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Abstract

We report the development of a theranostic collagen targeted cell penetrating drug delivery system toward treatment of cardiovascular disease. Caused by the action of matrix metalloproteinases (MMP), degraded collagen is a hallmark of unstable atherosclerotic plaques that are highly susceptible toward rupture. Targeting unstable plaques and delivering MMP blockers directly to plaque to inhibit MMP activity is a promising new strategy that requires the benefits and possibilities of nanodelivery approaches. The presented delivery system is designed to (a) target and bind to a cryptic epitope on collagen IV exposed through the degradative action of matrix metalloproteinase 2 (MMP2), (b) to image the targeting and cell uptake, and (c) to deliver the MMP14 inhibitor naphthofluorescein. In detail, the novel targeting unit is composed of a collagen-homing T-peptide and bound to a MMP2-cleavable activatable cell penetrating peptide (ACPP) which upon cleavage by MMP2 deposits the MMP14 blocker drug into cells, directly into contact with MMP 14 activating enzymes. To selectively attach both the targeting peptide and a reporting imaging dye, a nanosponge nanoparticle network is modified to present orthogonal aldehyde and thiol functional groups as surface units. The MMP14 inhibitor naphthofluorescein is loaded into the nanoparticle delivery system after postconjugation chemistries and finalizes the synthesis of this novel theranostic delivery system. The ability to evade phagocytosis is confirmed in vitroby using murine RAW cell line and effective cell uptake in vitroby using the MMP2 producing the HT1080 cell line is demonstrated. In this work, we have combined a highly specific targeting peptide directed against degraded collagen and a tailorable nanosystem that is deemed to deliver its potent drug load directly into cells, to inhibit the cascade for MMP activation which breaks down collagen structures leading to plaque rupture, the underlying cause of myocardial infarction and strokes.

Electrons in Earth's outer radiation belt are highly dynamic, with fluxes changing by up to orders of magnitude. The penetration of electrons from the outer belt to the inner belt is one such change observed during geomagnetic storms and was previously observed in electrons up to 1 MeV for some strong storms observed by the Van Allen Probes. We analyze pulse height analysis data from the Relativistic Electric and Proton Telescope (REPT) on the Van Allen Probes to produce electron flux measurements with lower minimum energy and significantly improved resolution compared to the standard REPT data and show that electron penetrations into the inner belt (L≤ 2) extend to at least 1.3 MeV and penetrations into the slot region (2 < L< 2.8) extend to at least 1.5 MeV during certain geomagnetic storms. We also demonstrate that these penetrations are associated with butterfly pitch angle distributions from 1 to 1.3 MeV. Electrons in Earth's outer radiation belt are highly dynamic with the amount and energy of them changing drastically, especially during geomagnetic storms. The penetration of electrons from the outer belt to the inner radiation belt is one such change and was previously observed in electrons with energies ≤1 MeV during some of the strongest storms during the Van Allen Probes mission. Electrons in the radiation belts also have a pitch angle that describes what portion of their motion is along or perpendicular to the direction of the magnetic field. Pitch angle distributions (PAD) are often used to gain information on the dynamics of the electrons, as unstable distributions can be caused by and indicative of wave activity that cannot always be measured directly. PADs with a minimum at 90°, called butterfly PADs, are one such unstable distribution that have previously been observed in penetrating electrons with energies ∼100–900 keV. We use instrument simulation to analyze data from the Van Allen Probes that could not previously be analyzed to show that the maximum energy of these penetrations is higher than previously observed, up to 1.3 MeV, and that these penetrations are associated with butterfly PADs at 1–1.3 MeV. REPT PHA data can be used to produce high energy resolution flux spectra of >1 MeV electronsElectron penetrations below L= 2 during strong geomagnetic storms extend in energy up to 1.3 MeVElectron penetrations below L= 2 at energies 1–1.3 MeV are associated with butterfly pitch angle distributions REPT PHA data can be used to produce high energy resolution flux spectra of >1 MeV electrons Electron penetrations below L= 2 during strong geomagnetic storms extend in energy up to 1.3 MeV Electron penetrations below L= 2 at energies 1–1.3 MeV are associated with butterfly pitch angle distributions

Regulatory T (Treg) cells are essential for immune tolerance of embryo implantation and insufficient Treg cells are implicated in early pregnancy loss. An abortion-prone mouse model was utilized to evaluate the utility of IL-2 complexed with JES6-1 anti-IL-2 antibody (IL-2/JES6-1) to boost uterine Treg cells and improve reproductive success. IL-2/JES6-1 but not IL-2/IgG control administered in the peri-conception phase to CBA/J females mated with DBA/2 males elicited a >2-fold increase in the proportion of CD4+T cells expressing FOXP3, and an increase in the ratio of FOXP3+Treg cells to FOXP3-T conventional cells, in the uterus and its draining lymph nodes at embryo implantation that was sustained into mid-gestation. An attenuated phenotype was evident in both thymic-derived and peripheral Treg cells with elevated CTLA4, CD25, and FOXP3 indicating improved suppressive function, as well as increased proliferative marker Ki67. IL-2/JES6-1 treatment reduced fetal loss from 31% to 10%, but this was accompanied by a 6% reduction in late gestation fetal weight, despite comparable placental size and architecture. Similar effects of IL-2/JES6-1 on Treg cells and fetal growth were seen in CBA/J females with healthy pregnancies sired by BALB/c males. These findings show that expanding the uterine Treg cell pool through targeting IL-2 signaling is a strategy worthy of further investigation for mitigating immune-mediated fetal loss.

PiT-2, a type III sodium-dependent phosphate transporter, is a causative gene for the brain arteriolar calcification in people with familial basal ganglion calcification. Here we examined the effect of PiT-2 haploinsufficiency on vascular calcification in uremic mice using wild-type and global PiT-2 heterozygous knockout mice. PiT-2 haploinsufficiency enhanced the development of vascular calcification in mice with chronic kidney disease fed a high-phosphate diet. No differences were observed in the serum mineral biomarkers and kidney function between the wild-type and PiT-2 heterozygous knockout groups. Micro computed tomography analyses of femurs showed that haploinsufficiency of PiT-2 decreased trabecular bone mineral density in uremia. In vitro, sodium-dependent phosphate uptake was decreased in cultured vascular smooth muscle cells isolated from PiT-2 heterozygous knockout mice compared with those from wild-type mice. PiT-2 haploinsufficiency increased phosphate-induced calcification of cultured vascular smooth muscle cells compared to the wild-type. Furthermore, compared to wild-type vascular smooth muscle cells, PiT-2 deficient vascular smooth muscle cells had lower osteoprotegerin levels and increased matrix calcification, which was attenuated by osteoprotegerin supplementation. Thus, PiT-2 in vascular smooth muscle cells protects against phosphate-induced vascular calcification and may be a therapeutic target in the chronic kidney disease population.

Anemia is characteristic of myelodysplastic syndromes (MDS). The mechanisms of anemia in MDS are unclear. Using a mouse genetic approach, here we show that dual deficiency of mDia1 and miR-146a, encoded on chromosome 5q and commonly deleted in MDS (del(5q) MDS), causes an age-related anemia and ineffective erythropoiesis mimicking human MDS. We demonstrate that the ageing bone marrow microenvironment is important for the development of ineffective erythropoiesis in these mice. Damage-associated molecular pattern molecules (DAMPs), whose levels increase in ageing bone marrow, induced TNFα and IL-6 upregulation in myeloid-derived suppressor cells (MDSCs) in mDia1/miR-146a double knockout mice. Mechanistically, we reveal that pathologic levels of TNFα and IL-6 inhibit erythroid colony formation and differentially affect terminal erythropoiesis through reactive oxygen species-induced caspase-3 activation and apoptosis. Treatment of the mDia1/miR-146a double knockout mice with all-trans retinoic acid, which promoted the differentiation of MDSCs and ameliorated the inflammatory bone marrow microenvironment, significantly rescued anemia and ineffective erythropoiesis. Our study underscores the dual roles of the ageing microenvironment and genetic abnormalities in the pathogenesis of ineffective erythropoiesis in del(5q) MDS.

The Data Activated Liu1Graph Engine – DALiuGE2– is an execution framework for processing large astronomical datasets at a scale required by the Square Kilometre Array Phase 1 (SKA1). It includes an interface for expressing complex data reduction pipelines consisting of both datasets and algorithmic components and an implementation run-time to execute such pipelines on distributed resources. By mapping the logical view of a pipeline to its physical realisation, DALiuGE separates the concerns of multiple stakeholders, allowing them to collectively optimise large-scale data processing solutions in a coherent manner. The execution in DALiuGE is data-activated, where each individual data item autonomously triggers the processing on itself. Such decentralisation also makes the execution framework very scalable and flexible, supporting pipeline sizes ranging from less than ten tasks running on a laptop to tens of millions of concurrent tasks on the second fastest supercomputer in the world. DALiuGE has been used in production for reducing interferometry datasets from the Karl E. Jansky Very Large Array and the Mingantu Ultrawide Spectral Radioheliograph; and is being developed as the execution framework prototype for the Science Data Processor (SDP) consortium of the Square Kilometre Array (SKA) telescope. This paper presents a technical overview of DALiuGE and discusses case studies from the CHILES and MUSER projects that use DALiuGE to execute production pipelines. In a companion paper, we provide in-depth analysis of DALiuGE’s scalability to very large numbers of tasks on two supercomputing facilities.

IMPORTANCE: Commercial virtual visits are an increasingly popular model of health care for the management of common acute illnesses. In commercial virtual visits, patients access a website to be connected synchronously—via videoconference, telephone, or webchat—to a physician with whom they have no prior relationship. To date, whether the care delivered through those websites is similar or quality varies among the sites has not been assessed. OBJECTIVE: To assess the variation in the quality of urgent health care among virtual visit companies. DESIGN, SETTING, AND PARTICIPANTS: This audit study used 67 trained standardized patients who presented to commercial virtual visit companies with the following 6 common acute illnesses: ankle pain, streptococcal pharyngitis, viral pharyngitis, acute rhinosinusitis, low back pain, and recurrent female urinary tract infection. The 8 commercial virtual visit websites with the highest web traffic were selected for audit, for a total of 599 visits. Data were collected from May 1, 2013, to July 30, 2014, and analyzed from July 1, 2014, to September 1, 2015. MAIN OUTCOMES AND MEASURES: Completeness of histories and physical examinations, the correct diagnosis (vs an incorrect or no diagnosis), and adherence to guidelines of key management decisions. RESULTS: Sixty-seven standardized patients completed 599 commercial virtual visits during the study period. Histories and physical examinations were complete in 417 visits (69.6%; 95% CI, 67.7%-71.6%); diagnoses were correctly named in 458 visits (76.5%; 95% CI, 72.9%-79.9%), and key management decisions were adherent to guidelines in 325 visits (54.3%; 95% CI, 50.2%-58.3%). Rates of guideline-adherent care ranged from 206 visits (34.4%) to 396 visits (66.1%) across the 8 websites. Variation across websites was significantly greater for viral pharyngitis and acute rhinosinusitis (adjusted rates, 12.8% to 82.1%) than for streptococcal pharyngitis and low back pain (adjusted rates, 74.6% to 96.5%) or ankle pain and recurrent urinary tract infection (adjusted rates, 3.4% to 40.4%). No statistically significant variation in guideline adherence by mode of communication (videoconference vs telephone vs webchat) was found. CONCLUSIONS AND RELEVANCE: Significant variation in quality was found among companies providing virtual visits for management of common acute illnesses. More variation was found in performance for some conditions than for others, but no variation by mode of communication.

CUORE is a 741 kg array of TeO2bolometers for the search of neutrinoless double beta decay of 130Te. The detector is being constructed at the Laboratori Nazionali del Gran Sasso, Italy, where it will start taking data in 2015. If the target background of 0.01 counts/(keV⋅kg⋅y)will be reached, in five years of data taking CUORE will have a 1σhalf life sensitivity of 1026y. CUORE-0 is a smaller experiment constructed to test and demonstrate the performances expected for CUORE. The detector is a single tower of 52 CUORE-like bolometers that started taking data in spring 2013. The status and perspectives of CUORE will be discussed, and the first CUORE-0 data will be presented.

The CUORE (Cryogenic Underground Observatory for Rare Events) experiment is an array of 741 kg of TeO2bolometers to search for neutrinoless double beta decay (ββ0ν) of 130Te. The detector is being constructed at the Laboratori Nazionali del Gran Sasso (Italy) where it will start operation in 2015. To test and demonstrate the possibility of realising such a large scale bolometric detector, a prototype (CUORE-0) has been realised. The CUORE-0 detector is a single tower of 52 CUORE-like bolometers. CUORE-0 data taking started in Spring 2013. The status of CUORE and the first CUORE-0 data are here reported.

The Mingantu Ultrawide Spectral Radioheliograph (MUSER) is a synthetic-aperture radio interferometer built in Ming'antu, Inner Mongolia, China. As a solar-dedicated interferometric array, the MUSER can produce high-quality radio images in a frequency range of 400 MHz-15 GHz with high temporal, spatial, and spectral resolution. Implementing of the data processing system for the MUSER is a major challenge to performing high-cadence imaging in wideband and obtaining more than two orders of higher multiple frequencies. There is an urgent need to build a pipeline for processing the massive amount of MUSER data generated each day. In this article, we present a high-performance distributed data processing pipeline (DDPP) built on the OpenCluster infrastructure for processing MUSER observational data, including data storage, preprocessing, image reconstruction, deconvolution, archiving, and real-time monitoring. We comprehensively elaborate the system architecture of the pipeline and the implementation of each subsystem. The DDPP is automatic, robust, scalable, and manageable. The processing performance under a parallel CPU/GPU hybrid system meets the requirements of MUSER data processing.

To compare the postoperative intraocular pressure (IOP) and incidence of early complications after trabeculectomy with releasable suture to standard trabeculectomy in Chinese patients with primary angle-closure glaucoma.

A series of donor-acceptor-donor (D-A-D) type blue thermally activated delayed fluorescence (TADF) emitters, namely, 2,7-DtBuCz-AD, 3,6-DtBuCz-AD, 3,6-DMAC-AD, and 3,6-DMAC-AD-CF3, were developed with highly rigid acridin-9(10H)-one (i.e. acridone [AD]) as acceptor. The regioisomeric effect study revealed that the attachment of donors at 3,6-sites of AD ring dramatically enhanced TADF ratio in comparison with the 2,7-site isomer. On the one hand, by varying donors from dimethylacridine (DMAC) to tert-butylcarbazole (tBuCz) at 3,6-sites of AD ring, the emission color purity of blue TADF emitters was improved from sky blue to deep blue. On the other hand, by introducing trifluoromethyl (CF3) onto 9-site phenyl ring of 3,6-DtBuCz-AD, the efficiency stability of the sky blue emission for 3,6-DMAC-AD-CF3was remarkably improved. The deep blue organic light-emitting diode (OLED) of 3,6-DtBuCz-AD exhibited a maximum external quantum efficiency (EQEmax) of 17.88% with CIE coordinates of (0.15, 0.08), which is among the best performances ever reported for deep blue TADF-OLEDs. The sky-blue OLED of 3,6-DMAC-AD realized an EQEmaxof 23.16%. And with the incorporation of CF3, the sky blue device of 3,6-DMAC-AD-CF3exhibited extremely low efficiency loss of only 5.1% at the high brightness of 1,000 cd/m2.

To date there has been no valid treatment for herpes simplex encephalitis (HSV). This study explores the protective activity of ethanol extract of Cynanchum paniculatum (bunge) kitagawafor treatment of HSV. Cell models and animal models were established and divided into 4 groups: normal group, virus group, cynanchum paniculatum group and Dexamethasone group. Flow cytometry was employed to detect apoptosis of cell model and TUNEL assay was chosen to detect apoptosis of animal tissues. The survival time of the animal models was observed. ELISA was used to measure TNF-a expression and the Greiss method to measure Nitric Oxide (NO) expression in the mouse brain. As a result, it was found that extract of Cynanchum paniculatumcan improve the survival rate of HSV-infected mice. The extract could prevent apoptosis in the neuron cell model and reduce apoptosis rate in brain tissue after HSV infection. With the extract intervention, TNF-a and NO levels in brain tissue were significantly decreased in the animal model. In conclusion, the extract of Cynanchum paniculatumcan prevent HSV-inducing impairment in the cell and animal model of HSE.

Background: The metabolic syndrome (MetS) has been found to be closely related with thrombotic diseases. The mechanism, however, is far from elucidated. Aim: This study was designed to investigate the relationship between endogenous resistin and thrombosis mediating factors, as well as its potential effects on the gene expression of cardiovascular disease biomarkers. Methods: Ninety patients satisfied the MetS criteria, and 55 healthy subjects were recruited as part of a single-center clinical study. Plasma levels of resistin, tissue factor (TF), tissue factor pathway inhibitor (TFPI), tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) were measured by enzyme-linked immunosorbent assays. The effect of resistin on the expression of cardiovascular disease biomarkers in human umbilical vein endothelial cells (HUVEC) was assayed by gene microarray. Results: 1) The average levels of resistin in MetS patients with or without acute myocardial or cerebral infarction were significantly higher than those of the controls. 2) The TF and TFPI increase was higher in MetS with infarction patients than in MetS patients. 3) In MetS with infarction patients, resistin was positively correlated with TF and PAI-1 (r=0.313, p=0.008; r=0.401, p=0.002, respectively). 4) In HUVEC, the microarray showed that apolipoprotein C-I, ACE, tumor necrosis factor receptor superfamily member 1A (TNFRSF1A) and member 5 (CD40) genes expression were dramatically increased by resistin. Conclusion: In patients with MetS, resistin is strongly associated with hypercoagulative and hypofibrinolitic activities. Moreover, resistin may induce thrombotic complications viamediating the lipoprotein metabolism and stimulating inflammation.

Intimal calcification is a feature of advanced atherosclerotic disease that predicts a two- to eightfold increase in the risk of coronary events. Type I collagen promotes vascular smooth muscle cell-mediated calcification, although the mechanism by which this occurs is unknown. The discoidin domain receptor 1 (DDR1) is a collagen receptor that is emerging as a critical mediator of atherosclerosis. To determine whether DDR1 is involved in intimal calcification, we fed male Ddr1−/−;Ldlr−/−and Ddr1+/+;Ldlr−/−mice an atherogenic diet for 6, 12, or 24 weeks. DDR1 deficiency significantly reduced the calcium content of the aortic arch, and microcomputed tomography demonstrated a significant decrease in hydroxyapatite deposition after 24 weeks of atherogenic diet. Reduced calcification was correlated with decreases in macrophage accumulation and tumor necrosis factor α staining, suggesting that the reduction in calcification was in part due to decreased inflammation. The chondrogenic markers type II collagen, type X collagen, and Sox-9 were expressed within the mineralized foci. An in vitroassay performed with vascular smooth muscle cells revealed that DDR1 was required for cell-mediated calcification of the matrix, and Ddr1+/+smooth muscle cells expressed more alkaline phosphatase activity, whereas Ddr1−/−smooth muscle cells expressed elevated levels of mRNA for nucleotide pyrophosphatase phosphodiesterase 1, an inhibitor of tissue mineralization. Taken together, our results demonstrate that DDR1 mediates an important mechanism for atherosclerotic calcification.

ABSTRACTThe clinical value of viral load and integration testing for human papillomavirus (HPV) remains unclear. Data on HPV type 18 (HPV18) is limited. We examined the HPV18 viral load and integration status of 78 women with normal cervix or neoplasia. While the crude viral load appeared to increase with lesion severity, the association was not significant after normalization with sample cellularity. Unlike reports for HPV16, the amino-terminal 1 region of HPV18 E2 was most frequently (71.0%) disrupted, representing the best marker for integration. A substantial proportion (57.1%) of invasive cancers harbored only the episomal genome, thus jeopardizing the clinical value of integration testing. A large proportion (41.7%) of normal/low-grade lesions showed viral integration, suggesting that integration of HPV18 starts early and is unlikely to be a sole determinant for progression. Interpretation of viral load should take into account the form of HPV infection as single infections had significantly higher viral loads than coinfections (P= 0.046). More data generated from routinely collected samples are warranted to verify the clinical value of viral load and integration testing. Viral load quantitation for HPV18 is premature for clinical use at this stage.

The Square Kilometre Array (SKA) project is an international cooperation project to build the largest radio telescope worldwide. Data processing is one of the biggest challenges of building the SKA telescope. As a distributed execution framework, the Data Activated Liu Graph Engine (DALiuGE) was proposed to be one of the candidates for addressing the massive data of the SKA. DALiuGE has many distinctive features, but its actual ability to handle scientific data is still not clear. In this paper, we perform an objective evaluation of the usability of DALiuGE for the execution performance, developer workload, and implementation difficulty of porting the SAGECal to DALiuGE. The evaluation results show that the DALiuGE enables fast integration of astronomical software, but there are significant differences in the efficiency of different parallel granularities. Even with the deep optimization of the program, there is still a gap between the current DALiuGE and the traditional MPI in execution performance. Therefore, we come to a preliminary conclusion that the DALiuGE has no performance advantage in batch processing of massive data. At the same time, it may be more suitable for application scenarios with more customized computational tasks, such as SKA science regional centers.

To investigate the expression of thioredoxin-interacting protein (TXNIP) during hypoxia and its dependency on hypoxia-inducible factor 1 (HIF-1) in pancreatic cancer cell lines.

We report on a systematic study of the use of palladium nanoparticles immobilized on spherical polyelectrolyte brushes – Pd@SPB – for Heck- and Suzuki-type coupling reactions. The spherical polyelectrolyte brush particles serving as carriers for the palladium nanoparticles consist of a solid polystyrene core with a radius of 46 4;nm onto which long chains of cationic polyelectrolytes are grafted. The palladium nanoparticles have directly been generated within this brush layer and the stabilization of the nanoparticles is effected by the colloidal carriers, no further surface stabilization is necessary. We demonstrate that these composite particles present robust catalysts for the Heck- and Suzuki-type coupling reactions. This was shown by carrying out the Suzuki- and Heck-type coupling reactions at relatively low temperatures (Suzuki reaction: 50 °C, Heck reaction: 70 °C). We demonstrate that the catalytic composite particles are not changed by these reaction conditions and retain their full activity for at least four runs. The yields obtained for both reactions are good to excellent. The mild operation conditions of the palladium nanoparticles are traced back to the absence of surface stabilization. Further mechanistic implications are discussed.

The main objective of this study was to determine whether active NH4+ excretion occurred in the giant mudskipper, Periophthalmodon schlosseri, during emersion. Our results demonstrated that continual ammonia excretion in P. schlosseri during 24 hr of emersion resulted in high concentrations (∼30 mmol l−1) of ammonia in fluid collected from the branchial surface. For fish injected intraperitoneally with 8 μmol g−1 ammonium acetate (CH3COONH4) followed by 24 hr of emersion, the cumulative ammonia excreted was significantly greater than that of the control injected with sodium acetate. More importantly, the ammonia excretion rate at hour 2 in fish injected with CH3COONH4 followed by emersion was greater than that in fish immersed in water as reported elsewhere, with the greatest change in the ammonia excretion rate occurring at hour 2. Assuming that the rate of endogenous ammonia production remained unchanged, 33% of the exogenous ammonia was excreted through the head region, presumably through the gills, during the first 6 hr of emersion. Indeed, at hour 6, the ammonia concentration in the branchial fluid increased to an extraordinarily high concentration of >90 mmol l−1. Therefore, our results confirm for the first time that P. schlosseri can effectively excrete a high load of ammonia on land, and corroborate the proposition that active NH4+ excretion through its gills contributes in part to its high tolerance of aerial exposure. Only 4.6% of the exogenous ammonia was detoxified to urea. The glutamate contents in the muscle and liver also increased significantly, but the glutamine contents remained unchanged. J. Exp. Zool. 307A:357–369, 2007. © 2007 Wiley‐Liss, Inc.

We present a comprehensive study of the interaction of spherical polyelectrolyte brushes (SPBs) with cationically modified polyacrylamide (CPAM), calcium carbonate (CaCO3) particles, and cellulose fibers. A link to the use of this system as a model for retention aids in the papermaking process is elaborated. Anionically functionalized SPBs with a high cation exchange capacity (CEC) are used together with CPAM as a model system for fiber flocculation and deposition of CaCO3, which are integral steps in the papermaking process. The flocculation efficiency is tested by means of a dynamic drainage jar. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) are used to analyze the system, the structure of the agglomerated flocs, and the mechanism of floc formation. The data suggest that the flocculation efficiency can be attributed to the high CEC of SPB in combination with the flexibility of grafted polyelectrolyte chains. FESEM images and AFM support the model of anionic SPBs acting as a particle bridge between fibers and CaCO3. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:233–241, 2006

A simple yet versatile method was developed to prepare a low-density polymerization initiator gradient, which was combined with surface-initiated atom transfer radical polymerization (ATRP) to produce a well-defined poly(2-hydroxyethyl methacrylate) (HEMA) gradient substrate. A smooth variation in film thickness was measured across the gradient, ranging from 20 Å to over 80 Å, but we observed a nonmonotonic variation in water contact angle. Fits of X-ray reflectivity profiles suggested that at the low graft density end, the polymer chain structure was in a “mushroom” regime, while the polymer chains at high graft density were in a “brush” regime. It was found that the “mushroom” region of the gradient could be made adhesive to cells by adsorbing adhesion proteins, and cell adhesion could be tuned by controlling the density of the polymer grafts. Fibroblasts were seeded on gradients precoated with fibronectin to test cellular responses to this novel substrate, but it was found that cell adhesion did not follow the expected trend; instead, saturated cell adhesion and spreading was found at the low grafting density region.

We present a study on the catalytic activity of platinum nanoparticles immobilized on spherical polyelectrolyte brushes that act as carriers. The spherical polyelectrolyte brushes consist of a solid core of poly(styrene) onto which long chains of poly(2-methylpropenoyloxyethyl) trimethylammonium chloride are grafted. These positively charged chains form a dense layer of polyelectrolytes on the surface of the core particles (“spherical polyelectrolyte brush”) that tightly binds divalent PtCl6^-2 ions. The reduction of these ions within the brush layer leads to nearly monodisperse nanoparticles of metallic platinum. The average size of the particles is approximately 2 nm. The composite particles exhibit excellent colloidal stability. The catalytic activity is investigated by photometrically monitoring the reduction of p-nitrophenol by an excess of NaBH4 in the presence of the nanoparticles. The kinetic data could be explained by the assumption of a pseudo-first-order reaction with regard to p-nitrophenol. In all cases, a delay time t0 has been observed, after which the reactions start. This time is shorter when the catalyst has already been used. All data demonstrate that spherical polyelectrolyte brushes present an ideal carrier system for metallic nanoparticles.

Tapered copolymer brushes of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) were synthesized via surface-initiated atom transfer radical polymerization (ATRP) by gradual addition of HEMA to a reaction mixture that originally only had MMA as monomer. The copolymer brush grew linearly with polymerization time. The tapered copolymer brushes responded to selective solvent treatments. For the same tapered copolymer brush, pretreating the surface with methylene chloride made the surface more hydrophobic; pretreating the surface with methanol increased the surface hydrophilicity. This change in surface properties was reversible and considered to be caused by the solvent induced rearrangement of the polymer brushes, which is supported by atomic force microscopy images of the surface. Our work demonstrates that the properties of the tapered copolymer brush could be finely tuned by careful control of the composition profile.

A method for direct, stereoselective preparation of (E)-α,β-unsaturated ketones from ketones and aldehydes, promoted by a novel pyrrolidine imide organocatalyst, has been developed in moderate to high yields. Unlike the Claisen−Schmidt condensation and Lewis acid catalyzed tandem aldol−dehydration processes, this method provides mild reaction conditions to access α,β-unsaturated ketones from simple, unmodified ketones.

This study investigated the expression profile of placental leptin and leptin receptor isoforms in preeclampsia, using placental tissue from normal pregnancies that were matched in gestational age and birth weight as controls. A total of 29 cases of preeclampsia were studied by immunohistochemistry, including 16 severe and 13 mild preeclampsia cases. Reverse transcriptase-polymerase chain reaction (RT-PCR) was further performed using RNA extracted from frozen tissue (10 severe preeclampsia, 10 mild preeclampsia, and 20 normal third trimester placentas). In all tissue sections, immunostaining signal was shown in the cytoplasmic compartment of the trophoblastic cells. Both the severe and mild preeclampsia groups showed significantly higher immunostaining for leptin compared with normal controls (p < 0.05), but there was no significant difference between the severe and mild preeclampsia groups (p > 0.05). There was no significant difference in immunostaining for leptin receptor between both severe and mild preeclampsia compared with controls (p > 0.05). RT-PCR showed significantly higher levels of mRNA transcripts of leptin in severe preeclampsia (p < 0.05), but not mild preeclampsia (p > 0.05), compared with normal controls. No significant difference in expression of all the receptor isoforms was demonstrated between both severe and mild preeclampsia groups compared with controls (p > 0.05). In conclusion, we confirmed an up-regulated expression of leptin in placental tissue in preeclampsia. However, there was no difference in the expression of all leptin receptor isoforms in placental tissue between preeclamptic and normal pregnancies. The leptin signal probably does not play a major primary role in the pathogenesis of preeclampsia.

Intravenous leiomyomatosis is a rare smooth muscle tumor. We report two cases of intravenous leiomyomatosis that grew along different routes of the venous system into the inferior vena cava and the right atrium. The different route of extension makes a difference in the ease of excision of tumor masses. Using MEDLINE together with the references in each publication, we identified all cases of intracardiac leiomyomatosis reported in the English literature in the period between 1980 and 2003 and performed a brief review on this potentially lethal disease entity.

The highly potent anti-HIV natural product daurichromenic acid was successfully synthesized in only five steps with 49% overall yield. The key step in the synthetic strategy involves a microwave-assisted tandem condensation and intramolecular SN2‘-type cyclization to form the 2H-benzopyran core structure.

Studies of the kinetics and mechanism of Candida antarctica Lipase B (CALB) catalyzed ε-caprolactone (ε-CL) polymerizations in toluene were performed. The kinetic plot of ln ([M]0/[M]t) vs time was carried out to 96% ε-CL conversion and Mn 11 970. The plot is linear (r² = 0.998), indicating that termination did not occur and the propagation rate is first order with respect to monomer concentration. Changes in the water (e.g., initiator) concentration did not change the polymerization rate but did change the number of chains [R−OH]. Thus, the polymerization is zero order with respect to [R−OH] and initiator concentration. A plot of ln kapp vs ln [enzyme] gave 0.7 as the reaction order of the enzyme concentration. The apparent activation energy for Novozyme-435 catalyzed ε-CL polymerization in toluene is 2.88 kcal mol^-1. This is well below 10.3 kcal mol^-1, the activation energy for aluminum alkoxide catalyzed ε-CL polymerization in toluene. Upward deviation from linearity for Mn vs fractional ε-CL conversion and decreases in the number of chains was accentuated by low enzyme water contents and high monomer conversion. These results are consistent with a competition between ring-opening chain-end propagation and chain growth by steplike polycondensations. CALB was irreversibly inhibited by modification with paraoxon at the lipase active site (Ser105). The modified enzyme was no longer active for the polymerization. This supports that the polymerizations studied herein occurred by catalysis at the active serine residue (Ser105) and not by other chemical or nonspecific protein-mediated processes.

Synchrotron infrared microspectroscopy (SIRMS) was used for the first time to image the distribution and secondary structure of an enzyme (lipase B from Candida antarctica, CALB) immobilized within a macroporous polymer matrix (poly(methyl methacrylate)) at 10 μm resolution. The beads of this catalyst (Novozyme435) were cut into thin sections (12 μm). SIRMS imaging of these thin sections revealed that the enzyme is localized in an external shell of the bead with a thickness of 80−100 μm. Also, the enzyme was unevenly distributed throughout this shell. Furthermore, by SIRMS-generated spectra, it was found that CALB secondary structure was not altered by immobilization. Unlike CALB, polystyrene molecules of similar molecular weight diffuse easily throughout Novozyme435 beads. Scanning electron micrograph (SEM) images of the Novozyme435 beads showed that the average pore size is 10 times larger than CALB or polystyrene molecules, implying that there is no physical barrier to enzyme or substrate diffusion throughout the bead. Thus, the difference between polystyrene and enzyme diffusivity suggests that protein−matrix and protein−protein interactions govern the distribution of the enzyme within the macroporous resin.

Ectopic calcification, the abnormal calcification of soft tissues, can have severe clinical consequences especially when localized to vital organs such as heart valves, arteries, and kidneys. Recent observations suggest that ectopic calcification, like bone biomineralization, is an actively regulated process. These observations have led a search for molecular determinants of ectopic calcification. A candidate molecule is osteopontin (OPN), a secreted phosphoprotein invariantly associated with both normal and pathological mineral deposits. In the present study, OPN was found to be a natural inhibitor of ectopic calcification in vivo. Glutaraldehyde-fixed aortic valve leaflets showed accelerated and fourfold to fivefold greater calcification after subcutaneous implantation into OPN-null mice compared to wild-type mice. In vitroand in vivostudies suggest that OPN not only inhibits mineral deposition but also actively promotes its dissolution by physically blocking hydroxyapatite crystal growth and inducing expression of carbonic anhydrase II in monocytic cells and promoting acidification of the extracellular milieu. These findings suggest a novel mechanism of OPN action and potential therapeutic approach to the treatment of ectopic calcification.

Osteopontin (OPN) is abundantly expressed in human calcified arteries. To examine the role of OPN in vascular calcification, OPN mutant mice were crossed with matrix Gla protein (MGP) mutant mice. Mice deficient in MGP alone (MGP−/− OPN+/+) showed calcification of their arteries as early as 2 weeks (wk) after birth (0.33 ± 0.01 mmol/g dry weight), and the expression of OPN in the calcified arteries was greatly up-regulated compared with MGP wild-types. OPN accumulated adjacent to the mineral and colocalized to surrounding cells in the calcified media. Cells synthesizing OPN lacked smooth muscle (SM) lineage markers, SM α-actin and SM22α. However, most of them were not macrophages. Importantly, mice deficient in both MGP and OPN had twice as much arterial calcification as MGP−/− OPN+/+ at 2 wk, and over 3 times as much at 4 wk, suggesting an inhibitory effect of OPN in vascular calcification. Moreover, these mice died significantly earlier (4.4 ± 0.2 wk) than MGP−/− OPN+/+ counterparts (6.6 ± 1.0 wk). The cause of death in these animals was found to be vascular rupture followed by hemorrhage, most likely due to enhanced calcification. These studies are the first to demonstrate a role for OPN as an inducible inhibitor of ectopic calcification in vivo.

Polymerizations of ε-CL catalyzed by Novozyme-435 (immobilized Lipase B from Candida antarctica) were studied at temperatures between 20 and 108 °C. The monomer conversion to polymer was remarkably rapid at ambient temperature. At 20 °C by 7 h, ε-CL conversion and product Mn were >97% and 17 800, respectively. Contrary to previous reports, the number of chains formed, as well as the product molecular weight, was almost identical for polymerizations at constant enzyme water content between 60 and 108 °C. Thus, differences in reaction temperature over a 48 °C range did not “free” water from “bound” states so that it could function for chain initiation. At 60 °C, variation in the enzyme water content from 0.6 to 1.9% increased the number of chains formed but did not change the polymerization propagation kinetics. Therefore, the enzyme water content and not the reaction temperature regulated the product molecular weight. In contrast, at 108 °C, an increase in the reaction water content from 0.6 to 1.8% increased both the number of chains and the polymerization propagation kinetics. Explanations for these differences in behavior as a function of temperature and water contents are discussed.

A novel photochromic system of europium with nicotinic acid (HL) and 1,10-phenanthroline (phen) was studied. The color of the system turns from yellow to green with a broad absorption band appearing in the range 550–830 nm under the irradiation by a mercury lamp. The pH value of the system plays an important role in the photochromic behavior. It is observed that a higher pH value is favorable to photochromism. With electrospray ionization mass spectrometry (ESIMS), we probed the possible species present in the aqueous solution. It was concluded that the complex EuL3(phen)2· H2O exists in the solution. To better understand its ESI mass spectrum, we give the possible fragmentation of EuL3(phen)2· H2O.