bluuebunny/crossref_metadata_2025 huggingface dataset:
Staphylococcus aureus biofilms
Authors: Singhal Deepti , Foreman Andrew , Bardy Josh‐Jervis , Wormald Peter‐John
Published: June 2011

Objectives/Hypothesis:

Chronic rhinosinusitis (CRS) patients with biofilms have persistent postoperative symptoms, ongoing mucosal inflammation, and recurrent infections. Recent evidence suggests that biofilms of differing species confer varying disease profiles in CRS patients. We aimed to prospectively investigate the effects of Staphylococcus aureus, Pseudomonas aeruginosa, Haemophilus influenzae, and fungal biofilms on outcomes following endoscopic sinus surgery (ESS).

Study Design:

Prospective blinded study.

Methods:

In this prospective blinded study, 39 patients undergoing ESS for CRS assessed their symptoms preoperatively using internationally accepted standardized symptom scoring systems and quality‐of‐life measures (10‐point visual analog scale, Sino‐Nasal Outcome Test‐20, global severity of CRS). Their sinonasal mucosa was graded (Lund–Kennedy scale) and extent of radiologic disease on computed tomography scans scored (Lund‐McKay scale). Random sinonasal tissue samples were assessed for different bacterial species forming biofilms by using fluorescent in‐situ hybridization and confocal laser microscopy. For 12 months after surgery, CRS symptoms, quality of life, and objective evidence of persisting disease were assessed by using the preoperative tools.

Results:

Different bacterial species combinations were found in 30 of 39 patients; 60% of these 30 biofilms were polymicrobial biofilms and 70% had S aureus biofilms. Preoperative nasendoscopy and radiologic disease severity were significantly worse in patients with multiple biofilms (P = .02 and P = .01, respectively), and they had worse postsurgery mucosal outcomes on endoscopy (P = .01) requiring significantly more postoperative visits (P = .04). Those with S aureus biofilms progressed poorly with their symptom scores and quality‐of‐life outcomes, with significant differences in nasendoscopy scores (P = .007).

Conclusions:

S. aureus biofilms play a dominant role in negatively affecting outcomes of ESS with persisting postoperative symptoms, ongoing mucosal inflammation, and infections.
Immunohistochemical detection of pepsin in laryngeal mucosa for diagnosing laryngopharyngeal reflux
Authors: Jiang Aiyun , Liang Maojin , Su Zhenzhong , Chai Liping , Lei Wenbin , Wang Zhangfeng , Wang Anjiang , Wen Weiping , Chen Minhu
Published: June 2011

Objectives/Hypothesis:

To investigate whether the pepsin immunohistochemical (IHC) staining of the laryngeal mucosa epithelia is an available test for diagnosing laryngopharyngeal reflux (LPR) in clinic.

Study Design:

Prospective case series.

Methods:

Biopsy specimens from interarytenoid mucosa of LPR patients (seven acid LPR and eight nonacid LPR) and 21 sex‐ and age‐matched normal controls were obtained for pepsin IHC staining. The diagnosis of LPR was based on 24‐hour combined multichannel intraluminal esophageal impedance pH monitoring. The results of IHC staining were semiquantitatively analyzed and scored as negative (−), weakly positive (+), moderately positive (++), and strongly positive (+++).

Results:

Six of seven acid LPR (85.7%) and six of eight nonacid LPR (75%) mucosa samples were moderate to strongly positive for intracellular pepsin. By contrast, only three of 21 normal controls (14.3%) were moderately positive. The difference in intracellular pepsin between LPR and the normal laryngeal mucosa was statistically significant (P < .01). No significant difference in intracellular pepsin was observed between the acid and nonacid LPR mucosal samples (P = .453). Using weak positivity (+) as a cutpoint, the presence of intracellular pepsin in the laryngeal mucosa had a sensitivity of 100% and a specificity of 47.6% in detecting LPR (P < .05). However, using the moderate positivity (++) as the cutpoint, the pepsin had a slightly decreased sensitivity of 80% but a sharply increased specificity of 85.7% (P < .05) in the detection of LPR.

Conclusions:

Pepsin IHC staining of the laryngeal mucosa appears to be a sensitive and specific test for diagnosing LPR in a clinical application.
Telemedicine—An efficient and cost‐effective approach in parathyroid surgery
Authors: Urquhart Andrew C. , Antoniotti Nina M. , Berg Richard L.
Published: June 2011

Objectives/Hypothesis:

To demonstrate the effectiveness and cost benefit of using telemedicine for the postoperative visit in patients undergoing parathyroidectomy for primary hyperparathyroidism.

Study Design:

Prospective noncontrolled study at a tertiary medical center of a cohort of 39 patients undergoing postoperative care after parathyroidectomy through TeleHealth at a number of sites at various distances from the primary surgical facility.

Methods:

From October 2006 through January 2010, 149 patients underwent parathyroidectomy for primary hyperparathyroidism at one tertiary medical center by a single surgeon. Age, sex, distance from the patient's home to the surgical center and to the TeleHealth site, effective completion of the TeleHealth visit, and postoperative complications were recorded.

Results:

Of the 149 patients who underwent parathyroidectomy, 39 had their postoperative visit using TeleHealth (26%). There were 26 females (67%) and 13 (33%) males. Mean age was 64 years. All visits were effectively carried out and completed with a nurse and the patient at a remote TeleHealth site and the surgeon at the surgical center site. There were no postoperative surgical complications noted with the visits. Average round‐distance travel saved was 119 miles. The travel distance saved translated into an average savings of $357.00 per patient (which included estimations of transportation costs and lost work time), with further immeasurable benefits to the patient and healthcare system.

Conclusions:

TeleHealth is a cost‐effective and efficient way to follow‐up with patients who have undergone parathyroidectomy, with significant convenience and financial benefits for the patient and healthcare system.
CO2 laser ablation and balloon dilation for acquired nasopharyngeal stenosis: A novel technique
Authors: Sidell Douglas , Chhetri Dinesh K.
Published: June 2011

Objectives/Hypothesis:

Although acquired nasopharyngeal stenosis (NPS) is frequently attributed to infectious and granulomatous processes, it can also occur secondary to external beam radiation therapy for head and neck cancer. NPS can be treated with local flaps, laser excision, nasal stenting, and combinations thereof. Unfortunately, the postoperative course is frequently complicated by scarring and restenosis that often necessitates multiple revision surgeries. The objective of this study is to report a novel endoscopic approach, employing the use of a flexible CO2 laser in combination with balloon dilation and mitomycin‐C application, allowing for the successful treatment of acquired NPS with lasting results.

Study Design:

Retrospective review of case series.

Methods:

An endoscope with a working channel is passed transnasally to the location of nasopharyngeal stenosis. A flexible CO2 laser fiber is then inserted via the working channel of the scope. Precise radial incisions are made on the stenosis using the laser under direct visualization. The laser is removed, and a controlled radial expansion balloon dilation device is inserted, advanced to span the segment of stenosis, and inflated to achieve adequate dilation. Mitomycin‐C is then applied topically to the area of dilation.

Results:

Three patients with severe NPS were treated using this novel technique. All patients had successful long‐lasting dilation of NPS without complications over a follow‐up period ranging from 12 to 18 months.

Conclusions:

Acquired NPS can be successfully treated with durable results with radial laser incisions and controlled radial expansion balloon dilation.
The effects of unilateral cochlear implantation on the tinnitus handicap inventory and the influence on quality of life
Authors: Amoodi Hosam A. , Mick Paul T. , Shipp David B. , Friesen Lendra M. , Nedzelski Julian M. , Chen Joseph M. , Lin Vincent Y. W.
Published: June 2011

Objectives/Hypothesis:

Cochlear implantation is now the standard of care in patients with significant sensorineural hearing loss. It is well known that patients with severe hearing loss also experience disabling tinnitus. The purpose of this study was to assess the effects of cochlear implants on the perception of tinnitus using the Tinnitus Handicap Inventory (THI).

Study Design:

Prospective, longitudinal study of 142 cochlear implant patients.

Methods:

The THI was administered to 142 patients pre‐ and postimplantation. Outcome measures were obtained 12 months after the implantation. Secondary analyses to examine the correlation between changes in THI scores and outcome measures such as Hearing Handicap Inventory, Hearing in Noise Test (HINT), and short‐form 36 (SF‐36) quality‐of‐life scores were performed.

Results:

Patients demonstrated statistically significant reduction of the THI scores including its subscales (P < .001). Prior to implantation, 37% of patients described their tinnitus as moderate to severe. Postoperatively, this percentage decreased to 10%. Cochlear implantation resulted in complete tinnitus suppression in 37% and tinnitus reduction in another 29% of patients. THI scores significantly correlated with three domains of the SF‐36 quality‐of‐life questionnaire, namely social, emotional, and general health domains.

Conclusions:

Cochlear implants have a significant suppressive effect on tinnitus in 66% of implant users. Although the reduction in the subjectively perceived tinnitus was statistically significant, it did not correlate with HINT; however, it did correlate with three quality‐of‐life domains, more significantly for those whose pretreatment conditions were moderate or worse.
Intraoperative photodynamic detection of normal parathyroid glands using 5‐aminolevulinic acid
Authors: Suzuki Takeshi , Numata Tsutomu , Shibuya Mariko
Published: June 2011

Objective

It is important to identify and save the normal parathyroid glands during head and neck surgery because of their role in regulating the blood calcium level, yet it is often difficult to localize normal parathyroid glands during surgery. Fluorescence‐guided parathyroidectomy in patients with hyperparathyroidism has already proved useful. However, there are few reports of fluorescence‐guided localization of normal parathyroid glands in humans. We investigated the utility of fluorescence‐guided localization of normal parathyroid glands during thyroidectomy and completed a spectral fluorescence analysis of the accumulation of 5‐aminolevulinic acid metabolites in the parathyroid glands.

Methods

Eight patients with benign thyroid disease and five with malignant thyroid tumors were given 20 mg/kg body weight of 5‐aminolevulinic acid orally 5 hours before surgery. After the posterior surface of the thyroid gland was exposed and the recurrent laryngeal nerve was identified, we illuminated the area with a violet‐blue light of 405 nm. Tissues showing red fluorescence were biopsied to analyze the spectral fluorescence.

Results

Under the violet‐blue light, normal parathyroid glands showed red fluorescence, while the surrounding structures such as the thyroid gland, muscles, and fat remained nonfluorescent. The spectral peak was observed at 635 nm indicating 5‐aminolevulinic acid metabolites. Histopathologically, the biopsied tissue corresponded to normal parathyroid glands.

Conclusions

5‐Aminolevulinic acid is useful to localize the normal parathyroid glands during thyroid surgery in humans.
Disruption of ephrin B/Eph B interaction results in abnormal cochlear innervation patterns
Authors: Zhou Constance Q. , Lee James , Henkemeyer Mark J. , Lee Kenneth H.
Published: June 2011

Objective:

To determine the expression patterns of B ephrins and Ephs in the cochlea and identify functional consequences of disruption of ephrin B/Eph B interactions in both cultured spiral ganglion neurons and in the cochlea of live animals.

Study Design:

The expression patterns of various B ephrins and Ephs were determined in mice with Lac‐Z mutation. Mice with null function of individual B ephrin and Eph proteins and those with multiple knockouts were studied for cochlear innervation patterns.

Methods:

Mice with B ephrins and Ephs disrupted with the β‐galactosidase gene were sacrificed at P6, and their cochleae isolated and processed for Lac‐Z staining to determine expression of these proteins in cochlear tissue. Spiral ganglion cells from wild‐type as well as ephrin B1 knockout mice were isolated and cocultured with Eph B2 expressing Cos1 cells and neurite lengths were determined. Fluorescent lipophillic dyes were used to label spiral ganglion cell nerve fibers to determine cochlear innervation patterns in wild‐type and knockout mice.

Results:

Eph B1, B2, and ephrin B2 but not B3 was expressed in the cochlea. Eph B2 inhibited outgrowth of spiral ganglion cell axons from wild‐type mice, but not from ephrin B1 knockout mice in culture. Knockout mice with null function of ephrin B1 alone or Eph B1, Eph B2, Eph B3 in combination demonstrated abnormal innervation patterns in the organ of Corti.

Conclusions:

Disruption of B ephrins and Ephs results in functional consequences in spiral ganglion cells, suggesting that these proteins play a role in establishing normal innervation patterns in the cochlea.
Improved growth curve measurements after supraglottoplasty
Authors: Meier Jeremy D. , Nguyen Shaun A. , White David R.
Published: June 2011

Objectives/Hypothesis:

To evaluate changes in growth curve measurements after supraglottoplasty and compare these patterns to patients with laryngomalacia treated conservatively.

Study Design:

Retrospective case–control study.

Methods:

Children treated surgically for laryngomalacia were compared to control groups of patients who underwent observation or medical treatment only. Body weight the day of surgery and on follow‐up visits was plotted on a standardized growth curve and the z‐score calculated.

Results:

A total of 15 patients were included that were observed (group 1), 71 patients that were treated with medical therapy only (group 2), and 29 patients that underwent surgery (group 3). The average z‐score at the time of surgery was significantly worse in group 3 (−0.854 ± 1.080), compared to the z‐score at the time of diagnosis in group 1 (−0.086 ± 0.834), and the time when antireflux therapy was initiated in group 2 (−0.120 ± 0.979). Within 3 months from surgery, significant improvement on the growth curve was seen in group 3 (P = .009). After 12 months, all three groups approached the mean on the growth curve.

Conclusions:

In this series, patients with severe laryngomalacia who warranted surgery presented with significantly lower percentile weight on a standardized growth curve than patients who required only medical or conservative treatment. Substantial improvement in growth curve percentile was seen in the immediate months following supraglottoplasty. Long‐term follow‐up after supraglottoplasty shows that infants return to a mean weight on the growth curve.
Transmastoid extradural–intracranial approach for repair of transtemporal meningoencephalocele: A review of 31 consecutive cases
Authors: Semaan Maroun T. , Gilpin David A. , Hsu Daniel P. , Wasman Jay K. , Megerian Cliff A.
Published: June 2011

Objective:

To review the clinical presentation, surgical techniques, and outcomes of the transmastoid extradural–intracranial (TMEDIC) approach for the treatment of transtemporal meningoencephalocele.

Hypothesis:

The TMEDIC is a safe and effective approach to repair meningoencephalocele originating from the middle or posterior cranial fossa.

Study Design:

Retrospective chart review.

Setting:

Academic neurotologic tertiary referral center.

Patients:

Thirty‐one consecutive patients diagnosed with transpetrous meningo(encephalo)cele, with or without cerebrospinal fluid leak, between January of 2003 and October of 2010.

Intervention:

TMEDIC approach for repairing herniated neural tissue through the tegmen or posterior fossa plate using the combination of autologous cartilage, fascia, and tissue sealant.

Main Outcome Measures:

Anatomic location, size, and number of defects, presence of herniated brain tissue, pre‐ and postoperative hearing thresholds, and failure rate.

Results:

Mean age was 62 ± 26 years. The etiology was spontaneous in 25/31 (80%), congenital in 3/31 (10%), chronic otitis media in 2/31 (6%), and posttraumatic in 1/31 (4%). Posttympanostomy tube clear otorrhea was the presenting sign in 21/31 (68%) of patients. The mean duration of symptoms was 26 months (range: 1–240). The defect involved the middle fossa (MF) floor in 25/31 (90%). Both the tegmen tympani and mastoideum were involved in 12/31 (39%) of patients and multiple dehiscences were seen in 7/31 (22%). In 17/31 (55%) of cases the size exceeded 1 cm. No recurrences were seen.

Conclusion:

The TMEDIC is a safe and effective method to repair transtemporal meningoencephalocele obviating the need for a middle fossa craniotomy in certain cases.
FIELD OBSERVATIONS OF WINDBLOWN SAND AND DUST IN THE TAKIMAKAN DESERT, NW CHINA, AND INSIGHTS INTO MODERN DUST SOURCES
Authors: Wang H. , Jia X.
Published: June 2011

Despite the importance of desert dust at global and regional scales, its exact provenance is often unclear. The Taklimakan Desert in northwest China is a common source of high‐frequency regional dust storms and is also a large source of global dust production. On the basis of field observations and the determination of the fraction of aeolian dust in surface samples, we characterized the relative intensity of windblown sand/dust processes in the Taklimakan and the volume of dust emitted (PM10) during these processes. Major dust sources were degraded lands on the eastern desert margin, the Gobi and alluvial, fluvial and aeolian sediments occurring on the desert margin. These areas have high PM10 emission capacity due to high‐surface PM10 concentrations and intensive windblown sand/dust activity. Despite having intensive windblown sand activity, the central desert had lower PM10 dust emission capacity (<1·6 kg day−1 m−2 in spring, <0·08 kg day−1 m−2 in other seasons) due to lower surface PM10 fraction. The dry Taitema Lake bed was a source of potentially high dust emissions (at least 4·4–17 kg day−1 m−2 for the monitoring period) due to the intensity windblown sand/dust activities, despite low PM10 concentrations. The dry river beds on the southeastern desert margin had lower dust emission potential due to low PM10 concentrations and windblown sand/dust activity. Most dust emission sources lie in the paths of prevailing winds, leading to aeolian dust transported to and deposited in the desert hinterland or Hotan, Yutian and Minfeng areas, where wind stream convergence leads to high‐frequency dust storms. Copyright © 2011 John Wiley & Sons, Ltd.
The Role of Dimension in Multivalent Binding Events: Structure–Activity Relationship of Dendritic Polyglycerol Sulfate Binding to L‐Selectin in Correlation with Size and Surface Charge Density
Authors: Weinhart Marie , Gröger Dominic , Enders Sven , Riese Sebastian B. , Dernedde Jens , Kainthan Rajesh K. , Brooks Donald E. , Haag Rainer
Published: June 2011

L‐, P‐, and E‐Selectin are cell adhesion molecules that play a crucial role in leukocyte recruitment from the blood stream to the afflicted tissue in an acute and chronic inflammatory setting. Since selectins mediate the initial contact of leukocytes to the vascular endothelium, they have evolved as a valuable therapeutic target in diseases related to inflammation by inhibition of the physiological selectin–ligand interactions. In a previous study, it was demonstrated that dPGS, a fully synthetic heparin analogue, works as an efficient inhibitor towards L‐ and P‐selectin in vitro as well as in vivo. Herein, the focus is directed towards the effect of size and charge density of the polyanion. The efficiency of L‐selectin inhibition via an SPR‐based in vitro assay and a cell‐based flow chamber assay is investigated with dPGS ranging from approximately 4 to 2000 kDa. SPR measurements show that the inhibitory potential of highly sulfated dPGS increases with size and charge density. Thereby, IC50 values from the micromolar to the low picomolar range are determined. The same tendency could be observed in a cell‐based flow chamber assay with three representative dPGS samples. This structure–affinity relationship of dPGS suggests that the strong inhibitory potential of dPGS is not only based on the strong electrostatic interaction with areas of cationic surface potential on L‐selectin but is also due to a steric shielding of the carbohydrate binding site by large, flexible dPGS particles.

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Characterization of Water‐Dispersible n‐Type Poly(benzimidazobenzophenanthroline) Derivatives
Authors: Wagner Michal , Österholm Anna , Hirvonen Sami‐Pekka , Tenhu Heikki , Ivaska Ari , Kvarnström Carita
Published: June 2011

Novel water dispersible poly(benzimidazobenzophenanthroline) polymers functionalized with poly(ethylene oxide) (BBL:PEO) have been investigated by cyclic voltammetry, in situ UV‐vis spectroscopy and atomic force microscopy. The cyclic voltammograms recorded during n‐doping indicate that the drop coated BBL:PEO films retain their properties despite functionalization. A small influence of the PEO side chains on redox properties of the investigated polymers was found, diminishing however after annealing. During spectroscopic experiments structural changes connected with polymer charging were observed (in accordance with a two electron transfer process). The functionalization of BBL with PEO side chains provided an easy processing method to obtain smooth and reproducible polymer films.

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Miscibility of Polythiophene‐graft‐poly(methyl methacrylate) brushes with Poly(vinylidene fluoride): Morphology, Optical and Conductivity Properties
Authors: Mandal Amit , Nandi Arun K.
Published: June 2011

Polythiophene‐graft‐poly(methyl methacrylate) brushes are synthesized by ATRP. They form miscible blends with poly(vinylidene fluoride) (PVDF) due to specific interactions between the >CO groups of PT‐g‐PMMA with the >CF2 groups of PVDF. PT‐g‐PMMA remains in the interlamellar, interfibrillar and interspherulitic regions of the PVDF crystals at both laterally and longitudinally aggregated states. In the blends both PVDF and PT‐g‐PMMA brushes have nanometer sizes, producing nanostructured polymer blends. The PL intensity can be tuned by varying the PT‐g‐PMMA concentration, and the blend exhibits good dc conductivity with a percolation threshold at 10 wt.‐% PT‐g‐PMMA. Conductivity data indicate a conformational transition of PT‐g‐PMMA chains with increasing temperature.

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Synthesis of Water‐Soluble Copolymers Carrying Long‐Chain (C12 to C30) Aliphatic Moieties
Authors: Barroso‐Bujans Fabienne , Yazdani‐Pedram Mehrdad , Frey Holger , Martínez Ricardo
Published: June 2011

Water‐soluble copolymers from mono‐1‐alkyl itaconates and N‐vinyl‐2‐pyrrolidone are synthesized and characterized. The mono‐1‐alkyl itaconates are prepared from itaconic anhydride and the related alcohol: 1‐dodecanol, 1‐octadecanol, 1‐docosanol, and 1‐triacontanol. The mono‐1‐triacontyl itaconate is synthesized from plant growth regulator policosanols extracted from Agave fourcrouydes, where 1‐triacontanol is the major product. The reactivity ratios, calculated according to the Mao‐Huglin method for copolymerizations conducted to medium‐high conversions, indicate a tendency toward alternation for all copolymerization reactions. Water solubility of copolymers is provided as a function of copolymer composition and aliphatic chain length.

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Pollen: A Novel, Biorenewable Filler for Polymer Composites
Authors: Lee Jung‐Hyun , Suttle Brandon M. , Kim Hyung‐Ju , Meredith J. Carson
Published: June 2011

Pollen has an exine shell with remarkable chemical stability, high‐strength, and unique microstructures that suggest use as a biorenewable polymer filler. Pollen‐filled polymers may offer potential for light‐weight, high‐strength materials that can displace some petroleum‐derived content with a sustainable plant‐based alternative. We report the first demonstration of the incorporation of pollen grains (short ragweed) on the mechanical, interfacial, and thermal properties of two polymers, poly(ε‐caprolactone) (PCL) and polystyrene (PS). Under certain solvent and annealing conditions, PS mechanical properties were improved synergistically upon addition of pollen, while those of PCL were always degraded, in strong agreement with wetting behavior of the polymer–pollen interface.

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The Effect of Mixing on the Mechanical Properties of Hyaluronan‐Based Injectable Hydrogels
Authors: Piskounova Sonya , Rojas Ramiro , Bergman Kristoffer , Hilborn Jöns
Published: June 2011

A method for determining the correlation between the mixing of two reactive polymers and the structural and mechanical properties of the formed hydrogels is presented. Rheological measurements show that insufficient mixing gives rise to soft and not fully crosslinked hydrogels while excessive mixing beyond gel point results in weaker hydrogels due to potential breakage of their 3D network. Furthermore, the hydrogels swell significantly more in cell culture medium than in phosphate‐buffered saline, attributed to interactions with additional molecules such as proteins. Thus, moderate mixing gives rise to the most homogenous and mechanically stable hydrogels and the choice of medium e.g., for release experiments, should be consistent in order to avoid unnecessary variations in the data caused by different swelling profiles.

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Functionalized Graphene–PVDF Foam Composites for EMI Shielding
Authors: Eswaraiah Varrla , Sankaranarayanan Venkataraman , Ramaprabhu Sundara
Published: June 2011

Novel foam composites comprising functionalized graphene (f‐G) and polyvinylidene fluoride (PVDF) were prepared and electrical conductivity and electromagnetic interference (EMI) shielding efficiency of the composites with different mass fractions of f‐G have been investigated. The electrical conductivity increases with the increase in concentration of f‐G in insulating PVDF matrix. A dramatic change in the conductivity is observed from 10−16 S · m−1 for insulating PVDF to 10−4 S · m−1 for 0.5 wt.% f‐G reinforced PVDF composite, which can be attributed to high‐aspect‐ratio and highly conducting nature of f‐G nanofiller, which forms a conductive network in the polymer. An EMI shielding effectiveness of ≈20 dB is obtained in X‐band (8–12 GHz) region and 18 dB in broadband (1–8 GHz) region for 5 wt.% of f‐G in foam composite. The application of conductive graphene foam composites as lightweight EMI shielding materials for X‐band and broadband shielding has been demonstrated and the mechanism of EMI shielding in f‐G/PVDF foam composites has been discussed.

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Synthesis and Polymerization of Renewable 1,3‐Cyclohexadiene Using Metathesis, Isomerization, and Cascade Reactions with Late‐metal Catalysts
Authors: Mathers Robert T. , Shreve Michael J. , Meyler Etan , Damodaran Krishnan , Iwig David F. , Kelley Diana J.
Published: June 2011

Synthesis and subsequent polymerization of renewable 1,3‐cyclohexadiene (1,3‐CHD) from plant oils is reported via metathesis and isomerization reactions. The metathesis reaction required no plant oil purification, minimal catalyst loading, no organic solvents, and simple product recovery by distillation. After treating soybean oil with a ruthenium metathesis catalyst, the resulting 1,4‐cyclohexadiene (1,4‐CHD) was isomerized with RuHCl(CO)(PPh3)3. The isomerization reaction was conducted for 1 h in neat 1,4‐CHD with [1,4–CHD]/[RuHCl(CO)(PPh3)3] ratios as high as 5 000. The isomerization and subsequent polymerization of the renewable 1,3‐CHD was examined as a two‐step sequence and as a one‐step cascade reaction. The polymerization was catalyzed with nickel(II)acetylacetonate/methaluminoxane in neat monomer, hydrogenated d‐limonene, and toluene. The resulting polymers were characterized by FTIR, DSC, and TGA.

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Temperature‐ and Redox‐Directed Multiple Self Assembly of Poly(N‐Isopropylacrylamide) Grafted Dextran Nanogels
Authors: Lv Weipeng , Liu Shuoqi , Feng Wenqian , Qi Junjie , Zhang Guoliang , Zhang Fengbao , Fan Xiaobin
Published: June 2011

Poly(N‐isopropylacrylamide) (PNIPAAm) grafted dextran nanogels with dodecyl and thiol end groups have been synthesized by RAFT process. Dodecyl‐terminated polymers (DexPNI) can be readily dissolved in water and further self assemble into ordered stable nanostructures through direct noncovalent interactions at room temperature. SEM, AFM and DLS measurements confirm the formation of spherical nanogels at hundred‐nanometer scales. The elevation of environment temperature will indirectly result in the formation of collapsed nanostructures due to the LCST phase transition of PNIPAAm side chains. Turbidimetry results show that the phase transition behaviors of DexPNI are greatly dependent on PNIPAAm chain length and polymer concentration: increasing PNIPAAm chain length and polymer concentration both lead to lower LCSTs and sharper phase transitions. Moreover, the dodecyl‐terminated polymers can transform into thiol‐terminated versions by aminolysis of trithiocarbonate groups, and further into chemical (disulfide) cross‐linked versions (SS‐DexPNI) by oxidation. SS‐DexPNI nanogels have “doubled” chain length of PNIPAAm, and hence sharper phase transitions. In situ DLS measurements of the evolution of hydrodynamic radius attest that the self assembly of SS‐DexPNI nanogels can be selectively directed by the change in either external temperature or redox potential. These nanogels thus are promising candidates for triggered intracellular delivery of encapsulated cargo. We can also expect that the polymer can be noncovalently (by dodecyl end groups) or covalently (by thiol end groups) coated on a series of nanomaterials (e.g., carbon nanotubes, graphene, gold nanomaterials) to build a variety of novel smart, and robust nanomaterials.

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Design of Bimodal PCL and PCL‐HA Nanocomposite Scaffolds by Two Step Depressurization During Solid‐state Supercritical CO2 Foaming
Authors: Salerno Aurelio , Zeppetelli Stefania , Di Maio Ernesto , Iannace Salvatore , Netti Paolo Antonio
Published: June 2011

This communication reports the design and fabrication of porous scaffolds of poly(ε‐caprolactone) (PCL) and PCL loaded with hydroxyapatite (HA) nanoparticles with bimodal pore size distributions by a two step depressurization solid‐state supercritical CO2 (scCO2) foaming process. Results show that the pore structure features of the scaffolds are strongly affected by the thermal history of the starting polymeric materials and by the depressurization profile. In particular, PCL and PCL‐HA nanocomposite scaffolds with bimodal and uniform pore size distributions are fabricated by quenching molten samples in liquid N2, solubilizing the scCO2 at 37 °C and 20 MPa, and further releasing the blowing agent in two steps: (1) from 20 to 10 MPa at a slow depressurization rate, and (2) from 10 MPa to the ambient pressure at a fast depressurization rate. The biocompatibility of the bimodal scaffolds is finally evaluated by the in vitro culture of human mesenchymal stem cells (MSCs), in order to assess their potential for tissue engineering applications.

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Low Temperature Aqueous Living/Controlled (RAFT) Polymerization of Carboxybetaine Methacrylamide up to High Molecular Weights
Authors: Rodriguez‐Emmenegger Cesar , Schmidt Bernhard V. K. J. , Sedlakova Zdenka , Šubr Vladimir , Alles Aldo Bologna , Brynda Eduard , Barner‐Kowollik Christopher
Published: June 2011

Among the class of zwitterionic polymers poly(carboxybetaine)s (poly(CB)s) are unique, emerging as the only ultra‐low fouling materials known allowing the preparation of biosensors, fouling resistant nanoparticles, and non‐adhesive surfaces for bacteria. Poly(carboxybetaine methacrylate) and poly(carboxybetaine acrylamide) have been prepared via atom transfer radical polymerization (ATRP), however a polymerization with living characteristics has not been achieved yet. Herein, the first successful living/controlled reversible addition fragmentation transfer (RAFT) polymerization of (3‐methacryloylamino‐propyl)‐(2‐carboxy‐ethyl)‐dimethyl‐ammonium (carboxybetaine methacrylamide) (CBMAA‐3) in acetate buffer (pH 5.2) at 70 and 37 °C is reported. The polymerization afforded very high molecular weight polymers (determined by absolute size exclusion chromatography, close to 250 000 g · mol−1 in less than 6 h) with low PDI (<1.3) at 70 °C. The polymerization was additionally carried out at 37 °C allowing to achieve yet lower PDIs (1.06 ≤ PDI ≤ 1.15) even at 90% conversion, demonstrating the suitability of the polymerization conditions for bioconjugate grafting. The living character of the polymerization is additionally evidenced by chain extending poly(CBMAA‐3) at 70 and 37 °C. Block copolymerization from biologically relevant poly[N‐(2‐hydroxypropyl)methacrylamide] macroCTAs was additionally performed.

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Frontal Polymerization: Polymerization Induced Destabilization of Peracrylates
Authors: Gugg Astrid , Gorsche Christian , Moszner Norbert , Liska Robert
Published: June 2011

Frontal photopolymerization has attracted much attention in the last decade as it allows the curing of thick films. Unfortunately, the use of peroxides, which feature appropriate storage stability, also requires inappropriately high initiation temperatures. Here, a new approach involving a copolymerisation‐induced destabilization of (meth)acrylate‐based peroxides that allows lower front temperatures is presented. The increasing degree of branching next to the carbonyl group lowers the decomposition temperature by at least 20 °C. In classical monomer formulations, sufficient storage stability is confirmed.

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Polymer Brushes Showing Non‐Fouling in Blood Plasma Challenge the Currently Accepted Design of Protein Resistant Surfaces
Authors: Rodriguez‐Emmenegger Cesar , Brynda Eduard , Riedel Tomas , Houska Milan , Šubr Vladimir , Alles Aldo Bologna , Hasan Erol , Gautrot Julien E. , Huck Wilhelm T. S.
Published: June 2011

Ultra‐low‐fouling poly[N‐(2‐hydroxypropyl) methacrylamide] (poly(HPMA)) brushes have been synthesized for the first time. Similar to the so far only ultra‐low‐fouling surface, poly(carboxybetaine acrylamide), the level of blood plasma fouling was below the detection limit of surface plasmon resonance (SPR, 0.03 ng · cm−2) despite being a hydrogen bond donor and displaying a moderate wettability, thus challenging the currently accepted views for the design of antifouling properties. The antifouling properties were preserved even after two years of storage. To demonstrate the potential of poly(HPMA) brushes for the preparation of bioactive ultra‐low fouling surfaces a label‐free SPR immunosensor for detection of G Streptococcus was prepared.

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Controllable Optical, Electrical, and Morphologic Properties of 3,4‐Ethylenedioxythiophene Based Electrocopolymerization Films
Authors: Gu Cheng , Liu He , Hu Dehua , Zhang Wensi , Lv Ying , Lu Ping , Lu Dan , Ma Yuguang
Published: June 2011

This contribution presents a kind of novel and neutral network films based on EDOT formed by in situ electrocopolymerization (ECP). The ECP films which are neutral and colorless exhibit the conductivity of 0.2–0.5 S · cm−1, WF of 4.79–5.20 eV, and RMS roughness of 3.51–5.26 nm. The electroluminescent devices where ECP films acted as hole‐transport layer (HTL) exhibit higher brightness, current density, efficiency (20–30% improvement), and stability than that of PEDOT:PSS HTL device. The ECP films also significantly benefit the stability of neighboring organic layer compared to PEDOT:PSS. This kind of new ECP films affords more opportunities to develop organic light‐emitting diodes (OLEDs) with high performances and stability.

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Modeling Anisotropic Elasticity of Fluid Membranes
Authors: Ramakrishnan N. , Kumar P. B. Sunil , Ipsen John H.
Published: June 2011

The biological membrane, which compartmentalizes the cell and its organelles, exhibits wide variety of macroscopic shapes of varying morphology and topology. A systematic understanding of the relation of membrane shapes to composition, external field, environmental conditions, etc. have important biological relevance. Here we review the triangulated surface model, used in the macroscopic simulation of membranes and the associated DTMC methods. New techniques to calculate surface quantifiers, that will facilitate the study of additional in‐plane orientational degrees of freedom, has been introduced. The mere presence of a polar and nematic fields, in the ordered phase, drives the ground state conformations of the membrane to a cylinder and tetrahedron, respectively.

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Full Molecular Weight Distribution in RAFT Polymerization. New Mechanistic Insight by Direct Integration of the Equations
Authors: Zapata‐González Iván , Saldívar‐Guerra Enrique , Ortiz‐Cisneros José
Published: June 2011

The full molecular weight distribution (FMWD) equations in RAFT polymerization are solved by direct integration for three models: intermediate radical termination (IRT), slow fragmentation (SF), and IRT with oligomers (IRTO). It is shown that the quasi steady state approximation (QSSA) is always applicable to living radicals, and also applicable to intermediate radicals in the IRT and IRTO models. The application of the QSSA allows for considerable simplification of the numerical solution of the equations. A marked bimodality is found for the FMWD of the SF model only. This suggests model discrimination by radical trapping experiments followed by GPC measurement of the total MWD.

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Effect of N‐(p‐coumaroyl)serotonin and N‐feruloylserotonin, major anti‐atherogenic polyphenols in safflower seed, on vasodilation, proliferation and migration of vascular smooth muscle cells
Authors: Takimoto Tetsuya , Suzuki Katsuya , Arisaka Harumi , Murata Takahisa , Ozaki Hiroshi , Koyama Naoto
Published: June 2011

Scope: The objective of this study is to investigate a vascular effect of N‐(p‐coumaroyl)serotonin (CS) and N‐feruloylserotonin (FS), major antioxidative indolic polyphenols in safflower seeds with anti‐atherogenic properties, with emphasis on effects on vascular smooth muscle cells (VSMCs).

Methods and results: Both CS and FS (each 10 to 100 μM) relaxed rat femoral arteries, which were pre‐contracted by 10−5 M phenylephrine or 50 mM KCl, independently of their endothelium. Both CS and FS also concentration‐dependently inhibited the increase of cytosolic free Ca2+ concentration ([Ca2+]i) that was induced by KCl or 5‐hydroxytryptamine in cultured rat VSMCs. Next, we examined the effects of CS and FS on platelet‐derived growth factor (PDGF)‐BB‐evoked proliferation and migration of the VSMCs. Both CS and FS inhibited PDGF‐BB‐evoked proliferation and migration of the VSMCs in a concentration‐dependent manner. They also inhibited PDGF‐BB‐induced phosphorylation of PDGF receptor β and ERK1/2, and Ca2+ release from sarcoplasmic reticulum in the VSMCs in a concentration‐dependent fashion.

Conclusion: These results indicated a possible vascular effect of CS/FS to inhibit the activation of VSMCs by blocking the increase of [Ca2+]i and/or blocking PDGF signaling. These may explain a part of anti‐atherogenic mechanism that underlies their ability to improve vascular distensibility and to inhibit aortic hyperplasia.
Role of membrane dynamics processes and exogenous molecules in cellular resveratrol uptake: Consequences in bioavailability and activities
Authors: Delmas Dominique , Lin Hung‐Yun
Published: June 2011

In the fields of nutrition prevention and therapy treatment, numerous studies have reported interesting properties of trans‐resveratrol (RSV), a natural polyphenol against pathologies such as vascular diseases, cancers, viral infections and neurodegenerative processes. These beneficial effects are supported by more studies showing the pleiotropic actions of RSV. Nevertheless, a crucial question concerning these effects is how the polyphenol, when applied to an organism, gains access to its targets. In this review, we focus on the biochemical and biological parameters involved in RSV transport, particularly the role of the phospholipid bilayer in RSV uptake (passive diffusion, carrier‐mediated transport) and of exogenous molecules modulating RSV transport and effects. The dynamic processes of the plasma membrane reveal the importance of the role of lipid composition in the fluidity, the lipid rafts in RSV endocytosis and the ATP‐binding cassette transporters in RSV efflux. Specific membrane receptors such as integrin αvβ3 contribute to RSV uptake and to activate signalling pathways involved in apoptosis. We discuss the role of intracellular receptors (i.e. aryl‐hydrocarbon and estrogen receptors). In addition, circulating molecules (i.e. albumin, haemoglobin, fatty acids, lipoproteins) play a role as RSV carriers. Finally, we developed a hypothesis concerning the relation between RSV uptake and its biological activities.
Extrusion cooking with glucose supplementation of fumonisin‐contaminated corn grits protects against nephrotoxicity and disrupted sphingolipid metabolism in rats
Authors: Voss Kenneth A. , Riley Ronald T. , Jackson Lauren S. , Jablonski Joseph E. , Bianchini Andreia , Bullerman Lloyd B. , Hanna Milford A. , Ryu Dojin
Published: June 2011

Scope: Fumonisin B1 (FB1) is a mycotoxin found in maize and maize‐based foods. It causes animal diseases and is a suspected risk factor for cancer and birth defects in humans. Extrusion cooking reduces FB1 concentrations in maize however toxicity caused by unknown degradation or FB1‐matrix reaction products might persist.

Methods and results: To test the efficacy of extrusion to reduce FB1 toxicity, Fusarium verticillioides fermented corn (= maize) grits (Batch‐1= 9.7 ppm FB1; Batch‐2= 50 ppm FB1) were extruded without (Batch‐1E; Batch‐2E) or with 10% glucose supplementation (Batch‐1EG; Batch‐2EG). FB1 concentrations were reduced 64% (Batch‐2E) to 94% (Batch‐1EG) after cooking. When the uncooked and processed grits were fed (50% w/w in rodent chow) to rats for up to 8 weeks, FB1 intakes averaged 354, 103, and 25.1 çg/kg body weight/day for Batch‐1, Batch‐1E and Batch‐1EG and 1804, 698, and 222 çg/kg body weight/day for the Batch‐2, Batch‐2E and Batch‐2EG, respectively. Nephrotoxicity including apoptotic lesions and elevated sphingoid base concentrations decreased in a dose‐dependent manner in groups fed Batch‐1, Batch‐1E, Batch‐2, Batch‐2E, or Batch‐2EG and was absent in the Batch‐1EG group.

Conclusion: Extrusion cooking, especially with glucose supplementation, is potentially useful to reduce FB1 concentrations and toxicity of FB1‐contaminated maize.
The inhibitory effects of 5‐hydroxy‐3,6,7,8,3′,4′‐hexamethoxyflavone on human colon cancer cells
Authors: Qiu Peiju , Guan Huashi , Dong Ping , Guo Shanshan , Zheng Jinkai , Li Shiming , Chen Yun , Ho Chi‐Tang , Pan Min‐Hsiung , McClements David Julian , Xiao Hang
Published: June 2011

Scope: Previously, we reported that 5‐hydroxy‐3,6,7,8,3′,4′‐hexamethoxyflavone (5HHMF), a polymethoxyflavone found in citrus peels, potently inhibited the growth of multiple human colon cancer cells. Herein, we further investigated the anti‐cancer mechanisms of 5HHMF in human colon cancer cells.

Methods and results: Colony formation assay revealed that 5HHMF dose dependently inhibited colony formation of multiple colon cancer cells. Western blot analysis demonstrated 5HHMF decreased nuclear β‐catenin levels and increased the E‐cadherin level in a dose‐dependent manner. 5HHMF also modified plasma membrane‐associated proteins, such as K‐Ras, EGFR, and their downstream effectors, such as Akt. Moreover, treatments with 5HHMF inhibited nuclear translocation of NF‐κB, which may contribute to its anti‐cancer effects. Add‐back study showed that the inhibitory effect of 5HHMF was not associated with the production of reactive oxygen species (ROS). In addition, 5HHMF treatment inhibited the capillary tube formation of human umbilical vein endothelial cells (HUVECs) on matrigel, suggesting a potential anti‐tumor angiogenesis effect.

Conclusion: Our results demonstrated that 5HHMF suppressed multiple oncogenic molecular events in colon cancer cells.
Unscented Transformation‐Based Filters: Performance Comparison Analysis for the State Estimation in Polymerization Processes with Delayed Measurements
Authors: Galdeano Rubén , Asteasuain Mariano , Sánchez Mabel
Published: June 2011

State estimation with delayed measurements is essential to the operation of polymer processes due to the limited availability of reliable online sensors and the unavoidable hold‐up time in the acquisition of critical variables data. In this work, a two‐timescale approach is applied to three filters based on the Unscented Transformation, the Unscented Kalman Filter, the Unscented Recursive Nonlinear Dynamic Data Reconciliation and the Reformulated Constrained Unscented Kalman Filter, in order to incorporate delayed measurements into their estimation scheme. A comprehensive comparative analysis is performed, which shows that the three of them have very good accuracy and convergence properties. However, the Unscented Kalman Filter performs better in terms of computational time.

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Components of Sleep Quality and Sleep Fragmentation in Rheumatoid Arthritis and Osteoarthritis
Authors: Taylor‐Gjevre R.M. , Gjevre J.A. , Nair B. , Skomro R. , Lim H.J.
Published: June 2011

Objectives

Poor sleep is increasingly recognized as contributing to a decreased quality of life, increased morbidity/mortality and heightened pain perception. The purpose of the present study was to assess components of sleep quality and self‐identified contributors to sleep fragmentation in rheumatoid arthritis (RA) and osteoarthritis (OA) patient populations.

Methods

Consecutive RA and OA clinic patients were invited to participate in a self‐administered questionnaire study which included the validated multi‐domain Pittsburgh Sleep Quality Index (PSQI), visual analogue scales for pain, fatigue, global functioning, modified Health Assessment Questionnaire (mHAQ), stress scores, the Centre for Epidemiologic Studies–Depression (CES–D) score, the 36‐item short form (SF‐36) quality of life measure, the Rheumatoid Arthritis Disease Activity Index (RADAI), the Epworth Sleepiness Scale (ESS), Berlin score for obstructive sleep apnoea (OSA) risk and the International Restless Legs Syndrome Study Group (IRLSSG) diagnostic criteria.

Results

The study population included 145 RA and 78 OA patients. PSQI global scores were >5 in 62% of RA and 67% of OA patients. Multivariate analysis identified global functioning and the CES–D to be independent predictors for higher global PSQI scores in RA patients, whereas in OA patients predictors were the mHAQ and SF‐36 mental component summary. Abnormalities in subjective sleep assessment, sleep latency, sleep duration, sleep efficiency, daytime dysfunction and increased sleep‐aid medication use were observed in both populations. The most common abnormality reported by both RA and OA patients was increased sleep fragmentation. The most frequent self‐identified cause for sleep disturbance was ‘need to use the washroom’ by 51% of RA and 49% of OA patients, and, second most common, ‘pain’ was identified as a cause for awakening by 33% of RA and 45% of OA patients.

Conclusions

A high prevalence of abnormal sleep quality in both RA and OA patient populations was observed. The most common abnormality was sleep fragmentation, with an increased sleep disturbance score. ‘Need to use the washroom’ and ‘pain’ were the most common self‐identified reasons for awakening from sleep. A review of sleep hygiene, optimization of urological status, and rheumatological disease symptomatic control may prove beneficial in terms of sleep health. Copyright © 2011 John Wiley & Sons, Ltd.