fixed ankle plantar flexion. Gait kinematics were recorded and calculated with 3D motion analysis. The difference between the shoe and each brace condition was analyzed by repeated-measures ANOVA. The primary outcome was knee flexion at initial contact. With greater than 10° simulated ankle equinus, the primary gait compensation pattern was increased knee flexion at initial contact. A significant degree of knee flexion occurred ranging from 7° to 22°. Our data suggests that observed knee flexion at initial contact may be a compensation pattern in individuals with >10° ankle equinus. However, in individuals with ≤10° ankle equinus, observed knee flexion may represent a true gait deviation. This has clinical significance in the realm of cerebral palsy for treatment planning to improve gait.

Three-dimensional analysis of molar compensation in patients with facial asymmetry and mandibular prognathism.

To evaluate the characteristic transverse dental compensations in patients with facial asymmetry and mandibular prognathism and to compare features of dental compensations between two types of mandibular asymmetry using 3-dimensional (3D) cone-beam computed tomography (CBCT). Seventy-eight adult patients with skeletal Class I (control group; n = 33; 19 men and 14 women) or skeletal Class III with facial asymmetry (experimental group; n = 45; 23 men and 22 women) were included. The experimental group was subdivided into two groups according to the type of mandibular asymmetry: translation type (T-type; n = 20) and roll type (R-type; n = 19). CBCT images were acquired before orthodontic treatment and 3D analyses were performed. The transverse dental distance was significantly different between the two groups only at the palatal root apex of the maxillary first molar (P < .05). In the experimental group, the first molar axes were compensated significantly on both arches except the maxillary nondeviated side. The vertical molar heights were different between the two groups only on the maxillary arch (P < .001). The R-type showed greater mandibular ramal length difference and menton deviation than the T-type (P < .001). In the R-type, transverse compensation of the maxillary first molars was more obvious than with the T-type, which resulted in canting in the maxillary occlusal plane. Mandibular asymmetry with prognathism showed a characteristic transverse dental compensation pattern. The mandibular asymmetry type influenced the amount and direction of molar compensation on the maxillary arch.

Anisotropic etching on Si{1 1 0}: experiment and simulation for the formation of microstructures with convex corners

We combine experiment, theory and simulation to design and fabricate 3D structures with protected edges and corners on Si{1 1 0} using anisotropic wet chemical etching in 25 wt% tetramethylammonium hydroxide (TMAH) at 71 °C. In order to protect the convex corners formed by <1 1 2 > and <1 1 0 > directions, two methods are considered, namely, corner compensation and two-step etching. The mask design methodology for corner compensation is explained for various microstructures whose edges are aligned along different directions. The detailed geometry of each compensation pattern is shown to depend on the desired etch depth. The two-step wet etching process is explored in order to realize improved sharp convex corners. Using the same etchant concentration and temperature, the second etching is carried out after mask inversion from silicon nitride (Si3N4) to silicon dioxide (SiO2), obtained by local oxidation of silicon (LOCOS) followed by nitride etching. Based on the use of the continuous cellular automaton (CCA), the simulation results for both corner undercutting and two-step etching show that the CCA is suitable for the analysis and prediction of anisotropic etching on Si{1 1 0} wafers.

Open-loop correction for an eddy current dominated beam-switching magnet.

A beam-switching magnet and the pulsed power supply it requires have been developed for the Japan Proton Accelerator Research Complex. To switch bunched proton beams, the dipole magnetic field must reach its maximum value within 40 ms. In addition, the field flatness should be less than 5 × 10(-4) to guide each bunched beam to the designed orbit. From a magnetic field measurement by using a long search coil, it was found that an eddy current in the thick endplates and laminated core disturbs the rise of the magnetic field. The eddy current also deteriorates the field flatness over the required flat-top period. The measured field flatness was 5 × 10(-3). By using a double-exponential equation to approximate the measured magnetic field, a compensation pattern for the eddy current was calculated. The integrated magnetic field was measured while using the newly developed open-loop compensation system. A field flatness of less than 5 × 10(-4), which is an acceptable value, was achieved.

Impact of farmer households’ livelihood assets on their options of economic compensation patterns for cultivated land protection

With rapid urbanization and the socio-economic transformation, cultivated land protection has gradually become a major concern in China. The economic compensation plays a crucial role in promoting cultivated land protection and improving the utilization ratio of cultivated land. Farmer household’s satisfaction has a great influence on the effectiveness of compensation. Therefore, households’ willingness to select the economic compensation pattern for cultivated land protection has been considered and re-examined. By employing Participatory Rural Appraisal method (PRA), 3 villages and 392 households were investigated and sampled in mesa and hilly areas of Chongqing. Then a quantitative analysis framework of household livelihood hexagon has been developed to quantify the livelihood assets of different farmer households. Finally, the Gray Relation Model and Probit Regression Model have been employed to explore the coupling relationship between the household livelihood assets and their compensation pattern options. The results show that there are both qualitative and spatial heterogeneity in household livelihood assets. We found that the inequality of livelihood assets is evident for five household types. There is a spatial trend that the higher the elevation, the less livelihood assets are. In addition, their options of economic compensation pattern vary from Chengdu Pattern to Foshan Pattern due to their difference in livelihood assets and difference in location. In detail, there is a coupling relationship between household livelihood assets and their compensation pattern; negative correlation is observed between natural assets value and household pattern options, while the other livelihood assets have positive impacts on compensation pattern in varying degrees, which from the top are psychological assets, human assets, physical assets, financial assets, and social assets respectively. A conceptual compensation pattern system has been designed to meet the demands for farmer households mainly according to their shortage in livelihood assets. In addition, compensation method, compensation standard, the basis of compensation and the source of compensation funds have been proposed accordingly.

Weight Rhythms: Weight Increases during Weekends and Decreases during Weekdays

Background/Aims: The week's cycle influences sleep, exercise, and eating habits. An accurate description of weekly weight rhythms has not been reported yet - especially across people who lose weight versus those who maintain or gain weight. Methods: The daily weight in 80 adults (BMI 20.0-33.5 kg/m²; age, 25-62 years) was recorded and analysed to determine if a group-level weekly weight fluctuation exists. This was a retrospective study of 4,657 measurements during 15-330 monitoring days. Semi-parametric regression was used to model the rhythm. Results: A pattern of daily weight changes was found (p < 0.05), with higher weight early in the week (Sunday and Monday) and decreasing weight during the week. Increases begin on Saturday and decreases begin on Tuesday. This compensation pattern was strongest for those who lost or maintained weight and weakest for those who slowly gained weight. Conclusion: Weight variations between weekends and weekdays should be considered as normal instead of signs of weight gain. Those who compensate the most are most likely to either lose or maintain weight over time. Long-term habits may make more of a difference than short-term splurges. People prone to weight gain could be counselled about the importance of weekday compensation.

Predicting the loss of ambulation in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a devastating muscle disease with pre mature loss of ambulation1. The disease is caused by deficiency of the sarco­ lemmal protein dystrophin and results in weakness affecting the proximal portions of the limbs, usually starting during the third and fourth years of life, in association with progressive loss of functional abilities1. The unique medical treatment available is steroid therapy, which appears to prolong walking capacity by at least two years2,3. Strength loss, such as in hip extension and ankle dorsiflexion, is considered the primary predictor of loss of ambu­ lation in DMD4, leading to progressively reduced walking capacity5,6. During the period of loss of ambulation, the children develop many compensatory movements to compensate for the weakness of limb­girdle muscles in the legs, such as the gluteus and quadriceps. The Gowers signal is the most famous compensatory movement, in which a patient,to rise from a sitting to a standing position, has to use his hands and arms to “walk” up his own body from a squatting position to compensate the reduced hip and thigh muscle strength. However, with the pro­ gression of the disease, compensatory movements are unable to avoid the loss of ambulation. Even in the first stage of the disease it is possible to quantify very early modifications in loco­ motion7. Doglio et al., using a Gait Analysis Laboratory, showed important functional changes in patients with DMD in the first stage of the disease7. These changes include alterations in spatial and temporal parameters (increases of cadence, and decreases of step length), increase in the range of anterior­posterior pelvic tilt and in pelvic rotation, in the pelvic obliquity and in the plantar­flexion of the ankle in swing. Differences in power generation and absorption at the hip joint and at the ankle joint were also detected, together with reduction in the flexor moment of the knee in mid­stance and in the dorsiflexor moment of the ankle in terminal stance with a consequent reduction in the peak­to­peak excursion. Thus, besides medical treatment, the physical therapy in multidisciplinary care is impe­ rative for alleviating muscle atrophy, skeletal deformities, and motor function deteriora­ tion8. Physical therapy might improve the function of those muscles that are more affected in the lower limbs, especially in the period of loss of ambulation. In this way, qualitative analysis of compensatory movements during functional tasks in the critical periods of loss of ambulation may allow for recognition of important changes in synergies to help pro­ fessionals provide more specific assistance and guidance to patients. Moreover, the use of steroids might prolong walking capacity while also modifying the compensation pattern. Consequently, analysis of the compensatory movements can also help during the follow up of steroid treatment response. The paper presented in this volume by Martini et al. aimed to show the main compensa­ tory movements in children with DMD immediately before walking loss.9 The authors des­ cribed and quantified compensatory movements while sitting down/rising from the floor, and while climbing up/down steps. The most frequently observed compensatory move­ ments were upper limbs support on the lower limbs/floor/handrail during all tasks and lumbar hyperlordosis, trunk support on handrail, equines foot, increased base of support, non­alternated descent, and pauses while climbing up/down steps. They also showed that sitting down/rising from the floor seems to be lost before climbing up/down steps in ambu­ latory children with DMD. Departamento de Neurologia, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.

Trend analysis of rapid shallow breathing indices during spontaneous breathing trial may improve predictive accuracy of extubation success

To determine the respiratory indices capable of improving predictive accuracy of extubation success through serial measurements of during spontaneous breathing trial (SBT) in automatic tube compensation (ATC) pattern of mechanical ventilation. For this prospective observational study, patients ventilated over 48 hours were enrolled according to the weaning criterion and underwent a 60 minutes spontaneous breathing trial (SBT) in ATC pattern (ATC = 100%, FiO2 = 0.4, PEEP = 0 cm H2O, PS = 0 cm H2O). During SBT, heart rate (HR) and mean artery pressure (MAP) were monitored continuously and minute volume (VE), respiratory rate (RR), tidal volume of spontaneous breath (VT), rapid shallow breathing index (RSBI), change and rate of change (ΔRSBI60_1 and ΔRSBI60_1/RSBI1, etc.) were recorded or calculated at the first, 30(th) and 60(th) minute of SBT. Patients tolerating the trial were extubated immediately. Clinical data and respiratory indices during SBT were compared between patients in extubation success group and those in extubation failure group. Predictive accuracy of extubation success was assessed by area under the receiver operating characteristic (ROC) curve (AUC) for each index. The duration of mechanical ventilation was longer in patients of extubation failure group than that of extubation success group (10.75 ± 2.73: 7.47 ± 5.11, P = 0.035) and extubation failure rate was 17.14%. During SBT, RSBI increased initially and then decreased in patients of extubation success group, but increased continuously in patients of extubation failure group. There were significant difference of ΔRSBI60_1 and ΔRSBI60_1/RSBI1 in patients between extubation success and failure groups (-11.5 ± 16.6: 12.1 ± 38.9, P = 0.001 and -17 ± 26: 13 ± 39, P = 0.028). AUCs of RSBI60, ΔRSBI60_1 and ΔRSBI60_1/RSBI1 were 0.75, 0.73 and 0.72 and the sensitivity, specificity and diagnostic accuracy 81.0%, 66.7% and 78.5% respectively. It is important to observe change of various respiratory indices dynamically during SBT in patients ventilated in ATC pattern. ΔRSBI60_1 and ΔRSBI60_1/RSBI1 have greater predictive value for extubation success. Stable or decreased RSBI60 means higher extubation success rate.

Effects of Parental Support and Friendship Support on Loneliness and Depression During Early and Middle Adolescence

Teenagers’ relationships with parents and friends undergo many changes during their adolescence. Friendship becomes increasingly important. However, researchers have found that support and warmth from parents still play an important role in fostering healthy socioemotional development for adolescents. Although lots of studies have explored the main effect of parental and friendship support on adolescent adjustments, few have examined the interaction between the two. It should be noted that at least three relationship patterns have been discovered according to existing research: an enhancement pattern, a compensation pattern and an independence pattern. But no consistent conclusion about these interaction patterns has been achieved, which is probably due to different emotional problems, ages and genders in different studies. So this study adopted the Chinese modified versions of the Network of Relationships Inventory, Friendship Quality Questionnaire, Loneliness Scale, and Children’s Depression Inventory, and specially focused on the interaction patterns between parental support and friendship support on adolescent loneliness and depression and their applicability to different stages and genders with a sample of 391 Chinese adolescents (211 boys and 180 girls) from grade 7 (early adolescence) and 10 (middle adolescence). The main findings were as follows. (1) On one hand, middle adolescents perceived significantly lower parental support and friendship quality than early adolescents did, but no significant difference was found in loneliness and depression. On the other hand, girls perceived obviously higher friendship support than boys did, and no other significant difference was observed between genders. (2) Friendship support was the better predictor for adolescent loneliness, whereasparental support was the better predictor for adolescent depression. (3) During early adolescence, parental support and friendship support had significant interactions in loneliness and depression while the specific interacting patterns were different. High level of parental support enhanced the positive effect of high friendship support on reducing loneliness (an enhancement pattern), whereas high friendship support compensated the negative effect of low level of parental support (a compensation pattern); High parental support and high friendship support enhanced each other in the positive effect on reducing depression (an enhancement- each-other pattern). (4) Contrasted to early adolescents, there was no significant interaction between parental support and friendship support on middle adolescent depression (an independence pattern). These interacting patterns of boys were similar to those of girls. It suggests that the effects of family and peers on adolescent emotional adjustments take several types of patterns, which can be applied to different adjustment problems and development stages.

Chromatic aberration free liquid crystal adaptive optics for flood illuminated retinal camera

A high-resolution, flood-illumination retinal camera using liquid crystal (LC) adaptive optics (AO) is presented. The retinal camera uses light at 780nm for ocular aberration measurement while light at 655nm and 593nm for retinal imaging. In order to avoid chromatic aberrations due to wavelength dependence of LC, we adopt an open-loop technique, in which dynamic correction of aberrations is applied only to the imaging light. A compensation pattern projected on the LC wavefront corrector is adjusted to provide phase wrapping of 2π for illumination light. We confirmed feasibility of this technique by performing in vivo retinal imaging experiments. Photoreceptors were clearly revealed at both imaging light at 655nm and 593nm. Feasibility of the technique was also supported by comparison of the retinal images taken by the present open-loop technique with those taken by the conventional closed-loop one and by analysis of the spatial distribution of the photoreceptors.

Research on the Computational Methods of Eco-Compensation Standard for Chan-Ba Ecological District in Xi’an Urban Areas

The computational methods of compensation standard are the focal point and are also difficulty in shaping of the eco-compensation mechanism. As for Xi’an Chan-Ba ecological district, there are three types of eco-compensation pattern: compensation for ecosystem services, compensation for river pollution, and compensation for water environment protection. The paper designs the computational methods for these three types of compensation pattern basing on eco-compensation theory, then calculates the amount of compensation based on the data acquired from Chan-Ba ecological district to test the applicability of the methods. The results show the methods are applicable and feasible

HIGH FREQUENCY COMPENSATING

A method and apparatus for increasing phase margin in a feedback circuit of an active noise reduction headphone. The method includes providing an acoustic block comprising an acoustic driver comprising a voice coil mechanically coupled along an attachment line to an acoustic energy radiating diaphragm, the acoustic block further comprising a microphone positioned along a line parallel to an intended direction of vibration of the acoustic diaphragm and intersecting the attachment line, the acoustic block characterized by a magnitude frequency response compensating the magnitude frequency response by a compensation pattern that has a positive slope over at least one spectral range above 10 kHz.

Non weaving spiders on native woodlands and Eucalyptus plantations in Western Mexico: diversity and distribution patterns

Eucalyptus spp. are commonly planted, forming non-native plantations, including the tropics and their wildlife conservation value is relatively unknown. Recent studies have concluded that secondary forests and tree plantations are less diverse than well-developed tropical rain forests. However, introduced Eucalyptus stands harbored similar species richness to surrounding native woodland in temperate woodlands in North America though the identity of the species present may differ. Species composition, as well as dominance curves and differences in community structure add additional insight to understanding faunistic responses to replacement of native woodland by Eucalyptus plantations. Here, we compared species richness, diversity patterns, and the distribution of non-weaving spiders between native woodlands and Eucalyptus plantations in a temperate region of Mexico. We found more Lycosidae species in all plantation stands. Other community attributes were not consistently different between plantations and native woodlands. This is explained by similarities between, and differences within, the understory of the two main vegetation types. Multivariate analyses identified three spider groups and five spider species could be identified as indicators of these groups. A comparison of the number of species of the wandering spiders between the two vegetation types suggests a compensation pattern that is reported here for the first time.

Mesoderm and ectoderm lineages in the crustacean Parhyale hawaiensis display intra-germ layer compensation

In Parhyale hawaiensis, the first three divisions are holoblastic and asymmetric, resulting in an embryo comprised of eight cells—four macromeres and four micromeres. Lineage studies performed at this stage demonstrate that the progeny of each cell contribute to specific portions of different germ layers. However, it is not known if this lineage pattern means a given blastomere is committed to its specific fate, indicative of mosaic development, or if regulation can occur between blastomere progeny so that the loss of a blastomere could be compensated for during development. Furthermore, if compensation occurs, what would be the source of such replacement? To investigate these possibilities, we performed ablation experiments at the eight-cell stage. We find that loss of blastomeres results in compensation. To determine the compensation pattern, we combined ablation and cell lineage tracing to reveal that progeny of mesoderm and ectoderm producing blastomeres display intra-germ layer compensation. Furthermore, by ablating lineages later in development, we identify a key interval between gastrulation and germband elongation after which compensation no longer occurs. Our results suggest that Parhyale possesses a mechanism to assess the status of mesoderm and ectoderm formation and alter development to replace the missing portions of these lineages.

Altered Enthalpy−Entropy Compensation in Picomolar Transition State Analogues of Human Purine Nucleoside Phosphorylase

Human purine nucleoside phosphorylase (PNP) belongs to the trimeric class of PNPs and is essential for catabolism of deoxyguanosine. Genetic deficiency of PNP in humans causes a specific T-cell immune deficiency, and transition state analogue inhibitors of PNP are in development for treatment of T-cell cancers and autoimmune disorders. Four generations of Immucillins have been developed, each of which contains inhibitors binding with picomolar affinity to human PNP. Full inhibition of PNP occurs upon binding to the first of three subunits, and binding to subsequent sites occurs with negative cooperativity. In contrast, substrate analogue and product bind without cooperativity. Titrations of human PNP using isothermal calorimetry indicate that binding of a structurally rigid first-generation Immucillin (K(d) = 56 pM) is driven by large negative enthalpy values (DeltaH = -21.2 kcal/mol) with a substantial entropic (-TDeltaS) penalty. The tightest-binding inhibitors (K(d) = 5-9 pM) have increased conformational flexibility. Despite their conformational freedom in solution, flexible inhibitors bind with high affinity because of reduced entropic penalties. Entropic penalties are proposed to arise from conformational freezing of the PNP.inhibitor complex with the entropy term dominated by protein dynamics. The conformationally flexible Immucillins reduce the system entropic penalty. Disrupting the ribosyl 5'-hydroxyl interaction of transition state analogues with PNP causes favorable entropy of binding. Tight binding of the 17 Immucillins is characterized by large enthalpic contributions, emphasizing their similarity to the transition state. Via introduction of flexibility into the inhibitor structure, the enthalpy-entropy compensation pattern is altered to permit tighter binding.

The Influence Of Ankle Instability On The Kinetics Of Gait Termination

Chronic ankle instability (CAI) is a common occurrence after an ankle sprain. Yet, some people (copers) maintain dynamic activities without recurrent injury. Alterations in both feed-forward and feedback control exist in CAI patients but little is known about alterations in copers. Understanding differences between copers and CAI patients may help elucidate the mechanism of CAI. PURPOSE: To examine control differences among controls, CAI, and copers during gait termination (GT). METHODS: Twenty controls (20.85 ± 1.6yr), 20 with CAI (20.5 ± 1.0yrs) and 20 copers (21.9 ± 2.9yrs) participated. Copers and CAI patients had a previous moderate ankle sprain but copers resumed all pre-injury activity without limitation or recurrent injury while CAI patients had recurrent sprains. Each subject was tested bilaterally (each limb as the lead and brake limb) during ten planned and ten unplanned GT trials. An auditory signal cued subjects to stop during randomly selected trials (unplanned GT) and catch trials ensured that anticipation of the auditory signal did not occur. Ground reaction forces, collected at 1200Hz, from two adjacent force plates were used to calculate the maximum propulsion (lead limb) and braking forces (brake limb). A 3×2×3 mixed model (group [control, CAI, coper], limb [involved/uninvolved], and task [planned GT, unplanned GT, catch]) MANOVA examined differences among force variables. RESULTS: Both control and coper subjects produced significantly less propulsive force than the CAI group (CAI: 11.2 N> healthy and 9.9N > copers). Subsequently, braking forces were higher for CAI patients than controls (45.5N greater) or copers (26.8N greater). CONCLUSION: CAI patients did not reduce their propulsive forces during GT trials (planned and unplanned) to the same extent as controls or copers and relied on greater braking forces to stop forward momentum. This indicates an altered motor program and slower neuromuscular response in CAI patients during GT. Further, both feed-forward and feedback neuromuscular control alterations appear to exist in CAI subjects. Copers, however, produce similar movement patterns as controls suggesting a return to normal neuromuscular control or successful compensation pattern which may represent a potential coping mechanism. Supported by SEATA Grant 2007-1

Thermodynamic characterization of a highly thermoactive extracellular pectate lyase from a new isolate Bacillus pumilus DKS1

An extracellular pectate lyase (EC 4.2.2.2) was purified from the culture filtrate of a newly isolated Bacillus pumilus DKS1 grown in pectin containing medium. Using ion-exchange and gel filtration chromatography, this enzyme was purified and found to have a molecular weight of around 35 kDa. The purified enzyme exhibited maximal activity at a temperature of 75 °C and pH 8.5. The presence of 1 mM calcium and manganese enhanced pectate lyase activity and was strongly inhibited by zinc, nickel and EDTA. The thermal inactivation studies revealed an entropy–enthalpy compensation pattern below a critical temperature. The alkaliphilicity and high thermostability of this pectate lyase may have potential implications in fibre degumming.

Features of partitioning pattern of two pancreatic enzymatic precursors: Trypsinogen and chymotrypsinogen in polyethyleneglycol–sodium citrate aqueous biphasic systems

The partitioning behaviour of bovine trypsinogen and alpha-chymotrypsinogen, enzymatic precursors with similar physicochemical properties, was investigated in different polyethyleneglycol/sodium citrate aqueous two-phase systems. The effect of different factors such as polyethyleneglycol molecular weight, pH, tie line length and temperature was also examined. The increase of pH and the decrease of polyethyleneglycol molecular weight displaced the partitioning equilibrium of both proteins to the top phase. An enthalpy–entropy compensation pattern was observed, indicating the participation of water molecules in the partitioning mechanism. TRPz phase equilibrium showed to be more displaced to the citrate-rich phase than ChTRPz for most of the assayed systems. From a practical view, the aqueous two-phase system formed by polyethylenglycol of molecular weight 1450 and sodium citrate pH 8.20 showed the best capability for separating both proteins. When a mixture formed by equal quantities of both zymogens was partitioned in this system, significant recoveries (about 60%) were obtained. Purity values were improved significantly (84–89%) by either developing a second extractive step or increasing the top–bottom volume ratio.

Litigation Risk and Executive Compensation

Standard principal-agent theory predicts that the pay-performance sensitivity (PPS) decreases in the risk of the firm. An alternative literature argues that entrenched executives as in weak governance firms use compensation contract to extract the rent, which renders risk irrelevant. This paper uses event study approach to test both principal-agent model and CEO power theory by examining how litigation events affect executive compensation. We examine how the litigation event affects both executive compensation incentive (PPS) and the compensation composition (equity pay versus cash pay). Consistent with principal-agent model prediction, we find that, after the initiation of litigation, PPS drops, performance-invariant component of the compensation (cash) increases and performance sensitivity component compensation (equity) decreases. Complementing analysis using litigation settlement as risk decreasing event provides further evidence that PPS increases after settlement and compensation shifts from cash back to equity. To test CEO power theory, we partition the event firms into firms with good and bad corporate governance. We find that the PPS in firms with bad corporate governance increases after lawsuit and decreases after the settlement, consistent with the story that litigation brings the bad compensation practice of poorly governed firms under the and forces firms to discipline their CEOs more during the litigation period. Overall, our empirical evidence shows that for the overall sample and particularly for the subsample of firms with good corporate governance, compensation pattern changes around corporate litigation are consistent with the predictions of standard principal agent theory. That being said, CEO power does seem to also play a role, as firms with bad corporate governance exhibit a pattern that is more consistent with a limelight effect around the litigation events.