bluuebunny/crossref_metadata_2025 huggingface dataset:
Combining Polymers with the Functionality of Proteins: New Concepts for Atom Transfer Radical Polymerization, Nanoreactors and Damage Self-reporting Materials
Authors: Bruns Nico , Lörcher Samuel , Makyła Katarzyna , Pollarda Jonas , Renggli Kasper , Spulber Mariana
Published: November 2013

Proteins are macromolecules with a great diversity of functions. By combining these biomolecules with polymers, exciting opportunities for new concepts in polymer sciences arise. This highlight exemplifies the aforementioned with current research results of our group. We review our
discovery that the proteins horseradish peroxidase and hemoglobin possess ATRPase activity, i.e. they catalyze atom transfer radical polymerizations. Moreover, a permeabilization method for polymersomes is presented, where the photo-reaction of an ?-hydroxyalkylphenone with block copolymer
vesicles yields enzyme-containing nanoreactors. A further intriguing possibility to obtain functional nanoreactors is to enclose a polymerization catalyst into the thermosome, a protein cage from the family of chaperonins. Last but not least, fluorescent proteins are discussed as mechanoresponsive
molecular sensors that report microdamages within fiber-reinforced composite materials.
Materials Taking a Lesson from Nature
Authors: Tian Liangfei , Croisier Emmanuel , Frauenrath Holger
Published: November 2013

Structural biomaterials with their often extraordinary properties and versatile functions are typically constructed from very limited sets of building blocks and types of supramolecular interactions. In this review we discuss how, inspired by nature's design principles for protein-based
materials, oligopeptide-modified polymers can be used as a versatile toolbox to program nanostructure and hierarchical structure formation in synthetic materials.
Synthesis of Nanometer-sized Rod–Coil Block Copolymers
Authors: König Hannah M. , Kilbinger Andreas F. M.
Published: November 2013

We present the solid-supported synthesis of a linear rigid rod-like tetradeca(p-benzamide) nanorod as well as a pentadeca( p -benzamide) nanorod carrying an amide N-hexyl side chain at the center of the rod (on the 8th amino acid of the molecule). These nanorods
were conjugated with solubilizing poly(ethylene glycol) chains and their solution aggregation was investigated. Both rod–coil block copolymers form soluble aggregates even in polar aprotic solvents such as DMF and DMSO. We show that sequence-controlled nanometer-sized shape persistent aramide scaffolds can readily be prepared using solid-supported synthesis.
Protein–Polymer Supramolecular Assemblies: A Key Combination for Multifunctionality
Authors: Palivan Cornelia G. , Zhang Xiaoyan , Meier Wolfgang
Published: November 2013

2D/3D structures resulting from self-assembly of amphiphilic block copolymers can be combined with bioactive compounds, such as proteins and enzymes, to create supramolecular assemblies with specific desired properties and functionality. Chemical tuning of the architecture and properties
of supramolecular assemblies to accommodate sensitive biomolecules allows the development of new soft hybrid materials that benefit from the robustness of polymers and from the functionality of biomolecules. The encapsulation/insertion of biomolecules (enzymes, mimics, proteins) in self-assembling
block copolymer vesicles enables design of 'nanoreactors' both in solutions and at surfaces for highly diverse applications, ranging from production of antibiotics to creation of artificial organelles. When membrane proteins are inserted into polymer membranes, it is possible to generate functional
membranes or active surfaces with a rapid and specific response. In addition, the selective binding of ligand-terminated polymers holds potential for targeted delivery of drugs, or for immobilization on solid support, to provide functional 3D assemblies on an extended surface.
Frontiers in Polymer Chemistry
Authors: Schlüter A. Dieter
Published: November 2013

The article shows how the initial concept of Staudinger on linear macromolecules was expanded topologically by increasing the cross-section diameter of polymer chains and by introducing sheet polymers with planar rather than the commonly known linear repeat units. The two concrete projects
addressed are the synthesis of dendronized and of two-dimensional polymers. It is explained how these novel macromolecules were achieved and which obstacles had to be overcome but also where these frontiers in polymer chemistry might lead to new insights in polymer science in general and novel
applications in particular. The article also provides insights into analytical issues because both target macromolecules are in an extraordinarily high molar mass range and contrast/sensitivity issues can turn rather serious in particular for the two-dimensional polymers.
Advances in Janus Nanoparticles
Authors: Reguera Javier , Kim Hyewon , Stellacci Francesco
Published: November 2013

The design and synthesis of Janus nanoparticles has attracted great scientific interest in recent years. Novel optical, electronic, magnetic, and superficial properties emerge from their dimensions and unique morphology at the nanoscale. Additional properties emerge from the binary
spatial distribution of functionalities on a single anisotropic nanoparticle, like amphiphilicity or new catalytic effects. As a result, Janus nanoparticles are highly versatile nanomaterials with great potential in different scientific and technological fields. In this paper, some of the
advances in inorganic – inorganic and inorganic–organic Janus nanoparticles are highlighted. First, the main strategies followed to synthesize Janus nanoparticles are described. Second, some of the properties and applications of Janus nanoparticles are described in four different fields: interfaces and emulsions, biomedicine, catalysis, and molecular colloids and suprastructures.
Phosphate Test 2.0
Authors: Stalder Etienne , Zumbuehl Andreas
Published: November 2013

The accurate measurement of the phosphate content of a liposomal suspension is important when working with differential scanning calorimetry. Standard phosphate tests date back several decades and require extended hands-on time. Here, we present a rapid version of a phosphate test taking
advantage of microwave-assisted chemical digestion and multiwell plate reading technology allowing for the fast and accurate testing of many samples in parallel.
Research Methods Coverage in Medical and Health Science Curricula in Nepal
Authors: Simkhada P , Van Teijlingen E , Pokharel T , Devkota B , Pathak RS
Published: November 2013

Higher education institutions in Nepal have been offering different types of health sciences programmes over the last few decades. With the growing number of education institutions, the range of programmes has also increased. Currently, five higher education institutions – TU, KU, PU, PoU and BPKIHS are providing health sciences course at undergraduate and graduate level. TU being the leading university to offer most of health science programmes, there is observable influence in the curriculum contents and design of the remaining four institutions. However, a variation is observed in structure of curriculum within and between institutions. The curricula of Pokhara University are better designed and recent compared to other while the curricula of TU are less revised and comparatively old. Curricula in general health sciences are detailed and favourable to research methodology contents. DOI: http://dx.doi.org/10.3126/nje.v3i3.9185 Nepal Journal of Epidemiology 2013;3(3): 253-258
Prescribing Skills for Undergraduate Medical Students: Time to Redress the Neglect?
Authors: Shankar PR
Published: November 2013

Challenges in teaching health science students about rational use of medicines include reservations of faculty members about the new learning resources, unfamiliarity with small group teaching, lack of involvement of pharmacologists in teaching therapeutics during the clinical years of training and non-involvement of pharmacists and pharmacologists in patient care activities10. These challenges have to be overcome and a major reorientation and refocusing of pharmacology departments in medical schools towards rational therapeutics may be needed. Modern medical education I feel focuses heavily on diagnosis of disease conditions. Considering the increasing complexity of modern treatment regimens, cost of care and the different stakeholders involved it is time ‘prescribing skills’ receive the attention and resources it richly deserves!DOI: http://dx.doi.org/10.3126/nje.v3i3.9186 Nepal Journal of Epidemiology 2013;3(3): 260-261
Alcohol Consumption by workers in automobile repair shops of a slum of Kolkata: An assessment with AUDIT instrument
Authors: Dasgupta A , Ray S , Pal J , Biswas R , Ray D , Ghosal A
Published: November 2013

Background   National Household Survey of Drug Use in the India in its systematic effort to document the nationwide prevalence of drug use including alcohol consumption reported that almost 21% of the adult male Indian consume alcohol in a year. To find out prevalence, pattern and consequences of drinking and determine the relationship of  alcohol use with demographic and socio-economic factors among auto-mobile repair workers. Materials and Methods A cross-sectional study was conducted among auto-mobile repair workers in the urban field practice area of All India Institute of Hygiene and Public Health, Kolkata. Results Prevalence of alcoholism in the community of automobile repair workers was found to be as high as 79%.  More than 50% of the alcoholics belonged to the hazardous and dependent variety according to the WHO developed AUDIT instrument.53.01% of the alcoholics consumed foreign liquor predominantly and 87.95% bought them from licensed liquor shops. Mean age of initiation of drinking was 18.67 years. Taking loan OR (95% CI) 3.51(1.56-7.92), gambling OR (95% CI) 3.38(1.48-7.69) and clinical signs of alcoholism OR (95% CI) 5.52 (2.13 - 14.29) were significantly associated with chronic alcohol abuse. A multivariate logistic regression model was created for socio-economic variables which showed education AOR (95%CI) 4.65(1.34- 16.31) and total number of family members AOR (95%CI) 5.33(1.31-25.02) were significantly associated with drinking status (Nagelkerke R2 for this model is 0.2585). ConclusionThe prevalence of alcoholism is high in the automobile repair workers and therefore all efforts must be made to reduce, if not eliminate, alcohol consumption among the workers of auto-mobile service centres.DOI: http://dx.doi.org/10.3126/nje.v3i3.9188 Nepal Journal of Epidemiology 2013;3(3): 269-274
Long-Term Performance of Pavement with High Recycled Asphalt Content
Authors: Anderson Evan D. , Daniel Jo Sias
Published: November 2013

This paper summarizes the findings of several case studies on the long-term performance of recycled asphalt pavement (RAP). The goal of these studies was to provide the paving community with documentation on the long-term performance of roadway sections with a high amount of RAP compared with virgin sections on the basis of available information. Roadway sections that contained more than 20% RAP and that had been in place for at least 10 years were identified across the United States with the help of local agencies. The long-term performances of these various recycled sections were compared directly with mixtures made with similar virgin materials via measurements of distress criteria. These distress criteria included rutting, cracking, ride quality, and any overall performance rating that the local agencies used to evaluate their pavement sections. The virgin sections were placed in the same general location and time frame as the recycled sections. The sections with high RAP content, on average, tended to exhibit a lower ride quality, more cracking, and better rutting resistance than the virgin sections, but the differences were not always statistically significant. The differences between the performance ratings for RAP and virgin pavements were within 5% to 10%. Overall, pavement sections with a high RAP content performed at a level comparable to that of virgin sections in these case studies.
Influence of Hydrogreen Bioasphalt on Viscoelastic Properties of Reclaimed Asphalt Mixtures
Authors: Hajj Elie Y. , Souliman Mena I. , Alavi Mohammad Zia , Salazar Luis Guillermo Loría
Published: November 2013

The incorporation of reclaimed asphalt pavement (RAP) into asphalt mixtures exposes some challenges from the design perspective because of the aged asphalt binder in RAP. Steps are being taken to offset the addition of stiff materials, often with the use of rejuvenating additives. This paper summarizes the laboratory evaluation of one of the available bio-rejuvenating agents called BituTech RAP. High RAP content mixtures used in Manitoba, Canada, were evaluated to study the impact of BituTech RAP on the viscoelastic properties of asphalt mixtures to overcome any possible moisture damage or thermal cracking problems that might arise in such a wet–freeze environment. The laboratory experiment consisted of the production and test of mixtures that contained 15% and 50% RAP, with and without BituTech RAP. The 2S2P1D analogical model was used to generate the complex modulus (E*) of the various evaluated mixtures and to assess the influence of BituTech RAP on the storage and loss moduli. The addition of BituTech RAP improved the moisture resistance of the mixtures that contained RAP, as observed after three freeze–thaw cycles. The addition of BituTech RAP restored the thermal cracking properties of the mixtures revealed by the thermal stress restrained specimen test. The use of BituTech RAP could result in cost savings without the need to use a softer binder, as long as the high-temperature properties of the mixtures were not jeopardized.
Reacted and Activated Rubber
Authors: Sousa Jorge B. , Vorobiev Andrey , Rowe Geoffrey M. , Ishai Ilan
Published: November 2013

Traditionally, asphalt rubber (AR) mixtures have been difficult to produce. Their production requires specialized plants and equipment, which has resulted in their high cost to manufacture. In part this difficulty is due to the need to produce AR binder by blending it at high temperatures for a significant period of time (typically at about 190°C for 45 min to 1 h). The complexities in the process have caused AR mixes to be significantly more expensive to produce than conventional paving mixtures. A new technology that produces a reacted and activated rubber (RAR), which is an elastomeric asphalt extender, has been developed by hot blending and activation of a rubber granulate with a selected asphalt binder and activated mineral binder stabilizer. RAR achieves results comparable to those of other types of polymer modified binders (PMBs). However, a principal advantage of RAR is that it can be added easily to any hot-mix asphalt manufacturing facility with systems designed to feed particulate material into a batch plant (pugmill) or drum mix plant. This paper describes how RAR is produced from raw constituent materials. Various binder tests contrast performance with typical paving grades and PMBs used in the United States. The implementation of RAR in various types of asphalt mixtures is discussed, and demonstrative examples of test results are provided. Tests on mixtures in wheel tracking and fatigue demonstrate how the binder performance tests translate into mixture performance. In all cases evaluated, the RAR mixtures outperformed nonmodified and even conventional rubber modified equivalent materials.
Assessment of Warm-Mix Asphalt for Heavy Traffic Airfields
Authors: Rushing John F. , Mejías-Santiago Mariely , Doyle Jesse D.
Published: November 2013

This paper presents the results of tests of warm-mix asphalt (WMA) mixtures designed for airfield pavements. The study was conducted in two phases. The first phase included laboratory tests on 11 WMA technologies. The tests in Phase 2 were performed on three WMA mixtures and one hot-mix asphalt (HMA) mixture produced in an asphalt plant. The evaluation included performance tests to assess WMA susceptibility to permanent deformation and moisture damage compared with that of HMA produced with the same aggregate blend. Test results indicated that WMA potentially was a viable product for surface mixtures on airfield pavements. Although WMA exhibited poorer performance than HMA in moisture damage tests on laboratory-produced specimens, the plant-produced mix indicated little difference compared with HMA. Rutting potential for WMA was somewhat greater than for HMA for mixtures produced both in the laboratory and in an asphalt plant according to asphalt pavement analyzer and Hamburg wheel tracking tests. Differences in performance of WMA mixtures were not attributed to a specific WMA technology category. Variations in performance test results between laboratory-produced specimens and plant-produced specimens were noted and indicated a need to require performance testing as part of a comprehensive quality assurance plan.
Low-Temperature Performance Characterization of Biomodified Asphalt Mixtures that Contain Reclaimed Asphalt Pavement
Authors: Hill Brian , Oldham Daniel , Behnia Behzad , Fini Elham H. , Buttlar William G. , Reis Henrique
Published: November 2013

The sustainability movement in paving materials has led to the increased use of reclaimed asphalt pavement (RAP). New developments in this area in the recent past include the use of biomodified asphalt binders (BMBs) such as those containing bio-oils derived from swine manure. The study reported in this paper examined the low-temperature properties of RAP and virgin BMB mixtures to determine if these mixtures exhibited better low-temperature performance than conventional hot-mix asphalt (HMA). Disk-shaped compact tension [DC(T)], Superpave® indirect tension (IDT), and acoustic emission (AE) tests were employed to characterize low-temperature properties of the asphalt mixtures. BMB mixtures exhibited higher DC(T) fracture energies than HMA at all RAP levels. In addition, BMB mixture fracture energy displayed a reduced dependence on RAP content. The difference in average fracture energy between BMB and HMA mixtures increased with higher RAP contents. Furthermore, BMB mixtures displayed consistently higher creep compliance, which indicated that these mixtures could alleviate thermal stresses more easily than HMA. A recently developed AE testing procedure evaluated the effects of BMB as well as RAP in the mixtures. The overall trends identified through AE testing were consistent with the findings from the DC(T) and IDT tests. In addition, AE results suggested a fundamental change in the behavior of the BMB RAP mixture relative to the HMA RAP mixture (i.e., rejuvenating effect). In general, it was observed that BMB RAP mixtures exhibited low-temperature cracking behavior superior to that of HMA mixtures.
Laboratory Evaluation of Asphalt Mixtures that Contain Biobinder Technologies
Authors: Mohammad Louay N. , Elseifi Mostafa A. , Cooper Samuel B. , Challa Harshavardhan , Naidoo Prem
Published: November 2013

The use of biobinder as a replacement for petroleum-based asphalt binders has received considerable attention in recent years. The objective of the study reported in this paper was to conduct a comprehensive laboratory evaluation of asphalt mixtures that contained biobinder technology at a content of 20%, 25.5%, 30%, and 50%. To achieve this objective, Superpave® performance grade (PG) of the modified blends was compared with the unmodified binder. In addition, laboratory tests were conducted to capture the mechanistic behavior of the mixtures against major distresses. Laboratory testing evaluated the rutting performance, moisture resistance, and fracture resistance of the produced mixtures with the use of the Hamburg loaded-wheel tester, the modified Lottman test, the semicircular bending test, and the thermal stress restrained specimen test. Results of the experimental program showed that the use of biobinder did not influence the final PG of the binder with the exception of one blend, which dropped one grade at low temperature. Mixtures modified with biobinder had rutting performances that were similar to, or improved, compared with those of the conventional mixes. With respect to moisture susceptibility, all mixtures, except the mixes prepared with PG 67-22, exceeded the 80% tensile strength ratio. However, when an antistripping agent was added, the tensile strength ratio of the mix with 50% biobinder exceeded 80%. At intermediate temperatures, the mixes that contained biobinder exhibited less fracture resistance than the conventional mixes did. Biobinder modification improved the low-temperature fracture performance of the mixtures compared with that of the conventional mixtures of similar PG.
Effects of Changing Virgin Binder Grade and Content on High Reclaimed Asphalt Pavement Mixture Properties
Authors: Willis J. Richard , Turner Pamela , de Goes Padula Flavio , Tran Nam , Julian Grant
Published: November 2013

Most highway agencies have decades of experience with hot-mix asphalt whose percentage of reclaimed asphalt pavement (RAP) has remained low to moderate because of the general perception that RAP mixtures may be more susceptible to various modes of cracking. As the RAP proportion increases, so does the potential for an increase in mixture stiffness and a decrease in resistance to cracking. Two proposed ways to increase the durability of RAP mixtures are to (a) increase the amount of virgin binder in the asphalt mixture and (b) decrease the performance grade of the virgin binder. To assess these options, 0%, 25%, and 50% RAP mixtures at optimum asphalt content were designed with a standard PG 67-22 virgin asphalt binder. These mixtures were tested to evaluate surface cracking, reflection cracking, and rutting with the use of an energy ratio, overlay tester, and asphalt pavement analyzer, respectively. These tests also were conducted on RAP mixtures with 0.25% and 0.50% higher asphalt contents and at the optimum asphalt content with the use of a softer virgin binder. In addition, the linear amplitude sweep methodology was used to assess the fatigue properties of the blended binders. The results showed that, to improve resistance to cracking, the amount of virgin asphalt should be increased by 0.1% for every 10% of RAP binder in the mixture for up to 30% RAP binder. Once the RAP binder exceeds 30%, a softer grade of asphalt should be used to increase the mixture's resistance to cracking. All mixtures should be assessed for rutting susceptibility.
Forensic Study on the Cracking of New Jersey's Long-Term Pavement Performance Specific Pavement Study Sections
Authors: Bennert Thomas , Maher Ali
Published: November 2013

In 2010, New Jersey's long-term pavement performance (LTPP) Specific Pavement Study (SPS-5) sections closed out. Before the rehabilitation of these pavement sections, an extensive coring and forensic study was conducted to characterize the material properties of the virgin and the 30% reclaimed asphalt pavement (RAP) asphalt mixtures used on the project. Along with field cores, raw materials (i.e., aggregates, binder, loose mix) were procured from FHWA-LTPP Materials Reference Library. Visual distress surveys from the LTPP database were collected and used to compare the mixture performance with the general field performance. Overall, the field performance indicated that the virgin and the 30% RAP sections initiated cracking within 1 to 3 years of each other, given the section evaluated. Once cracking began, however, the 30% RAP sections cracked at a faster rate than the virgin sections; this behavior resulted in higher crack counts even though the 30% RAP section had a softer binder (i.e., AC-10 versus AC-20). The overlay tester (OT), disk-shaped compact tension [DC(T)], and low-temperature indirect tension and creep compliance were used to characterize intermediate and low-temperature cracking properties of the mixtures. Asphalt binder characterization included performance grading, master stiffness curves, and linear amplitude sweep (LAS) testing to characterize the stiffness and fatigue properties of the asphalt binders. The material testing program showed that the mixture test results matched the observed field cracking performance better than the asphalt binder testing conducted on the extracted and recovered asphalt binders. The OT and DC(T) tests appeared to be the most sensitive to the cracking performance differences between the virgin and 30% RAP mixtures, while the LAS test appeared to rank the fatigue performance of the 30% RAP mixture better than that of the virgin mixture, which contradicted the observed field performance.
Performance Enhancement of Crumb Rubber–Modified Asphalts through Control of the Developed Internal Network Structure
Authors: Ragab Mohyeldin , Abdelrahman Magdy , Ghavibazoo Amir
Published: November 2013

Control of the internal network structure of crumb rubber–modified asphalt (CRMA) was investigated for its effect on property development in the study presented in this paper. The investigation included evaluation by rheological and interrupted shear tests. Rheological testing involved the monitoring of the changes of the produced complex modulus (G*) and phase angle (δ) for CRMA. In the interrupted shear tests, the shear stress profile for the produced CRMA was investigated. It was found that triggering the critical conditions of the combined interaction of speed, temperature, and time was essential to inducing the formation of the three-dimensional network structure within CRMA. Such triggering conditions played an important role in the swelling, dissolution, and release of crumb rubber modifier components into the asphalt liquid phase. Gel permeation chromatography was used to characterize the nature of modifications that led to the occurrence of a three-dimensional network structure within the produced CRMA. The formation of a three-dimensional network structure for CRMA played a major role in the enhancement of its rheological properties in terms of its stiffness and elasticity. Superior improvements in the stiffness and elasticity indicated improved rutting resistance as well as alleviated permanent deformation problems.
Performance Characterization of Asphalt Mixtures at High Asphalt Binder Replacement with Recycled Asphalt Shingles
Authors: Ozer Hasan , Al-Qadi Imad L. , Kanaan Ahmad I. , Lippert Dave L.
Published: November 2013

Recycled materials can be used effectively in asphalt mixtures to replace virgin asphalt binder or virgin aggregates. Virgin material (asphalt binder or aggregate) can be replaced with reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) in asphalt mixtures. The study presented in this paper examined the effect of high asphalt binder replacement (ABR) for an asphalt mixture with a low number of design gyrations (a low N-design) and RAP and RAS on performance indicators (e.g., permanent deformation, fracture, fatigue potentials, stiffness). A developed experimental program included complex modulus, fracture, overlay reflective cracking resistance, low-temperature cracking, wheel track permanent deformations, and push–pull fatigue tests. The ABR, combinations of RAS and RAP asphalt binder, and levels in the mix ranged from 43% to 64%. Potential permanent deformation resistance of the mixtures was improved in the presence of RAS. Fracture tests at low temperature revealed no significant difference between the specimens prepared at varying percentages of ABR. Fatigue potential of mixtures increased with an increase in RAS content and ABR. The specimens prepared with 2.5% RAS and PG 46-34 showed the best fatigue potential performance. The impact of asphalt binder bumping was highlighted by the results of all tests. The improvement in fatigue life and fracture energy was noticeable when the asphalt binder type was changed from PG 58-28 to PG 46-34 at the highest ABR level. The complex modulus test results can provide crucial information about the mix viscoelastic properties, such as relaxation potential and long-term stiffness. These results can be used, along with fracture test results, to evaluate mix brittleness at relatively high ABR levels.
Moisture Damage Evaluation of Asphalt Mixes that Contain Mining Byproducts
Authors: Dave Eshan V. , Baker Justin
Published: November 2013

The availability of mineral aggregates for pavement construction is continuously depleting. The aggregate manufacturing process requires significant amounts of energy, which ranges from 10 to 30 MJ/ton. The process also produces 5 kg/ton of carbon dioxide (CO2), which causes significant amounts of greenhouse gas emissions. With the annual consumption of approximately 1.2 billion tons of aggregates in the United States, the environmental impact is significant. More than 125 million tons of fine-grained, crushed siliceous material is generated annually through iron ore mining in northern Minnesota. Typically, this material is referred to as “taconite tailings” and usually ends up as landfill near mining operations. This paper describes a moisture damage evaluation of asphalt mixes that contained significant fractions of aggregate as taconite tailings. The evaluation was conducted with the use of the conventional AASHTO T 283 test procedure as well as an approach with a fracture energy basis. The paper presents comparative results for two mixes: one made with taconite tailings and the other with conventional granite aggregates. The results indicated that a mix that contained taconite had acceptable moisture-damage resistance. The results also pointed out the limitations of the AASHTO T 283 procedure, especially the process of moisture conditioning. The fracture energy results indicated that, although mixes underwent reduced tensile strength, the overall capability of mix to strain without cracking significantly increased after the AASHTO-recommended moisture conditioning process. The study also included a set of samples that were field-conditioned over the winter and spring months. The mechanical behavior of field-conditioned samples was quite different from the behavior of samples conditioned in the laboratory with the AASHTO procedure.
Modeling of the Resilient Modulus for Recycled Asphalt Pavement Applications in Base Course Layers
Authors: Noureldin Ehab , Abdelrahman Magdy
Published: November 2013

The resilient modulus (MR) is an important parameter for the base course layer in the pavement design process. Use of recycled asphalt pavement (RAP) for this layer must take into consideration the effect of various factors that may occur in the field on the MR. Previous numerical models used for the granular base layer could be used for the RAP. The study reported here examined the suitability of RAP procedures under the effect of different factors (e.g., water content, dry density, freeze–thaw cycles). Various percentages of the RAP (50%, 75%, and 100% by weight) were employed in this research. All the models included in the study took into account the effect of state of stresses directly, but they also considered the other factors mentioned and the effect of their interactions with the MR indirectly. The intent of the study was twofold: (a) to determine the adequacy of the models employed in the use of the RAP procedure in the base course layer and (b) to determine which model best described RAP behavior under the effects of the tested factors. On the basis of a review of the literature, nine prediction models were chosen to investigate the granular base course layers so as to predict MR for RAP. A pilot analysis was made of these models to compare the measured and predicted values of MR under the tested factors. Three models showed a good prediction for the MR. These three models were reassessed in a sensitivity analysis on regression parameters to choose the best-fit model for the RAP applications.
Changing our culture to advance patient safety
Authors: Berger Mitchel S. , Wachter Robert M. , Greysen S. Ryan , Lau Catherine Y.
Published: December 2013

“Changing our culture to advance patient safety” served as the theme of the 81st Annual Meeting of the American Association of Neurological Surgeons and is an issue of personal importance to the author. To improve outcomes for patients and prevent avoidable surgical errors, neurosurgeons must change the culture that currently exists in the operating room so that safety concerns are of the utmost importance and that each member of the care team has a personal sense of accountability. Doing this will involve implementing and consistently applying systems-based strategies to ensure an adequate level of safeguards; improving communication with all members of the care team and dismantling authority gradients; and maintaining a well-trained and well-rested workforce.
Patterns of recurrence after stereotactic radiosurgery for treatment of meningiomas
Authors: Kuhn Elizabeth N. , Taksler Glen B. , Dayton Orrin , Loganathan Amritraj G. , Vern-Gross Tamara Z. , Bourland J. Daniel , Laxton Adrian W. , Chan Michael D. , Tatter Stephen B.
Published: December 2013

Object

The purpose of this study was to evaluate patterns of failure after stereotactic radiosurgery (SRS) for meningiomas and factors that may influence these outcomes.

Methods

Based on a retrospective chart review, 279 patients were treated with SRS for meningiomas between January 1999 and March 2011 at Wake Forest Baptist Health. Disease progression was determined using serial imaging, with a minimum follow-up of 6 months (median 34.2 months).

Results

The median margin dose was 12.0 Gy (range 8.8–20 Gy). Local control rates for WHO Grade I tumors were 96.6%, 84.4%, and 75.7% at 1, 3, and 5 years, respectively. WHO Grade II and III tumors had local control rates of 72.3%, 57.7%, and 52.9% at 1, 3, and 5 years, respectively. Tumors without pathological grading had local control rates of 98.7%, 97.6%, and 94.2% at 1, 3, and 5 years, respectively. Of the local recurrences, 63.1% were classified as marginal (within 2 cm of treatment field). The 1-, 3-, and 5-year rates of distant failure were 6.5%, 10.3%, and 16.6%, respectively, for Grade I tumors and 11.4%, 17.2%, and 22.4%, respectively, for Grade II/III tumors. Tumors without pathological grading had distant failure rates of 0.7%, 3.2%, and 6.5% at 1, 3, and 5 years, respectively. Wilcoxon analysis revealed that multifocal disease (p < 0.001) and high-grade histology (WHO Grade II or III; p < 0.001) were significant predictors of local recurrence. Additionally, male sex was a significant predictor of distant recurrence (p = 0.04). Multivariate analysis also showed that doses greater than or equal to 12 Gy were associated with improved local control (p = 0.015).

Conclusions

In this patient series, 12 Gy was the minimum sufficient margin dose for the treatment of meningiomas. Male sex is a risk factor for distant failure, whereas high-grade histology and multifocal disease are risk factors for local failure.
Current standing and frontiers of gene therapy for meningiomas
Authors: De la Garza-Ramos Rafael , Flores-Rodríguez Jessica V. , Martínez-Gutiérrez Juan Carlos , Ruiz-Valls Alejandro , Caro-Osorio Enrique
Published: December 2013

Meningiomas are among the most common intracranial tumors. The treatment of choice for these lesions is complete resection, but in 50% of cases it is not achieved due to tumor location and/or surgical morbidities. Moreover, benign meningiomas have high recurrence rates of up to 32% in long-term follow-up. Molecular analyses have begun to uncover the genetics behind meningiomas, giving rise to potential genetics-based treatments, including gene therapy. The authors performed a literature review on the most relevant genes associated with meningiomas and both current and potential gene therapy strategies to treat these tumors. Wild-type NF2 gene insertion, oncolytic viruses, and transfer of silencing RNA have all shown promising results both in vitro and in mice. These strategies have decreased meningioma cell growth, proliferation, and angiogenesis. However, no clinical trial has been done to date. Future research and trials in gene insertion, selective inhibition of oncogenes, and the use of oncolytic viruses, among other potential treatment approaches, may shape the future of meningioma management.
Atypical meningiomas: is postoperative radiotherapy indicated?
Authors: Lee Kangmin D. , DePowell John J. , Air Ellen L. , Dwivedi Alok K. , Kendler Ady , McPherson Christopher M.
Published: December 2013

Object

The role of postoperative radiation therapy after surgery for atypical meningiomas remains controversial. In this retrospective cohort study, the authors examine the recurrence rates for atypical meningiomas after resection (with or without adjuvant radiotherapy) and identify which factors were associated with recurrence.

Methods

Of 90 patients with atypical meningiomas who underwent surgery between 1999 and 2009, 71 (79%) underwent gross-total resection (GTR) and 19 (21%) underwent subtotal resection (STR); 31 patients received adjuvant radiotherapy. All tumors were pathology-confirmed WHO Grade II atypical meningiomas. Univariate and multivariate analyses were performed to identify factors associated with recurrence-free survival.

Results

Among 90 patients, 17 developed tumor recurrence (81% recurrence-free survival at 5 years). In the overall group, adjuvant radiotherapy reduced the recurrence rate to 9% from 19% at 5 years (p = 0.048). After STR, adjuvant radiotherapy significantly reduced recurrence from 91% to 20% (p = 0.0016). However, after GTR, adjuvant radiotherapy did not significantly reduce the recurrence rate (16.7% without radiation therapy vs 11.8% with radiation therapy) (p = 1.00). Five factors independently predictive of tumor recurrence included mitotic index, sheeting, necrosis, nonuse of radiation therapy, and STR. Further recursive partitioning analysis showed significant increases in risk for patients older than 55 years with mitoses and sheeting.

Conclusions

Adjuvant radiotherapy was effective at lowering recurrence rates in patients after STR but delivered no significant improvement in patients after GTR. Given that rates after GTR were similar with or without adjuvant radiotherapy, close observation without postoperative radiation therapy may be a viable option for these patients. Patients older than 55 years and those with mitoses noted during pathological examination had a significant risk of recurrence after GTR; for these patients, postoperative radiotherapy is recommended.
Ores Sources, Smelters and Archaeometallurgy: Exploring Iron Age Metal Production in the Southern Waterberg, South Africa
Authors: Bandama Foreman , Chirikure Shadreck , Hall Simon
Published: November 2013

The Southern Waterberg in Limpopo Province is archaeologically rich, especially when it comes to evidence of pre-colonial mining and metal working. Geologically, the area hosts important mineral resources such as copper, tin and iron which were smelted by agriculturalists in the precolonial period. In this region however, tin seems to be the major attraction given that Rooiberg is still the only source of cassiterite in southern Africa to have provided evidence of mining before European colonization. This paper reports the results of archaeological and archaeometallurgical work which was carried out in order to reconstruct the technology of metalworking as well as the cultural interaction in the study area and beyond. The ceramic evidence shows that from the Eiland Phase (1000–1300 AD) onwards there was cross borrowing of characteristic decorative traits amongst extant groups that later on culminated in the creation of a new ceramic group known as Rooiberg. In terms of mining and metal working, XRF and SEM analyses, when coupled with optical microscopy, indicate the use of indigenous bloomery techniques that are widespread in pre-colonial southern Africa. Tin and bronze production was also represented and their production remains also pin down this metallurgy to particular sites and excludes the possibility of importing of finished tin and bronze objects into this area.
The Early Neolithic Pottery of Ifri Oudadane, NE Morocco – Qualitative and Quantitative Evidence
Authors: Linstädter Jörg , Wagner Gregor
Published: November 2013

This paper presents the Early and Late Neolithic pottery of Ifri Oudadane, a littoral shelter in Northeast Morocco containing both Epipalaeolithic as well as Neolithic deposits. The transition is indicated by the appearance of domesticated plant and animal species, pottery and diverse changes in lithic technology. A domesticated lentil dated to 7.6 ka cal BP may mark the onset of this transitional process. With the help of 22 14C-ages the Early Neolithic deposit can be subdivided in three phases (ENA, ENB, ENC). In addition, the ENC phase contained the remains of a sporadic Late Neolithic occupation. Pottery decoration of the initial ENA phase (7.6–7.3 ka cal BP) is dominated by single Cardium impressions forming horizontal and vertical bands of impressions arranged vertical, horizontal or oblique. The successive ENB phase represents the main occupation phase between 7.1 and 6.6 ka cal BP. By means of statistical methods its assemblage, which consists of 243 vessel units, could be further subdivided (ENB1, ENB2). While ENB1 (7.1–6.9 ka cal BP) is still characterised by single Cardium impressions, the transition to ENB2 is marked by the appearance of Cardium and, later, comb impressions made using rocker stamp technique as well as a few impressions of points and spatulas, striations and modelled applications. Thus the pottery assemblage of Ifri Oudadane offers insights into the first occurrence of pottery in Mediterranean Northwest Africa and opens up the possibility for an internal classification of the Early Neolithic.
The Acquisition of Ceramics by Hunter-Gatherers on the Middle Zambezi in the First and Second Millennium AD
Authors: Kinahan John
Published: November 2013

An archaeological survey of the Linyanti and Liambezi marshlands in north-eastern Namibia revealed a number of hunting and fishing sites with first millennium AD farming community ceramics as well as evidence suggesting the adoption of ceramic technology by hunter-gatherers in this area during the second millennium AD. These finds have implications for the archaeology of recent southern African hunter-gatherers: they suggest both practical criteria for the recognition of ceramics obtained by trade during the spread of food production through southern Africa in the last two millennia, and point to a likely scenario for the appearance sui generis of ceramics associated with Khoe-speaking nomadic pastoralists.
The Fauna from the UNO/BU Excavations at Bieta Giyorgis (Aksum) in Tigray, Northern Ethiopia: Campaigns 1995–2003; Pre-Aksumite, 700–400 BC to Late Aksumite, AD 800–1200
Authors: Chaix Louis
Published: November 2013

The excavations of the joint mission of the University of Naples ‘L’Orientale’ and the Department of Archaeology at Boston University (USA) on the hill of Bieta Giyorgis at Aksum, Ethiopia, recovered numerous animal bones from various contexts dating from Pre-Aksumite to Late Aksumite levels, around 700 BC to AD 1200. The fauna is dominated by domestic mammals. Among them, cattle (Bos taurus and Bos indicus) are dominant. Age structure and butchering marks indicate an intense exploitation of these animals. Domestic caprines (sheep and goats) are also present. Their exploitation is focused on young individuals. Donkey, dog and domestic fowl were found in small numbers. Wild mammals are very rare. Long-distance contacts are illustrated by remains of marine fish and worked cowries from the Red Sea.
Primary hypoparathyroidism presenting as refractory status epilepticus
Authors: Roy Mukut , Sengupta Nilanjan , Sahana Pranab Kumar , Das Chanchal , Dasgupta Ranen
Published: December 2013

A case of adult onset primary hypoparathyroidism is reported highlighting the effect of phenytoin therapy on calcium metabolism. This patient of brain calcinosis syndrome (BCS) presented with refractory status epilepticus despite on full dose phenytoin. Seizures were controlled with correction of hypocalcemia. A change of anti-epileptic therapy to lamotrigine and supplementation with calcium and calcitriol kept the patient seizure free for last 10 months till last follow up. DOI: http://dx.doi.org/10.3329/bccj.v1i2.17203 Bangladesh Crit Care J September 2013; 1 (2): 99-101
An Unusual Case of Acute Adrenal Insufficiency
Authors: Das Chanchal , Sahana Pranab Kumar , Sengupta Nilanjan , Roy Mukut , Dasgupta Ranen
Published: December 2013

Empty Sella Syndrome (ESS) may be asymptomatic or manifested as features of multiple pituitary hormone deficiencies. In a patient of suspected hypopituitarism, multiple pituitary hormonal axes should be tested to rule out concomitant hormones deficiencies. In Hypopituitarism, treatment of hypoadrenalism should be undertaken first before giving levothyroxine replacement to prevent adrenal insufficiency. DOI: http://dx.doi.org/10.3329/bccj.v1i2.17206 Bangladesh Crit Care J September 2013; 1 (2): 107-108
Duplex Study of Carotid Artery in Patients with Ischemic Stroke
Authors: Sultana Nasreen , Bari AKM Faslul , Majumder Touhidul Karim , Islam Md Rafiqul , Hossain Ferdous Ara
Published: November 2013

Objective: To determine the frequency and characteristics of carotid artery stenosis in acute ischemic stroke patients and to assess the significance of common risk factors for carotid stenosis in these patients. Method: It was cross-sectional observational study which was carried out in neurology department of Bangabandhu Sheikh Mujib Medical University (BSMMU) during the period of January 2010 to December 2011 and one hundred patients admitted with acute ischemic stroke were included in the study. Doppler ultrasound was performed during hospitalization to find out carotid artery stenosis. Statistics analysis was done with SPSS - 14. Results: Out of one hundred (100) patients, eighty (80%) were males and twenty were (20%) were females. The patients were dividing into two groups with and without carotid stenosis. Less than 50% carotid artery stenosis (insignificant stenosis) was seen in 40% ( n=40) cases and significant stenosis was seen in 60% (n=60) patients. Overall 86% (n= 46) out of 60 patients were found to have carotid artery stenosis on the ipsilateral side corresponding to the ischemic lesion and 19% (n=11) had stenosis on the contralateral side. Out of significant stenosis ,mild (50% stenosis) in 12% (n=7) patients, moderate ( 51-69% ) stenosis in 50%( n= 30 ) patients and severe (>70%) stenosis in twenty (n=33%) patients . Near total occlusion was seen in three (5%) patients. The presence of stenosis was significantly correlated with older age and the presence of multiple risk factors. Conclusion: Carotid artery stenosis is strongly associated with ischemic stroke. Doppler studies are recommended for the high risk patients for the primary as well as secondary prevention of ischemic stroke.DOI: http://dx.doi.org/10.3329/bjn.v28i2.17172 Bangladesh Journal of Neuroscience 2012; Vol. 28 (2): 67-73