bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of various offset settings in the Fenwal Amicus during hematopoietic progenitor cell collection to increase lymphocyte yield and reduce cross‐cellular contamination
Authors: Burgstaler Edwin A. , Porrata Luis F. , Markovic Svetomir N. , Winters Jeffrey L.
Published: September 2010

Introduction:

Autologous HPC collection focus has been CD34+ cell yield but product content of other cells is important for patient survival, complications, and resource utilization.

Methods:

Prospective, paired study examining MNC and RBC offsets (opens and closes collect valve, respectively) was performed using Fenwal Amicus. Lymphocyte, CD34+ cell yields, and cross‐cellular contamination were compared using different MNC/RBC offsets and retrospective Spectra data.

Results:

In paired comparisons, median lymphocyte yields were significantly different only between 0.0/7.0 (17.6 × 109) and 1.5/5.0 (14.5 × 109) offsets. CD34+ yields were not significantly different between offsets except 1.0/7.0 and 1.5/5.0 (230.3 vs. 156.7 × 106). Granulocytes, RBC, and PLT were significantly greater with higher RBC offset. Comparing all offsets, 1.5/5.0 collected fewer lymphocytes, granulocytes, RBC, and PLT. 1.5/6.0 offsets collected more lymphocytes than 1.5/5.0 but fewer granulocytes and RBC than others except 1.5/5.0. For 1.5/6.0 offsets, PLT content was higher than 1.5/5.0, equivalent to the other offsets, and less than Spectra. CD34+ yields for 1.5/6.0 offsets were equivalent to others except 1.0/7.0. Manufacturer's default (2.3/6.8) collected equivalent lymphocytes and CD34+ to all offsets (except 1.0/7.0) and Spectra. Cross‐cellular contamination was higher than 1.5/5.0 and 1.5/6.0 but equivalent to others with more RBC and fewer PLT than Spectra.

Conclusion:

For maximum lymphocyte yield and minimum contamination, 1.5/6.0 offsets appear optimal. For minimum lymphocyte yield and contamination, 1.5/5.0 offsets would be preferred. Manufacturer's default has CD34+ cell and lymphocyte yields similar to 1.5/6.0 with greater contamination. Amicus can achieve lymphocyte and CD34+ yields similar to Spectra but has significantly less PLT removal. J. Clin. Apheresis, 2010. © 2010 Wiley‐Liss, Inc.
Mononuclear cell collection in patients treated with extracorporeal photochemotherapy by using the off‐line method: A comparison between COBE Spectra AutoPbsc version 6.1 and Amicus cell separators
Authors: Perseghin Paolo , Incontri Arianna
Published: September 2010

Background:

The first step (MNC collection) during extracorporeal photochemotherapy by using the off‐line method is of paramount importance, since the product should be highly MNC‐enriched with low RBC count to avoid UV‐A intercepting by erythrocytes.

Material and methods:

10 patients (nine with chronic GvHD and one with bullous pemphigoid) underwent MNC collection on subsequent days either with the COBE Spectra AutoPbsc version 6.1 or the Amicus Crescendo cell separator. Total and differential WBC count were performed on peripheral blood samples before procedure and on the yields. The procedure parameters were recorded for comparison between the two devices. Analysis included descriptive statistics and paired t‐test.

Results:

No clinically relevant side effect with the exception of mild paresthesias was observed during the 20 MNC collections. Furthermore, no difference were observed as to pre‐collection hematological parameters. The mean total nucleated cell count in the yield was 6.99 ± 2.39 × 109 with a MNC content of 5.9 ± 2.19 × 109 in the Spectra group and 6.15 ± 2.02 × 109 with 5.29 ± 2.39 × 109 in the Amicus group (P = 0.407 and P = 0.540, respectively). PLT content was higher in the yield from the Spectra group when compared to the Amicus group (1.54 × 1011 ± 0.74 vs. 0.53 × 1011 ± 0.34, P = 0.001). Moreover, no difference were observed in the RBC content in the product : 3.38 mL ± 1.91 vs. 4.59 mL ± 2.09, P = 0.191, when COBE Spectra and Amicus were compared, respectively.

Conclusions:

Both devices provide a satisfactory MNC collection for further UV‐A treatment. J. Clin. Apheresis, 2010. © 2010 Wiley‐Liss, Inc.
Autoimmunity in transfusion babesiosis: A spectrum of clinical presentations
Authors: Herman Jay H. , Ayache Saleh , Olkowska Danuta
Published: September 2010

Transfusion‐acquired babesiosis can be an asymptomatic or self‐limited febrile hemolytic illness in a healthy host. A persistent, relapsing, and/or fulminant course with the development of life‐threatening complications may be seen in immunocompromised or splenectomized patients. As in malaria, erythrocyte parasitemia is often associated with nonimmune hemolysis, and can be treated with erythrocytapheresis. Just as warm autoantibodies have been reported in malaria infection, the development of autoantibody‐mediated immune hemolysis has been reported in babesiosis. We treated a previously healthy male with multiple injuries from a motor vehicle accident necessitating massive transfusion. Late in the hospitalization, his blood smear revealed Babesia microti, confirmed by PCR study and serology. This was eventually traced to a unit of blood from an asymptomatic blood donor that was transfused during his initial trauma care. Specific antibiotic therapy was begun, and severe hemolysis from a high parasite burden required red blood cell exchange which led to rapid abatement of the hemolysis. He had a positive DAT (IgG with a pan‐reactive eluate) but no serum autoantibody. This persisted for 10 days following cessation of hemolysis, and became negative while still on antibiotics while his parasite burden became undetectable. Reports of autoimmunity associated with community acquired babesiosis often have severe hemolysis from their autoantibodies, but our case shows that autoantibodies may also follow transfusion‐acquired babesiosis. The nature of the autoantigen is unknown. J. Clin. Apheresis, 2010. © 2010 Wiley‐Liss, Inc.
What's at stake in the EU bailout?
Authors: Tokic Damir
Published: September 2010

The European Union is at the crossroads. The current financial crisis in Greece will show if the people of Europe are ready for the final step of European integration‐the political union. Will they form one? Or will they revert to nationalism, abandoning both the euro and the EU?

Can the EU survive? And what should investors do? © 2010 Wiley Periodicals, Inc.
Can you handle business uncertainty?
Authors: Glotzhober Bob
Published: September 2010

A veteran of the financial services industry, “Coach Bob” Glotzhober has spent more than two decades teaching individuals and corporations how to stay afloat during emotionally turbulent times. In this article he shares strategies that can help you and your company handle the current economic crisis. © 2010 Wiley Periodicals, Inc.
Greece: How can companies manage the new risks?
Authors: Lobo Bento J. , Wann Christi , Fulmer Jr. John G.
Published: September 2010

CEOs and CFOs must understand that political risk can have a significant impact on a company's profitability. The current situation in Greece is a prime example of this. But how does the risk of Greece's default affect U.S. firms doing business with Greek companies? The authors examine the impact on two kinds of U.S. firms: those exporting to Greece and those importing from Greece. The authors then look at ways to manage the impact of sovereign risk of default. © 2010 Wiley Periodicals, Inc.
Foreign investment: Impact on China's economy
Authors: Tang Roger Y. W. , Metwalli Ali M. , Marie Smith Ola
Published: September 2010

Foreign direct investment (FDI) has been a key driver of economic growth, globalization of business, and the expansion of international trade. And in today's age of the Internet and globalization, the impact of FDI and foreign‐invested enterprises (FIEs) on a hosting country's economy will be more profound than it was in the twentieth century.

Given all that, what roles are FIEs playing in the economy of the world's most populous country‐China? And what are the implications for investors? © 2010 Wiley Periodicals, Inc.
IFRS and the financial crisis
Authors: Olsen Lori , Weirich Thomas R.
Published: September 2010

The Securities and Exchange Commission continues to encourage convergence of U.S. generally accepted accounting principles (GAAP) and international financial reporting standards (IFRS)‐despite the fact that IFRS did not stop the current financial crises in Greece, Spain, and other European countries. In fact, one study found that IFRS fair value accounting intensified the impact of the crisis.

So why should the United States continue on the path to adopt IFRS?

The authors examine how we've come to this point, the current financial crisis, and where we seem to be going. © 2010 Wiley Periodicals, Inc.
Basel 2: How will new bank capital rules affect your company?
Authors: Sagner James S.
Published: September 2010

Governments, central bankers, and regulators have a most pressing concern: how can they restore confidence and stability in the global financial system? The latest Basel Accords try to do it by setting international standards on the amount of capital banks must maintain to manage financial and operational risks. But there hasn't been adequate analysis of Basel 2's implications, warns the author of this article.

The question for companies is: what actions should you take now if your bank faces the new Basel 2 capital requirements? © 2010 Wiley Periodicals, Inc.
Should we audit the fed?
Authors: Marie Smith Ola , San Miguel Paul
Published: September 2010

The U.S. Federal Reserve has been under fire lately for its policies and secrecy. Many critics are arguing that we need to audit the Fed‐and legislation to that effect has been introduced in Congress and voted on. But should we audit the Fed? The authors take a close look at how the Fed works and the controversies that surround it. © 2010 Wiley Periodicals, Inc.
Defined benefit plans: How rule changes may affect your firm
Authors: Woodlock Peter , Peng Gang
Published: September 2010

Recent changes to U.S. rules and regulations governing defined benefit plans will impact companies in several key ways, warn the authors of this article. The landscape has changed for pension funding. © 2010 Wiley Periodicals, Inc.
Octahedral designs
Authors: Linek Václav , Stevens Brett
Published: September 2010

An oriented octahedral design of order v, or OCT(v), is a decomposition of all oriented triples on v points into oriented octahedra. Hanani [H. Hanani, Decomposition of hypergraphs into octahedra, Second International Conference on Combinatorial Mathematics (New York, 1978), Annals of the New York Academy of Sciences, 319, New York Academy of Science, New York, 1979, pp. 260–264.] settled the existence of these designs in the unoriented case. We show that an OCT(v) exists if and only if v≡1, 2, 6 (mod 8) (the admissible numbers), and moreover the constructed OCT(v) are unsplit, i.e. their octahedra cannot be paired into mirror images. We show that an OCT(v) with a subdesign OCT(U) exists if and only if v and u are admissible and v≥u+4. © 2010 Wiley Periodicals, Inc. J Combin Designs 18:319–327, 2010
Potential application of aqueous two‐phase systems for the fractionation of RNase A and α‐Lactalbumin from their PEGylated conjugates
Authors: González‐Valdez José , Cueto Luisa F. , Benavides Jorge , Rito‐Palomares Marco
Published: September 2010

BACKGROUND: PEGylation reactions often result in a heterogeneous population of conjugated species and unmodified proteins that presents a protein separations challenge. Aqueous two‐phase systems (ATPS) are an attractive alternative for the potential fractionation of native proteins from their PEGylated conjugates. The present study characterizes the partition behaviors of native RNase A and α‐Lac and their mono and di‐PEGylated conjugates on polyethylene glycol (PEG)—potassium phosphate ATPS.

RESULTS: A potential strategy to separate unreacted native protein from its PEGylated species was established based upon the partition behavior of the species. The effect of PEG molecular weight (400–8000 g mol−1), tie‐line length (15–45% w/w) and volume ratio (VR; 0.33, 1.00 and 3.00) on native and PEGylated proteins partition behavior was studied. The use of ATPS constructed with high PEG molecular weight (8000 g mol−1), tie‐line lengths of 25 and 35% w/w, and VR values of 1.0 and 3.0 allowed the selective fractionation of native RNase A and α‐Lactalbumin, respectively, from their PEGylated conjugates on opposite phases. Such conditions resulted in an RNase A bottom phase recovery of 99%, while 98% and 88% of mono and di‐PEGylated conjugates, respectively were recovered at the top phase. For its part, α‐Lac had a bottom phase recovery of 92% while its mono and di‐PEGylated conjugates were recovered at the top phase with yields of 77% and 76%, respectively.

CONCLUSIONS: The results reported here demonstrate the potential application of ATPS for the fractionation of PEGylated conjugates from their unreacted precursors. Copyright © 2010 Society of Chemical Industry
Medium composition effects on solute partitioning in solid–liquid two‐phase bioreactors
Authors: Khan Tanya R. , Daugulis Andrew J.
Published: September 2010

Biphasic systems such as two‐phase partitioning bioreactors (TPPBs) have been used to alleviate biological inhibition by sequestering inhibitory compounds within an immiscible phase. The use of solid polymer beads as this auxiliary phase provides a fully biocompatible alternative to potentially toxic organic solvents. While guidelines exist for the rational selection of the polymer phase, the effect of the aqueous phase composition on molecular sequestration has not been explored in the literature. This work aims to identify aspects of medium composition that influence the partitioning of target molecules into the sequestering phase. Using benzaldehyde as the target molecule and Hytrel G3548L (DuPont) as the polymer phase, pH, temperature, salt and glucose concentrations, as well as ethanol concentrations, were examined for their effects on the partition coefficient. pH and temperature were observed to have no significant effect on benzaldehyde partitioning. Salt and glucose additions increased the partition coefficient by 173% and 30%, respectively, compared with pure reverse osmosis (RO) water, while increasing ethanol concentration was found to decrease the partition coefficient from 44 ( ± 1.6) to 1 ( ± 0.3). Strategic changes to the aqueous phase can be made to improve affinity of the sequestering phase for target molecules. This provides a simple and cost‐effective method to potentially improve TPPB system performance. Copyright © 2010 Society of Chemical Industry
Histopathologic findings of HPV and p16 positive HNSCC
Authors: Mendelsohn Abie H. , Lai Chi K. , Shintaku I Peter , Elashoff David A. , Dubinett Steven M. , Abemayor Elliot , St. John Maie A.
Published: September 2010

Objective:

Human papilloma virus (HPV) and p16INKa (p16) positivity in head and neck squamous cell carcinomas (HNSCCs) is currently thought to be an encouraging prognostic indicator. However, the histopathologic changes responsible for this behavior are poorly understood. It is our objective to elucidate these histopathologic characteristics to help define the clinical utility of these markers.

Design:

Retrospective cohort study.

Methods:

71 HNSCC tumors between July 1, 2008 and August 30, 2009 were examined for HPV, p16, and epidermal growth factor receptor (EGFR). Specified pathologic features were examined: perivascular invasion (PVI), perineural invasion (PNI), grade of squamous differentiation, basaloid classification.

Results:

HPV and p16 had no direct impact on perineural or perivascular invasion. However, HPV and p16 were strongly predictive of poorly differentiated tumors, as well as basaloid squamous cell carcinoma (SCCA) (P < .001). Additionally, upon multivariate analysis, HPV(+) and p16(+) tumors had an increased risk of nodal metastasis (HPV: odds ratio [OR] = 23.9 (2.2, 265.1) p = .01; p16: OR = 6.5 (1.4, 31.2) p = .02; PVI: OR = 6.0 (1.6, 22.8) p < .01). The area under the curve (AUC) of receiver operating characteristic (ROC) curves demonstrated improved predictive value for lymph node metastasis above standard H&E histopathologic features (76.7%) for both HPV (83.2%) and p16 (81.3%) individually.

Conclusions:

HPV(+) and p16(+) are highly predictive for poorly differentiated tumors and basaloid SCCA. Additionally, HPV and p16 positivity demonstrate superior predictive value for lymph node metastasis above standard H&E histopathologic features. Although exact recommendations should be tempered by considerations of primary tumor subsite, T‐stage, and depth of invasion, head and neck multidisciplinary teams should strongly consider aggressive lymph node treatment for any HPV(+) or p16(+) tumor. Laryngoscope, 2010
A new thread guide instrument for endoscopic arytenoid lateropexy
Authors: Rovó László , Madani Shahram , Sztanó Balázs , Majoros Valéria , Smehák György , Szakács László , Jóri József
Published: September 2010

Objectives/Hypothesis:

The varied etiology of bilateral vocal cord immobility (BVCI) requires a wide range of surgical approaches. A new endolaryngeal thread guide instrument (ETGI) is presented here for a minimally invasive endoscopic lateropexy of the arytenoid cartilage, which might serve as a basis for a simple solution for the main types of BVCI.

Study Design:

Prospective study of BVCI patients who underwent surgery, including 22 bilateral vocal cord paralyses (BVCP), 12 mechanical fixations (MF), 10 posterior glottic stenoses, and two rheumatoid ankyloses.

Methods:

The ETGI is based on a built‐in movable curved blade with a hole at its tip to guide a thread in and out again between the skin and the laryngeal cavity. The loops formed around the arytenoid cartilage cause abduction. In cases of fixations, the cricoarytenoid joints were properly mobilized as a first step with a combination of cold technique and CO2 laser.

Results:

As spirometric tests proved, 32 patients achieved improved breathing ability. One temporary tracheostomy was necessary and one patient with ongoing radiotherapy could not be decannulated. Subjectively, twelve patients' voices improved or approximated normal quality due to complete vocal cord recoveries on at least one side after lateropexy was ceased. Incomplete recovery with more or less impaired voice was observed in 16 cases. Three MF patients and two BVCP patients with poor overall health condition had severe dysphonia.

Conclusions:

Combined with simple and readily available methods, endoscopic arytenoid lateropexy is an effective solution for BVCIs with various etiologies. The ETGI facilitates this procedure with rapid and safe creation of fixating loops at the proper position. Laryngoscope, 2010
Learning curve for competency in flexible laryngoscopy
Authors: Laeeq Kulsoom , Pandian Vinciya , Skinner Margret , Masood Hamid , Stewart Charles M. , Weatherly Robert , Cummings Charles W. , Bhatti Nasir I.
Published: September 2010

Objectives/Hypothesis:

The purpose of our study was to identify the number of attempts required to attain competency in performing flexible laryngoscopy.

Study Design:

Cross‐sectional prospective study.

Methods:

Fifteen medical students were recruited to perform flexible laryngoscopy on a mannequin. Each participant was given unlimited time and attempts to perform the procedure until considered competent by the evaluator for two consecutive attempts. Three evaluators used a flexible laryngoscopy checklist to score performance on each step of the procedure. Time required to perform the procedure was recorded, as well as number of times the scope hit the mucosa. The criteria for attaining competence were achieving a minimum score of 3 out of 5 on all the items of the checklist and being deemed competent by the evaluator.

Results:

A total of 105 flexible laryngoscopies were performed by 15 medical students. A mean of six attempts (range, 2–17) were necessary for a medical student to become competent in performing flexible laryngoscopy. An 80% probability of becoming competent was achieved with the 14th attempt. An inverse relationship was noted between the number of times the scope hit the mucosa and the probability of being competent. The time taken to perform the procedure decreased with increasing number of attempts.

Conclusions:

Our results suggest that it takes six attempts on average for a novice to become competent in performing flexible laryngoscopy. This finding has implications for residency programs because it indicates the learning curve can be overcome in the laboratory rather than with patients. Laryngoscope, 2010
Rhinitis medicamentosa as a cause of increased intraoperative bleeding
Authors: Robison Jacob G. , Pant Harshita , Ferguson Berrylin J.
Published: September 2010

Rhinitis medicamentosa occurs with repeated and prolonged use of topical decongestants. The resultant reduced ability to respond to decongestants mediated via enlarged capillary endothelial gaps can lead to profuse bleeding during turbinate surgery. We recommend that patients with rhinitis medicamentosa be weaned off topical decongestants prior to elective turbinate surgery to minimize this complication. The management of rhinitis medicamentosa and a case of intraoperative hemorrhage are presented. Laryngoscope, 2010
Coblation removal of laryngeal Teflon granulomas
Authors: Meslemani Danny , Benninger Michael S.
Published: September 2010

Laryngoscope, 2010
Pediatric sleep apnea and craniofacial anomalies: A population‐based case–control study
Authors: Lam Derek J. , Jensen Christine C. , Mueller Beth A. , Starr Jacqueline R. , Cunningham Michael L. , Weaver Edward M.
Published: September 2010

Objective:

To investigate the association between craniofacial anomalies and diagnosis with obstructive sleep apnea (OSA) in a large, population‐based sample of children.

Design:

Retrospective case–control study.

Methods:

Cases of OSA (n = 1,203) were identified by International Classification of Diseases‐9 codes consistent with OSA in the 1987–2003 Washington State inpatient discharge database among children ≤18 years of age and born in Washington state. For each case, five controls without OSA (n = 6,015) were randomly selected from the remaining Washington State births, frequency matched by birth year. Congenital anomaly diagnoses and covariates were extracted from discharge data for all inpatient hospitalizations during the study period and linked birth certificate data. Multiple logistic regression was used to calculate adjusted odds ratios (OR) and 95% confidence intervals (CI) for the associations between congenital anomalies (including subgroups) and OSA.

Results:

An OSA diagnosis was strongly associated with the presence of any craniofacial anomaly (adjusted OR 38, 95%CI [24, 60]) and, in particular, with orofacial cleft (adjusted OR 40, 95%CI [17, 94]) and Down syndrome (adjusted OR 51, 95%CI [20, 128]). OSA was less associated with any noncraniofacial malformation (adjusted OR 4.1, 95%CI [3.1, 5.3]), which may reflect the relatively small effect of inpatient exposure bias in the associations above.

Conclusions:

The presence of congenital craniofacial anomalies is strongly associated with inpatient diagnosis of OSA. These findings persist even after control of major potential biases. Parents and clinicians should consider screening for OSA among children with craniofacial anomalies. Laryngoscope, 2010
Presence of olfactory event‐related potentials predicts recovery in patients with olfactory loss following upper respiratory tract infection
Authors: Rombaux Philippe , Huart Caroline , Collet Stéphanie , Eloy Philippe , Negoias Simona , Hummel Thomas
Published: September 2010

Objectives/Hypothesis:

The aim of the present study was to evaluate the course of olfactory dysfunction in patients with olfactory loss following infections of the upper respiratory tract.

Study Design:

Prospective cohort.

Methods:

A total of 27 patients were included; each patient was evaluated twice. Psychophysical testing of olfactory function was performed with the Sniffin' Sticks test and chemosensory functions with event‐related potential (ERP).

Results:

At T1, 15 patients were considered hyposmic, 12 as anosmic. Accordingly, nine and 27 patients demonstrated olfactory ERP. At T2, 16 and 11 patients were considered as hyposmic and anosmic, and 11 demonstrated olfactory ERP. Analysis of variance did not show significant differences for any parameters between T1 and T2: threshold, discrimination, identification (TDI) scores at the Sniffin' Sticks and amplitudes and latencies of N1 and P2 in the ERP. However, seven patients demonstrated an increase of more or equal to six points at the TDI score, indicating significant improvement. Four of the seven patients had olfactory ERP at T1 (57%); of those patients who did not show improvement, five of 20 (25%) exhibited olfactory ERP. Thus, the presence of olfactory ERP predicts a positive evolution of olfactory function with a relatively high specificity of 83%.

Conclusions:

The current findings clearly confirm earlier results on recovery rate of postinfectious olfactory loss. The new finding is that the presence of olfactory ERP at the first consultation is also a positive predictive factor of a favorable outcome in this disease. Laryngoscope, 2010
Experimental validation of the effects of microvasculature pigment packaging on in vivo diffuse reflectance spectroscopy
Authors: Rajaram Narasimhan , Gopal Ashwini , Zhang Xiaojing , Tunnell James W.
Published: September 2010

Background

Diffuse reflectance spectroscopy (DRS) uses the steady‐state diffuse reflectance measured from the tissue surface to determine absorption and scattering properties of sampled tissue. Many inverse models used to determine absorber properties have assumed a homogeneous distribution of blood. However, blood in tissue is confined to blood vessels that occupy a small fraction of the overall volume. This simplified assumption can lead to large errors when measuring optical properties. The objective of this study was to examine the effect of confining absorbers to small volumes, such as the microvasculature, on in vivo DRS.

Study Design

We fabricated multi‐layer microfluidic devices to mimic blood vessels with a size similar to skin microvasculature. We studied the effect of varying channel size (diameter = 22 and 44 µm) and absorber concentration (10–80% food color dye in water) on diffuse reflectance measurements. We also examined the in vivo reflectance from normal skin and non‐melanoma skin cancer on 14 patients.

Results

Our results demonstrate that both absorption coefficient and vessel diameter affect the diffuse reflectance spectra. An empirically calculated packaging correction factor based on our experiments shows good agreement with previous theoretical derivations of the same factor. In vivo measurements on normal skin and basal cell carcinoma show that incorporating a correction factor greatly improves the fit of the inverse model to the spectra. In addition, there were statistically significant differences in measured mean vessel diameter and blood volume fraction between normal skin and basal cell carcinoma.

Conclusion

We have demonstrated experimentally the effect of pigment packaging in blood vessels over a physiologically relevant range of blood vessel size and absorption. The correction factors implemented to account for the packaging effect could potentially be used as diagnostic parameters for diagnosing skin cancers. Lasers Surg. Med. 42:680–688, 2010. © 2010 Wiley‐Liss, Inc.
Comparison of Er:YAG laser, piezoelectric, and drill osteotomy for dental implant site preparation: A biomechanical and histological analysis in sheep
Authors: Stübinger Stefan , Biermeier Kristina , Bächi Beatus , Ferguson Stephen J. , Sader Robert , von Rechenberg Brigitte
Published: September 2010

Background and Objectives

The aim of this study was to examine the influence of implant bed preparation, using either Er:YAG laser ablation, piezoelectric surgery or drill osteotomy, on osseointegration of titanium dental implants after 4, 6, and 8 weeks.

Material and Methods

A total of 108 implants (Camlog) were placed in the pelvis of 6 sheep (18 implants/sheep). Implant sites were prepared by an Er:YAG laser, a dental drill or a piezoelectric device. For each time period, six implants were used for biomechanical removal torque testing and six implants for a semi‐quantitative histological assessment of the bone‐to‐implant contact (BIC).

Results

An initially missing implant adjusted site preparation led to slightly higher BIC and torque values in the piezoelectric and laser groups due to a press‐fit effect after 4 weeks. Statistical analysis of the average mean BIC after 4, 6, and 8 weeks revealed no significant differences (P > 0.05) between the different osteotomy techniques. Comparison of individual removal torque values showed the highest value for laser osteotomy after 8 weeks (1,698.50 ± 67.52 Nmm), which was significantly higher than the corresponding value for drill osteotomy (P = 0.006).

Conclusion

Although BIC and removal torque values decreased in the laser and piezoelectric groups at 6 weeks during an active remodeling process, favorable and superior BIC as well as torque values could be demonstrated at 8 weeks. Thus laser and piezoelectric osteotomy seem to be at least comparable to drill osteotomy, concerning early osseointegration and implant stability. Lasers Surg. Med. 42:652–661, 2010. © 2010 Wiley‐Liss, Inc.
Conjugation of Methacrylamide Groups to a Model Protein via a Reducible Linker for Immobilization and Subsequent Triggered Release from Hydrogels
Authors: Verheyen Ellen , Delain‐Bioton Lise , van der Wal Steffen , el Morabit Najim , Barendregt Arjan , Hennink Wim E. , van Nostrum Cornelus F.
Published: September 2010

An efficient strategy is reported to introduce methacrylamide groups on the lysine residues of a model protein (lysozyme) for immobilization and triggered release from a hydrogel network. A novel spacer unit was designed, containing a disulfide bond, such that the release of the protein can be triggered by reduction. The modified proteins were characterized by MALDI‐TOF MS, titration of free NH2 residues and spectral analysis. The modification reaction is well controlled, and the number of introduced functions can be tailored by changing the reaction conditions. Gel electrophoresis experiments showed that the methacrylamide modified protein can be immobilized in a polyacrylamide hydrogel and subsequently released by reduction of the spacer by which the protein was grafted to the polymeric network.

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Highly Elastic and Deformable Hydrogel Formed from Tetra‐arm Polymers
Authors: Sakai Takamasa , Akagi Yuki , Matsunaga Takuro , Kurakazu Manami , Chung Ung‐il , Shibayama Mitsuhiro
Published: September 2010

After decades of efforts by many researchers, we have succeeded in realizing a near‐ideal polymer network. This network, the Tetra network, is made by cross‐end‐coupling of tetra‐arm polymer modules. The mechanical energy dissipation was extremely low (tan δ ≈ 10−4). The macroscopic stress–strain relationship of the Tetra network was in good agreement with that of microscopic elastic blobs. The maximum breaking strength was extremely high (≥27 MPa). These results indicate that the Tetra network is closer to an ideal polymer network than any other conventional model networks. Because the Tetra network can be treated as uniformly packed elastic blobs, it should help apply the knowledge of single polymer chains seamlessly to the design of polymer materials and help further develop the theory of rubber elasticity.

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Thermal Degradation of Cellulose Nanocrystals Deposited on Different Surfaces
Authors: Suchy Miro , Vuorinen Tapani , Kontturi Eero
Published: September 2010

Thermal degradation of cellulose nanocrystals deposited on flat solid surfaces was monitored by AFM coupled with analysis of obtained images using image processor. The nanocrystals deposited on TiO2 substrate showed different degradation patterns compared to those deposited on the nanosized layer of amorphous cellulose. The degradation was complete within 20 minutes at 300 °C. The nanocrystal deposited on amorphous cellulose resisted the heat treatment up to 120 minutes. Visual comparison and analysis of the AFM images clearly demonstrated the impact of temperature on the degradation rate of the nanocrystals deposited on TiO2 substrate.
Utilizing Polymer Blends to Prepare Ultrathin Films with Diverse Cellulose Textures
Authors: Kontturi Eero , Nyfors Laura , Laine Janne
Published: September 2010

This paper presents an overview of the recent work on ultrathin polymer blend films containing cellulose. Three systems prepared via trimethylsilyl cellulose derivative, which is subsequently hydrolyzed to cellulose, are presented: polystyrene/cellulose, poly(methyl methacrylate)/cellulose and polystyrene‐block‐polyethyleneoxide/cellulose. Diverse textures emerge within the films depending on the interactions between the polymers and their interactions with the substrate as well as on different solubilities of the polymers. Furthermore, an ultrathin film containing a cellulose/xylan blend is presented. This film was deposited directly from a common solvent (dimethylacetamide/lithium chloride) and it did not exhibit distinct morphological patterns comparable to the blends with synthetic polymers.
Comparison of Benzyl Celluloses Synthesized in Aqueous NaOH and Dimethyl Sulfoxide/Tetrabutylammonium Fluoride
Authors: Rohleder Esther , Heinze Thomas
Published: September 2010

Cellulose was benzylated starting from the dissolved polymer in dimethyl sulfoxide (DMSO)/tetrabutylammonium fluoride trihydrate (TBAF) and heterogeneously in aqueous NaOH as reaction media. Differences in the distribution of benzyl moieties within the anhydroglucose unit in dependence on the synthesis pathway couldn't be found. However, as revealed by means of 1H‐NMR spectroscopy, significant differences in the distribution of substituents along the cellulose chains occurred. Conventionally synthesized samples (in aqueous NaOH), even in the presence of a phase transfer catalyst, possess a block‐wise distribution of substituents, while a dissolution of cellulose in DMSO/TBAF prior to the reaction gives products that are uniformly substituted along the cellulose chains.
Pure Cellulose Nanoparticles from Trimethylsilyl Cellulose
Authors: Kostag Marc , Köhler Sarah , Liebert Tim , Heinze Thomas
Published: September 2010

Silyl ethers of cellulose are promising derivatives of the biopolymer because they exhibit thermoplastic behavior at higher functionalization, may be applied as intermediate in subsequent reactions and have a high tendency to form defined supramolecular structures. Trimethylsilylation can be carried out by applying ionic liquids (ILs) such as 1‐ethyl‐3‐methylimidazolium acetate (EMIMAc) as reaction medium. Pure trimethylsilyl cellulose (TMSC) can be efficiently synthesized with 1,1,1,3,3,3‐hexamethyldisilazane (HMDS) yielding products with degrees of substitution (DS) up to 2.89. During the synthesis of highly functionalized derivatives, precipitation of the TMSC occurred, which simplifies the recycling of the IL. The tendency of TMSC toward the formation of supermolecular structures was exploited for the formation of pure cellulose nanospheres by a simple dialysis process. FTIR spectroscopy confirmed the complete removal of the TMS functions during this process. Scanning electron microscopy, dynamic light scattering, atomic force microscopy, and particle size distribution analysis showed that cellulose particles with a size of 100 to 200 nm are accessible in this simple manner.
Novel Xylan Gels Prepared from Oat Spelts
Authors: Hettrich Kay , Fanter Carola
Published: September 2010

Gels and pastes are used in many areas including application in the cosmetic, pharmaceutical and medical industries. A xylan derivative with pasty consistency was prepared in addition to the synthesis of xylan ethers and esters. The water content of the gel can be widely varied. The gel is formed although the xylan contains no cross‐linking group. The hydrophobic and hydrophilic nature of the xylan gel can be adjusted by modifying the xylan. All of the gels can be dried using different methods (air drying, solvent exchange as well as freeze drying) and the dried gels can again disperse in water. The gels were characterised by porosity measurements (mercury intrusion), dynamic vapour sorption (DVS), scanning electron microscopy (SEM) and dispersion stability investigation respectively.
Technological Opportunities for the Implementation of Anti‐Microbial Activities into Dry‐Wet Shaped Cellulose Fibres
Authors: Meister Frank , Kolbe Axel , Krieg Markus , Mooz Michael
Published: September 2010

Metal cations are valuable antimicrobial additives for controlling of bacteria growth on textile fibres. By means of multiple actions they are able to suppress the undesirable microbe action also during wound healing. Dry‐wet shaping technology offers numerous opportunities for implementation of antimicrobial activities into textile structures (fibres, yarn, fabrics). The degree of load, insertion step as well as type of additive (Ag, Cu, Zn) presents a broad field of physical modification of dry‐wet spun cellulose fibres. The investigation of antimicrobial activities of manufactured fibres and yarns exhibit bactericide or bacteriostatic effects against typical pathogenic germs. Ag contents higher than 30 ppm in fibres and 0.06 per cent in yarns as well as Cu contents higher than 100 ppm in fibres and about 0.5 per cent in yarns are fairly effective for a permanent antimicrobial effect. Fabrics based on the developed fibres and yarns could already been successfully commercialised by innovative small and medium sized enterprises (SME).
Loading of Bacterial Cellulose Aerogels with Bioactive Compounds by Antisolvent Precipitation with Supercritical Carbon Dioxide
Authors: Haimer Emmerich , Wendland Martin , Schlufter Kerstin , Frankenfeld Katrin , Miethe Peter , Potthast Antje , Rosenau Thomas , Liebner Falk
Published: September 2010

Bacterial cellulose aerogels overcome the drawback of shrinking during preparation by drying with supercritical CO2. Thus, the pore network of these gels is fully accessible. These materials can be fully rewetted to 100% of its initial water content, without collapsing of the structure due to surface tension of the rewetting solvent. This rehydration property and the high pore volume of these material rendered bacterial cellulose aerogels very interesting as controlled release matrices. Supercritical CO2 drying, the method of choice for aerogel preparation, can simultaneously be used to precipitate solutes within the cellulose matrix and thus to load bacterial cellulose aerogels with active substances. This process, frequently termed supercritical antisolvent precipitation, is able to perform production of the actual aerogel and its loading in one single preparation step. In this work, the loading of a bacterial cellulose aerogel matrix with two model substances, namely dexpanthenol and L‐ascorbic acid, and the release behavior from the matrix were studied. A mathematical release model was applied to model the interactions between the solutes and the cellulose matrix. The bacterial cellulose aerogels were easily equipped with the reagents by supercritical antisolvent precipitation. Loading isotherms as well as release kinetics indicated no specific interaction between matrix and loaded substances. Hence, loading and release can be controlled and predicted just by varying the thickness of the gel and the solute concentration in the loading bath.
Cryo‐FIB‐Preparation and Cryo‐SEM Investigation of Gold Nanolayers Used as Absorber for Laser Welding of Polymer Foils
Authors: Neuber M. , Cismak A. , Heilmann A.
Published: September 2010

The morphology of welded polymer foils was investigated by Scanning Electron Microscopy (SEM) using Focused Ion Beam (FIB) technology for cross‐sectional preparation. Due to the sensitive structure of the copolymer Ethylene Tetrafluororethylene (ETFE), FIB preparation and SEM investigation were performed at cryo conditions. A gold nanolayer was used as absorber for the laser beam to weld the transparent copolymer foils. The embedding of the gold nanolayer inside the welding seam and its influence on the mechanical stability of the welding seams was demonstrated.
Polymer Nanostructures by Forced Assembly: Process, Structure, and Properties
Authors: Ponting Michael , Hiltner Anne , Baer Eric
Published: September 2010

The process of micro‐ and nanolayer coextrusion of polymeric systems with good layer uniformity is described. Coextrusion through a series of layer multiplying die elements has enabled the production of films containing tens to thousands of layers with individual layer thicknesses from the micro‐ to the nanoscale. Improvements in layer uniformity are discussed through optimization of layer multiplier die design, selection of viscosity matched polymer systems, and incorporation of surface layer capabilities. Design of ‘uneven’ split layer multiplication dies has enabled the coextrusion of layered films with a wide variety of layer thickness distributions having up to a 10× difference in the individual film layer thicknesses. Coextrusion of layered polymer films with individual layer thicknesses down to the nanoscale has resulted in the production of novel systems with improved properties. Nanolayered polymer films were utilized to develop an all‐plastic polymer laser, to fabricate gradient refractive index lenses, and to investigate gas barrier enhancement of crystalline polymer nanolayers confined to induce a high aspect ratio, in‐plane, single‐crystal‐like lamellar structure.
Extrusion Induced Morphologies and Properties of Layered Block Copolymer/Polystyrene Mixtures
Authors: Adhikari R. , Buschnakowski M. , Lebek W. , Godehardt R. , Michler G. H. , Knoll K.
Published: September 2010

Using transmission electron microscopy (TEM) and tensile testing, we investigated the morphology and the micro‐deformation processes in a new kind of highly asymmetric polystyrene/polybutadiene based triblock copolymer and its blends with general purpose polystyrene (GPPS). The emphasis has been put on the analysis of blends morphology evolved under extrusion conditions and the impact of the later on the micromechanical behaviour of the blends. It was found that the phase separated structures were strongly oriented along the extrusion direction leading to the anisotropic mechanical behaviour. The blends showed more ductile performance and lesser strength on loading the sample perpendicular to the extrusion direction. The ductile to brittle transition was observed when the morphology of the blends was dominated by the glassy phase for 60 wt.‐% GPPS.
Cycloolefin‐Copolymer/Polyethylene (COC/PE) Blend Assists with the Creation of New Articular Cartilage
Authors: Petrtyl M. , Bastl Z. , Krulis Z. , Hulejova H. , Polanska M. , Lisal J. , Danesova J. , Cerny P.
Published: September 2010

It is shown that the initial biomechanical stability of the applied COC/PE blend in the treated tissue locality, the initial integrity of biomaterials substituting the subchondral bone by polymer implant, the initial bearing capacity and the vertical position of these biomaterials have a mayor influence on the regeneration of new articular cartilage and subchondral bone. These aspects are essential for a prosperous treatment of osteochondral defects. Results reveal that the initial biomechanical stiffness of materials (substituting the subchondral bone) has a fundamental influence on both the quality and the quantity of new articular cartilage and subchondral bone. Research is also aimed at the application of suitable biologically tolerated polymer material, its surface modifications, verifications of the vertical position of implants in relation to the articular cartilage surface and ensuring the initial biomechanical stability of the polymer implant.
Solvent Influences the Morphology and Mechanical Properties of Electrospun Poly(L‐lactic acid) Scaffold for Tissue Engineering Applications
Authors: Asran A.Sh. , Salama M. , Popescu C. , Michler G.H.
Published: September 2010

Electrospun micro‐ and nanofiber scaffolds have gained interest in biomedical applications, especially in tissue engineering, because they can be used to reproduce the structure of the extracellular matrix (ECM) of natural tissue. The selection of the solvent is an important factor which affects the diameter, the surface morphology and the crystallinity of the electrospun fibers, and, accordingly, their mechanical properties as well as their degradation kinetics. Furthermore, the surface morphology of the electrospun fibres can be controlled by solvent vapour pressure to produce porous structures which might be helpful for cell adhesion and proliferation. In the present work, poly (L‐lactic acid) (PLLA) has been electrospun using solvents with different vapour pressures to investigate the influences of the solvent vapour pressure on morphology, diameter, crystallinity and mechanical properties of the electrospun fiber scaffolds. The results show that the vapour pressure of the solvents (or solvent mixtures) play an important role in the fiber diameter and crystallinity. Furthermore, the crystallinity of the fibers is increased by lowering the vapour pressure of the used solvent. In addition, the mechanical properties (e.g., tensile strength and Young's modulus) are strongly dependent on morphological features such average fibers diameter. The smaller the average diameter, the higher the tensile strength and Young's modulus.
A U.S. survey of patients with Parkinson's disease: Satisfaction with medical care and support groups
Authors: Dorsey E. Ray , Voss Tiffini S. , Shprecher David R. , Deuel Lisa M. , Beck Christopher A. , Gardiner Irenita F. , Coles Margaret A. , Burns Richard S. , Marshall Frederick J. , Biglan Kevin M.
Published: September 2010

Relatively little is known about patient satisfaction with Parkinson's disease (PD) care and the use of support groups in the United States. We surveyed members of the Muhammad Ali Parkinson's Disease Registry to assess satisfaction with medical care and to evaluate support group use. Satisfaction was measured on a 5‐point Likert scale, with high satisfaction defined as a four or five. We used multiple logistic regression to identify factors associated with high satisfaction and support group use. The response rate was 38% (726 of 1923). Most (57%) expressed high satisfaction with PD care. Individuals were most satisfied with the time their provider spent with them (61%) and PD education (56%) but least satisfied with prognostic information (35%) and information about non‐drug interventions (28%). Patients seeing a PD specialist were three times more satisfied with their care than those seeing a general neurologist (OR = 3.00, 95% CI: 1.92–4.71; P < 0.0001). Support group use is common, and 61% of survey respondents had attended one at any point. Caucasian race (OR = 2.85, 95% CI: 1.45–5.61), PD duration (OR = 1.05 per year, CI: 1.01–1.10), and PD specialist care (OR = 1.80, CI: 1.16–2.77) were associated with greater support group attendance. Overall, 49% reported high satisfaction with their support group. The greatest concerns were specific needs not being addressed (15%) and insufficient expertise within the group (14%). Most individuals with Parkinson's disease expressed high levels of satisfaction, especially with specialist care. Specialty care and improved education, in the clinic or through support groups, may enhance satisfaction and health care quality. © 2010 Movement Disorder Society