bluuebunny/crossref_metadata_2025 huggingface dataset:
Fractures in High-Strength Bolts due to Hydrogen Induced Stress Corrosion – Causes and Corrective Actions
Authors: Hoche H. , Oechsner M.
Published: March 2017

Delayed brittle fractures of high-strength bolts of the strength class 10.9 are presented, taking the example of three damage cases. The respective damage mechanisms could be attributed to hydrogen induced stress corrosion which was caused, in turn, by hydrogen absorption during operation. The examples were chosen with a particular focus on the material condition‘s susceptibility which explains the cause for the occurrence of the damage mechanism. However, in only one of the three cases the susceptibility was evident and could be explained by violations of normative specifications and an unfavorable material choice. Whereas in the two other examples, only slight or no deviations from the standards and/or regulations could be found.

The influencing parameters that caused the damage, those that further promoted the damage, as well as possible corrective actions are discussed taking into account the three exemplary damage cases.
Preparation and Performance Evaluation of SPEEK/Polyaniline Composite Membrane for Direct Methanol Fuel Cell
Authors: Sultan A. S. , Adewole J. K. , Al-Ahmed A. , Nazal M. , Zaidi S. M. Javaid
Published: March 2017

Polymer composites comprising sulfonated poly(ether ether ketone) (SPEEK) and 10 to 50 wt% of Poly(trimellitic anhydride chloride-co-4,4′-methylenedianiline) (PTCMA) were prepared by solution casting. The effects of PTCMA concentrations on morphological, thermal and transport properties (water uptake, methanol permeability, ion exchange capacity and proton conductivity) were investigated. A morphological analysis revealed an homogenous dense microstructure for all the composites. Also, transport property tests revealed that the water uptake, methanol permeability and ion exchange capacity were enhanced by the addition of PTCMA whereas proton conductivity deteriorated. As shown by a thermogravimetric analysis, the difference between the thermal properties of the pure SPEEK and the composites was insignificant. Overall, the composites were observed to display a better global performance in terms of transport properties than pure SPEEK.
Microstructure and Mechanical Properties of Nanocomposite Based on Polypropylene/Ethylene Propylene Diene Monomer/Graphene
Authors: Haghnegahdar M. , Naderi G. , Ghoreishy M. H. R.
Published: March 2017

Polypropylene (PP)/ethylene propylene diene monomer (EPDM)/ graphene nanosheets (GNs) were compounded by a two-step melt mixing process via an internal mixer (brabender plasticorder). The effect of GNs, graphene oxide (GOSs) and graphene oxide functionalized with PP chains (PP-g-GOSs) on various blend properties were investigated. Wide X-ray diffraction (WAXD) patterns and transmission electron microscopy (TEM) images of the prepared nanocomposites revealed that the nanofillers were mostly dispersed into the PP phase and the dispersion state of GNs was improved with functionalization of graphene. SEM photomicrographs indicated that rubber droplets were distributed in the PP phase and a reduction of the dispersed EPDM droplet size was observed most likely due to increase in the viscosity of the PP-phase during melt mixing. The effects of nanofillers on thermal, mechanical and rheological properties were reported, and the obtained results were discussed in terms of morphology, state of dispersion and distribution of the nanofillers within the PP matrix. As for the mechanical properties, an improvement of 56% in tensile modulus and 48% in tensile strength, while 72% reduction in elongation at break was observed. The DMTA results revealed that the nanocomposites based on PP-g-GOSs had lower damping behavior and the intensity of the loss factor decreased by increasing the GNs content. These results indicate the presence of a strong interfacial interaction between the nanoplatelets and the polymer matrix.
An Engineering Model that Simulates Pantographing Occurring in the Shaping Process of Reinforced Uncured Rubber Parts
Authors: Debbaut B.
Published: March 2017

When a material volume consisting of an uncured rubber matrix reinforced with two non-parallel sets of embedded reinforcement wires or cords is subjected to large deformations, pantographing may occur. In other words, the angles between reinforcement wires change. We introduce a simple phenomenological fluid model suitable for the numerical prediction of pantographing, as can be encountered in industrial processes such as the manufacturing of rubber tires or reinforced hoses. The reinforced material is described with an orthotropic continuous fluid model. Here the reinforcement wires or cords are accounted for by the orthotropy, whose direction is locally affected by the deformation undergone by the matrix, and is updated accordingly. The model is subsequently applied to the simulation of a sagging experiment, where the role of pantographing is illustrated.
Morphology and Thermal Behavior of TPU/PP Blends Modified with Maleic Anhydride Grafted SEBS-g-MA Block Copolymer
Authors: Bulatović V. O. , Mihaljević A. , Bajsić E. G. , Holjevac T. G.
Published: March 2017

The effect of the maleic anhydride grafted styrene-ethylene/butylene-styrene (SEBS-g-MA) block copolymer on the properties of thermoplastic polyurethane (TPU) and polypropylene (PP) blends were studied. TPU/PP and TPU/PP/SEBS-g-MA blends with different weight ratios were prepared in a twin-screw extruder. The thermal properties of the blends were investigated via differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The morphological structure of the blends as well as the effect of SEBS-g-MA block copolymer on the reduction of domain size and particle dispersion were investigated via scanning electron microscopy (SEM). The results from the uncompatibilized blends clearly indicated immiscibility of TPU and PP resulting in undesirable properties. The thermal properties of TPU/PP blends were improved by compatibilization with SEBS-g-MA. Addition of the SEBS-g-MA block copolymer resulted in a finer dispersion of the minor phase and clearly improved interfacial adhesion.
Field Evaluation of Pilot Vehicles and Portable Traffic Control Signals With and Without a Flagger
Authors: Finley Melisa D. , Theiss LuAnn
Published: March 2017

The national Manual on Uniform Traffic Control Devices (MUTCD) does not prohibit the use of a pilot vehicle in conjunction with portable traffic control signals (PTCSs), but it does require that a flagger be stationed on the approach to the activity area where a pilot vehicle is being used. This negates the main advantage of using PTCSs—the removal of the flagger from the transition area. To assess compliance with pilot vehicles and PTCSs with and without flaggers, field studies were conducted at lane closures on two-lane, two-way roads in Texas. Only 2.7% and 2.3% of drivers did not comply with the PTCSs and pilot vehicle for both conditions studied (with and without a flagger, respectively). The similar violation rates between treatments showed that there was no significant or practical difference between violations at a PTCS with and without a flagger when a pilot vehicle was used. The overall recommendation is that the national MUTCD be changed to allow the use of a pilot vehicle in conjunction with PTCSs without a flagger at lane closures on two-lane, two-way roadways. In an effort to provide pilot vehicle drivers, especially those with less experience, an initial estimate of the minimum green time needed to clear the vehicle queue at the PTCS, an easy tool was developed.
Calibration of a Digital Camera for Rapid Auditing of In Situ Intersection Illumination
Authors: Gbologah Franklin E. , Guin Angshuman , Purcell Roger , Rodgers Michael O.
Published: March 2017

The regular auditing of installed roadway lighting performance is essential in ensuring that in situ light levels are within design specifications despite the effects of lamp deterioration or changes in roadway functional class. However, existing guidelines for measuring roadway lighting performance are tedious and often impractical for transportation agencies and municipalities, which are already faced with time and resource constraints. A method for calibrating a digital single lens reflex camera for rapid assessment of illumination levels at roadway intersections is developed in this paper. The method uses an image analysis approach to extract pixel information in a digital image and link it to the scene luminance. It uses high-precision light meters to perform an initial calibration of the digital camera that has proved to be stable over long periods. The method was tested with field data, and the results indicate that average scene luminance derived from this method differs by less than 4% from the average observed scene luminance captured by high-precision luminance meters involving a rigorous field measurement methodology. The methodology developed in this study offers transportation agencies and municipalities a rapid, inexpensive, and efficient method for auditing the adequacy of roadway illumination.
Effect of Specimen Size and Curing Condition on the Compressive Strength of Alkali-Activated Concrete
Authors: Thomas Robert James , Peethamparan Sulapha
Published: March 2017

Alkali-activated concrete is a rapidly emerging sustainable alternative to portland cement concrete. The compressive strength behavior of alkali-activated concrete has been reported by various studies to a limited extent, but these discussions have been based on minimal evidence. Furthermore, although it is known that specimen size has a distinct effect on the apparent compressive strength of concrete, this effect has yet to be modeled for alkali-activated concrete. This paper presents the results of a comprehensive study of the effects of curing condition (i.e., moist-cured at ambient temperature for 28 days or heat-cured at 50çC for 48 h) and specimen size on the compressive strength of sodium silicate–activated fly ash and slag cement concrete. The heat-cured strength of alkali-activated slag cement concrete was linearly related to the moist-cured strength; the former was about 5% greater than the latter. Heat curing also improved the strength of alkali-activated fly ash concrete, although the effect was greatly magnified for lower-strength mixtures and was much less significant at higher strengths. Existing size effect laws employed for portland cement concrete proved reasonably accurate in describing the effect of specimen size on the apparent strength of alkali-activated slag cement concrete. However, these existing models greatly underestimated the size effect in alkali-activated fly ash concrete; the authors suggest that this finding was the result of significant microcracking in the alkali-activated fly ash concrete.
Use of Fly Ash to Minimize Deicing Salt Damage in Concrete Pavements
Authors: Suraneni Prannoy , Azad Vahid J. , Isgor O. Burkan , Weiss W. Jason
Published: March 2017

Premature damage has been observed at the joints in numerous concrete pavements where calcium chloride and magnesium chloride deicing salts have been used. This damage results from a reaction between the deicing salt and the calcium hydroxide (CH) in the hydrated cement paste. This reaction leads to the formation of an expansive product known as calcium oxychloride (CAOXY). The use of supplementary cementitious materials as a replacement for cement has been proposed to reduce the CH that is available in the mixture to react with the deicing salts. Reducing the CH can reduce the amount of CAOXY that forms. In this study, mixtures representative of paving concrete were made with cements and fly ashes from across the country. CH amounts were determined by using thermogravimetric analysis, and CAOXY amounts were determined by using low-temperature differential scanning calorimetry. Various replacement levels of fly ash were used to demonstrate that the main parameter that influences the amounts of CH and CAOXY that form is the replacement level of fly ash. This paper proposes that a prescriptive specification requiring 35% cement replacement by volume with fly ash would reduce the damage caused by CAOXY formation and further proposes a performance specification to limit the CAOXY formation to below 15 g/100 g paste.
Load Spectra–Incorporated Fatigue Cracking Model Implementation and Case Study
Authors: Hu Sheng , Zhou Fujie , Scullion Tom
Published: March 2017

Traffic loading is one of the key factors that may cause asphalt concrete pavement fatigue cracking. Axle load spectra input provides an opportunity for evaluating the pavement response under real traffic loads throughout the pavement design life. This paper describes the methodology of incorporating axle load spectra into the mechanistic–empirical fatigue cracking model that uses a fracture mechanics method to determine crack propagation. The paper also presents the incorporation of the method into the Texas mechanistic–empirical flexible pavement design system. Several load spectra cases were studied, and the percentages of the corresponding fatigue cracking areas were predicted and compared. The comparison results confirmed the necessity of load spectra analysis. Overall, the implemented load spectra–incorporated asphalt concrete fatigue cracking model generated rational results. Further research is continuing on field validation and calibration.
Updates to Hourly Climate Data for Use in AASHTOWare Pavement Mechanistic–Empirical Design
Authors: Brink Wouter , Von Quintus Harold , Osborne Leon F.
Published: March 2017

The AASHTOWare Pavement Mechanistic–Empirical Design software requires hourly temperature, wind speed, percentage sunshine, precipitation, and relative humidity to properly calculate pavement damage and distresses. Actual or measured values, which vary hourly throughout a day for a given site, are required to properly capture the damage caused by environmental loadings. Currently the mechanistic–empirical design hourly climatic data contain approximately 1,200 U.S. and 300 Canadian stations. The U.S. stations typically contain data from 1995 through 2005, and data from the Canadian stations vary in length from 10 to 50 years, with the exception of some weather stations. Some agencies expanded their historical weather data to include longer periods of time. This paper documents the process and data sources that were used to update the current set of climate stations with climate data dating back to 1979 using the North American Regional Reanalysis (NARR) database. The results of the comparison between new climate files and the existing older climate data files for use in pavement design are presented. Overall, the NARR-generated climate data showed a very good comparison. The paper details the background of the NARR and its limitations and compares the performance predictions made by using the old and new climate data. The results indicate there is no systematic bias between the two climate data sets.
Integrating the Dynamic Modulus of Asphalt Mixes in the 1993 AASHTO Design Method
Authors: Hamdar Yara S. , Chehab Ghassan R.
Published: March 2017

The AASHTO Guide for Design of Pavement Structures 1993 (1993 Design Guide) remains the most widely used pavement design manual by highway agencies and design consultants around the world. As defined in the 1993 Design Guide, the structural coefficient of a pavement layer ( ai) is an abstract measure of the relative ability of a unit thickness of a given material to function as a structural component of the pavement. Nevertheless, the assumed ai values of the asphalt layers and a proposed relationship between ai and the resilient modulus do not account for the mechanical and physical properties of asphalt materials, traffic volume and speed, layer thicknesses (thin versus thick pavements), climate, and unbound layer properties. The purpose of this research was to enhance the design methodology incorporated in the 1993 Design Guide by integrating asphalt mixture properties in the design process. The objective was to devise a relationship between the structural coefficient ( ai) of the asphalt layer and the effective dynamic modulus (|E*|eff.) of the corresponding asphalt mix to yield a more realistic estimate of the structural capacity of the asphalt layer. The paper illustrates the development of a multilinear relationship between ai, (|E*|eff.), and the resilient modulus of the aggregate base layer. Pavement structural designs for various asphalt mixes and design inputs using the developed ai–(|E*|eff.) relationship yielded asphalt layer thicknesses that were generally smaller than those obtained using the typical ai value of 0.44 for the asphalt layer and closer to thicknesses obtained with the AASHTO mechanistic–empirical design method using the Pavement ME software.
Randomized, double-blinded, placebo-controlled trial comparing two multimodal opioid-minimizing pain management regimens following transsphenoidal surgery
Authors: Shepherd Deborah M. , Jahnke Heidi , White William L. , Little Andrew S.
Published: March 2017

OBJECTIVE

Pain control is an important clinical consideration and quality-of-care metric. No studies have examined postoperative pain control following transsphenoidal surgery for pituitary lesions. The study goals were to 1) report postoperative pain scores following transsphenoidal surgery, 2) determine if multimodal opioid-minimizing pain regimens yielded satisfactory postoperative pain control, and 3) determine if intravenous (IV) ibuprofen improved postoperative pain scores and reduced opioid use compared with placebo.

METHODS

This study was a single-center, randomized, double-blinded, placebo-controlled intervention trial involving adult patients with planned transsphenoidal surgery for pituitary tumors randomized into 2 groups. Group 1 patients were treated with scheduled IV ibuprofen, scheduled oral acetaminophen, and rescue opioids. Group 2 patients were treated with IV placebo, scheduled oral acetaminophen, and rescue opioids. The primary end point was patient pain scores (visual analog scale [VAS], rated 0–10) for 48 hours after surgery. The secondary end point was opioid use as estimated by oral morphine equivalents (OMEs).

RESULTS

Of 136 patients screened, 62 were enrolled (28 in Group 1, 34 in Group 2). The study was terminated early because the primary and secondary end points were reached. Baseline characteristics between groups were well matched except for age (Group 1, 59.3 ± 14.4 years; Group 2, 49.8 ± 16.2 years; p = 0.02). Mean VAS pain scores were significantly different, with a 43% reduction in Group 1 (1.7 ± 2.2) compared with Group 2 (3.0 ± 2.8; p < 0.0001). Opioid use was significantly different, with a 58% reduction in Group 1 (26.3 ± 28.7 mg OME) compared with Group 2 (62.5 ± 63.8 mg OME; p < 0.0001).

CONCLUSIONS

Multimodal opioid-minimizing pain-management protocols resulted in acceptable pain control following transsphenoidal surgery. IV ibuprofen resulted in significantly improved pain scores and significantly decreased opioid use compared with placebo. Postoperative multimodal pain management, including a nonsteroidal antiinflammatory medication, should be considered after surgery to improve patient comfort and to limit opioid use.

Clinical trial registration no.: NCT02351700 (clinicaltrials.gov)

■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: randomized, controlled trial; evidence: Class III.
Impact of bifurcation angle and inflow coefficient on the rupture risk of bifurcation type basilar artery tip aneurysms
Authors: Rashad Sherif , Sugiyama Shin-ichiro , Niizuma Kuniyasu , Sato Kenichi , Endo Hidenori , Omodaka Shunsuke , Matsumoto Yasushi , Fujimura Miki , Tominaga Teiji
Published: March 2017

OBJECTIVE

Risk factors for aneurysm rupture have been extensively studied, with several factors showing significant correlations with rupture status. Several studies have shown that aneurysm shape and hemodynamics change after rupture. In the present study the authors investigated a static factor, the bifurcation angle, which does not change after rupture, to understand its effect on aneurysm rupture risk and hemodynamics.

METHODS

A hospital database was retrospectively reviewed to identify patients with cerebral aneurysms treated surgically or endovascularly in the period between 2008 and 2015. After acquiring 3D rotational angiographic data, 3D stereolithography models were created and computational fluid dynamic analysis was performed using commercially available software. Patient data (age and sex), morphometric factors (aneurysm volume and maximum height, aspect ratio, bifurcation angle, bottleneck ratio, and neck/parent artery ratio), and hemodynamic factors (inflow coefficient and wall shear stress) were statistically compared between ruptured and unruptured groups.

RESULTS

Seventy-one basilar tip aneurysms were included in this study, 22 ruptured and 49 unruptured. Univariate analysis showed aspect ratio, bifurcation angle, bottleneck ratio, and inflow coefficient were significantly correlated with a ruptured status. Logistic regression analysis showed that aspect ratio and bifurcation angle were significant predictors of a ruptured status. Bifurcation angle was inversely correlated with inflow coefficient (p < 0.0005), which in turn correlated directly with mean (p = 0.028) and maximum (p = 0.014) wall shear stress (WSS) using Pearson's correlation coefficient, whereas aspect ratio was inversely correlated with mean (0.012) and minimum (p = 0.018) WSS.

CONCLUSIONS

Bifurcation angle and aspect ratio are independent predictors for aneurysm rupture. Bifurcation angle, which does not change after rupture, is correlated with hemodynamic factors including inflow coefficient and WSS, as well as rupture status. Aneurysms with the hands-up bifurcation configuration are more prone to rupture than aneurysms with other bifurcation configurations.
Efficacy and safety of corpus callosotomy after vagal nerve stimulation in patients with drug-resistant epilepsy
Authors: Hong Jennifer , Desai Atman , Thadani Vijay M. , Roberts David W.
Published: March 2017

OBJECTIVE

Vagal nerve stimulation (VNS) and corpus callosotomy (CC) have both been shown to be of benefit in the treatment of medically refractory epilepsy. Recent case series have reviewed the efficacy of VNS in patients who have undergone CC, with encouraging results. There are few data, however, on the use of CC following VNS therapy.

METHODS

The records of all patients at the authors' center who underwent CC following VNS between 1998 and 2015 were reviewed. Patient baseline characteristics, operative details, and postoperative outcomes were analyzed.

RESULTS

Ten patients met inclusion criteria. The median follow-up was 72 months, with a minimum follow-up of 12 months (range 12–109 months). The mean time between VNS and CC was 53.7 months. The most common reason for CC was progression of seizures after VNS. Seven patients had anterior CC, and 3 patients returned to the operating room for a completion of the procedure. All patients had a decrease in the rate of falls and drop seizures; 7 patients experienced elimination of drop seizures. Nine patients had an Engel Class III outcome, and 1 patient had a Class IV outcome. There were 3 immediate postoperative complications and 1 delayed complication. One patient developed pneumonia, 1 developed transient mutism, and 1 had persistent weakness in the nondominant foot. One patient presented with a wound infection.

CONCLUSIONS

The authors demonstrate that CC can help reduce seizures in patients with medically refractory epilepsy following VNS, particularly with respect to drop attacks.
The effect of cranioplasty following decompressive craniectomy on cerebral blood perfusion, neurological, and cognitive outcome
Authors: Shahid Adnan Hussain , Mohanty Manju , Singla Navneet , Mittal Bhagwant Rai , Gupta Sunil Kumar
Published: March 2017

OBJECTIVE

Decompressive craniectomy is an established therapy for refractory intracranial hypertension. Cranioplasty following decompressive craniectomy not only provides protection to the brain along with cosmetic benefits, but also enhances rehabilitation with meaningful functional recovery of potentially reversible cortical and subcortical damaged areas of the affected as well as the contralateral hemisphere. The aim of the study was to assess neurological and cognitive outcome as well as cerebral blood flow after cranioplasty.

METHODS

Thirty-four patients admitted for replacement cranioplasty after decompressive craniectomy for head injury were studied prospectively. Clinical, neurological, and cognitive outcomes were assessed by the Glasgow Outcome Scale (GOS), the Glasgow Coma Scale, and a battery of cognitive tests, respectively. Simultaneously, cerebral blood perfusion was assessed by technetium-99m ethyl cysteinate dimer (99mTc-ECD) brain SPECT imaging 7 days prior to and 3 months after cranioplasty.

RESULTS

Prior to cranioplasty 9 patients (26.5%) had GOS scores of 5 and 25 patients (73.5%) had GOS scores of 4, whereas postcranioplasty all 34 patients (100%) improved to GOS scores of 5. Approximately 35.3%–90.9% patients showed cognitive improvement postcranioplasty in various tests. Also, on comparison with brain SPECT, 94% of patients showed improvement in cerebral perfusion in different lobes.

CONCLUSIONS

Cranioplasty remarkably improves neurological and cognitive outcomes supported by improvement in cerebral blood perfusion.
Interactions between glioma and pregnancy: insight from a 52-case multicenter series
Authors: Peeters Sophie , Pagès Mélanie , Gauchotte Guillaume , Miquel Catherine , Cartalat-Carel Stéphanie , Guillamo Jean-Sébastien , Capelle Laurent , Delattre Jean-Yves , Beauchesne Patrick , Debouverie Marc , Fontaine Denys , Jouanneau Emmanuel , Stecken Jean , Menei Philippe , De Witte Olivier , Colin Philippe , Frappaz Didier , Lesimple Thierry , Bauchet Luc , Lopes Manuel , Bozec Laurence , Moyal Elisabeth , Deroulers Christophe , Varlet Pascale , Zanello Marc , Chretien Fabrice , Oppenheim Catherine , Duffau Hugues , Taillandier Luc , Pallud Johan
Published: March 2017

OBJECTIVE

The goal of this study was to provide insight into the influence of gliomas on gestational outcomes, the impact of pregnancy on gliomas, and the identification of patients at risk.

METHODS

In this multiinstitutional retrospective study, the authors identified 52 pregnancies in 50 women diagnosed with a glioma.

RESULTS

For gliomas known prior to pregnancy (n = 24), we found the following: 1) An increase in the quantified imaging growth rates occurred during pregnancy in 87% of cases. 2) Clinical deterioration occurred in 38% of cases, with seizures alone resolving after delivery in 57.2% of cases. 3) Oncological treatments were immediately performed after delivery in 25% of cases. For gliomas diagnosed during pregnancy (n = 28), we demonstrated the following: 1) The tumor was discovered during the second and third trimesters in 29% and 54% of cases, respectively, with seizures being the presenting symptom in 68% of cases. 2) The quantified imaging growth rates did not significantly decrease after delivery and before oncological treatment. 3) Clinical deterioration resolved after delivery in 21.4% of cases. 4) Oncological treatments were immediately performed after delivery in 70% of cases. Gliomas with a high grade of malignancy, negative immunoexpression of alpha-internexin, or positive immunoexpression for p53 were more likely to be associated with tumor progression during pregnancy. Deliveries were all uneventful (cesarean section in 54.5% of cases and vaginal delivery in 45.5%), and the infants were developmentally normal.

CONCLUSIONS

When a woman harboring a glioma envisions a pregnancy, or when a glioma is discovered in a pregnant patient, the authors suggest informing her and her partner that pregnancy may impact the evolution of the glioma clinically and radiologically. They strongly advise a multidisciplinary approach to management.

■ CLASSIFICATION OF EVIDENCE Type of question: association; study design: case series; evidence: Class IV.
Case report of a 6-year-old girl with Mycoplasma hominis ventriculoperitoneal shunt infection
Authors: Sato Masanori , Kubota Noriko , Katsuyama Yoshihiko , Suzuki Yota , Miyairi Yosuke , Minami Kisei , Kasai Masashi
Published: March 2017

Mycoplasma hominis is a rare causative pathogen for surgical site infections after neurosurgical procedures. This organism lacks a cell wall, rendering it undetectable by Gram staining and making it resistant to beta-lactam antibiotics. In addition, some special techniques are required to identify this organism. Thus, it is very difficult to diagnose infections caused by this pathogen. Here, the authors report a pediatric case of M. hominis ventriculoperitoneal shunt (VPS) infection with central nervous system involvement for which beta-lactam antibiotics were not effective and Gram staining revealed no pathogens. Because few cases have been described that involve the treatment of M. hominis infection after neurosurgery, in this case the patient's serum and CSF were monitored for antibiotic drug concentrations. Successful treatment of the infection was achieved after approximately 6 weeks of administration of clindamycin and ciprofloxacin antibiotics in addition to external ventricular drain revision and subsequent VPS replacement. When beta-lactam antibiotics are ineffective and when Gram staining cannot detect the responsible pathogens, it is important to consider M. hominis as the atypical pathogen.
Antibacterial and anti-hemolytic activity of tannins from Pimenta dioica against methicillin resistant Staphylococcus aureus
Authors: Al-Harbi Reham , Al-wegaisi Razan , Moharram Fatma , Shaaban Mona Ibrahem , Abd El-Rahman Ola
Published: March 2017

High rate of resistance among Staphylococcus infection initiates scientists to discover new antibiotics. The objective of this study is to determine the effect of tannins isolated from the Pimenta dioica leaves on Staphylococcus aureus and methicillin resistant S. aureus as well as to evaluate their effect on hemolysin production. The antimicrobial activity of 4,6-(S)-hexahydroxydiphenoyl-(α/β)-D-glucopyranose and casuarinin, pedunculagin and nilocitin tannins from P. dioica was examined using agar diffusion method. Moreover, minimum inhibitory concentrations were evaluated by microtiter plate assay method. Pedunculagin and nilocitin exhibited antibacterial and anti-hemolytic effect against S. aureus. This will open the era for in vivo assessment of such compounds for clinical applications.
Laser IR fragmentation of molecular clusters: the role of channels for energy input and relaxation, the influence of surroundings, and the dynamics of fragmentation
Authors: Makarov G N
Published: March 2017

The results of research into the infrared (IR) laser fragmentation of molecular clusters by resonant vibrational excitation of their constituent molecules are presented with special attention given to the role of cluster environment, the energy input and relaxation channels, and dynamical aspects. For this purpose, the results of experiments with free homogeneous and mixed molecular clusters and of experiments with clusters inside or on the surface of large inert gas clusters are analyzed, the laser excitation pulses varying in wavelength and duration. Data on the character and rate of cluster fragmentation, and on the intramolecular and intracluster vibrational energy relaxation times in clusters are discussed. Results of an investigation into the structure and dynamics of molecular clusters and atomic-molecular complexes obtained by IR photodissociation spectroscopy and the spectroscopy of photofragments are analyzed. Methods for generating heterogeneous molecular clusters, for size-selecting clusters. and for studying the IR dissociation and IR fragmentation of clusters are also briefly considered.
Metal-Insulator-Metal Single Electron Transistors with Tunnel Barriers Prepared by Atomic Layer Deposition
Authors: Karbasian Golnaz , McConnell Michael , George Hubert , Schneider Louisa , Filmer Matthew , Orlov Alexei , Nazarov Alexei , Snider Gregory
Published: March 2017

Single electron transistors are nanoscale electron devices that require thin, high-quality tunnel barriers to operate and have potential applications in sensing, metrology and beyond-CMOS computing schemes. Given that atomic layer deposition is used to form CMOS gate stacks with low trap densities and excellent thickness control, it is well-suited as a technique to form a variety of tunnel barriers. This work is a review of our recent research on atomic layer deposition and post-fabrication treatments to fabricate metallic single electron transistors with a variety of metals and dielectrics.
Kullback-Leibler Divergence and Mutual Information of Experiments in the Fuzzy Case
Authors: Markechová Dagmar
Published: March 2017

The main aim of this contribution is to define the notions of Kullback-Leibler divergence and conditional mutual information in fuzzy probability spaces and to derive the basic properties of the suggested measures. In particular, chain rules for mutual information of fuzzy partitions and for Kullback-Leibler divergence with respect to fuzzy P-measures are established. In addition, a convexity of Kullback-Leibler divergence and mutual information with respect to fuzzy P-measures is studied.
A Urea Potentiometric Biosensor Based on a Thiophene Copolymer
Authors: Lai Cheng-Yuan , Foot Peter , Brown John , Spearman Peter
Published: March 2017

A potentiometric enzyme biosensor is a convenient detector for quantification of urea concentrations in industrial processes, or for monitoring patients with diabetes, kidney damage or liver malfunction. In this work, poly(3-hexylthiophene-co-3-thiopheneacetic acid) (P(3HT-co-3TAA)) was chemically synthesized, characterized and spin-coated onto conductive indium tin oxide (ITO) glass electrodes. Urease (Urs) was covalently attached to the smooth surface of this copolymer via carbodiimide coupling. The electrochemical behavior and stability of the modified Urs/P(3HT-co-3TAA)/ITO glass electrode were investigated by cyclic voltammetry, and the bound enzyme activity was confirmed by spectrophotometry. Potentiometric response studies indicated that this electrode could determine the concentration of urea in aqueous solutions, with a quasi-Nernstian response up to about 5 mM. No attempt was made to optimize the response speed; full equilibration occurred after 10 min, but the half-time for response was typically <1 min.
Quantum Theory from Rules on Information Acquisition
Authors: Höhn Philipp
Published: March 2017

We summarize a recent reconstruction of the quantum theory of qubits from rules constraining an observer’s acquisition of information about physical systems. This review is accessible and fairly self-contained, focusing on the main ideas and results and not the technical details. The reconstruction offers an informational explanation for the architecture of the theory and speciﬁcally for its correlation structure. In particular, it explains entanglement, monogamy and non-locality compellingly from limited accessible information and complementarity. As a by-product, it also unravels new ‘conserved informational charges’ from complementarity relations that characterize the unitary group and the set of pure states.
Optimum Design and Operation of an HVAC Cooling Tower for Energy and Water Conservation
Authors: García Cutillas Clemente , Ruiz Ramírez Javier , Lucas Miralles Manuel
Published: March 2017

The energy consumption increase in the last few years has contributed to developing energy efficiency policies in many countries, the main goal of which is decreasing CO 2 emissions. One of the reasons for this increment has been caused by the use of air conditioning systems due to new comfort standards. In that regard, cooling towers and evaporative condensers are presented as efficient devices that operate with low-level water temperature. Moreover, the energy consumption and the cost of the equipment are lower than other systems like air condensers at the same operation conditions. This work models an air conditioning system in TRNSYS software, the main elements if which are a cooling tower, a water-water chiller and a reference building. The cooling tower model is validated using experimental data in a pilot plant. The main objective is to implement an optimizing control strategy in order to reduce both energy and water consumption. Furthermore a comparison between three typical methods of capacity control is carried out. Additionally, different cooling tower configurations are assessed, involving six drift eliminators and two water distribution systems. Results show the influence of optimizing the control strategy and cooling tower configuration, with a maximum energy savings of 10.8% per story and a reduction of 4.8% in water consumption.
Experimental Investigation of the Transpired Solar Air Collectors and Metal Corrugated Packing Solar Air Collectors
Authors: Zheng Wandong , Zhang Huan , You Shijun , Fu Yindan
Published: March 2017

The thermal performance of three novel solar air collectors with perforating corrugated plate, slit-perforated plate, and corrugated packing were experimentally studied in this paper. Experiments were conducted in Tianjin to study the thermal and dynamic performance of the collectors in cold and severe cold regions. A chamber with a PID (Proportion Integration Differentiation) temperature controller was designed to control the inlet air temperature of the three collectors. Effects of radiation intensity, inlet air temperature, and flow rate on the thermal efficiency and outlet air temperature were experimentally studied. The results indicated that the thermal efficiency of the three collectors in severe cold regions could be much higher than 50% and the collector with perforating corrugated plate had the highest thermal efficiency. The inlet air flow rate had significant effects on the thermal comfort of buildings in cold and severe cold regions and it should be lower than 45 m3/h. The results indicated that the pressure drops of collectors with perforating corrugated plate were a little larger than the collectors with slit-perforated plate, but the thermal efficiency and outlet air temperature was higher. Therefore, the collector with perforating corrugated plate was more suitable to use in cold and severe cold regions.
A Study on the Optimization of Surfactants in the Main and Vice Slug in Weak Base ASP Flooding
Authors: Huang Bin , Zhang Wei , Liu Huan , Fu Cheng , Feng Pengxin , Wang Ying
Published: March 2017

In ASP (Alkali-Surfactant-Polymer) flooding processes, surfactants help to enhance oil recovery by lowering the interfacial tension between the oil and water. However, due to the high cost of surfactants and the stability of the emulsion that varies with surfactant concentration, it is necessary to optimize the surfactant concentration in ASP flooding. In this study, we combined numerical simulation and physical experimental research to solve this problem. In order to screen for the optimal surfactant concentration in the main and vice slugs, CMG (Computer Measurement Group) numerical simulation software was used to change the surfactant concentration in the injected compound system and the oil recovery factor and the recovery percent of reserves were compared. The physical experiments were also carried out with different surfactant concentrations and the results verified the simulation results. It shows that the recovery factor increases with the surfactant concentration. The optimal surfactant concentration in the main and vice slug are 0.3% and 0.15%, respectively. As for improving the recovery factor, it is more efficient to increase the mass fraction of the surfactant in the vice slug than in the main slug. It demonstrates that the amount of surfactant in the main slug plays a more important role in displacing oil from the formation.
Control Strategy Optimization for Parallel Hybrid Electric Vehicles Using a Memetic Algorithm
Authors: Cheng Yu-Huei , Lai Ching-Ming
Published: March 2017

Hybrid electric vehicle (HEV) control strategy is a management approach for generating, using, and saving energy. Therefore, the optimal control strategy is the sticking point to effectively manage hybrid electric vehicles. In order to realize the optimal control strategy, we use a robust evolutionary computation method called a “memetic algorithm (MA)” to optimize the control parameters in parallel HEVs. The “local search” mechanism implemented in the MA greatly enhances its search capabilities. In the implementation of the method, the fitness function combines with the ADvanced VehIcle SimulatOR (ADVISOR) and is set up according to an electric assist control strategy (EACS) to minimize the fuel consumption (FC) and emissions (HC, CO, and NOx) of the vehicle engine. At the same time, driving performance requirements are also considered in the method. Four different driving cycles, the new European driving cycle (NEDC), Federal Test Procedure (FTP), Economic Commission for Europe + Extra-Urban driving cycle (ECE + EUDC), and urban dynamometer driving schedule (UDDS) are carried out using the proposed method to find their respectively optimal control parameters. The results show that the proposed method effectively helps to reduce fuel consumption and emissions, as well as guarantee vehicle performance.
Structure from Motion (SfM) Photogrammetry with Drone Data: A Low Cost Method for Monitoring Greenhouse Gas Emissions from Forests in Developing Countries
Authors: Mlambo Reason , Woodhouse Iain , Gerard France , Anderson Karen
Published: March 2017

Structure from Motion (SfM) photogrammetry applied to photographs captured from Unmanned Aerial Vehicle (UAV) platforms is increasingly being utilised for a wide range of applications including structural characterisation of forests. The aim of this study was to undertake a first evaluation of whether SfM from UAVs has potential as a low cost method for forest monitoring within developing countries in the context of Reducing Emissions from Deforestation and forest Degradation (REDD+). The project evaluated SfM horizontal and vertical accuracy for measuring the height of individual trees. Aerial image data were collected for two test sites; Meshaw (Devon, UK) and Dryden (Scotland, UK) using a Quest QPOD fixed wing UAV and DJI Phantom 2 quadcopter UAV, respectively. Comparisons were made between SfM and airborne LiDAR point clouds and surface models at the Meshaw site, while at Dryden, SfM tree heights were compared to ground measured tree heights. Results obtained showed a strong correlation between SfM and LiDAR digital surface models (R2 = 0.89) and canopy height models (R2 = 0.75). However, at Dryden, a poor correlation was observed between SfM tree heights and ground measured heights (R2 = 0.19). The poor results at Dryden were explained by the fact that the forest plot had a closed canopy structure such that SfM failed to generate enough below-canopy ground points. Finally, an evaluation of UAV surveying methods was also undertaken to determine their usefulness and cost-effectiveness for plot-level forest monitoring. The study concluded that although SfM from UAVs performs poorly in closed canopies, it can still provide a low cost solution in those developing countries where forests have sparse canopy cover (<50%) with individual tree crowns and ground surfaces well-captured by SfM photogrammetry. Since more than half of the forest covered areas of the world have canopy cover <50%, we can conclude that SfM has enormous potential for forest mapping in developing countries.
Costs of Lost opportunities: Applying Non-Market Valuation Techniques to Potential REDD+ Participants in Cameroon
Authors: Thompson Dara , Swallow Brent , Luckert Martin
Published: March 2017

Reduced Emissions from Deforestation and Forest Degradation (REDD+) has been systematically advanced within the UN Framework Convention on Climate Change (UNFCCC). However, implementing REDD+ in a populated landscape requires information on local costs and acceptability of changed practices. To supply such information, many studies have adopted approaches that explore the opportunity cost of maintaining land as forest rather than converting it to agricultural uses. These approaches typically assume that the costs to the smallholder are borne exclusively through the loss or gain of the production values associated with specific categories of land use. However, evaluating the value of land to smallholders in incomplete and messy institutional and economic contexts entails other considerations, such as varying portfolios of land holdings, tenure arrangements, restricted access to capital, and unreliable food markets. We suggest that contingent valuation (CV) methods may provide a more complete reflection of the viability of REDD+ in multiple-use landscapes than do opportunity cost approaches. The CV approach eliminates the need to assume a homogenous smallholder, and instead assumes heterogeneity around social, economic and institutional contexts. We apply this approach in a southern rural Cameroonian context, through the lens of a hypothetical REDD+ contract. Our findings suggest local costs of REDD+ contracts to be higher and much more variable than opportunity cost estimates.
GSMNet: A Hierarchical Graph Model for Moving Objects in Networks
Authors: Zhang Hengcai , Lu Feng
Published: March 2017

Existing data models for moving objects in networks are often limited by flexibly controlling the granularity of representing networks and the cost of location updates and do not encompass semantic information, such as traffic states, traffic restrictions and social relationships. In this paper, we aim to fill the gap of traditional network-constrained models and propose a hierarchical graph model called the Geo-Social-Moving model for moving objects in Networks (GSMNet) that adopts four graph structures, RouteGraph, SegmentGraph, ObjectGraph and MoveGraph, to represent the underlying networks, trajectories and semantic information in an integrated manner. The bulk of user-defined data types and corresponding operators is proposed to handle moving objects and answer a new class of queries supporting three kinds of conditions: spatial, temporal and semantic information. Then, we develop a prototype system with the native graph database system Neo4Jto implement the proposed GSMNet model. In the experiment, we conduct the performance evaluation using simulated trajectories generated from the BerlinMOD (Berlin Moving Objects Database) benchmark and compare with the mature MOD system Secondo. The results of 17 benchmark queries demonstrate that our proposed GSMNet model has strong potential to reduce time-consuming table join operations an d shows remarkable advantages with regard to representing semantic information and controlling the cost of location updates.
Simplifying the Preparation of Pollen Grains for MALDI-TOF MS Classification
Authors: Lauer Franziska , Seifert Stephan , Kneipp Janina , Weidner Steffen
Published: March 2017

Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) is a well-implemented analytical technique for the investigation of complex biological samples. In MS, the sample preparation strategy is decisive for the success of the measurements. Here, sample preparation processes and target materials for the investigation of different pollen grains are compared. A reduced and optimized sample preparation process prior to MALDI-TOF measurement is presented using conductive carbon tape as target. The application of conductive tape yields in enhanced absolute signal intensities and mass spectral pattern information, which leads to a clear separation in subsequent pattern analysis. The results will be used to improve the taxonomic differentiation and identification, and might be useful for the development of a simple routine method to identify pollen based on mass spectrometry.