bluuebunny/crossref_metadata_2025 huggingface dataset:
Histomorphometric analysis of the osseointegration of four different implant surfaces in the femoral epiphyses of rabbits
Authors: Le Guehennec Laurent , Goyenvalle Eric , Lopez‐Heredia Marco‐Antonio , Weiss Pierre , Amouriq Yves , Layrolle Pierre
Published: October 2008

Objectives: The surface properties of titanium dental implants are key parameters for rapid and intimate bone–implant contact. The osseointegration of four implant surfaces was studied in the femoral epiphyses of rabbits.

Material and methods: Titanium implants were either grit‐blasted with alumina or biphasic calcium phosphate (BCP) ceramic particles, coated with a thin octacalcium phosphate (OCP) layer, or prepared by large‐grit sand blasting and acid‐etched (SLA). After 2 and 8 weeks of implantation, the bone‐implant contact and bone growth inside the chambers were compared. Scanning electron microscopy (SEM) and profilometry showed distinct microtopographies.

Results: The alumina‐Ti, BCP‐Ti and OCP‐Ti groups had similar average surface roughness in the 1–2 μm range whereas the SLA surface was significantly higher with a roughness averaging 4.5 μm. Concerning the osseointegration, the study demonstrated a significantly greater bone‐to‐implant contact for both the SLA and OCP‐Ti surfaces as compared with the grit‐blasted surfaces, alumina‐ and BCP‐Ti at both 2 and 8 weeks of healing.

Conclusion: In this animal model, a biomimetic calcium phosphate coating gave similar osseointegration to the SLA surface. This biomimetic coating method may enhance the apposition of bone onto titanium dental implants.
Influence of microgap location and configuration on the periimplant bone morphology in submerged implants. An experimental study in dogs
Authors: Weng Dietmar , Nagata Maria José Hitomi , Bell Matthias , Bosco Alvaro Francisco , De Melo Luiz Gustavo Nascimento , Richter Ernst‐Jürgen
Published: October 2008

Objectives: The vertical location of the implant‐abutment connection influences the periimplant bone morphology. It is unknown, however, whether different microgap configurations cause different bone reactions. Therefore, in this study the bone morphologies of two different implant systems were compared.

Material and methods: Three months after tooth extraction in eight mongrel dogs, two grit‐blasted screw implants with internal Morse taper connection (ANK group) were placed on one side whereas the contralateral side received two oxidized screw implants with external hex (TIU group). One implant on each side was placed level with the bone (equicrestal), the second implant was inserted 1.5 mm below bone level (subcrestal). After 3 months the implants were uncovered. Three months after stage two surgery, histometrical evaluations were performed in order to assess the periimplant bone levels (PBL), the first bone‐to‐implant contact points (BICP), the width (HBD) and the steepness (SLO) of the bone defect.

Results: All implants osseointegrated clinically and histologically. Bone overgrowth of the microgap was seen in ANK implants only. No significant differences between ANK and TIU could be detected in neither vertical position for PBL and BICP. However, a tendency in favor of ANK was visible when the implants were placed subcrestally. In the parameters HBD (ANK equicrestal −0.23 mm; TIU equicrestal −0.51 mm; ANK subcrestal +0.19 mm; TIU subcrestal −0.57 mm) and SLO (ANK equicrestal 35.36°; TIU equicrestal 63.22°; ANK subcrestal 20.40°; TIU subcrestal 44.43°) more pronounced and significant differences were noted.

Conclusions: Within the limits of this study, it is concluded that different microgap designs cause different shapes and sizes of the periimplant (‘dish‐shaped’) bone defect in submerged implants both in equicrestal and subcrestal positions.
Incidence of inter‐proximal papilla between a tooth and an adjacent immediate implant placed into a fresh extraction socket: 1‐year prospective study
Authors: Lops Diego , Chiapasco Matteo , Rossi Alessandro , Bressan Eriberto , Romeo Eugenio
Published: October 2008

Background: Implant single‐tooth replacement with a natural appearance is a challenging and demanding procedure. The aim of this prospective study was to identify the factors affecting the presence of an inter‐proximal papilla between a tooth and an implant.

Methods: Forty‐six patients with a total of 46 teeth scheduled for tooth extraction and immediate implant placement into fresh sockets were included in the study. Immediate implants were positioned after teeth removal. After 4 months of healing, the implants were restored with single crown fixed prostheses. The following parameters were assessed: (1) presence/absence of the inter‐proximal papilla, (2) gingival index, (3) inter‐implant–tooth distance (ITD) and (4) distance from the base of the contact point to the inter‐dental bone (CPB). A computerized analysis was performed to determine ITD and CPB values after converting perioapical radiographs to digitalized images. Statistical analyses were performed to determine the effect of ITD and CPB on the presence or absence of the inter‐proximal papilla.

Results: All the implants were restored, so that a 100% of implant survival rate was observed after 12 months of function. Mean values were recorded for ITD and CPB parameters, respectively. When ITD was 3–4 mm, and CPB was 3–5 mm, the inter‐proximal papilla was significantly present (P<0.05).

Conclusions: The recommended inter‐proximal space dimensions are 3–4 mm between an implant and the adjacent tooth, and 3–5 mm between the base of the CPB. The interaction between the surgical and prosthetic plans represents the key factor to optimize the edentulous site for predictable anterior single‐implant esthetics.
Comparative osteogenesis of maxilla and iliac crest human bone marrow stromal cells attached to oxidized titanium: a pilot study
Authors: Akintoye Sunday O. , Giavis Parascevi , Stefanik Derek , Levin Lawrence , Mante Francis K.
Published: October 2008

Objectives: Severe alveolar bone loss affects dental implant placement. Bone augmentation by grafting iliac crest bone rich in osteoprogenitor cells such as bone marrow stromal cells (BMSCs) requires a second surgical procedure in non‐orofacial bone. Skeletal site‐specific osteogenesis indicates maxilla and mandible BMSCs are highly proliferative and exhibit osteogenic properties superior to iliac crest BMSCs. Alveolar bone can be easily obtained during routine dental surgery, but it is unclear if titanium‐attached alveolar BMSCs will retain their superior osteogenic properties. This study evaluated and compared in vitro osteogenic properties of titanium‐attached maxilla and iliac crest BMSCs in same individuals.

Material and methods: Primary culture of maxilla and iliac crest BMSCs from four normal healthy volunteers was expanded in culture. In 24‐well plates, first passage BMSCs were seeded directly (1 × 104 cells/well) on oxidized titanium disks (1.27 cm diameter and 2 mm thickness) or tissue culture plate. Each cell type was assessed for affinity for titanium, post‐attachment survival and osteogenic differentiation based on alkaline phosphatase and osteopontin expressions.

Results: There was no difference in the affinity of maxilla and iliac crest BMSCs to titanium. However, titanium‐attached maxilla BMSCs were apparently more osteogenically responsive than iliac crest cells based on calcium accumulation and gene expression of alkaline phosphatase and osteopontin. But these differences were not statistically significant in this small patient sample.

Conclusion: Maxilla and iliac crest BMSCs have similar attachment affinity for titanium. This pilot study indicates that titanium‐attached maxilla BMSCs are more osteogenically responsive and may be a viable and more readily available donor graft material in implant dentistry.
Immunohistochemical PGP 9.5 positivity in human osteoblasts may indicate that compensatory and dysplastic craniofacial growth are under control by peripheral nerves
Authors: Kjær I , Nolting D
Published: October 2008

Structured Abstract

Authors –  Kjær I, Nolting D

Objectives –  The purpose was to examine human osteoblasts immunohistochemically in order to clarify the significance of the innervation for alveolar bone growth.

Setting and Sample Population –  Unstained sections available from 21 normal human mandibles (foetal gestational ages: 14–22 weeks).

Material and Methods –  Before sectioning in 1980–1990, the mandibular tissue had been fixed in 4% neutral‐buffered formaldehyde for 5 days. Tissue blocks were then decalcified in equal parts of 2% citric acid and 20% sodium citrate for 7–15 days, dehydrated, embedded in paraffin, and sagittally cut into 4‐μm‐thick serial sections and mounted on Superfrost® Plus microscope slides. Sections were dried overnight at 40°C. In the present study, paraffin sections were deparaffinized and treated with Tris‐EDTA (Merck, Germany), pH 9.0, and immunohistochemically tested with polyclonal rabbit anti‐PGP 9.5, and the EnVision™+/HRP dual link (K4065; DAKO Denmark A/S, Denmark) method.

Results –  A pronounced protein gene product (PGP) 9.5 activity was registered in osteoblasts from alveolar bone in all specimens. In all cases, the activity was intense at the top of and labially to the alveolar bone, while less or no activity was observed on the inner lingual aspects of the alveolar processes. Osteoclasts and osteocytes reacted vaguely or negatively.

Conclusion –  As the present study has demonstrated that human osteoblast activity in the alveolar bone seemingly responds to innervation, it is suggested that the peripheral nervous system via the trigeminal ganglion regulates compensatory and dysplastic alveolar bone formation.
Periodontal condition of the mandibular anterior dentition in patients with conventional and self‐ligating brackets
Authors: Pandis N , Vlachopoulos K , Polychronopoulou A , Madianos P , Eliades T
Published: October 2008

Structured Abstract

Authors –  Pandis N, Vlachopoulos K, Polychronopoulou A, Madianos P, Eliades T

Objectives –  To explore whether the use of self‐ligating brackets is associated with better values for periodontal indices because of the lack of elastomeric modules and concomitantly, reduced availability of retentive sites for microbial colonization and plaque accumulation.

Setting and Sample Population –  Private practice of the first author. Patients were selected using the following inclusion criteria: age range 12–17 years, fixed appliances on both arches, aligned mandibular arch, and absence of oral habits and anterior crossbites.

Materials and Methods –  Prospective cohort investigation. Participants were grouped for bracket type, thus 50 patients formed the conventional bracket cohort and 50 patients the self‐ligating bracket cohort. Both cohorts were followed with the purpose to examine periodontal status. Average length of follow‐up was 18 months. This time period was considered adequate for a proportion of study participants to experience the outcome of interest. Outcome variables were plaque index, gingival index, calculus index, and probing depth for the two bracket cohorts.

Results –  No difference was found in the indices recorded between the two bracket cohorts studied.

Conclusion –  Under the conditions as applied in this study, the self‐ligating brackets do not have an advantage over conventional brackets with respect to the periodontal status of the mandibular anterior teeth.
Skull thickness in patients with skeletal Class II and Class III malocclusions
Authors: Arntsen T , Kjær I , Sonnesen L
Published: October 2008

Structured Abstract

Authors –  Arntsen T, Kjær I, Sonnesen L

Objectives –  To measure skull thickness in a group of subjects with skeletal Class II and a group with skeletal Class III malocclusion and compare these results with a group with Class I occlusion.

Setting and Sample Population –  Department of Orthodontics, School of Dentistry, University of Copenhagen. The Class II group comprised 25 females aged 17–42 (mean 26.0). The Class III group comprised 53 patients, 29 females aged 17–39 (mean 24.2) and 24 males aged 17–38 (mean 22.6). The control group comprised 39 subjects, 19 females and 20 males, aged 22–30, with a neutral occlusion and normal vertical and sagittal jaw relationship.

Material and Methods –  The thickness of the frontal, parietal and occipital bones was measured on lateral radiographs of patients with skeletal Class II and Class III and compared with the control group. Method error ranged from 0.30 to 0.60 mm and reliability coefficients from 0.79 to 0.97. Unpaired t‐tests were used for evaluating differences in thickness.

Results –  Females with skeletal Class II malocclusion had a significantly thinner occipital bone and thicker frontal bones than the control females. Skull thickness in Class III malocclusion was comparable to the control group.

Conclusion –  The most important outcome of this study was reduced skull thickness in the occipital area and thickening of the frontal bone in females with skeletal Class II malocclusion compared with females with Class I. Deviations in the theca cranii are thus associated with skeletal Class II malocclusions.
Temporomandibular joint adaptations following two‐phase therapy: an MRI study
Authors: Wadhawan N , Kumar S , Kharbanda OP , Duggal R , Sharma R
Published: October 2008

Structured Abstract

Authors –  Wadhawan N, Kumar S, Kharbanda OP, Duggal R, Sharma R

Aim –  To document the alterations within the condyle‐glenoid fossa (C‐GF) complex and the positional changes of the glenoid fossa in the cranium after removable functional appliance therapy and after the completion of fixed appliance therapy.

Setting and Sample –  The Department of Orthodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India. The study sample consisted of 12 growing children (eight girls and four boys) between 10 and 14 years of age with skeletal Class II division 1 malocclusion selected on well defined criteria.

Materials and Methods –  All patients were treated with either the Twin Block or the Bionator appliance followed by fixed appliances. Mean total treatment duration was 28 months. The changes in and around the C‐GF complex were evaluated using MRI at pre‐treatment stage, after functional appliance therapy and at the completion of fixed mechanotherapy.

Results –  Forward condylar position within the glenoid fossa and articular disc retrusion with respect to the condylar head were statistically significant after functional appliance therapy. However, the condyles had a relatively concentric position within the glenoid fossa, while the articular disc resumed its pre‐treatment position at the end of the treatment. Linear measurements from the centre of the external auditory meatus to the post‐glenoid spine revealed a 1.3‐mm forward relocation of the post‐glenoid spine along the Frankfurt Horizontal plane.

Conclusions –  Forward relocation of the C‐GF complex seems to be one of the mechanisms of action of functional appliances, while the internal anatomic arrangement within the temporomandibular joint (TMJ) complex normalizes to its pre‐treatment position.
Structure‐Based Design of a Novel Class of Potent Inhibitors of InhA, the Enoyl Acyl Carrier Protein Reductase from Mycobacterium Tuberculosis: A Computer Modelling Approach
Authors: Subba Rao Gita , Vijayakrishnan Rajakrishnan , Kumar Manoj
Published: October 2008

The NADH‐dependent Enoyl‐ACP reductase (InhA) of Mycobacterium tuberculosis has been shown to be the primary target of the frontline drug isoniazid (INH). However, INH must be first activated by katG gene, mutations in which have mediated resistance to INH. Recently, direct inhibitors of InhA have been reported. Using a structure‐based approach, we have identified a tripeptide inhibitor with the sequence WYW, which is 100 times more potent than the existing inhibitors. It is therefore, a potential lead compound for the development of new anti‐TB drugs.
Frequency of Mediterranean mutation among a group of Saudi G6PD patients in Western region‐Jeddah
Authors: GARI M. A. , CHAUDHARY A. G. , AL‐QAHTANI M. H. , ABUZENADAH A. M. , WASEEM A. , BANNI H. , AL‐SAYES F. M. , AL‐HARBI A. , LARY S.
Published: October 2008

Glucose‐6‐phosphate dehydrogenase deficiency (G6PD), a common human enzymatic defects characterized by extreme molecular and biochemical heterogeneity is found to have a variable frequency in different regions. The molecular basis of polymorphic variants in Saudi Arabia have yet to be fully addressed to. Accordingly, a study was designed to determine the frequency of G6PD gene mutations in G6PD deficient cases. From forty‐seven unrelated G6PD‐deficient subjects, DNA was extracted individually from peripheral blood samples and exons 6 and 7 of the G6PD gene were amplified by PCR. Mutation analysis was carried out by using conformation sensitive gel electrophoresis (CSGE), followed by direct DNA sequencing. The results showed definite altered CSGE patterns. Two mutations were resolved in exon 6 of G6PD gene; Mediterranean mutation and Sibari mutation, not previously reported so far; while no mutation was detected in exon 7. The frequency of exons 6 mutations responsible for G6PD deficiency (Mediterranean type) is reported for the first time from this region, with a figure of 50.1%. The absence of other mutations in exon 7 causing G6PD deficiency points to the low genetic diversity in the studied population.
Discrepancies between APTT results determined with different evaluation modes on automated coagulation analyzers
Authors: MILOS M. , HERAK D. COEN. , ZADRO R.
Published: October 2008

Modern photo‐optical coagulometers collect optical data in the form of reaction curves and offer a possibility to determine clotting times at different points of clot formation by using different evaluation modes. The objectives of this study were to determine the possible impact of an evaluation mode on activated partial thromboplastin time (APTT) results and to investigate potential benefits from visual inspection of obtained reaction curves. APTT was determined by using actin FS as reagent on two coagulometers (Siemens Medical Solutions) in 174 plasma samples with three different evaluation modes: fixed absorbance (FA), drifting baseline (DB), and point of inflexion (POI) on Behring coagulation timer (BCT), and with DB mode on Behring coagulation system (BCS). Statistically significant difference of APTT results applying the Friedman’s test (P < 0.0001) followed by Dunn’s multiple comparison test (P < 0.05) was obtained in all tested samples between POI mode and all other evaluation modes, independently of analyzer used. The differences obtained indicated that laboratory professionals must be aware of possible different evaluation modes on different analyzers, and establish evaluation mode‐specific reference intervals. Moreover, correctness of a reported result could be confirmed only by visual analysis of the reaction curve.
HOMOSEXUALITY: PSYCHOTHERAPEUTIC ISSUES
Authors: Downey Jennifer I. , Friedman Richard C.
Published: October 2008

abstract The ideas of psychoanalytically‐oriented psychotherapists about human sexuality have changed radically in recent years. During the past three decades we have worked toward revising traditional psychoanalytic ideas about sexual orientation in particular. This revision has contributed to changes in clinical theory and practice, and we review both our own work, and these changes, in this article. We have approached the many complex scientific and clinical problems in this field from a developmental, biopsychosocial perspective. We have also emphasized the importance of integrating psychoanalytic theories of sexuality with advances in neuroscience, descriptive psychiatry and sexology generally.

In this article we draw on our experience as researchers and clinicians to discuss such common clinical problems in psychotherapeutic work with non‐heterosexual patients as assessment of the patient, homophobia, internalized homophobia, gender differences among patients and therapists, the ageing patient, sexual orientation of the therapist, and transference and countertransference.
Parabolic Trough Analysis and Enhancement Techniques
Authors: Lu¨pfert Eckhard , Pottler Klaus , Ulmer Steffen , Riffelmann Klaus-J. , Neumann Andreas , Schiricke Bjo¨rn
Published: October 2008

Analysis of geometry and optical properties of solar parabolic trough collectors uses a number of specific techniques that have demonstrated to be useful tools in prototype evaluation. These are based on photogrammetry, flux mapping, ray-tracing, and advanced thermal testing. They can be used to assure the collector quality during construction and for acceptance tests of the solar field. The methods have been applied on EuroTrough collectors, cross-checked and compared. This paper summarizes results in collector shape measurement, flux-measurement, ray-tracing, and thermal performance analysis for parabolic troughs. It is shown that the measurement methods and the parameter analysis give consistent results. The interpretation of the results and their annual evaluation give hints on identified relevant improvement potentials for the following generation of solar power plant collectors.
Criteria to Establish an Evaluation Methodology for the Qualification of the Visual Impact of Solar Thermal Systems on Urban Landscapes
Authors: Lo´pez Germa´n , Lo´pez Enrique , Marti´nez Jaime , Lillo Isidoro
Published: October 2008

This paper introduces the criteria to establish a methodology for the valuation and evaluation of the visual impact that may be produced by solar thermal energy systems on urban landscapes. A systematics to interrelate the characteristics of solar thermal systems and the characteristics of the urban landscape by means of matrixes is introduced. Three different urban landscape typologies have been considered. The result of the interaction shall be the visual impact of a solar thermal system on an urban landscape, which may vary from a minimum to a maximum (including different levels of acceptance).
Divided Storage in an Indirect Integral Collector Storage With Immersed Heat Exchanger
Authors: Davidson Jane H. , Ragoonanan Vishard , Homan Kelly O.
Published: October 2008

Experiments are presented to demonstrate the benefit of dividing an indirect integral collector storage into two storage compartments. Transient discharge experiments were conducted in an undivided and equally divided 126 liter rectangular storage vessel with a height to depth aspect ratio of 9.3:1 and inclined at 30 degrees. A 240-tube copper heat exchanger with a total surface area of 2.38 m2 was immersed in the storage fluid. For the divided storage, the tube-side now path was in series through the two compartments. Water flow rate through the heat exchanger was varied from 0.05 to 0.15 kg/s to demonstrate the effect of the number of transfer units (NTU) on comparative performance of undivided and divided storage vessels. Reported measurements include transient storage temperature distribution, heat exchanger outlet temperature, and delivered energy of the divided and undivided storage. Results are generally in agreement with a prior analytical model. The divided storage provides higher heat exchanger outlet temperatures during most of the discharge and higher cumulative delivered energy. The benefit increases with increasing NTU. For a flow rate of 0.05 kg/s, corresponding to a nominal NTU of 7, the divided storage delivers approximately 11% more energy than the undivided storage when 126 liters of hot water, representing 76% of the stored energy, has been delivered.
Assessment of the Partial Model Stability of the Quasi-Dynamic Collector Test Under Outdoor Conditions EN 12975 by the Application of Uncertainty Analysis
Authors: Kratzenberg M. G. , Beyer H. G. , Colle S. , Albertazzi A. , Gu¨ths S. , Fernandes D. , Oikawa P. M. V. , Machado R. H. , Petzoldt D.
Published: October 2008

Outdoor collector tests are inherently performed under variable weather conditions. Whereas ISO 9806 sets strong restrictions for the conditions of usable data sets for the steady-state collector test SST, EN12975 allows more variable ambient conditions for the quasi-dynamic collector test QDT. This results in shorter collector test times, but could have drawbacks for the uncertainties including the reproducibility of the test results, i.e. the parameters of the collector model. As the weather conditions are never the same within several tests, outdoor collector tests are not repeatable only reproducible. It is thus to be expected, that the uncertainties of the collector parameters gained by a quasi-dynamic test are higher than those from the steady-state test. In this paper we evaluate the collector parameters and their uncertainties for a covered collector using both the SST, and QDT test methods. As basis for this comparison, we apply a large data set from 2 months of operation under quasi-dynamic conditions. This set is then separated into various single data sets which either fulfill the conditions for a complete steady-state or a complete quasi-dynamic test. For the quasi-dynamic test various sets could be identified. For each of these tests, the parameters and their uncertainties are calculated. This allows for the comparison of both, the model coefficients and their uncertainties. It is tested whether the coefficients extracted from each of the ‘quasi-dynamic sets’ are in coherence or stable within a 95% confidence by using statistical procedures.
Research of Combined Heating and Cooling by Solar Ground-Source Heat Pump and PCM Thermal Storage
Authors: Wu Li-Xia , Zheng Mao-Yu
Published: October 2008

In severely cold climate, significant amount of energy is used to heat buildings. Both the theoretical computation and experiments show that it is difficult and uneconomical to use solar energy collected merely in winter. A new method has been developed to store solar energy during summer, fall, and spring for winter heating. This paper presents in details the combined heating and cooling system by solar ground-source heat pump (GSHP) and short-term phase change material (PCM) thermal storage. The hybrid system and season-shift mode can make the sustainable use of solar energy possible. As for the above system, the solar energy collected is stored into soil through the U-tube heat exchanger. In winter, the thermal energy is taken out for heating using the GSHP. At the end of the heat supply season, the underground soil temperature may drop below 0°C. Then some heat exchangers begin to store the heat into soil while others stop. In summer, the U-tube heat exchanger is used to produce low temperature water without compressor to cool the room. The project was supported by the Energy Conservation Laboratory at Harbin Institute of Technology (HIT). The whole systems, which have run for over two years, consist of a flat plate solar hot water system installed on the roof, a soil thermal storage system, a GSHP system, a PCM thermal storage system and heating-cooling system. The measured results show an average heating coefficient of performance (COP) of 3.2 in winter and the cooling coefficient of performance (COP) of 18.0 in summer. The PCM thermal storage system has been investigated by numerical simulation and experiments in the cold climate. In most time of winter, the PCM thermal storage system was used to supply heat, while solar GSHP was also used during continuous cloudy days and severely cold days. The result shows that above method is feasible. The most advantage of this system is that it does not need the usual energy equipment. The numerical analysis has been used to investigate the thermal energy balance of the underground soil. The variation of the soil temperature field around the U-tube heat exchanger has also been studied, not only for the single exchanger but also for multiple exchangers. The underground soil makes the yearly thermal balance possible because the solar energy supplies the heat that is extracted from the soil for heating in winter. Then this system can operate for a long period.
Properties of CuInS2 Thin Films Fabricated by SEL Method
Authors: Park Gye-Choon , Jeong Woon-Jo , Yang Hyeon-Hun , Jung Hae-Duck , Lee Jin , Kim Seong-Ku
Published: October 2008

CuInS2 thin films were fabricated by sulphurization of S/In/Cu Stacked elemental layers (SEL) on slide glass substrates by annealing in vacuum of 10−3 Torr at temperature of 50 °C ∼ 350 °C. Some S/In/Cu SEL were vacuum annealed under a sulfur atmosphere. The thin films thus annealed were analyzed by measuring structural, electrical and optical properties. When CuInS2 thin films were made under a sulfur atmosphere, lattice constant of a and grain size of the thin film were a little larger than those in only vacuum annealing. The largest lattice constant of a and grain size was 5.63 Å and 1.2 μm respectively. Also, when the thin films were made under a sulfur atmosphere, conduction types were all p-type with resistivities of around 10−1 Ωcm and optical energy band gaps of the films were a little larger than those in only vacuum and the largest optical energy band gap of CuInS2 thin film was 1.53 eV.
Improved Design Parameters for a Liquid Desiccant Dehumidifier in Confined Spaces
Authors: Dong D. , Liu M.
Published: October 2008

Investigations of a desiccant dehumidifier system have been performed for humidity control application in confined spaces. A previous study revealed that the base dehumidifier system can reduce moisture condensation by 22% over a conventional exhaust ventilation system. The current study aims to develop improved design requirements for a desiccant dehumidifier. The energy consumption of an exhaust ventilation system and an improved dehumidifier system was compared. To investigate the improved desiccant dehumidification system, numerical simulations were conducted and an objective function was established. This paper presents simulated results for an existing desiccant dehumidification system and an improved system, in which improved parameters are used. Use of the improved design parameters can reduce moisture condensation by 26.6% over a base dehumidifier system and shorten the dehumidifier performance period by 14%. Energy consumption with the sole use of an exhaust system is compared with that of the improved dehumidifier system under the same conditions. The results show that energy consumption can be substantially reduced, by 63%, in the improved dehumidifier system with the same amount of moisture condensation on surfaces of the confined space.
A Real Options Methodology for Evaluating Risk and Opportunity of Natural Ventilation
Authors: Greden Lara V. , Glicksman Leon R. , Lopez-Betanzos Gabriel
Published: October 2008

The variable, uncertain nature of climate imposes risk in using solar and building technologies, such as natural ventilation (NV). To maximize the potential benefit from NV while reducing risk, a building could be designed for NV along with the “real option” to install mechanical cooling in the future, if needed. Traditional evaluation procedures use expected values, which fail to acknowledge the value of uncertainty when system performance is a non-linear function of the uncertain variable. A real options methodology is proposed to evaluate the flexible building design under climate uncertainty. A building energy simulation is used to obtain probability distributions of the cost savings of the option-based NV strategy and of the time when (if) the mechanical cooling system is installed. A simplified stochastic temperature generator is used, and it may be used to evaluate real options for other technologies sensitive to future climate. The results of a real options analysis provide information to project investors on a) the likelihood of exercising the option, and b) the improved financial value of the technology when implemented with a flexible strategy.
Photoelectrolytic Production of Hydrogen: Annex-14 of the IEA Hydrogen R&D Program
Authors: Luzzi Andreas
Published: October 2008

Nine research groups from four countries have been collaborating for 4.5 years under Annex-14 with the aim to advance the science underlying photoelectrolytic hydrogen production from water-splitting. Significant research progress has been made in the areas of material science (semiconductor photoelectrodes, light absorption, photocatalyst stability and charge transfer) and systems development (monolithic multijunction systems, two-photon tandem systems, dual-bed redox systems and monomaterial two-step systems), resulting in the synthesis as well as development of new photoactive materials and the demonstration of various photoelectrochemical (PEC) water-splitting prototype devices, limited to typical laboratory-size miniature scales.
Solar Hydrogen Production by a Two-Step Cycle Based on Mixed Iron Oxides
Authors: Roeb Martin , Sattler Christian , Klu¨ser Ruth , Monnerie Nathalie , de Oliveira Lamark , Konstandopoulos Athanasios G. , Agrafiotis Christos , Zaspalis V. T. , Nalbandian L. , Steele Andrew , Stobbe Per
Published: October 2008

A very promising method for the conversion and storage of solar energy into a fuel is the dissociation of water to oxygen and hydrogen, carried out via a two-step process using metal oxide redox systems such as mixed iron oxides, coated upon multi-channeled honeycomb ceramic supports capable of absorbing solar irradiation, in a configuration similar to that encountered in automobile exhaust catalytic converters. With this configuration, the whole process can be carried out in a single solar energy converter, the process temperature can be significantly lowered compared to other thermo-chemical cycles and the re-combination of oxygen and hydrogen is prevented by fixing the oxygen in the metal oxide. For the realization of the integrated concept, research work proceeded in three parallel directions: synthesis of active redox systems, manufacture of ceramic honeycomb supports and manufacture, testing and optimization of operating conditions of a thermochemical solar receiver-reactor. The receiver-reactor has been developed and installed in the solar furnace in Cologne, Germany. It was proven that solar hydrogen production is feasible by this process demonstrating that multi cycling of the process was possible in principle.
Design and Analysis of an Urban Building Integrated PV System
Authors: Kantamsetti Shveta , Raskauskas Mary , Torres Vanessa , Singh Pritpal
Published: October 2008

The objective of the present project is to estimate the power generated from solar energy absorbed by photovoltaic panels mounted on the fac¸ade of a building in an urban environment, taking into account shading and reflection from neighboring buildings. A simple prototype of an urban development has been designed and modeled in AutoCAD, with the help of AccuRender. This paper includes the simulation of the model, taking into consideration the building geometry, orientation with respect to the sun, material properties of the surrounding buildings, and ground reflections. Also included is a discussion about a scaled physical model that is being used to validate the computer modeling, followed by a case study on the installation of a BIPV system on Ten Penn Center in Center City, Philadelphia.
Analysis of Running Energy Consumption of Fresh Air Cooling Systems
Authors: Zhao Jianing , Guo Jun , Sun Weimeng
Published: October 2008

Utilization of renewable energy becomes more and more attractive and crucial for sustainable buildings. A cooling system, using outdoor fresh air and combining with the conventional all-air system or running along during different seasons, is discussed in this study. Running energy consumption of this system is analyzed by a mathematical model using the Genetic Algorithm (GA) combined with the traditional Lagrange method. To evaluate and apply this new system, energy consumption of the chiller unit, water and air sub-systems, as well as the total energy consumption of such a system is compared with that of the conventional all-air system. Consequently, the total energy consumption is selected as the criterion of energy efficiency. The results show that the cooling system bears considerably energy efficient, and that it reduces energy consumption at least 14% and 12%, compared with the constant air volume and variable air volume system, respectively.
Structural Comparison of CIGSS Thin Film Absorber Layer Fabricated on SS and Ti Substrates
Authors: Kadam Ankur A. , Dhere Neelkanth G.
Published: October 2008

Copper indium gallium selenide sulfide, CuIn1−xGaxSe2−ySy (CIGSS) absorber layer was prepared on stainless steel (SS) and SiO2-coated titanium substrates. Comparative study was carried out to analyze the variation in the crystal quality depending on the substrate. Identical parameters were used for deposition and selenization/sulfurization of metallic precursors. This paper presents the observations made on the basis of surface morphology using scanning electron microscopy, crystal quality by x-ray diffraction and chemical composition and concentration-depth profiles by x-ray energy dispersive spectroscopy and Auger electron spectroscopy respectively. Film fabricated on both the substrate had chalcopyrite structure with variation of stoichiometry as well as morphology. Selenization/sulfurization cycle must be modified depending upon the substrate to obtain high quality CIGSS film.
Development of Optimal Design of Solar Water Heating System by Using Evolutionary Algorithm
Authors: Fong K. F. , Chow T. T. , Hanby V. I.
Published: October 2008

There are growing initiatives to promote renewable energy in Hong Kong, particularly for solar energy. In order to encourage wider application of centralized solar water heating system for high-rise residential buildings, it is important to pursue an optimal design to get significant energy saving potential. In this regard, system optimization would be useful, as it can relate to a number of design variables of the solar water heating system such as the tilt angle and surface azimuth of the solar collectors, the storage capacity of the hot water calorifier, and the flow rate of the circulation pump set for the solar collectors. The objective function is to maximize the year-round energy saving by using the solar heating instead of conventional domestic electric heating. For the methodology of optimization, evolutionary programming, one of the paradigms of evolutionary algorithm, was applied. This has been proven to be effective for optimization problems with a non-linear and multi-dimensional nature. To generate values for the objective function, a TRNSYS plant simulation model was developed and coupled with the optimization algorithm. From the optimization results, it is suggested that the solar collectors can be installed onto the external shading devices as an integrated architectural feature, since the optimal tilt angle is 21° and relatively flat. The optimal surface azimuth is southwest 16° instead of due south. For the engineering design, both the optimal values of calorifier storage capacity and pump flow rate show that the calculations from normal design practice may not achieve an optimal performance. Therefore, an effective methodology of optimization and simulation is essential to generate an optimal design in a holistic approach.
Investigation on the Use of Nanofluids to Enhance Heat Pipe Performance
Authors: Israeli Tomer , Reddy T. Agami , Cho Young I.
Published: October 2008

This paper reports on preliminary experimental results on using nanofluids to enhance the thermal performance of heat pipes. Our experience with preparing copper oxide (CuO) nanofluids is described. Contrary to earlier studies which report infinite shelf life, we found that nanofluid stability lasted for about three weeks only; an issue which merits further study. We have also conducted various experiments to measure the variation of thermal conductivity and surface tension with CuO nanofluid concentration. Actual experiments on nanofluid heat pipes were also performed which indicated an average 12.5% decrease in the overall thermal resistance of the heat pipe using nanofluid of 3% vol concentration. This observed improvement is fairly consistent with our predictions using a simple analytical thermal network model for heat pipe overall resistance and the measured nanofluid conductivity. The results, though encouraging, need more careful and elaborate experimental studies before the evidence can be deemed conclusive.
Hysteresis Current Control of a Permanent Magnet Brushless DC Motor PV Pumping System
Authors: Moussi A. , Terki A. , Asher Greg
Published: October 2008

This paper presents the optimal operation of a photovoltaic pumping system. The operation of a permanent magnet brushless DC motor driving a centrifugal pump is investigated. The motor is controlled through a hysteresis current loop and an outer speed loop with a PI type controller. The proportional and integral gains are set to their optimal values. In order to optimise the overall system efficiency, a Maximum power point tracker is also used. Simulation is carried out by formulating the mathematical model for the photovoltaic source, MPPT, motor and pump load. System performances are investigated under different levels of solar insolation. The effectiveness of the proposed controller is also demonstrated.
Three Years Experience With Solar Air Condition in the EAR Office Tower in Pristina/Kosovo
Authors: Holter Christian
Published: October 2008

Since 2002 the Nine-story building of the headquarters of the European Agency for the Reconstruction of Kosovo is equipped with a solar thermal driven heating and cooling system. The performance fulfils the expectations fully and proof the chosen design and sizing of the system. Solar energy can cover around 75% of the cooling demand and a reasonable fraction of the heating too.
Understanding Surface Instability Patterns in Nanoscale Thin Films
Authors: Huang Rui , Im Se Hyuk , Pang Yaoyu
Published: October 2008

Thin films of nanoscale thickness are common in integrated systems and devices. Subjected to interactions of diverse physical origins, the nanoscale thin films often undergo structural and/or morphological instability and develop a variety of surface patterns. Two examples are discussed in this paper. An epitaxial thin film undergoes surface roughening and form self-assembled quantum dots [1]. A thin metal film bonded to a polymer substrate develops various wrinkle patterns [2]. We develop nonlinear models and numerical methods to simulate the evolution processes. The results reveal very rich dynamics of surface pattern formation and suggest potential means for the control and making of ordered patterns.
Fabrication of First-Level Carbon Nanotube Interconnect Via Structures by Thermal Chemical Vapor Deposition
Authors: Wang Yunyu , Yao Zhen , Li Shi , Ho Paul S.
Published: October 2008

As devices continue to scale down to the 50 nm technology node, current Cu/low k interconnect technology will face a number of challenges including reduced current carrying capabilities, decreased thermal conductivity, and reliability problems due to electromigration at large current densities. Carbon nanotubes (CNTs) with their unique structural, thermal and electrical transport properties have been suggested as a promising candidate as interconnect structures for future microelectronics. In this study we have demonstrated the growth of vertically aligned, highly dense CNT arrays by thermal chemical vapor deposition (CVD). It was found that a thin layer of tantalum (Ta), which was originally used as the barrier layer in copper interconnects, may enhance a uniform growth and better vertical alignments of CNT arrays. We have also developed a nanofabrication process of the first-level CNT via structures.
Complex Patterning by Vertical Interchange Atom Manipulation Using Atomic Force Microscopy
Authors: Sugimoto Yoshiaki , Pou Pablo , Custance Oscar , Jelinek Pavel , Abe Masayuki , Perez Ruben , Morita Seizo
Published: October 2008

The ability to incorporate individual atoms in a surface following predetermined arrangements may bring future atom-based technological enterprises closer to reality. Here, we report the assembling of complex atomic patterns at room temperature by the vertical interchange of atoms between the tip apex of an atomic force microscope and a semiconductor surface. At variance with previous methods, these manipulations were produced by exploring the repulsive part of the short-range chemical interaction between the closest tip-surface atoms. By using first-principles calculations, we clarified the basic mechanisms behind the vertical interchange of atoms, characterizing the key atomistic processes involved and estimating the magnitude of the energy barriers between the relevant atomic configurations that leads to these manipulations.
A Stochastic Single-Molecule Event Triggers Phenotype Switching of a Bacterial Cell
Authors: Choi Paul J. , Cai Long , Frieda Kirsten , Xie X. Sunney
Published: October 2008

By monitoring fluorescently labeled lactose permease with single-molecule sensitivity, we investigated the molecular mechanism of how an
Escherichia coli
cell with the
lac
operon switches from one phenotype to another. At intermediate inducer concentrations, a population of genetically identical cells exhibits two phenotypes: induced cells with highly fluorescent membranes and uninduced cells with a small number of membrane-bound permeases. We found that this basal-level expression results from partial dissociation of the tetrameric lactose repressor from one of its operators on looped DNA. In contrast, infrequent events of complete dissociation of the repressor from DNA result in large bursts of permease expression that trigger induction of the
lac
operon. Hence, a stochastic single-molecule event determines a cell's phenotype.
Relation Between Obesity and Blunted Striatal Response to Food Is Moderated by
Taq
IA A1 Allele
Authors: Stice E. , Spoor S. , Bohon C. , Small D. M.
Published: October 2008

The dorsal striatum plays a role in consummatory food reward, and striatal dopamine receptors are reduced in obese individuals, relative to lean individuals, which suggests that the striatum and dopaminergic signaling in the striatum may contribute to the development of obesity. Thus, we tested whether striatal activation in response to food intake is related to current and future increases in body mass and whether these relations are moderated by the presence of the A1 allele of the
Taq
IA restriction fragment length polymorphism, which is associated with dopamine D2 receptor (
DRD2
) gene binding in the striatum and compromised striatal dopamine signaling. Cross-sectional and prospective data from two functional magnetic resonance imaging studies support these hypotheses, which implies that individuals may overeat to compensate for a hypofunctioning dorsal striatum, particularly those with genetic polymorphisms thought to attenuate dopamine signaling in this region.
Current-Induced Spin-Wave Doppler Shift
Authors: Vlaminck Vincent , Bailleul Matthieu
Published: October 2008

Spin transfer appears to be a promising tool for improving spintronics devices. Experiments that quantitatively access the magnitude of the spin transfer are required for a fundamental understanding of this phenomenon. By inductively measuring spin waves propagating along a permalloy strip subjected to a large electrical current, we observed a current-induced spin wave Doppler shift that we relate to the adiabatic spin transfer torque. Because spin waves provide a well-defined system for performing spin transfer, we anticipate that they could be used as an accurate probe of spin-polarized transport in various itinerant ferromagnets.
Talk Instead of Yelling
Authors: Manheim Frank T.
Published: October 2008

Earth: The Sequel
. The Race to Reinvent Energy and Stop Global Warming.
By Fred Krupp and Miriam Horn
. Norton, New York, 2008. 287 pp. $24.95, C$24.95. ISBN 9780393066906.

Noting that achieving a sustainable-energy economy will require tremendous effort, the author profile innovators and investors whose actions hold the promise of averting the climate crisis.