Commensurate Effect Research Articles

Sexual dimorphism in the antigen-specific T cell response in S. Typhimurium infections within extra-lymphoid tissues

Abstract Differences in susceptibility to and severity of infectious diseases between the sexes are well established. Females often generate a beneficially stronger immune response when combatting infection but show an increased risk of developing autoimmunity. While the sex-related hormone estradiol is known to affect CD4 T cell cytokine release in vitro, less is known about T cells behavior in vivo. To address this, we intravenously infected male and female mice with attenuated Salmonella Typhimurium (S. Tm). By day 15 post infection (p.i.), male mice showed significantly lower rates of survival. Males also generated a higher number of S. Tm-specific CD4 T cells in the liver but, conversely, displayed higher bacterial burdens. To isolate the role of sex hormones, mice were gonadectomized before reaching sexual maturity and then infected. Ovariectomized mice lost significantly more weight than ovary-intact females by day 15 p.i. Like normal males, ovariectomized females demonstrated a significantly higher number of S. Tm-specific CD4 T cells but also higher liver bacterial burdens. To investigate the role of extra-lymphoid tissues such as the liver, we infected lymphotoxin-alpha (LTa) mice that genetically lack lymphoid tissues. Surprisingly, we found the stark difference in survival and CD4 T cell expansion between the sexes was lost. These differences in T cell expansion, and the commensurate effect on survival, in the presence or absence of endogenous sex hormones or lymphoid tissues indicate that females may have evolved a separate ability to regulate immune responses outside of traditional lymphoid organs. These studies will provide insights into sex-based differences seen in cellular immunity against bacterial pathogens in vivo. Supported by a grant from the Keck Foundation

Sexual dimorphism in the antigen-specific T cell response in S. Typhimurium infections within extra-lymphoid tissues

Abstract Differences in the immune response between the sexes, particularly in the susceptibility to and severity of infectious diseases, are well established. Females commonly generate a more robust response that is beneficial when combatting infections but leads to an increased risk of developing autoimmune disorders. While the sex-related hormone, estradiol (E2), is known to affect CD4 T cell cytokine release in vitro, less is known about how T cells differ in non-lymphoid tissues in vivo or how lymphoid tissues might influence T cell responses to infection. To address this, we intravenously infected lymphotoxin-alpha (LTa) male and female mice that genetically lack lymphoid tissues save for a small, disorganized spleen that was either left intact or removed surgically, with attenuated Salmonella enterica sp. Typhimurium (S. Tm). In infected mice lacking all lymphoid tissues, rates of survival between the sexes were similar. In sharp contrast, females with intact spleens had a significantly lower rate of survival in comparison to their male counterparts. We show that, in mice with or without intact spleens, the number of S. Tm-specific CD4 T cells are higher in male livers on day 10 post infection; however, by day 15, female mice with intact spleens had significantly increased CD4 T cell expansion in comparison to male mice with intact spleens, correlating to lower survival. This difference in T cell expansion, and the commensurate effect on survival, in the presence or absence of lymphoid tissue indicate that females may have evolved a separate ability to regulate immune responses outside of traditional lymphoid organs. These studies will provide insights into sex-based differences seen in cellular immunity against bacterial pathogens in vivo.

Social Value of Patents: Evidence from the U.S. Court of Appeals for the Federal Circuit

To encourage invention, society awards inventors exclusive rights through patents. Patent law trades off incentives to invent new technologies against reduced access to already invented technology. However, patent law being national, it is difficult to investigate the trade off without confound by national economic and scientific changes. We exploit a unique quasi-natural experiment which changed patent law sub-nationally, within the United States. Beginning 1982, the Court of Appeals for the Federal Circuit shifted law in favor of patent owners, to degrees varying geographically by judicial circuit. For businesses in complex technology industries, we find that the CAFC increased costs to users by more than US$5.6 billion per year, but did not significantly affect the technological quality of patented inventions. Our work contributes to a more nuanced appreciation of socially optimal patent law. Shifting the law in favor of patent owners, a policy to encourage innovation, seemed to increase economic rents without commensurate effect on invention quality.

Borrowing of information across patient subgroups in a basket trial based on distributional discrepancy.

SummaryBasket trials have emerged as a new class of efficient approaches in oncology to evaluate a new treatment in several patient subgroups simultaneously. In this article, we extend the key ideas to disease areas outside of oncology, developing a robust Bayesian methodology for randomized, placebo-controlled basket trials with a continuous endpoint to enable borrowing of information across subtrials with similar treatment effects. After adjusting for covariates, information from a complementary subtrial can be represented into a commensurate prior for the parameter that underpins the subtrial under consideration. We propose using distributional discrepancy to characterize the commensurability between subtrials for appropriate borrowing of information through a spike-and-slab prior, which is placed on the prior precision factor. When the basket trial has at least three subtrials, commensurate priors for point-to-point borrowing are combined into a marginal predictive prior, according to the weights transformed from the pairwise discrepancy measures. In this way, only information from subtrial(s) with the most commensurate treatment effect is leveraged. The marginal predictive prior is updated to a robust posterior by the contemporary subtrial data to inform decision making. Operating characteristics of the proposed methodology are evaluated through simulations motivated by a real basket trial in chronic diseases. The proposed methodology has advantages compared to other selected Bayesian analysis models, for (i) identifying the most commensurate source of information and (ii) gauging the degree of borrowing from specific subtrials. Numerical results also suggest that our methodology can improve the precision of estimates and, potentially, the statistical power for hypothesis testing.

Sleep and Reproductive Health.

The reproductive function of humans is regulated by several sex hormones which are secreted in synergy with the circadian timing of the body. Sleep patterns produce generic signatures that physiologically drive the synthesis, secretion, and metabolism of hormones necessary for reproduction. Sleep deprivation among men and women is increasingly reported as one of the causes of infertility. In animal models, sleep disturbances impair the secretion of sexual hormones thereby leading to a decrease in testosterone level, reduced sperm motility and apoptosis of the Leydig cells in male rats. Sleep deprivation generates stressful stimuli intrinsically, due to circadian desynchrony and thereby increases the activation of the Hypothalamus-Pituitary Adrenal (HPA) axis, which, consequently, increases the production of corticosterone. The elevated level of corticosteroids results in a reduction in testosterone production. Sleep deprivation produces a commensurate effect on women by reducing the chances of fertility. Sleeplessness among female shift workers suppresses melatonin production as well as excessive HPA activation which results in early pregnancy loss, failed embryo implantation, anovulation and amenorrhea. Sleep deprivation in women has also be found to be associated with altered gonadotropin and sex steroid secretion which all together lead to female infertility. Poor quality of sleep is observed in middle-aged and older men and this also contributes to reduced testosterone concentrations. The influence of sleep disturbances post-menopausal is associated with irregular synthesis and secretion of female sex steroid hormones.

Consideration of enthalpic and entropic energy contributions to the relative rates of chalcopyrite dissolution in the presence of aqueous cationic impurities

To understand the effect of aqueous impurities on chalcopyrite dissolution during acid metalliferous drainage and hydrometallurgical processes, batch dissolution experiments were carried out at 650 and 750mV (SHE), pH1 and 35–75°C in the presence or absence of aqueous cationic additives. Activation energies (Ea) for chalcopyrite dissolution in the presence of additives at 750mV, derived using a modified ‘time to a given fraction’ method, demonstrate that Ea varies with reaction extent. The overall trend of evolution from interface- to transport-controlled mechanism was independent of additive type or addition. This suggests that it is not primarily variation in the enthalpy of dissolution that controls the significant changes in relative dissolution rates on addition of additives.Rather, the relative dissolution rates on addition of aqueous cations are found to relate to the M–O framework volume (M and O being the cationic additive and oxygen within H2O in the first sphere of hydration, respectively). There is good inverse linear correlation between this volume and the relative dissolution rate per unit ionic strength which varies as K+>Al3+>no additive>Mg2+>Na+>Ca2+. It is proposed that this effect is related to the relative strength of hydration of the additives with the commensurate entropic effect on solute hydration being advantageous for chalcopyrite dissolution on K+ and Al3+ addition and detrimental for the other additives. H4SiO4, the dominant aqueous species upon Si addition under the conditions examined, has low affinity for water, resulting in a detrimental entropic contribution to solute hydration and dissolution. The effect of Fe addition on relative dissolution rate is convoluted by the role of Fe3+ as the primary oxidant for chalcopyrite dissolution. On addition of aqueous Fe to dissolution at 750mV, the effect is detrimental due to the detrimental effect on the entropy of hydration of the solute and the relative abundance of Fe3+. At 650mV the effect of the greater presence of Fe3+ due to Fe addition dominates and the dissolution rate is enhanced.

The effect of humidity on hydroxyl and ozone production by nanosecond discharges

The interplay of humidity and non-equilibrium, transient plasma was studied via ignition experiments in a C2H4–air mixture, concentration measurements in humid air, and detailed simulations. Hydroxyl (OH) and ozone (O3) produced via non-equilibrium plasma were characterized in a flowing H2O–air mixture at atmospheric pressure with varying the levels of humidity using planar laser-induced fluorescence (PLIF) and UV absorption, respectively. The OH, which was created in the discharge streamers, peaked at a concentration of ∼5×1014/cm3 and then decayed below 1×1014/cm3 after ∼100µs. O3, which is long lived, peaked at a concentration of 1.4×1015/cm3. An increase in humidity from XH2O≈0.2% to 1% resulted in a monotonic increase in the concentration of OH and a 67% decrease in that of O3. Zero-dimensional Boltzmann modeling of non-equilibrium plasma discharges in humid air showed qualitative agreement with these results and points to the decrease in O concentration (with increasing humidity) as the reason for the decreased O3 concentration. In spite the dramatic decline in XO3 with increased humidity, there was no strong commensurate effect on ignition and flame propagation in C2H4–air mixtures: Peak pressure rise rate was at its maximum value at XH2O=1% but was only 25% less at XH2O=5%.

GNSS multipath detection using three-frequency signal-to-noise measurements

A new technique for detecting GNSS multipath interference by comparing signal-to-noise (SNR) measurements on three frequencies is presented. Depending on the phase lag of the reflected signal with respect to the direct signal, multipath interference can be either constructive or destructive, with a commensurate effect on the measured SNR. However, as the phase lag is frequency dependent, the SNR is perturbed differently on each frequency. Thus, by differencing SNR measurements on different frequencies and comparing the result with that obtained in a low-multipath environment, multipath can be detected. Using three frequencies makes the process more robust. A three-frequency SNR-based multipath detector has been developed and calibrated using measurements from GPS Block IIF satellites in a low-multipath environment. The new detector has been tested in a range of urban environments and its multipath detection capability verified by showing that the MP observables oscillate when the new detection statistic is above a threshold value determined using data collected in a low-multipath environment. The new detector is also sensitive to diffraction.

Disaster Risk Reduction and the Earthquake Code: A Disconnect

The application of current earthquake engineering knowledge through structural design codes has greatly reduced the loss of life from earthquakes in countries where the use of such codes has been normal practice for several decades. However it has not had a commensurate effect on disaster risk reduction as was clearly demonstrated in Christchurch by the Canterbury earthquakes. Although the great majority of lives which were lost were the result of the failure of just one modern building - which evidence suggests was from poor design and not a code problem - many modern buildings, while performing well in terms of life safety, were nevertheless damaged beyond repair imposing major economic and social costs on the citizens of Christchurch in particular and, through greatly increased insurance premiums, New Zealand generally. This paper describes the disconnect between the nature of disaster risk reduction and current structural earthquake engineering design philosophy which arises because disasters are a function of community size as well as building vulnerability, whereas current design philosophy is focused entirely on the safety of individual buildings. It draws on ideas jointly developed with the late Paul Grundy and is presented as a tribute to his major contribution to this field.

Aphid-repellent pheromone E-β-farnesene is generated in transgenic Arabidopsis thaliana over-expressing farnesyl diphosphate synthase2

Plant-synthesized sesquiterpenes play a pivotal role in chemotactic interactions with insects. Biosynthesis of functionally diverse sesquiterpenes is dependent on the availability of a pool of the precursor farnesyldiphosphate (FDP). In Arabidopsis thaliana, FPS2, encoding cytosolic farnesyldiphosphate synthase, is implicated in the synthesis of cytosolic FDP, but it is not known whether enhanced levels of FDP have a commensurate effect on sesquiterpene-mediated defence responses. This study examined transgenic arabidopsis plants generated to over-express FPS2 in order to determine if any effects could be observed in the response of aphids, Myzus persicae. Transgenic arabidopsis plants were generated to over-express FPS2 to produce FPS2 in either the cytosol or the chloroplasts. Morphochemical analyses of the transgenic plants were carried out to detremine growth responses of roots and shoots, and for GC-MS profiling of sesquiterpenes. Aphid response to hyrdo-distillate extracts and head-space volatiles from transgenic plants was assessed using a bioassay. Either over-expression of FPS2 in the cytosol or targetting of its translated product to chlorplasts resulted in stimulatory growth responses of transgenic arabidopsis at early and late developmental stages. GC-MS analysis of hydro-distillate extracts from aerial parts of the plants revealed biosynthesis of several novel sesquiterpenes, including E-β-farnesene, an alarm pheromone of aphids. Both entrapped volatiles and hydro-distillate extracts of the transgenic leaves triggered agitation in aphids, which was related to both time and dose of exposure. Over-expression of FPS2 in the cytosol and targeting of its translated product to chloroplasts in arabidopsis led to synthesis of several novel sesquiterpenes, including E-β-farnesene, and induced alarm responses in M. persicae. The results suggest a potential for engineering aphid-resistant strains of arabidopsis.

Impact-Evaluation of Baby Friendly Hospital Initiative: Case Study of Bassa LGA, Plateau State, Nigeria

Study aimed to evaluate the impact of impact of BFHI on the world, especially at the grassroots, through Level of awareness, Influence and Effect. A total of 450 women were studied between the months of March and November 2010 in Bassa LGA in Plateau State, Nigeria. Relatively high level mere-awareness of BFHI X(23.5); SD (0.036), opinion about effect on lactating mothers X (82.8); SD (0.36) and willingness to practice and campaign X (54.6); SD (0.143) respectively are positive indicators, despite strong negative factors on idea about BFHI duration X (19.9); SD (1.2). However, relatively high level of awareness of BFHI has little influence and thus, commensurate little effect on the women. The fact that the third world countries still see BFHI and EBF practice as an idea of the developed world confirms ineffective communication as a major impediment to appreciable positive effect. Keyword: BFHI, Awareness, Impact, Evaluation, Promotion, Bassa.

Role of surface chemical groups on carbon nanotubes in nucleation for polymer crystallization: Interfacial interaction and steric effect

Effects of surface functionalization of carbon nanotubes (CNTs) on their nucleation ability for poly(l-lactide acid) during isothermal and nonisothermal crystallization were investigated. The results showed that the surface functional groups reduced the nucleation ability of CNTs. The polarity of the functional CNTs was notably changed due to the presence of covalent groups (i.e., –OH, –COOH, and –F), giving rise to varied interactions with PLA chains. Three types of CNTs possessed different nucleation ability, depending on interfacial interaction and steric effect. Thereinto, by virtue of the superior polarity of –COOH group, the nucleation efficiency of CNTs-COOH surpassed that of CNTs-OH and CNTs-F despite the larger bulk of –COOH group, which might impede the movement of polymer chains towards the CNT surface. The steric hindrance of –F group was weaker than that of –OH group while the interfacial interaction was opposite, thus CNTs-OH and CNTs-F showed a commensurate effect on accelerating PLA crystallization. On the basis of surface-induced conformational ordering, a necessary approach for CNT-induced polymer crystallization was suggested that the functional groups played a counteraction or competition on nucleation efficiency of functional CNTs attributing to the interfacial interaction and the steric effect.

Increasing pulse wave velocity in a realistic cardiovascular model does not increase pulse pressure with age

The mechanism of the well-documented increase in aortic pulse pressure (PP) with age is disputed. Investigators assuming a classical windkessel model believe that increases in PP arise from decreases in total arterial compliance (C(tot)) and increases in total peripheral resistance (R(tot)) with age. Investigators assuming a more sophisticated pulse transmission model believe PP rises because increases in pulse wave velocity (c(ph)) make the reflected pressure wave arrive earlier, augmenting systolic pressure. It has recently been shown, however, that increases in c(ph) do not have a commensurate effect on the timing of the reflected wave. We therefore used a validated, large-scale, human arterial system model that includes realistic pulse wave transmission to determine whether increases in c(ph) cause increased PP with age. First, we made the realistic arterial system model age dependent by altering cardiac output (CO), R(tot), C(tot), and c(ph) to mimic the reported changes in these parameters from age 30 to 70. Then, c(ph) was theoretically maintained constant, while C(tot), R(tot), and CO were altered. The predicted increase in PP with age was similar to the observed increase in PP. In a complementary approach, C(tot), R(tot), and CO were theoretically maintained constant, and c(ph) was increased. The predicted increase in PP was negligible. We found that increases in c(ph) have a limited effect on the timing of the reflected wave but cause the system to degenerate into a windkessel. Changes in PP can therefore be attributed to a decrease in C(tot).

Zeolite Structure Direction by Simple Bis(methylimidazolium) Cations: The Effect of the Spacer Length on Structure Direction and of the Imidazolium Ring Orientation on the19F NMR Resonances

A series of doubly charged structure-directing agents based on two methylimidazolium moieties linked by a linear bridge of n = 3,4,5, or 6 methylene groups has been used in the synthesis of pure silica zeolites in the presence of fluoride. All of them yielded zeolite TON while only the one with n = 4 was able to produce also zeolite MFI at highly concentrated conditions. In this MFI zeolite, two distinct (19)F MAS NMR resonances with about equal intensity were observed, indicating two different chemical environments for occluded fluoride. With the singly charged 1-ethyl-3-methylimidazolium cation, which can be formally considered as the "monomer" of the bis-imidazolium cation with n = 4, TON and MFI were also obtained, and again two (19)F MAS NMR resonances now with largely dissimilar intensities were observed in MFI. Molecular mechanics simulations support a commensurate structure-direction effect for n = 4 in MFI, with each imidazolium ring, in two different orientations, sitting close to the [4(1)5(2)6(2)] cage. Periodic DFT calculations suggest that F in MFI resides always in the [4(1)5(2)6(2)] cages, with the different (19)F resonances observed being due to the different orientation of the closest imidazolium ring.

Geometric Factors Impacting Adhesive Lap Joint Strength and Design

Too often adhesive thickness, adherend thickness and other geometric factors are not explicitly considered in adhesive joint design. This study includes experimental and computational research exploring the means of enhancing the engineering design process for adhesive lap joints to include such effects. It clearly demon-strated that both the cleavage stresses and the shear stresses, near the bond termini, play important roles in lap 'shear' joint failure. Finite Element and Fracture Mechanics analyses were used to examine the energy release rate applied to growth of cracks in adhesive lap joints. Lap joints with similar geometries to those analyzed were designed, fabricated and tested. In a separate set of experiments the bond termini were constrained in the direction normal to the uniaxial loading. If the strength of lap shear joints is dominated by the adhesive shear strength, then constraining the lateral motion of the bond termini should have little or no effect on the overall shear strength of the adhesive joint. This work clearly demonstrates that this is not the case. If cleavage stresses are important in lap joints then constraining the bond termini, in a direction normal to the bond area, should have a commensurate effect on the overall strength of the lap joint. None of the ASTM standardized 'lap shear tests' provide any insight into this premise. This paper also presents analyses and experimental results for lap joints to which several methods of lateral constraint were applied near the bond termini. The analytical and numerical methods described and used for explaining and predicting such effects might be a useful adhesive joint design tool.

Swarming motility and the control of master regulators of flagellar biosynthesis

Swarming motility is the movement of bacteria over a solid surface powered by rotating flagella. The expression of flagellar biosynthesis genes is governed by species-specific master regulator transcription factors. Mutations that reduce or enhance master regulator activity have a commensurate effect on swarming motility. Here we review what is known about the proteins that modulate swarming motility and appear to act upstream of the master flagellar regulators in diverse swarming bacteria. We hypothesize that environmental control of the master regulators is important to the swarming phenotype perhaps at the level of controlling flagellar number.

General learning ability regulates exploration through its influence on rate of habituation

“General intelligence” is purported to influence diverse domain-specific learning abilities in humans, and previous research indicates that an analogous trait is expressed in CD-1 outbred mice. In humans and mice, exploratory tendencies are predictive of general cognitive abilities, such that higher cognitive abilities are associated with elevated levels of exploration. However, in mice, repeated exposure to novel environments outside the home cage has been found to up-regulate exploratory tendencies but has no commensurate effect on general learning abilities, suggesting that exploratory tendencies do not causally influence general cognitive performance. This leaves open the question of what is responsible for the robust relationship observed between exploration and general learning abilities? In the present experiments, we find that differential rates of habituation (e.g., to a novel open field) between animals of high and low general learning abilities accounts for the relationship between exploration and learning abilities. First, we up-regulated exploration by exposing mice to a series of novel environments. Similar to its lack of effect on learning tasks, this up-regulation of exploration had no commensurate effect on habituation to novel objects or stimuli. Next we examined the relationship between general learning abilities and exploration under conditions where habituation had a high or low impact on exploratory behaviors. A strong correlation between general learning abilities and exploration was observed under conditions where the levels of habituation (to a novel object or an open field) between animals of high and low general learning abilities were allowed to vary. However, this same correlation was attenuated when the level of habituation attained by animals of high and low general learning abilities was asymptotic or held constant across animals. In total, these results indicate that the relationship between exploration and general learning abilities is accounted for by the impact of habituation (itself a form of learning) on behaviors indicative of exploration.

Direct versus indirect pathways of salmon-derived nutrient incorporation in experimental lotic food webs

The objective of our study was to examine how salmon carcass subsidization through alternative trophic pathways affected stream food web productivity. Three salmon carcass treatments (dissolved carcass nutrients only, dissolved carcass nutrients + carcass material, and a carcass-free control) were replicated five times in artificial stream channels. We quantified changes in water chemistry and the production of periphyton, macroinvertebrates, and age 0+ steelhead trout (i.e., sea-run rainbow trout, Oncorhynchus mykiss ) over 65 days. Dissolved ammonium and periphyton chlorophyll a concentrations increased for an approximate 2-week period in both carcass-augmented treatments. However, there was no commensurate effect on periphyton ash-free dry mass. Total macroinvertebrate biomass was significantly greater in the presence of nutrients + material after 65 days, but no such increase was observed in response to the addition of dissolved nutrients only. Despite modest and inconsistent effects at lower trophic levels, both the nutrients only and nutrients + material treatments increased the growth and condition of age 0+ steelhead trout, with significantly greater gains occurring in the presence of nutrients + material. These data suggest that while salmon carcasses can enhance the short-term growth of juvenile salmonids via bottom-up pathways, the availability and direct consumption of carcass biomass may promote a substantial amount of additional production.

Discordant Effects of β‐Blockade on Central Aortic Systolic and Brachial Systolic Blood Pressure: Considerations Beyond the Cuff

The role of beta-blockers in uncomplicated hypertension has been challenged recently. Compared with other antihypertensives, beta-blockers are less effective for preventing cardiovascular events in patients with uncomplicated hypertension. Moreover, a recent meta-analysis of placebo-controlled clinical trials concluded that atenolol is not more efficacious than placebo for preventing cardiovascular events in patients with hypertension. Although these agents lower blood pressure measured conventionally over the brachial artery with a blood pressure cuff, they do not exert a commensurate effect on blood pressure in the central aorta. Central aortic blood pressure and aortic augmentation index are strong predictors of left ventricular hypertrophy, an independent risk factor for cardiovascular events. Emerging data are illuminating the antihypertensive paradox whereby antihypertensive agents may elicit discordant effects on central and peripheral blood pressure and hemodynamics. Vasodilatory antihypertensives, such as renin-angiotensin-aldosterone system inhibitors and calcium channel blockers, elicit reductions in central aortic blood pressure equal to or greater than that in the brachial artery. Conversely, beta-blockers lower central aortic blood pressure to a lesser degree even when blood pressure measured by sphygmomanometry is reduced substantially. Given the strong relationship between central aortic blood pressure and target organ damage, the effectiveness of beta-blockers may be overestimated in practice on the basis of conventional blood pressure measurements alone. Differences in central and peripheral blood pressure may account for the lack of cardiovascular protection afforded by beta-blockers in clinical trials and could account for a portion of the apparent "benefit beyond blood pressure" reduction with other classes of antihypertensive agents. Future studies should aim to better clarify the role of central aortic blood pressure in the treatment of hypertension. In the meantime, the effects of antihypertensive drugs on blood pressure "beyond the brachial blood pressure cuff" should be considered when prescribing antihypertensive agents for a patient.

Poly(propylene imine) dendrimers as plasticizers for polyvinyl chloride

AbstractFourth and fifth generation poly(propylene imine) dendrimers and methyl and benzyl functionalized copolymers of these dendrimers are solution blended with poly(vinyl chloride) (PVC). The methyl‐derivative copolymer is observed to be dispersed in PVC as judged by optical and dynamic scanning calorimetry measurements. This dispersion leads to a substantial reduction in the glass transition temperature and a commensurate plasticization effect, demonstrating that functionalized dendrimer copolymers can successfully plasticize semicrystalline polymers. This plasticization is thought to occur as a result of additional free volume from the highly branched structure of the dendrimer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1970–1975, 2007