bluuebunny/crossref_metadata_2025 huggingface dataset:
Targeting Teaching: Does the Medium Matter? Online versus Paper Coursework
Authors: Hernández-Julián Rey , Peters Christina
Published: May 2012

If individuals process information differently when it is accessed electronically rather than on paper, then the transition from paper to electronic text may affect learning and retention. Using a randomized experiment, we compare learning outcomes of economics students who use electronic teaching tools with students who access the same material on paper. We find that students who submit homework online complete more assignments but have lower classroom attendance rates. However, there is no effect on exam scores. This suggests that while an electronic medium may enable instructional material to be accessed more easily, it does not significantly impact learning.
A Survey of US Dental Practices’ use of Social Media
Authors: Henry Rachel K , Molnar Amy , Henry Jon C
Published: May 2012

Aim

Social media is becoming the way for businesses, including health care professionals, to communicate with consumers. The study examines the use of social media by dental practices in the US.

Materials and methods

An electronic survey was sent to 22,682 dentists in the United States. The survey consisted of questions related to the use of social media in the dental practice. Data was analyzed using descriptive statistics and comparisons were made using a Fisher's exact test.

Results

A total of 573 responses were received. Social media was used in 52% of dental practices, the most common being Facebook. The use of social media was most commonly for marketing purposes (91%). Dentists younger than 45 years old were more likely to use social media in their practice than dentists 45 years or older (p < 0.001).

Conclusion

Dental practices actively use social media for marketing and communication. Many dentists are unsure how to measure the success of social media in their practice. Additional research is needed to measure the success of social media in a dental practice.

Clinical significance

Social media is a common way practices market and interact with their patients. There are some difficulties in determining what appropriate content for social media is and how to evaluate the success.

How to cite this article

Henry RK, Molnar A, Henry JC. A Survey of US Dental Practices’ use of Social Media. J Contemp Dent Pract 2012;13(2):137-141.
Relating the Marginal Fit of the Castings to the Accuracy of the Impressions made from Laminated Hydrocolloid Impression Technique: A Comparative Study
Authors: Sinha Manish , Thakur Bhavana , Gaikwad Ajay , Chaudhari Lalitkumar Dnyandeo , Kulkarni Adwait , Kulkarni Harshal
Published: May 2012

Aim

Relating the marginal fit of the castings, to the accuracy of the impression produced using laminated hydrocolloid impression technique, alginate and double-mixed polyvinyl siloxane. Basic objective of the study is to check the feasibility of the use of laminated hydrocolloid impression technique in the fixed partial denture.

Materials and methods

The precisely machined metal die was designed to simulate standard complete metal crown preparation. The preparation was mounted on cylindrical base of 20 mm length and diameter of 10 mm. Seven impressions were made from the each impression material onto the metal die, and total 21 impressions were obtained from all three impression materials, which were poured by the die stone, and stone die was prepared. Wax patterns were fabricated on stone dies obtained from each impression and then casting was done. All the castings were checked for the marginal fit on metal die after applying a uniform standardized load of 30 pounds using measuring microscope.

Results

Result revealed that the marginal fit of the castings obtained from group II (laminated hydrocolloid technique) and group III (double-mix polyvinyl polysiloxane) did not show the significant difference between the two of them. Marginal gap of the castings obtained from group I are significantly greater in comparison to the castings obtained from groups II and III (p < 0.01).

Conclusion

Group II (laminated hydrocolloid technique) impression material may be the choice of many clinicians over group III (double-mix polyvinyl polysiloxane) impression material. Group I (alginate impression material), though very cost-effective and easy to handle may not able to produce accurate results.

Clinical significance

The study gives overview of the best impression material that can be used clinically. Laminated hydrocolloid technique is the technique of choice.

How to cite this article

Sinha M, Thakur B, Gaikwad A, Chaudhari LD, Kulkarni A, Kulkarni H. Relating the Marginal Fit of the Castings to the Accuracy of the Impressions made from Laminated Hydrocolloid Impression Technique: A Comparative Study. J Contemp Dent Pract 2012;13(2):167-172.
A Nonsurgical Technique for the Removal of Overextended Gutta-Percha
Authors: Silva Emmanuel JNL , Herrera Daniel R , Lima Thiago F , Zaia Alexandre A
Published: May 2012

Aim

The present report describes and discusses a nonsurgical technique for the removal of overextended gutta-percha.

Background

Mechanical irritation results from overextension and the overextended material used during root canal obturation could produce an inflammatory reaction with an area of rarefaction in the periapical tissues. The healing process is not affected by the presence of filling materials as it is well tolerate by the periapical tissues, but it is accepted that a higher failure rate is found in overfilled teeth.

Case report

This clinical report describes one case with an overextended gutta-percha cone and a new nonsurgical technique to remove this material.

Conclusion

The technique described is a conservative, safe and plausible option to remove extruded gutta-percha in periapical area.

Clinical significance

Overextended gutta-percha cones could increase the failure of endodontic therapy. Commonly surgical procedures are indicated to remove this overextended material, but this nonsurgical technique could be a better treatment alternative and could increase the chances of success.

How to cite this article

Silva EJNL, Herrera DR, Lima TF, Zaia AA. A Nonsurgical Technique for the Removal of Overextended Gutta-Percha. J Contemp Dent Pract 2012;13(2):219-221.
Oral Rehabilitation of a Patient with Amelogenesis Imperfecta using Removable Overlay Denture: A Clinical Report
Authors: Vojdani Mahroo , Ghodsi S , Rasaeipour S
Published: May 2012

Aim

The aim of this study was oral rehabilitation of 17-yearold patient with amelogenesis imperfecta using removable overlay denture in order to satisfy her esthetic and functional expectations and enhance her self-image.

Background

Amelogenesis imperfecta (AI) is a group of genetic disorders that primarily affect the quality and quantity of amelogenesis in both primary and permanent dentitions. The main clinical characteristics are severe attrition, tooth sensitivity and unesthetic appearance.

Case report

This clinical report illustrates the oral rehabilitation of a 17-year-old girl with hypoplastic-hypomature type of AI with cobalt-chromium (Co-Cr) overlay removable partial denture (ORPD) that is one of the most economical and biocompatible replacements for noble metal and nickel-chromium (Ni-Cr) alloy.

Conclusion

The presented case report suggests that Co-Cr ORPD can be a good temporary or even permanent treatment option for AI patients with limited budget, low esthetic concerns or medical limitations.

Clinical significance

There are major advantages in cast metal ORPDs; they are simpler, less traumatic and less expensive than fixed prosthetic options. This case report supports their use in patients with amelogenesis imperfecta.

How to cite this article

Ghodsi S, Rasaeipour S, Vojdani M. Oral Rehabilitation of a Patient with Amelogenesis Imperfecta using Removable Overlay Denture: A Clinical Report. J Contemp Dent Pract 2012;13(2):227-231.
A Starter's Guide to Preclinical Teeth Arrangement: Simplified Clinometer
Authors: Reddy K Srinivas , Rao N Venugopal , Sudheer A , Rao C Sathya Nageswar
Published: May 2012

Arrangement of artificial teeth in a bilaterally symmetrical fashion with proper inclinations of teeth had been a challenging task for beginners. A variety of tools and guiding equipment have been developed to help students to learn teeth arrangement. Unfortunately, those tools were either costly or unsuitable for use with mean value articulators. This article attempts to introduce a simplified clinometer which can be attached to mean value articulator and can be used as a guide to arrange teeth in a bilaterally symmetrical manner by the undergraduates in both clinical and preclinical set-up.

Clinical significance

Training of the future dentists in sound esthetic principles in a preclinical environment, using this device, will increase the final clinical efficacy of their work.

Aim

The aim of this article is to provide a simple but effective device to undergraduate students to help them learn teeth arrangement easily and systematically.

How to cite this article

Rao NV, Sudheer A, Rao CSN Reddy KS. A Starter's Guide to Preclinical Teeth Arrangement: Simplified Clinometer. J Contemp Dent Pract 2012;13(2):236-239.
Dynamic Lowenstein Occupational Therapy Cognitive Assessment–Geriatric Version (DLOTCA–G): Assessing Change in Cognitive Performance
Authors: Katz Noomi , Averbuch Sarah , Bar-Haim Erez Asnat
Published: May 2012

OBJECTIVE. We studied the internal consistency reliability and construct validity of the new Dynamic Lowenstein Occupational Therapy Cognitive Assessment–Geriatric Version (DLOTCA–G), a dynamic version of the Lowenstein Occupational Therapy Cognitive Assessment–Geriatric Version (LOTCA–G), and examined the properties of the mediation system.

METHOD. Participants included 61 clients hospitalized after stroke in three rehabilitation centers (mean age = 77.6 yr, standard deviation [SD] = 6.2) and 52 healthy control participants (mean age = 77.8 yr, SD = 6.4). All participants were assessed with the DLOTCA–G.

RESULTS. Internal consistency reliability showed moderate to high α coefficient levels in all domains (αs = .68–.85) except the Memory domain (α = .26). Both groups benefitted from mediation, but the stroke clients needed more concrete levels of mediation (Levels 3–5).

CONCLUSION. The addition of mediation to the LOTCA–G is effective in providing insights into clients’ cognitive status and learning potential. Our findings are similar to the results of the validation study for the DLOTCA for adults and support the use and benefits of the dynamic version.
Minimally Invasive Sliding Hip Screw Insertion Technique
Authors: Khan Asif Z. , Parker Martyn J.
Published: May 2012

Sliding hip screws (SHS) are commonly used for fixation of extra-capsular hip fractures, and there is increasing use of minimally invasive methods of insertion of such devices. We describe a case series of 579 consecutive patients operated on by the senior author using such a technique. Data were collected prospectively and analysed retrospectively. The technique involves a 5cm incision, retraction of vastus lateralis superiorly by a chain retractor, and use of a SHS clamp to stabilise the plate on the femur. The patients had a mean age of 81 years, surgery time of 43 minutes and hospital stay of 17 days. 77% were female and 35% required a blood transfusion post-operatively. Everyone was mobilised fully weight-bearing post-operatively. Follow-up was at six weeks for radiographic review and then subsequently at one year. The commonest complications were superficial wound infection (1.7%), detachment of the plate (0.9%) and cut-out of the lag screw (0.5%).
Working With Native Americans on Water Issues
Authors: Walker Stephen A. , Baker Keri‐Ann C.
Published: May 2012

There are 566 federally recognized Native American tribes in the United States. They are independent sovereign nations. Court cases have found that Indian tribes have a status that is higher than a state. This special status provides tribes with unique sovereignty rights that are recognized in the allocation of water. There are various ways tribes' water rights are adjudicated. These include formal tribal water settlements that are ratified by Congress, other agreements, judicially declared water rights, and the Winters Doctrine.
Accepting the Affordability Challenge
Authors: Mumm Jason
Published: May 2012

Wouldn't it surprise people to know that in exchange for 25 cents, they could soak themselves with about 50 gallons of water? That's enough water to take about two baths, wash a load of laundry, run a dishwasher about 10 times, or brush your teeth about 400 times. But here's a question: If water is so ridiculously cheap, why is it that everyone seems to think that it's so impossibly expensive?
Bringing Water to the World
Authors: Breslin Ned , Lacey Marcia
Published: May 2012

Journal Editor Marcia Lacey sat down with Ned Breslin, Chief Executive Officer, Water For People (WFP), to talk about the organization, how it's evolved, and what its philosophies are in this interview conducted at AWWA headquarters in Denver, Colorado. For 21 years, WFP has been bringing water and sanitation to people who otherwise would have no access to it. Breslin discusses WFP's four guiding principles that work together to meet the basic human need to have access to safe drinking water.
Studying optical and nonlinear optical properties of synthesized azo dyes doped in polymer and liquid crystal using birefringence and Z‐ scan techniques
Authors: Nataj Nahid Hosain , Mohajerani Ezeddin , Nemati Hosein , Moheghi Alireza , Yazdanbakhsh Mohammad Reza , Goli Mohammad , Mohammadi Asadollah
Published: April 2012

The authors report the effect of the structure of new synthesized photo‐responsive azo dyes, based on N‐benzyl‐N‐ethyl‐aniline on their optical and nonlinear optical properties, when doped in polymer and liquid crystal (LC) hosts. Anisotropic response of dyes doped with polymer polymethyl methacrylate is studied using photo‐induced birefringence experiment and the optical nonlinearity of dyes doped in LC 5CB is measured using z‐scan technique. A correlation is established between dipole moment and optical/nonlinear optical response, which makes it possible to develop molecular design strategies to create structures with suitable anisotropic response and nonlinearity in various host systems for different applications. It is also shown how very little change in the structure of the dye may cause severe changes in the dipole moment and its nonlinear response. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Study of biodegradable polylactide/poly(butylene carbonate) blend
Authors: Wang Xuemei , Zhuang Yugang , Dong Lisong
Published: April 2012

Polylactide (PLA) was melt blended with poly(butylene carbonate) (PBC) in an effort to improve the toughness of the PLA without compromising its biodegradability and biocompatibility. The miscibility, morphology, thermal behavior, and mechanical properties of the blends were investigated. The blend was an immiscible two‐phase system with PBC uniformly dispersed within the PLA matrix. Because of the interfacial function, the incorporation of PBC accelerated the crystallization rate of PLA. By the incorporation of PBC, a polylatide‐based material with high stiffness and toughness was achieved. Even at 10% of PBC, high elongation at break of 139% was obtained, while the tensile strength remained as high as 50.7 MPa. The Pukanszky model gave credit to modest interfacial adhesion between PLA and PBC although PLA/PBC is an immscible blend. The plastic deformation, occurring via debonding process, is an important energy‐dissipation process and leads to a toughened, biodegradable polymer blend. The important point is that the toughening mechanism requires only modest level of adhesion between particles and the polymer. The molecular mobility is a crucial factor for yield stress and plastic flow. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Study of biodegradation evolution during composting of polyethylene–starch blends using scanning electron microscopy
Authors: Vieyra H. , Aguilar‐Méndez M. A. , San Martín‐Martínez E.
Published: April 2012

The end product of low‐density polyethylene–starch was manufactured by injection molding process. Four starch concentrations (10, 25, 40, and 50%) were used for blend preparations, which were injected into the mold of a 250 mL commercial cup. A control sample of neat polyethylene (PE) was also included. Square coupons (4 cm × 4 cm) of each blend were buried in the middle of a 50 cm pile of compost. Samples were recovered, washed, dried, and weighed after 25, 50, 75, 100, and 125 days beneath the compost. Scanning electron microscopy (SEM) analysis was performed on the samples to track the biodegradability evolution. A SEM scandium analyzer was used to measure the size and number of pores and the eroded area. Weight loss measurements were conducted to validate the SEM observations. Total biodegradation time was determined by mathematical analysis and graphical extrapolation. SEM analysis revealed the formation of pores, cavities, discontinuities, and cracks resulting from the time beneath the compost. Pore measurements revealed that the specimen composed of 40% starch and submerged for 125 days experienced up to 25% eroded area. Pure PE remained practically unchanged for the 125‐day period. Fourier transform infrared spectroscopy studies also demonstrated the biodegradation of PE in PE–starch blends. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synergistic inhibition of human glioma cell line by temozolomide and PAMAM‐mediated miR‐21i
Authors: Qian Xiao‐Min , Shi Zhen‐Dong , Ren Yu , Liu Chao‐Yong , Ji Ya‐Ru , Long Li‐Xia , Pu Peiyu , Sheng Jing , Yuan Xu‐Bo , Kang Chun‐Sheng
Published: April 2012

Temozolomide (TMZ) is a promising chemotherapeutic agent for treating glioblastomas. However, resistance develops quickly and with a high frequency. Efforts to overcome chemoresistance are, therefore, critically needed. In present study, a poly(amidoamine; PAMAM) dendrimer was used as a vector to deliver microRNA‐21 inhibitor (miR‐21i) into U87 cells and the chemosensitivity of the combination effect of miR‐21i and TMZ for glioma therapy was investigated. Flow cytometry analysis showed the uptake efficiency of microRNA‐21 inhibitor after complexation with PAMAM. Real‐time PCR and in situ hybridization indicated that, compared with TMZ or miR‐21i treated cells, cells simultaneously treated with miR‐21i and TMZ showed a remarkable decrease in the microRNA‐21 (miR‐21) level. The transfection of miR‐21i enhanced the chemosensitivity by significantly decreasing the IC50 value of TMZ to glioma cells. Knockdown of miR‐21 promoted the cells' apoptosis, and at the same time, inhibited cell invasion. In conclusion, the combination treatment of glioma cells with TMZ and miR‐21i could yield a synergistic effect in inhibition of human glioma cell line. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
How does a polymerized compounding affect the nucleation effect of a sorbitol derivative nucleating agent in isotactic polypropylene melt crystallization?
Authors: Yi Qing‐Feng , Wen Xiao‐Jing , Niu Hui , Dong Jin‐Yong
Published: April 2012

In this article, we investigate the effect of a new polymerized compounding method on the nucleation behavior of a sorbitol derivative nucleating agent for isotactic polypropylene (iPP). This method uses a sorbitol derivative nucleating agent, for example, 1,3: 2,4‐dimethylbenzylidene sorbitol (DMBS), which displays itself as aggregated fibrillar crystals, as a support for C2‐symmetric ansa‐metallocenes best represented by rac‐Me2Si[2‐Me‐4‐Naph‐Ind]2ZrCl2. Activating this DMBS‐supported metallocene catalyst with methylaluminoxane, a following in situ propylene polymerization results in the formation of iPP/DMBS composition polymers having controllable DMBS concentrations (by virtue of polymerization productivity control), with the DMBS dispersion driven by catalyst fragmentation. Three iPP/DMBS composition polymers having DMBS concentrations of 0.22, 031, and 0.52 wt % were prepared by this means, which, along with their analog melt‐mixed counterparts, were subjected to melt crystallization kinetics and crystal morphology studies using differential scanning calorimetry, polarized optical microscopy, and UV–vis spectroscopy. With systematically higher nucleation efficiencies and lower crystallization activation energies, the polymerized iPP/DMBS composition polymers exhibited generally stronger DMBS nucleation effects when compared with their melt‐mixed counterparts. Such a benefit was accounted for by a more homogeneous dispersion and better wettability by iPP matrix of DMBS that led to the formation of more nucleation sites and faster crystallization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Free radical polymerization of butyl acrylate in monodispersed droplets: Comparison between two heating strategies
Authors: Zhendong Liu , Yangcheng Lu , Bodong Yang , Guangsheng Luo
Published: April 2012

Monodispersed droplets could be easily generated in coaxial microdevice, and a reaction based upon these discrete droplets is an attractive approach thanks to isolated reaction units, efficient mixing, and precise residence time control. In this work, free radical polymerization of butyl acrylate was conducted in monodispersed droplets of several hundred microns. Two different heating methodologies, microwave heating and conventional heating with oil bath were adopted to initiate polymerization, respectively. The polymerization under conventional heating could be regarded as an isothermal process, while the polymerization under microwave heating gradually underwent a temperature increase. So the poly (butyl acrylate) obtained by microwave heating has larger average molecular weight and higher polydispersity index. Meanwhile, the conversion of butyl acrylate was significantly improved by microwave heating compared with conventional heating, even though the reaction temperature under microwave heating might be lower than the temperature of the oil bath. This remarkable enhancement was a direct proof of the nonthermal effect of the microwave field for free radical polymerization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Progression of leprosy neuropathy: a case series study
Authors: Vital Robson T. , Illarramendi Ximena , Nascimento Osvaldo , Hacker Mariana A. , Sarno Euzenir N. , Jardim Marcia R.
Published: April 2012

A need still exists to determine the clinical and neurophysiological characteristics of leprosy neuropathy at distinct times of the disease by different methods that measure the various nerve fiber functions. A prospective clinical study was performed with 10 paucibacillary (PB) and 12 multibacillary (MB) patients evaluated at diagnosis and one year after cessation of multidrug therapy (MDT). Peripheral nerve function was assessed clinically and by means of the sympathetic skin response, skin vasomotor reflex, and nerve conduction study (NCS). At diagnosis, 73% of the total 22 patients had nerve function impairment (NFI). Autonomic function (χ2= 5.5, P= 0.019) and NCS (χ2= 7.765, P= 0.01) were significantly more altered in MB than PB patients. At final evaluation, NFI of the MB patients had worsened, especially among the six who had leprosy reaction. As the NFI of PB patients showed improvement, a significant difference between the two groups (χ2= 12.320, P= 0.001) was observed. A high prevalence of neuropathy was observed in newly diagnosed patients. Associating different tests with a thorough clinical neurological evaluation increases detection rates.
Does cerebral lateralization develop? A study using functional transcranial Doppler ultrasound assessing lateralization for language production and visuospatial memory
Authors: Groen Margriet A. , Whitehouse Andrew J. O. , Badcock Nicholas A. , Bishop Dorothy V. M.
Published: April 2012

In the majority of people, language production is lateralized to the left cerebral hemisphere and visuospatial skills to the right. However, questions remain as to when, how, and why humans arrive at this division of labor. In this study, we assessed cerebral lateralization for language production and for visuospatial memory using functional transcranial Doppler ultrasound in a group of 60 typically developing children between the ages of six and 16 years. The typical pattern of left‐lateralized activation for language production and right‐lateralized activation for visuospatial memory was found in the majority of the children (58%). No age‐related change in direction or strength of lateralization was found for language production. In contrast, the strength of lateralization (independent of direction) for visuospatial memory function continued to increase with age. In addition, boys showed a trend for stronger right‐hemisphere lateralization for visuospatial memory than girls, but there was no gender effect on language laterality. We tested whether having language and visuospatial functions in the same hemisphere was associated with poor cognitive performance and found no evidence for this “functional crowding” hypothesis. We did, however, find that children with left‐lateralized language production had higher vocabulary and nonword reading age‐adjusted standard scores than other children, regardless of the laterality of visuospatial memory. Thus, a link between language function and left‐hemisphere lateralization exists, and cannot be explained in terms of maturational change.
Vibrational and electronic circular dichroism monitoring of copper(II) coordination with a chiral ligand
Authors: Wu Tao , Zhang Xiao‐Peng , Li Cheng‐Hui , Bouř Petr , Li Yi‐Zhi , You Xiao‐Zeng
Published: April 2012

Novel copper(II) coordination compounds with chiral macrocyclic imine ligands derived from R‐/S‐camphor were asymmetrically synthesized and characterized with the aid of chiroptical spectroscopies. Crystal structures of both enantiomers were determined by single crystal X‐ray diffraction analysis. Circular dichroism (CD) spectra were analyzed using a simplified exciton model as well as quantum chemical computations. The absolute configuration of the copper(II) coordination compounds determined from CD was found consistent with the crystal data. The copper(II) complexes were further investigated by vibrational CD (VCD) measurement combined with density functional theory calculation. The complex formation was evidenced by spectral shifts of the characteristic bands in the CD and VCD spectra. Chirality 24:451–458, 2012. © 2012 Wiley Periodicals, Inc.
Absolute configurations of integracins A, B, and 15′‐dehydroxy‐integracin B
Authors: Liu Hai‐Li , Huang Xiao‐Yin , Li Jia , Xin Guo‐Rong , Guo Yue‐Wei
Published: April 2012

Integracins A (1) and B (2), potent HIV‐1 integrase inhibitors, and 15′‐dehydroxy‐integracin B (3) were isolated for the first time from Chinese mangrove plant Sonneratia hainanensis. Their absolute configurations were determined by the Mosher's method and specific rotation analysis of alcohols (6 and 7) obtained from integracin A in two steps and by chemical correlation. Integracin A (1) also exhibited significant cytotoxicity against the tumor cell lines HepG2 and NCI‐H460 with both 100% inhibitions at 25 µg/ml. Chirality 24:459–462, 2012. © 2012 Wiley Periodicals, Inc.
Chiral recognition of metalaxyl enantiomers by human serum albumin: evidence from molecular modeling and photophysical approach
Authors: Ding Fei , Li Xiu‐Nan , Diao Jian‐Xiong , Sun Ye , Zhang Li , Sun Ying
Published: April 2012

Metalaxyl is an acylamine fungicide, belonging to the most widely known member of the amide group. This task is aimed to scrutinize binding region and spatial structural change of principal vector human serum albumin (HSA) complex with (R)‐/(S)‐metalaxyl by exploiting molecular modeling, steady‐state and time‐resolved fluorescence, and circular dichroism (CD) approaches. According to molecular modeling, (R)‐metalaxyl is situated within subdomains IIA and IIIA and the affinity of site I with (R)‐metalaxyl is greater than site II, whereas (S)‐metalaxyl is only located at subdomain IIA and the affinity of (S)‐metalaxyl with site I is superior compared with that with (R)‐metalaxyl. This coincides with the competitive ligand binding, guanidine hydrochloride‐induced unfolding of protein, and hydrophobic 8‐anilino‐1‐naphthalenesulfonic acid experiments; the acting forces between (R)‐/(S)‐metalaxyl and HSA are hydrophobic, π–π interactions, and hydrogen bonds, as derived from molecular modeling. Fluorescence emission manifested that the complex of (R)‐/(S)‐metalaxyl to HSA is the formation of adduct with an affinity of 104 M−1, which corroborates the time‐resolved fluorescence that the static type was operated. Furthermore, the changes of far‐UV CD spectra evidence the polypeptide chain of HSA partially unfolded after conjugation with (R)‐/(S)‐metalaxyl. Through this work, we envisage that it can offer central clues on the biodistribution, absorption, and bioaccumulation of (R)‐/(S)‐metalaxyl. Chirality 24:471–480, 2012. © 2012 Wiley Periodicals, Inc.
Chiral separation of cathinone derivatives used as recreational drugs by HPLC‐UV using a CHIRALPAK® AS‐H column as stationary phase
Authors: Mohr Stefan , Taschwer Magdalena , Schmid Martin G.
Published: April 2012

Cathinone derivatives gained high popularity on the recreational drugs market during the past 10 years. All these compounds are chiral, and the pharmacological potency of the enantiomers of these stimulants is supposed to differ. The goal of this research was to develop a reliable and easy‐to‐perform high‐performance liquid chromatography ultraviolet method for the chiral separation of a set of 24 cathinone derivatives. A commercially available CHIRALPAK® AS‐H column consisting of amylose tris [(S)‐α‐methylbenzylcarbamate] coated on 5‐µm silica gel was found to be suitable to resolve a majority of the tested compounds. High‐performance liquid chromatography measurements were performed in normal phase mode under isocratic conditions with a mobile phase consisting of hexane, isopropanol, and triethylamine at a flowrate of 1 ml/min. The ratio between hexane and isopropanol was optimized by means of three model substances. Under final conditions with a mobile phase of hexane, isopropanol, and triethylamine (97:3:0.1), 19 out of 24 compounds were successfully resolved into their enantiomers and detected at a wavelength of 254 nm. A correlation between the substituents of the nitrogen atom and the separation results are shown. Furthermore, enantiomer separation results of four cathinone derivatives were compared with the results of their amphetamine analogs. Chirality 24:486–492, 2012. © 2012 Wiley Periodicals, Inc.
Tracking chiral polychlorinated biphenyl sources near a hazardous waste incinerator: Fresh emissions or weathered revolatilization?
Authors: Asher Brian J. , Ross Matthew S. , Wong Charles S.
Published: April 2012

The Swan Hills Treatment Centre (SHTC), located in central Alberta, is the primary facility in Canada for incinerating polychlorinated biphenyls (PCBs). Past studies have shown significant contamination by PCBs and other pollutants of the immediate surrounding region. However, it is unclear whether the major source of contamination to the region's atmosphere is historical release incidents or long-term emissions. To answer this question, concentrations of PCBs and enantiomer fractions of several PCB congeners were determined in soil and air, via polyurethane foam passive samplers, over several seasons between 2005 and 2008. Concentrations in both media were highest for samples collected closest to the SHTC, demonstrating a concentration profile typical of a point source. Enantiomer analysis revealed racemic profiles in air for all congeners, while soil was significantly nonracemic for PCB 95, indicating significant microbial degradation of this congener. However, the primary source of this congener, and likely others, in the surrounding atmosphere is recent and continual releases from the SHTC, rather than the release of weathered PCBs previously deposited to local soils. In addition, enantiomer compositions for PCBs 95 and 149 yielded minimum biotransformation half-lives of 25 and 97 years, respectively, suggesting an expected gradual decline in the region's PCB load once fresh inputs cease. Environ. Toxicol. Chem. 2012; 31: 1453–1460. © 2012 SETAC
Environmental and human exposure to soil chlorinated and brominated polycyclic aromatic hydrocarbons in an urbanized region
Authors: Ni Hong-Gang , Zeng Eddy Y.
Published: April 2012

Nine chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/BrPAHs) and five parent polycyclic aromatic hydrocarbons (PAHs) were measured in urban surface soil and fly ash samples collected from Shenzhen, south China in winter 2010. The concentrations of total Cl/BrPAHs and PAHs in soil ranged from below the reporting limit to 142 ng/g and from 4.34 to 158 µg/g, respectively, and in fly ash they ranged from 17.7 to 19.5 ng/g and 26.1 to 28.3 µg/g, respectively. Concentrations of Cl/BrPAHs and parent PAHs were not significantly correlated with each other in soil or in fly ash, suggesting that Cl/BrPAHs were formed mainly by mechanisms other than direct halogenation of parent PAHs. Estimated mass inventories of 2-BrFlu varied from 68.1 kg in commercial land to 669 kg in countryside land, the highest among all Cl/BrPAHs. Loss fluxes via soil erosion accounted for only small proportions of total soil mass inventories of Cl/BrPAHs. Average daily human intake via soil ingestion decreased with increasing age, with 2-BrFlu as the main contributor. Children of 0 to 8 years old were the most sensitive subgroup (13.7 pg/kg body wt/d for total Cl/BrPAHs), and females were more sensitive than males in the same age group. The mean dioxin-like toxic equivalency quotient (TEQ) concentration of total Cl/BrPAHs (0.008 ng-TEQ/g) was lower in soil than in fly ash (0.06 ng-TEQ/g). Conversely, the mean TEQ concentration of total parent PAHs (2.23 ng-TEQ/g) was higher in soil than in fly ash. Environ. Toxicol. Chem. 2012; 31: 1494–1500. © 2012 SETAC
Phototoxicity of TiO2 nanoparticles under solar radiation to two aquatic species: Daphnia magna and Japanese medaka
Authors: Ma Hongbo , Brennan Amanda , Diamond Stephen A.
Published: April 2012

One target of development and application of TiO2 nanoparticles (nano-TiO2) is photochemical degradation of contaminants and photo-killing of microbes and fouling organisms. However, few ecotoxicological studies have focused on this aspect of nano-TiO2, specifically whether this photoreactivity might significantly increase hazard and risk of the materials in the natural environment. In the present study, we evaluated acute phototoxicity of nano-TiO2 under simulated solar radiation (SSR) to two aquatic species–Daphnia magna and Japanese medaka, using 48-h and 96-h assays, respectively. A thorough characterization of the exposure system was performed by measuring particle agglomeration and TiO2 concentration in suspension in a time-course manner. Sedimentation and loss of bulk concentration of nano-TiO2 particles occurred at all concentrations above 2 mg/L and was more significant as concentration increased. Phototoxicity of nano-TiO2 under SSR was enhanced by two to four orders of magnitude as compared to toxicity under ambient laboratory light, with a 48-h median lethal concentration (LC50) of 29.8 µg/L in D. magna and a 96-h LC50 of 2.2 mg/L in medaka. Our results also indicate that these effects are dependent on simultaneous exposure of the organisms to nanoparticles and SSR. This dramatic increase in toxicity of nano-TiO2 at environmentally realistic levels of SSR indicates the need to incorporate this mode of action into risk assessment for nano-TiO2 and other photoreactive nanomaterials. Environ. Toxicol. Chem. 2012; 31: 1621–1629. © 2012 SETAC
Serum insulin‐like, growth factor binding protein‐related protein 1 (IGFBP‐rP1) and endometrial cancer risk in Chinese women
Authors: Zhan Yan , Wang Jiamin , Ma Yu , Liu Zhiwei , Xu Haiming , Lu Shiming , Lu Bingjian
Published: April 2012

Hyperinsulinemia and the metabolic syndrome confer increased risks of endometrial carcinoma. The roles of insulin, and, insulin‐like growth factor‐binding proteins (IGFBPs) in the etiology of endometrial carcinoma, remain unclear. We recruited 206 patients with endometrial carcinoma and 350 healthy women to a case–control study of fasting insulin and IGFBP‐related protein 1 (IGFBP‐rP1) in a Chinese tertiary centre. Patients with endometrial carcinoma had higher insulin concentrations (14.8 ± 16.7 vs. 8.1 ± 9.4 μU/mL; p < 0.001) and lower IGFBP‐rP1 levels (17.5 ± 17.2 vs. 22.4 ± 22.8 μg/L; p = 0.018) than controls. High insulin and IGFBP‐rP1 levels were both positively and negatively associated with endometrial cancer (odds ratio for the highest tertile versus the lowest tertile: insulin: 4.11; 95% CI = 2.61–6.47; IGFBP‐rP1: 0.38; 95% CI = 0.24–0.60). Logistic regression analysis confirmed the associations between endometrial carcinoma and fasting insulin or IGFBP‐rP1 after adjustments for age, BMI, serum glucose, cholesterol, triglycerides and high‐density lipoprotein cholesterol (odds ratio for the highest tertile versus the lowest tertile: insulin: 2.13; 95% CI = 1.30–3.49; IGFBP‐rP1: 0.57; 95% CI = 0.34–0.94). Hyperinsulinemia and high IGFBP‐rP1 levels confer altered risks for endometrial carcinoma.
Perfluorinated alginate for cellular encapsulation
Authors: Gattás‐Asfura Kerim M. , Fraker Christopher A. , Stabler Cherie L.
Published: April 2012

Molecules of pentadecafluorooctanoyl chloride (PFC) were grafted onto alginate (Alg) using a linear poly(ethylene glycol) linker and amide bonds. The resulting Alg‐PFC material was characterized by proton nuclear magnetic resonance and infrared spectroscopies. The degree of PFC functionalization significantly influenced the physical and chemical properties of Alg‐PFC, particularly when the resulting polymer was ionically crosslinked into hydrogels. Alg‐PFC hydrogel beads fabricated via Ba2+ crosslinking were found to match the permeability properties of control alginate beads, except upon swelling over time in culture media. When used to encapsulate MIN6 cells, a beta cell line, Alg‐PFC beads demonstrated enhanced cell proliferation over alginate control beads. These results indicate that Alg‐PFC hydrogels retain some of the PFC's biological‐relevant benefits, such as enhancement of mass transport and bioinertness, to enhance cellular viability within alginate three‐dimensional hydrogel environments. We envision these functionalized hydrogels to be particularly useful in the encapsulation of cells with a high metabolic demand, such as pancreatic islets. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 2012.
Micropatterned antibody‐terminated nanocomposites (MANs) fabricated using layer‐by‐layer lift‐off (LBL‐LO) technique
Authors: Shaik Jameel , Mills David K.
Published: April 2012

Patterned functional biomolecular surfaces have been created using a wide range of fabrication methods for applications in cell‐based studies, with the most common methods based on photolithography or soft lithography. In this study, a simple fabrication method combining photolithography, layer‐by‐layer (LbL) self‐assembly, and photoresist lift‐off (LO) was used to create spatially defined nanocomposite micropatterns of antibodies on polyelectrolyte‐protein multilayer beds. The two components of the micropatterned surfaces consisted of an anti‐CD44 rat monoclonal antibody atop a vitronectin‐coated multilayer film and an anti‐rat osteopontin (MPIIIB101) anitibody atop a fibronectin‐coated multilayer film. The micropatterned antibody‐terminated nanocomposites (MANs) were characterized using bright field microscopy, surface profilometry, and atomic force microscopy. The results demonstrate that LbL‐LO method can be successfully used to create patterns of proteins and antibodies in precise spatial arrangements. The MAN surfaces can be utilized in many bionanotechnology applications, including patterned cell cocultures or tricultures, cytotoxicity testing, drug screening, and biosensing. In addition, the general fabrication approach used in this study is applicable to other antibodies and other ligands. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2012.
Preparation and Characterization of Epoxy/Inorganic Anti‐electrostatic Nanocomposites Using Submicrometer Al(OH)3 and Colloid Al2O3
Authors: Chen Jung‐Hui , Liu Shao‐Te , Cheng Pao‐Swu
Published: April 2012

New organic‐inorganic hybrid materials and their anti‐electrostatic hybrid membranes are prepared via sol‐gel process. The polycondensation of epoxy oligomers and AEAPS/Al2O3 complexes which are organically surface modified submicrometer aluminum trihydroxide inorganic fillers with an active aminoterminal silane coupling agent, N‐(2‐aminoethyl)‐3‐aminopropyltrimethoxysilane (AEAPS), are performed. AEAPS enhances the interfacial interactions between the inorganic fillers and epoxy polymers. Meanwhile, this coupling agent maintains well dispersion of fillers in these composites. To improve the mechanical strength and thermal stability, pyromellitic dianhydride (PMDA) is used as curing agent. These hybrid films prepared from this method have excellent physical properties, such as UV‐shielding, high transmission in visible resign (> 85%), high hardness (7∼8H) , high adhesive force (7∼8) and low relative surface resistance (9.71 × 1011∼1.26 × 1010 Ω/cm2) with anti‐electrostatic characters. For thermal resistance, the best Td value of epoxy/PMDA/AEAPS/Al2O3 is 378.6 °C which is 85.4 °C higher than that of neat epoxy resin. Physical properties of these materials are almost the same as those of the nanocomposites prepared from expensive colloid Al2O3. Evidences from TEM micrograph show that the inorganic additives are dispersed evenly in organic matrix with nanometer scale.
A new algorithm for solving differential equations
Authors: Hosseini K. , Biazar J. , Ansari R. , Gholamin P.
Published: April 2012

Different analytic methods have been proposed to solve differential equations, so far. In this paper, a novel analytic method that efficiently solves ODEs is presented. This method requires only the calculation of the first Adomian polynomial, namely A0, and does not need to solve the functional equation in each iteration, as well as provides less computational work than other existing methods. Some important ordinary differential equations including the Lane–Emden equation of index m, the logistic nonlinear differential equation, and the Riccati equation are considered to illustrate the efficiency of the proposed algorithm. Copyright © 2012 John Wiley & Sons, Ltd.
Design of laminated piezocomposite shell transducers with arbitrary fiber orientation using topology optimization approach
Authors: Kiyono C.Y. , Silva E.C.N. , Reddy J.N.
Published: April 2012

Sensor and actuator based on laminated piezocomposite shells have shown increasing demand in the field of smart structures. The distribution of piezoelectric material within material layers affects the performance of these structures; therefore, its amount, shape, size, placement, and polarization should be simultaneously considered in an optimization problem. In addition, previous works suggest the concept of laminated piezocomposite structure that includes fiber‐reinforced composite layer can increase the performance of these piezoelectric transducers; however, the design optimization of these devices has not been fully explored yet. Thus, this work aims the development of a methodology using topology optimization techniques for static design of laminated piezocomposite shell structures by considering the optimization of piezoelectric material and polarization distributions together with the optimization of the fiber angle of the composite orthotropic layers, which is free to assume different values along the same composite layer. The finite element model is based on the laminated piezoelectric shell theory, using the degenerate three‐dimensional solid approach and first‐order shell theory kinematics that accounts for the transverse shear deformation and rotary inertia effects. The topology optimization formulation is implemented by combining the piezoelectric material with penalization and polarization model and the discrete material optimization, where the design variables describe the amount of piezoelectric material and polarization sign at each finite element, with the fiber angles, respectively. Three different objective functions are formulated for the design of actuators, sensors, and energy harvesters. Results of laminated piezocomposite shell transducers are presented to illustrate the method. Copyright © 2012 John Wiley & Sons, Ltd.
An algorithm to identify medical practices common to both the General Practice Research Database and The Health Improvement Network database
Authors: Cai Bing , Xu Weifeng , Bortnichak Edward , Watson Douglas J.
Published: April 2012

Purpose

To identify practices common to both the General Practice Research Database and The Health Improvement Network database for purposes of combining the databases for analysis without duplicate records.

Methods

We developed two independent algorithms to identify practices common to the two databases. The first used the total number of patients in the therapy and clinical data sets and the total number of etoricoxib and celecoxib users each year during the study period. The second used the total number of patients stratified by gender and four different categories of birth year. Further checking of potential matched practice pairs identified by the two algorithms was performed by comparing the patient‐level medical records by birth year, dates of clinical visits, and diagnosis codes.

Results

Three hundred twelve potential matched pairs of practices were found by both algorithms. Fifteen additional potential pairs were matched by only one algorithm: 13 by algorithm 1 (A1) only and 2 by algorithm 2 (A2) only. The examination of the patient‐level visit dates and diagnosis codes for the matches revealed that all of the 327 potential pairs of duplicate practices were in fact the same practice in the two databases.

Conclusions

The two algorithms successfully found the practices common to the two different databases without de‐identifying the practices. The identification of the common practices allows for combining the two databases without duplicate records to create a larger data set for analysis, with 168 more practices than when using the General Practice Research Database alone, or with 268 more practices than when using The Health Improvement Network alone. Copyright © 2012 John Wiley & Sons, Ltd.
2,3‐bis(5‐Hexylthiophen‐2‐yl)‐6,7‐bis(octyloxy)‐5,8‐di(thiophen‐2‐yl) quinoxaline: A good construction block with adjustable role in the donor‐π‐acceptor system for bulk‐heterojunction solar cells
Authors: Li Shuang , He Zhicai , Yu Jian , Chen Su'an , Zhong Aoshu , Wu Hongbin , Zhong Cheng , Qin Jingui , Li Zhen
Published: April 2012

Three 2,3‐bis(5‐hexylthiophen‐2‐yl)‐6,7‐bis(octyloxy)‐5,8‐di(thiophen‐2‐yl)‐quinoxaline (BTTQ)‐based conjugated polymers, namely, PF‐BTTQ (P1), PP‐BTTQ (P2), and PDCP‐BTTQ (P3), were successfully synthesized for efficient polymer solar cells (PSCs) with electron‐rich units of fluorene and dialkoxybenzene and electron‐deficient unit dicyanobenzene, respectively. All the polymers exhibited good solubility in common organic solvents and good thermal stability. Their deep‐lying HOMO energy levels enabled them good stability in the air and the relatively low HOMO energy level assured a higher open circuit potential when used in PSCs. Bulk‐heterojunction solar cells were fabricated using these copolymers blended with a fullerene derivative as an acceptor. All of them exhibited promising performance, and the best device performance with power conversion efficiency up to 3.30% was achieved under one sun of AM 1.5 solar simulator illumination (100 mW/cm2). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012