bluuebunny/crossref_metadata_2025 huggingface dataset:
Bone Response to Implant‐Supported Frameworks with Differing Degrees of Misfit Preload: In Vivo Study in Rabbits
Authors: Jemt Torsten , Lekholm Ulf , Johansson Carina B.
Published: April 2007

Purpose:

To study the bone response around implants placed in tibia of rabbits that supported misfitting superstructures secured with different degrees of preload.

Materials and Methods:

Twelve rabbits were provided with two terminal 10‐mm and one intermediate 7‐mm‐long implant in each tibia. After an integration time of about 9 weeks, nine of the animals received one control framework each (n = 9), designed with good fit to all three implants. In the other tibia of these animals, and in both tibias in the remaining three rabbits, test frameworks (n = 15) were connected with a vertical misfit of about 1 mm to the intermediate implant. The intermediate set screws were tightened with a torque ranging from 15 Ncm to 26 Ncm in the different test frameworks. The fascia and skin was then sutured back over the implants. After a loading period of 2 to 3 weeks, the animals were sacrificed, and histomorphometric measurements were made and correlated to the different levels of preload of the central implant.

Results:

The mean bone‐to‐metal contact for the three best consecutive threads of the central implant was 40% for both test and control sites (p > .05). Compared to the other regions of the implant thread, less bone‐to‐metal contact was found at the tip of the test implant threads in the low preload group (p < .05). However, the same relation was not observed in the high preload group. A significant correlation was observed between increasing degree of preload in the central screw joint and increasing bone‐to‐metal contact, most obviously noticed at the tip of the implant thread (p < .01).

Conclusions:

Misfit stress levels of clinical magnitudes do not seem to jeopardize osseointegration per se. On the contrary, clinical levels of preload stress seem to significantly promote bone remodeling at the tip of the implant thread.
Immediate Function of Brånemark Implants in the Esthetic Zone: A Retrospective Clinical Study with 6 Months to 4 Years of Follow‐up
Authors: Maló Paulo , Rangert Bo , Dvärsäter Lisbeth
Published: April 2007

Background:

Immediate implant function is a psychological benefit for the patient and makes a substantial reduction in treatment cost possible. Currently, immediate function using Brånemark implants has become an accepted alternative for complete‐arch fixed restorations in mandibles and for overdenture support for some other screw‐shaped implants. Clinical documentation is lacking for other applications.

Purpose:

The purpose of this study was to investigate a concept for immediate function of Brånemark implants supporting fixed prosthesis in the esthetic regions of the jaws.

Materials and Methods:

This retrospective clinical study included 49 consecutively treated patients with 94 implants supporting 54 fixed prostheses, all in esthetically critical regions: 23 of the prostheses were bridges, 14 in maxillae and 9 in mandibles; 31 of the prostheses were crowns, 22 in maxillae and 9 in mandibles. At surgery, the implant platform was positioned above the surrounding bone level and bicortical anchorage was the goal whenever possible. The minimum insertion torque for accepting the implant for immediate function was 32 Ncm. Provisional implant‐supported prostheses without occlusal contacts were delivered at time of surgery, and final prostheses with normal occlusion were delivered 5 months later.

Results:

Eighty‐five of the implants (90%) have passed the 1‐year and 40 (43%) the 2‐year follow‐ups, respectively. Two implants failed in one patient before the 6‐month follow‐up, and another two implants between the 6‐month and the 1‐year follow‐up, in two other patients, giving a cumulative survival rate of 96%. The average bone resorption was 0.8 mm after the first year as evaluated from 35 patients with readable radiographs. The failed implants were replaced after 3 to 4 months with immediate function; these were successful in all cases (not included in this study). The number of complications was small and did not differ in character from those normally encountered at implant treatment using a conventional protocol.

Conclusions:

The cumulative survival rate of 96% at 1 and 2 years indicates that immediate function of Brånemark implants used in the esthetic zone in both jaws can be a viable concept. All failures occurred in fresh extraction sites, and extra care is recommended to avoid situations with ongoing inflammation in these situations.
A Clinical, Radiographic, and Microbiologic Comparison of Astra Tech and Brånemark Single Tooth Implants
Authors: Puchades‐Roman Lorena , Palmer Richard M. , Palmer Paul J. , Howe Leslie C. , Ide M. , Wilson Ron F.
Published: April 2007

Background: The soft tissues around single tooth implants differ fundamentally from the gingiva around natural teeth. There are very limited data comparing soft tissues around different implant systems.

Aim: To assess whether the design characteristics of dental implants, particularly the implant‐abutment junction, may affect the dimensions and health of the peri‐implant soft tissues and radiographic bone levels.

Subjects and Method: Fifteen Astra Tech and 15 Brånemark single tooth implants that had been in function for a minimum of 2 years in 30 partially dentate subjects were examined for plaque accumulation, probing depth, and bleeding on probing and compared to contralateral healthy teeth. Standardized radiographs were taken to measure the most coronal bone to implant contact on the mesial and distal surfaces. In addition, samples of subgingival plaque were taken on paper points and examined by darkfield microscopy.

Results: Significantly higher mean probing depths (p < .001) and higher mean percentage of spirochetes (p= .003) were found at implants compared to teeth. In this sample, the Brånemark implants had significantly higher probing depths than the Astra Tech implants (median and interquartile range: Astra Tech 2.7 mm [2–3], Brånemark 3.3 mm [3–3.7] p= .026) and the most coronal bone to implant contact was closer to the implant–abutment junction in the Astra Tech implants (Astra Tech 0.6 mm [0.2–0.9], Brånemark 1.6 mm [1.4–2.0]. p < .001).

Conclusion: Although there were statistically significant differences between the two implant systems, the clinical differences were small and probably reflect differences in the biologic width in relation to the location and design of the implant‐abutment junction.
Augmentation of Exposed Implant Threads with Autogenous Bone Chips: Prospective Clinical Study
Authors: Widmark Göran , Ivanoff Carl‐Johan
Published: April 2007

Background: Autogenous bone chips can be harvested during drilling of implant sites and may be used as a graft material for bone augmentation and coverage of exposed implant threads.

Purpose: The aim of this prospective study was to evaluate the possibility of augmenting exposed implant threads with autogenous bone chips.

Materials and Methods: Twenty‐one consecutive patients treated with screw‐shaped oral implants with exposed threads due to buccal fenestration or marginal defects were augmented with autogenous bone harvested with a bone trap during drilling of the implant site. Both marginal (9 sites) and fenestration defects (12 sites), with 4 to 14 exposed implant threads, were registered clinically and with photography. The number of exposed implant threads was measured before and at second‐stage surgery 6 months after augmentation.

Results: Complete bone coverage of the exposed implant threads was seen in 12 of the 21 implant sites. Six sites showed one to two remaining exposed threads, two showed about 40% coverage, and one showed flattening of the defect but with eight of nine exposed threads at 6 months follow‐up. The mean bone gain was 81% in patients with a marginal defect and 82% in patients with a fenestration defect.

Conclusion: The results from this clinical study show that it is possible to gain bone over exposed implant threads by augmentation with autogenous bone chips.

Conclusion It is concluded that it is possible to achieve coverage of exposed implant threads by augmentation with autogenous bone chips harvested during drilling of implant sites.
Re‐Establishment of the Atomic Composition and the Oxide Structure of Contaminated Titanium Surfaces by Means of Carbon Dioxide Laser and Hydrogen Peroxide: An In Vitro Study
Authors: Mouhyi Jaâfar , Sennerby Lars , Wennerberg Ann , Louette Pierre , Dourov Nicolas , van Reck Jack
Published: April 2007

Background: In clinical situations with peri‐implant bone resorption, re‐integration of the exposed implant surface is sometimes preferable, which requires a clean surface. Previous investigations have shown that cleaning of contaminated titanium surfaces using chemical and abrasive methods is difficult.

Purpose: The aim of this investigation was to evaluate the efficacy of different combinations of chemical and physical methods (citric acid, hydrogen peroxide, and carbon dioxide [CO2] laser irradiation) for removal of contaminants and subsequent reconstruction of the surface oxide of intraorally contaminated titanium foils.

Materials and Methods: Commercially pure titanium foils (99.6%, 55 mm in size) were contaminated by placement on dentures in volunteering patients, simulating a peri‐implantitis situation. The contaminated foils and clean control foils were treated by seven and six combinations of citric acid, hydrogen peroxide, and CO2 laser irradiation, respectively. The effect of the cleaning procedures was evaluated by x‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM).

Results: The initial elemental composition of the contaminated foils was 70% carbon (C), 20% oxygen (O), 10% nitrogen (N), and only traces of titanium (Ti) (< 1%). One treatment proved to be more effective than the others: irradiations by 5‐second cycles of superpulsed CO2 laser at a power of 7 W, 10‐millisecond pulse width, and with an 80‐Hz frequency on a wet surface, followed by repeated application of supersaturated citric acid for 30 seconds, each time followed by rinsing with ultrapure water until all tissue remnants had been removed. Finally, hydrogen peroxide of 10‐mM concentration was added to the implant surface and evaporated by CO2 laser at the same settings. This treatment protocol resulted in 10% Ti, 45% O, 41% C, and 2 to 3% N, a composition comparable to that of unused foils:9% Ti, 40% O, 48% C, and traces of N and chlorine (CI). X‐ray photoelectron spectroscopy profiles showed that the thickness of the surface oxide was restored and even augmented with this protocol for treatment of contaminated titanium.

Conclusion: A combination of citric acid, hydrogen peroxide, and CO2 laser irradiation seems to be effective for cleaning and reestablishment of the atomic composition and oxide structure of contaminated titanium surfaces.
One‐Year Prospective Evaluation of the Early Loading of Unsplinted Conical Brånemark Fixtures with Mandibular Overdentures Immediately following Surgery
Authors: Payne Alan G.T. , Tawse‐Smith Andrew , Kumara Rohana , Thomson W. Murray
Published: April 2007

Background: Prospective evaluation of the early loading of unsplinted Branemark implants with mandibular over‐dentures opposing conventional dentures is not evident in the implant‐related literature.

Purpose: To clinically evaluate progressive and early loading of 20 unsplinted conical Brånemark implants in edentulous mandibles with overdentures.

Materials and Methods: Ten edentulous patients all had two conical Brånemark implants placed in the anterior mandible with mandatory primary stability with bicortical anchorage. Ball abutment connection was performed simultaneously. Previously constructed conventional mandibular dentures were temporarily relined with tissue conditioner postoperatively and worn with moderation for the first 2 weeks to allow progressive loading. Early loading of the implants followed after 2 weeks, with inclusion of the respective matrices in the mandibular dentures, using a definitive reline procedure.

Results: All patients successfully functioned with their mandibular implant overdentures from 2 to 52 weeks postoperatively. Mean marginal bone loss was within established criteria for success:0.22 mm (SD = 0.48 mm) mesially and 0.30 mm (SD = 0.39 mm) distally on the conical implants. Mobility tests using the Periotest instrument became more negative, although not at statistically significant levels. Difficulties in the management of the peri‐implant mucosa between surgery and loading at 2 weeks were observed in 40% of the patients.

Conclusions: These preliminary 1‐year results show that successful early loading of unsplinted conical Brånemark implants with mandibular overdentures is possible.
Tilted Implants as an Alternative to Maxillary Sinus Grafting: A Clinical, Radiologic, and Periotest Study
Authors: Aparicio Carlos , Perales Pilar , Rangert Bo
Published: April 2007

Background: Owing to mechanical and anatomic difficulties, implant treatment in the atrophic maxilla represents a challenge. The maxillary sinus floor augmentation procedure is still not universally accepted because of its complexity and its unpredictability.

Purpose: In this study, a combination of tilted and axial implants was used in patients with severely resorbed posterior maxillae as an alternative to sinus grafting.

Materials and Methods: Twenty‐five patients were rehabilitated with 29 fixed partial prostheses supported by 101 Brånemark System implants. Fifty‐nine implants were installed in an axial and 42 in a tilted direction. The average follow‐up period was 37 months (range:21–87 mo post loading).

Results: After 5 years, the implant cumulative success rate was 95.2% (survival: rate 100%) for the tilted implants and 91.3% (survival rate:96.5%) for the axial implants, and the prosthesis survival rate was 100%. At the fifth year, the average marginal bone loss was 1.21 mm for the tilted implants and 0.92 mm for the axial ones. The mean Periotest values (PTV) at loading time were ‐2.62 and ‐3.57, and after 5 years the PTVs were ‐4.73 and ‐5.00 for the tilted and the axial implants, respectively. During the follow‐up, all prostheses but two were mechanically stable, retightening of 18 abutment screws and of 5 gold screws in 14 prostheses was done, and fracture of two abutment screws and two occlusal surfaces was experienced.

Conclusions: Results indicate that the use of tilted implants is an effective and safe alternative to maxillary sinus floor augmentation procedures.
Brånemark Implants and Osteoporosis: A Clinical Exploratory Study
Authors: Friberg Bertil , Ekestubbe Annika , Mellström Dan , Sennerby Lars
Published: April 2007

Background: Oral implant treatment on patients with poor jaw‐bone texture has shown increased failure rates in series of studies.

Purpose: The purpose of the present study was to retrospectively follow patients with osteoporosis of the axial or appendicular skeleton, including the jaw bone, being subjected to oral implant treatment. The outcome of inserted implants, when using an adapted bone site preparation technique and extended healing periods, was evaluated.

Materials and Methods: Based on data obtained from preoperative radiographs, patient medical history, and resistance of the jaw bone perceived during drilling, 14 of 16 patients were referred to the Osteoporosis Laboratory, Sahlgren University Hospital, Göteborg, Sweden, for bone density measurements. Two patients already had an established diagnosis of osteoporosis. Fourteen jaws in 13 patients (11 females, 2 males; mean age:68 yr) were subsequently subjected to oral implant treatment with a total of 70 implants (Brånemark System) of various designs. The mean follow‐up period was 3 years and 4 months (range:6 mo‐11 yr).

Results: Osteoporosis of either the spine, the hip, or both regions was diagnosed in 14 patients, and osteopenia was diagnosed in 2 patients. Two implants failed, and the overall implant survival rate at the end of the study period was 97.0% for maxillae and 97.3% for mandibles. The marginal bone resorption at the 1‐year follow‐up concurs with the outcome of other studies, irrespective of the preoperative bone texture present.

Conclusion: The outcome of the present study showed that implant placement in patients in whom the average bone density showed osteoporosis in both lumbar spine and hip as well as poor local bone texture may be successful over a period of many years.
Immediate Provisional for Single‐Tooth Implant Replacement with Brånemark System: Preliminary Report
Authors: Hui Edward , Chow James , Li Douglas , Liu Jerry , Wat Peter , Law Henry
Published: April 2007

Background: The success of osseointegrated implants ad modum Brånemark for single‐tooth restorations is documented. Future developments should aim at improving the benefits to patients by decreasing treatment time, minimizing surgical stages, and maximizing esthetic outcomes. Using knowledge from studies of immediate implant placement, one‐stage, immediate loading protocols, the authors developed the immediate provisional.

Purpose: The purpose of this study was to develop a protocol to provide an immediate solution for restoring a single missing tooth in the esthetic zone. The protocol should be simple, predictable, cost effective, and allow the use of other techniques to improve esthetic outcome.

Materials and Method: This prospective clinical study included 24 patients treated from August 1999 to October 2000. Single‐tooth implant replacement was done according to immediate provisional protocol. Thirteen of the 24 patients had immediate implant placement after tooth extraction. All implants were placed in the esthetic zone. During surgery, emphasis was placed on obtaining primary stability by achieving bicortical anchorage and maximum insertion torque of at least 40 Ncm. CeraOne (Nobel Biocare) abutments were used, and provisional crowns were fabricated immediately before wound closure. The occlusion was protected by adjacent teeth.

Results: Within the follow‐up period of between 1 month and 15 months, all fixtures in the 24 patients were stable. Crestal bone loss greater than one thread‐width was not detected. The esthetic result was considered satisfactory by all patients.

Conclusions: The implant placement and restoration protocol used in this study showed promising initial results for both the immediate implant and healed extraction site groups. The desirable goals of patient satisfaction, excellent esthetic outcomes, and no increase in treatment cost were achieved in this protocol. Further studies to elucidate the potential of the immediate provisional protocol are justified.
Histologic Analysis of Clinical Biopsies Taken 6 Months and 3 Years after Maxillary Sinus Floor Augmentation with 80% Bovine Hydroxyapatite and 20% Autogenous Bone Mixed with Fibrin Glue
Authors: Hallman Mats , Lundgren Stefan , Sennerby Lars
Published: April 2007

Background: Bovine hydroxyapatite (Bio‐Oss®, Geistlich Pharmaceutical, Wollhausen, Switzerland) has been suggested to be used in maxillary sinus floor augmentation procedures prior to or in conjunction with implant placement. However, the long‐term histologic fate of this material is not well understood.

Purpose: The aim with this study was to histologically evaluate the tissue response in patients to a mixture of bovine hydroxyapatite (BH), autogenous bone, and fibrin glue 6 months and 3 years after a maxillary sinus floor augmentation procedure.

Materials and Method: Biopsies were taken from a group of 20 consecutive patients 6 months (n = 16) and 3 years (n = 12) after maxillary sinus floor augmentation with a mixture of BH (80%), autogenous bone (20%), and fibrin glue and prepared for histologic analysis.

Results: Light microscopy and morphometry from biopsies taken after 6 months showed various amounts of mineralized bone tissue. The specimen area was occupied by 54.1 ± 12.6% nonmineralized tissue, followed by 21.2 ± 24.5% lamellar bone, 14.5 ± 10.3% BH particles, and 10.2 ± 13.4% woven bone. The nonmineralized tissue seen in bone‐forming areas consisted of a loose connective tissue, rich with vessels and cells. There were no signs of resorption of the BH particles. The lamellar bone appeared to have originated from the recipient site and was seldom in contact with the BH particles. After 3 years, the nonmineralized tissue area had decreased to 36.0 ± 19.0% (p > .05) and consisted mainly of bone marrow tissue. The surface area of lamellar bone had increased to 50.7 ± 22.8% (p > .05), and there was almost no immature bone. The mean specimen area occupied by BH particles, was 12.4 ± 8.7% and had not changed from 6 months (not significant). Moreover, the sizes of the particles were similar after 6 months and 3 years. The degree of BH particle–bone contact had increased from 28.8%± 19.9% after 6 months to 54.5 ± 28.8% after 3 years (p > .05).

Conclusion: Histology of specimens from maxillary sinuses augmented with 80% BH particles, 20% autogenous bone, and fibrin glue showed a positive bone tissue response after 6 months and 3 years after augmentation of the maxillary sinus floor prior to implant placement in a group fo 20 patients. The bone surrounding and in contact with the BH particles after 6 months was mainly immature woven bone, which with time was replaced by mature lamellar bone filling the interparticle space as observed in the 3‐year specimens. Moreover, bone‐integrated BH particles seem to be resistant to resorption. The results indicate that the procedure may be considered when only small amounts of intraoral autogenous bone graft are available.
New Fabrication System for Dental Implant Surgical Stents: Time‐Saving Laboratory Technique Using a Light‐Curing Resin and Transparent Artificial Teeth
Authors: Tsuzuki Takashi , Matsuura Takashi , Kido Hirofumi , Ishikawa Masatsugu , Ukon Shinichi , Sato Hironobu
Published: April 2007

Background: Surgical stents are a prerequisite for dental implant diagnosis. However, the traditional fabrication method including wax‐up, investment, and resin polymerization is time consuming.

Purpose: This article introduces a new fabrication system using a light‐curing resin and transparent artificial teeth to reduce time spent in the laboratory.

Materials and Method: The process of this system includes placing the light‐curing resin and the artificial teeth on the partially edentulous dentition and alveolar ridge, making an appropriate pattern for the stent, light‐curing for 5 minutes, briefly polishing, and making holes for titanium guide pins.

Results: This system requires only 30 to 40 minutes in the laboratory to complete a stent after mounting the casts on the articulator. Owing to the elasticity of the light‐curing resin, this system eliminates the need for a blockout procedure on the undercuts of existing teeth on the casts, protects the casts from breakage, and provides the appropriate retention intraorally without any retainers. As well, titanium guide pins embedded in the stent were clearly identified by panoramic and computed tomographies.

Conclusions: The new fabrication system proposed here can be time saving and, further, serve benefits for radiographic diagnosis.
It's cheap to be colorful
Authors: Leutenegger Alexandra , D'Angelo Cecilia , Matz Mikhail V. , Denzel Andrea , Oswald Franz , Salih Anya , Nienhaus G. Ulrich , Wiedenmann Jörg
Published: April 2007

Pigments homologous to the green fluorescent protein (GFP) contribute up to ∼ 14% of the soluble protein content of many anthozoans. Maintenance of such high tissue levels poses a severe energetic penalty to the animals if protein turnover is fast. To address this as yet unexplored issue, we established that the irreversible green‐to‐red conversion of the GFP‐like pigments from the reef corals Montastrea cavernosa (mcavRFP) and Lobophyllia hemprichii (EosFP) is driven by violet–blue radiation in vivo and in situ. In the absence of photoconverting light, we subsequently tracked degradation of the red‐converted forms of the two proteins in coral tissue using in vivo spectroscopy and immunochemical detection of the post‐translational peptide backbone modification. The pigments displayed surprisingly slow decay rates, characterized by half‐lives of ∼ 20 days. The slow turnover of GFP‐like proteins implies that the associated energetic costs for being colorful are comparatively low. Moreover, high in vivo stability makes GFP‐like proteins suitable for functions requiring high pigment concentrations, such as photoprotection.
Adrenocortical zonation factor 1 is a novel matricellular protein promoting integrin‐mediated adhesion of adrenocortical and vascular smooth muscle cells
Authors: Li Dan , Mukai Kuniaki , Suzuki Tsuneharu , Suzuki Reiko , Yamashita Shuji , Mitani Fumiko , Suematsu Makoto
Published: April 2007

Expression of a previously cloned secretory protein named adrenocortical zonation factor 1 (AZ‐1, also called Tin‐ag‐RP or lipocalin 7) is tightly linked with the zonal differentiation of adrenocortical cells. It is also present in vascular smooth muscle (VSM), although its function has remained unknown. In this study, the location of AZ‐1 was specified to the basal laminae along adrenocortical sinusoidal capillaries and surrounding VSM cells in the arterial system, consistent with the fact that AZ‐1 was extractable under denaturing conditions as a 52 kDa polypeptide. Purified recombinant AZ‐1 exhibited abilities to bind to fibronectins via the first type III repeat (anastellin) and to collagens with affinities in submicromolar ranges. AZ‐1 immobilized on substratum or bound to collagens or anastellin promoted adhesion and spreading of adrenocortical cells. Although VSM cells spread on AZ‐1 slowly, AZ‐1 bound to anastellin facilitated the spreading. The adhesion activity of AZ‐1 was mediated by a subset of integrins, including α1β1, α2β1, and α5β1, in a cell type‐specific manner. Collectively with the putative role of AZ‐1 in the adrenocortical zonation, we propose that AZ‐1 potentially regulates functions of adrenocortical and VSM cells by modulating cell–matrix interactions.
NEMO oligomerization in the dynamic assembly of the IκB kinase core complex
Authors: Fontan Elisabeth , Traincard François , Levy Samuel G. , Yamaoka Shoji , Véron Michel , Agou Fabrice
Published: April 2007

NF‐κB essential modulator (NEMO) plays an essential role in the nuclear factor κB (NF‐κB) pathway as a modulator of the two other subunits of the IκB kinase (IKK) complex, i.e. the protein kinases, IKKα and IKKβ. Previous reports all envision the IKK complex to be a static entity. Using glycerol‐gradient ultracentrifugation, we observed stimulus‐dependent dynamic IKK complex assembly. In wild‐type fibroblasts, the kinases and a portion of cellular NEMO associate in a 350‐kDa high‐molecular‐mass complex. In response to constitutive NF‐κB stimulation by Tax, we observed NEMO recruitment and oligomerization to a shifted high‐molecular‐mass complex of 440 kDa which displayed increased IKK activity. This stimulus‐dependent oligomerization of NEMO was also observed using fluorescence resonance energy transfer after a transient pulse with interleukin‐1β. In addition, fully activated, dimeric kinases not bound to NEMO were detected in these Tax‐activated fibroblasts. By glycerol gradient ultracentrifugation, we also showed that: (a) in fibroblasts deficient in IKKα and IKKβ, NEMO predominantly exists as a monomer; (b) in NEMO‐deficient fibroblasts, IKKβ dimers are present that are less stable than IKKα dimers. Intriguingly, in resting Rat‐1 fibroblasts, 160‐kDa IKKα–NEMO and IKKβ–NEMO heterocomplexes were observed as well as a significant proportion of NEMO monomer. These results suggest that most NEMO molecules do not form a tripartite IKK complex with an IKKα–IKKβ heterodimer as previously reported in the literature but, instead, NEMO is able to form a complex with the monomeric forms of IKKα and IKKβ.
Caenorhabditis elegans expresses a functional ArsA
Authors: Tseng Yuen‐Yi , Yu Chan‐Wei , Liao Vivian Hsiu‐Chuan
Published: April 2007

Because arsenic is the most prevalent environmental toxin, it is imperative that we understand the mechanisms of metalloid detoxification. In prokaryotes, arsenic detoxification is accomplished by chromosomal and plasmid‐borne operon‐encoded efflux systems. Bacterial ArsA ATPase is the catalytic component of an oxyanion pump that is responsible for resistance to arsenite (As(III)) and antimonite (Sb(III)). Here, we describe the identification of a Caenorhabditis elegans homolog (asna‐1) that encodes the ATPase component of the Escherichia coli As(III) and Sb(III) transporter. We evaluated the responses of wild‐type and asna‐1‐mutant nematodes to various metal ions and found that asna‐1‐mutant nematodes are more sensitive to As(III) and Sb(III) toxicity than are wild‐type animals. These results provide evidence that ASNA‐1 is required for C. elegans' defense against As(III) and Sb(III) toxicity. A purified maltose‐binding protein (MBP)–ASNA‐1 fusion protein was biochemically characterized, and its properties compared with those of ArsAs. The ATPase activity of the ASNA‐1 protein was dependent on the presence of As(III) or Sb(III). As(III) stimulated ATPase activity by 2 ± 0.2‐fold, whereas Sb(III) stimulated it by 4.6 ± 0.15‐fold. The results indicate that As(III)‐ and Sb(III)‐stimulated ArsA ATPase activities are not restricted to bacteria, but extend to animals, by demonstrating that the asna‐1 gene from the nematode, C. elegans, encodes a functional ArsA ATPase whose activity is stimulated by As(III) and Sb(III) and which is critical for As(III) and Sb(III) tolerance in the intact organism.
Inadequacy of Patent Regime on Traditional Medicinal Knowledge—A Diagnosis of 13‐Year Traditional Medicinal Knowledge Patent Experience in China
Authors: Li Xuan , Li Weiwei
Published: April 2007

This article is intended to reveal the root problems that prevent traditional knowledge from being effectively protected by a patent regime. A close review of the 13‐year Chinese patent experience on traditional medicinal knowledge is made for this purpose. Through examination of characteristics of traditional medicinal knowledge in China, the article argues that novelty is not a primary barrier for patent protection; rather, patentability and industrial application are the key obstacles. Given the unique characteristics of traditional medicinal knowledge, it is necessary to establish a sui generis regime to protect traditional medicinal knowledge better.
Evaluation of Reinforcement Learning for Optimal Control of Building Active and Passive Thermal Storage Inventory
Authors: Liu Simeng , Henze Gregor P.
Published: April 2007

This paper describes an investigation of machine learning for supervisory control of active and passive thermal storage capacity in buildings. Previous studies show that the utilization of active or passive thermal storage, or both, can yield significant peak cooling load reduction and associated electrical demand and operational cost savings. In this study, a model-free learning control is investigated for the operation of electrically driven chilled water systems in heavy-mass commercial buildings. The reinforcement learning controller learns to operate the building and cooling plant based on the reinforcement feedback (monetary cost of each action, in this study) it receives for past control actions. The learning agent interacts with its environment by commanding the global zone temperature setpoints and thermal energy storage charging∕discharging rate. The controller extracts information about the environment based solely on the reinforcement signal; the controller does not contain a predictive or system model. Over time and by exploring the environment, the reinforcement learning controller establishes a statistical summary of plant operation, which is continuously updated as operation continues. The present analysis shows that learning control is a feasible methodology to find a near-optimal control strategy for exploiting the active and passive building thermal storage capacity, and also shows that the learning performance is affected by the dimensionality of the action and state space, the learning rate and several other factors. It is found that it takes a long time to learn control strategies for tasks associated with large state and action spaces.
A Calculating Method Of Albedo and Experimental Study of its Influence on Building Heat Environment in Summer
Authors: Zhi Chen , Bingfeng Yu , Pingjun Shang
Published: April 2007

One of the characters of urbanization is that cities develop spatially. The harmful effects of urban heat island put a burden on environmental preservation, energy saving, and thermal comfort. High-albedo materials can lower temperatures effectively when exposed to solar radiation. According to the albedo change of the wall-facing materials of urban buildings, two building models were constructed, of which the internal and external microclimate parameters were measured under certain meteorological conditions in summer. The analytical results of the internal heat environments show that employing high-albedo coatings on the building exterior wall was an active and effective approach to mitigating the high temperatures in the urban environment and its consequences. Moreover, an integral method was used to calculate albedo, which supplies an effective way in the selection of coatings, the performance analysis of the heat insulation, and the assessment of the building microheat environment.
Practical Field Alignment of Parabolic Trough Solar Concentrators
Authors: Diver Richard B. , Moss Timothy A.
Published: April 2007

In this paper a new technique for parabolic trough mirror alignment based on the use of an innovative theoretical overlay photographic (TOP) approach is described. The technique is a variation on methods used to align mirrors on parabolic dish systems. It involves overlaying theoretical images of the heat collection element (HCE) in the mirrors onto carefully surveyed photographic images and adjustment of mirror alignment until they match. From basic geometric principles, for any given viewer location the theoretical shape and location of the reflected HCE image in the aligned mirrors can be predicted. The TOP approach promises to be practical and straightforward, and inherently aligns the mirrors to the HCE. Alignment of an LS-2 mirror module on the rotating platform at the National Solar Thermal Test Facility (NSTTF) with the TOP technique along with how it might be implemented in a large solar field is described. Comparison of the TOP alignment to the distant observer approach on the NSTTF LS-2 is presented and the governing equations used to draw the theoretical overlays are developed. Alignment uncertainty associated with this technique is predicted to be less than the mirror slope error.
A 300kW Solar Chemical Pilot Plant for the Carbothermic Production of Zinc
Authors: Wieckert C. , Frommherz U. , Kräupl S. , Guillot E. , Olalde G. , Epstein M. , Santén S. , Osinga T. , Steinfeld A.
Published: April 2007

In the framework of the EU-project SOLZINC, a 300-kW solar chemical pilot plant for the production of zinc by carbothermic reduction of ZnO was experimentally demonstrated in a beam-down solar tower concentrating facility of Cassegrain optical configuration. The solar chemical reactor, featuring two cavities, of which the upper one is functioning as the solar absorber and the lower one as the reaction chamber containing a ZnO/C packed bed, was batch-operated in the 1300–1500 K range and yielded 50 kg/h of 95%-purity Zn. The measured energy conversion efficiency, i.e., the ratio of the reaction enthalpy change to the solar power input, was 30%. Zinc finds application as a fuel for Zn/air batteries and fuel cells, and can also react with water to form high-purity hydrogen. In either case, the chemical product is ZnO, which in turn is solar-recycled to Zn. The SOLZINC process provides an efficient thermochemical route for the storage and transportation of solar energy in the form of solar fuels.
Simulation of a Volumetric Solar Reformer
Authors: Ben-Zvi R. , Karni J.
Published: April 2007

The Directly-Irradiated Annular Pressurized Receiver (DIAPR) volumetric solar absorber was adapted to operate as a methane reformer by coating the absorber pins with catalyst. A computational model is applied to assess and improve the system design. The simulation entails the solution of reactive flow and heat transfer. A detailed parametric study is presented and analyzed here. An experimental system based on the present results was built and testing is currently underway.
Behavior of Bimetallic Absorber in Parabolic Collectors During DSG to Low Powers
Authors: Flores Vicente , Almanza Rafael
Published: April 2007

Thermal and mechanical behaviors of absorbers of different material for its application in parabolic collectors during the direct steam generation, with low mass flows (90kg∕hto120kg∕h) and low pressures (9×102kPato16×102kPa) were studied. The distribution of temperatures in the absorber periphery of copper, steel, and bimetallic copper-steel were analyzed using a theoretical model with the influence of a stratified two-phase flow in the internal wall of the absorber, as well as heat flux in a section of the external wall; the previous situation led to the construction of the copper-steel absorber and experimentally to a comparison with a steel absorber. In the experimental part, the thermal and mechanical analysis of the three absorbers is included, emphasizing the thickness of the wall and the thermal conductivity of each material, under the same thermohydraulic conditions. The theoretical and experimental work is analyzed for solar beam irradiance arriving from below the absorber for an east-west orientation.
Lysostaphin in Treatment of Neonatal
Staphylococcus aureus
Infection
Authors: Oluola Okunola , Kong Lingkun , Fein Mindy , Weisman Leonard E.
Published: April 2007

This study describes lysostaphin's effect against methicillin-sensitive
Staphylococcus aureus
in suckling rats. Standard techniques determined minimal inhibitory and bactericidal concentrations, pharmacokinetics, and efficacy. The numbers of surviving rats after vancomycin, oxacillin, and lysostaphin treatment were comparable and were different from that of controls (
P
< 0.00001). Lysostaphin appears effective in the treatment of neonatal
S. aureus
infection.
Inhibitory Activities of Three Classes of Acyclic Nucleoside Phosphonates against Murine Polyomavirus and Primate Simian Virus 40 Strains
Authors: Lebeau Ilya , Andrei Graciela , Krečmerová Marcela , De Clercq Erik , Holý Antonin , Snoeck Robert
Published: April 2007

Murine polyomavirus and simian virus 40 were used to evaluate the potencies of the compounds of three classes of acyclic nucleoside phosphonates: (i) the original HPMP (3-hydroxy-2-phosphonomethoxypropyl) and PME (2-phosphonomethoxyethyl) derivatives, (ii) the 6-[2-(phosphonomethoxy)alkoxy]-2,4-diaminopyrimidine (DAPy) derivatives, and (iii) a new class of HPMP derivatives containing a 5-azacytosine moiety. The last class showed the highest activities and selectivities against both polyomaviruses.
Comprehensive Analysis of the Effects of Ordinary Nutrients on Hepatitis C Virus RNA Replication in Cell Culture
Authors: Yano Masahiko , Ikeda Masanori , Abe Ken-ichi , Dansako Hiromichi , Ohkoshi Shogo , Aoyagi Yutaka , Kato Nobuyuki
Published: April 2007

To date, only a limited number of studies have reported finding an influence of ordinary nutrients on hepatitis C virus (HCV) RNA replication. However, the effects of other nutrients on HCV RNA replication remain largely unknown. We recently developed a reporter assay system for genome-length HCV RNA replication in hepatoma-derived HuH-7 cells (OR6). Here, using this OR6 assay system, we comprehensively examined 46 nutrients from four nutrient groups: vitamins, amino acids, fatty acids, and salts. We found that three nutrients—β-carotene, vitamin D2, and linoleic acid—inhibited HCV RNA replication and that their combination caused additive and/or synergistic effects on HCV RNA replication. In addition, combined treatment with each of the three nutrients and interferon alpha or beta or fluvastatin inhibited HCV RNA replication in an additive manner, while combined treatment with cyclosporine synergistically inhibited HCV RNA replication. In contrast, we found that vitamin E enhanced HCV RNA replication and negated the effects of the three anti-HCV nutrients and cyclosporine but not those of interferon or fluvastatin. These results will provide useful information for the treatment of chronic hepatitis C patients who also take anti-HCV nutrients as an adjunctive therapy in combination with interferon. In conclusion, among the ordinary nutrients tested, β-carotene, vitamin D2, and linoleic acid possessed anti-HCV activity in a cell culture system, and these nutrients are therefore considered to be potential candidates for enhancing the effects of interferon therapy.
Effects of Carbapenem Exposure on the Risk for Digestive Tract Carriage of Intensive Care Unit-Endemic Carbapenem-Resistant
Pseudomonas aeruginosa
Strains in Critically Ill Patients
Authors: Peña C. , Guzmán A. , Suarez C. , Dominguez M. A. , Tubau F. , Pujol M. , Gudiol F. , Ariza J.
Published: April 2007

To determine the epidemiology and risk factors for carbapenem-resistant
Pseudomonas aeruginosa
(CR-PA) digestive tract colonization, weekly rectal and pharyngeal swabs were obtained in two serial incidence surveys (266 patients). Forty-two (16%) patients were CR-PA colonized (12 [29%] on admission and 30 [71%] in intensive care units). Pulsed-field gel electrophoresis showed extensive clonal diversity, although one specific clone (type B) was isolated from 11 patients. The presence of similar genotypes of CR-PA colonizing 30% of the CR-PA-colonized patients suggests the occurrence of cross-colonization; in addition, 10 pairs of carbapenem-susceptible
P. aeruginosa
(CS-PA) and subsequent CR-PA strains isolated from the same patients were found to be clonally identical and were considered to have been endogenously acquired (33%). All endogenously acquired CR-PA strains were isolated after exposure to a carbapenem, and 80% showed a phenotype of imipenem resistance (IR pattern) alone, while 67% of the CR-PA strains acquired by cross-transmission exhibited a multiresistant (MR) phenotype, with previous carbapenem exposure in 44%. Logistic regression analysis identified severity of acute illness (odds ratio [OR], 1.0; 95% confidence interval [CI], 1.0 to 1.1), prior carbapenem use (OR, 7.8; 95% CI, 1.7 to 35.3), and prior use of fluoroquinolones (OR, 11.0; 95% CI, 1.7 to 67.9) as independent risk factors for CR-PA digestive tract colonization. Overall, the local epidemiology of CR-PA digestive tract colonization was characterized by polyclonal endemicity with phenotype patterns of IR and MR divided evenly between patients. Restricting the use of particular agents, such as carbapenems and fluoroquinolones, should be considered advisable to minimize the problem of this antibiotic resistance. However, the possible risk for development of collateral unexpected bacterial resistance patterns should be accurately monitored.
Serum Differentially Alters the Antifungal Properties of Echinocandin Drugs
Authors: Paderu Padmaja , Garcia-Effron Guillermo , Balashov Sergey , Delmas Guillaume , Park Steven , Perlin David S.
Published: April 2007

Antifungal efficacies of the echinocandin drugs caspofungin, micafungin, and anidulafungin were reduced significantly in the presence of 50% human serum, which yielded nearly equivalent MICs or minimum effective concentrations against diverse
Candida
spp. and
Aspergillus
spp. Consistent with a direct drug interaction, serum decreased the sensitivity of glucan synthase to echinocandin drugs.
In Vitro Activities of CG400549, a Novel FabI Inhibitor, against Recently Isolated Clinical Staphylococcal Strains in Korea
Authors: Yum Jong Hwa , Kim Chang Ki , Yong Dongeun , Lee Kyungwon , Chong Yunsop , Kim Cheol Min , Kim Jeong Mi , Ro Seonggu , Cho Joong Myung
Published: April 2007

The in vitro activities of CG400549, a novel FabI inhibitor, were compared to those of linezolid and commonly used antimicrobials against recent bacterial isolates. CG400549 had an MIC
90
of 0.5 μg/ml for
Staphylococcus aureus
strains and was more potent than either linezolid or vancomycin.
Neisseria gonorrhoeae
Isolates with Reduced Susceptibility to Cefixime and Ceftriaxone: Association with Genetic Polymorphisms in
penA
,
mtrR
,
porB1b
, and
ponA
Authors: Lindberg Robert , Fredlund Hans , Nicholas Robert , Unemo Magnus
Published: April 2007

The recent emergence and transmission of
Neisseria gonorrhoeae
isolates with reduced susceptibility to expanded-spectrum cephalosporins such as cefixime and ceftriaxone have been reported. The aim of this study was to determine the correlation of different polymorphisms in the
penA
,
mtrR
,
porB1b
(
penB
), and
ponA
genes of
N. gonorrhoeae
with reduced susceptibility to cefixime and ceftriaxone. Eighteen gonococcal isolates with reduced cefixime and ceftriaxone susceptibility (Cef
i
) and two susceptible isolates were characterized using serovar determination, antibiograms,
N. gonorrhoeae
multiantigen sequence typing (NG-MAST), and sequencing of
penA
,
mtrR
,
porB1b
, and
ponA
alleles. For the Cef
i
isolates (
n
= 18), the MICs of cefixime and ceftriaxone ranged between 0.032 to 0.38 μg/ml and 0.064 to 0.125 μg/ml, respectively. These isolates were assigned five different serovars and six divergent NG-MAST sequence types. Eleven isolates (61%) with higher MICs of cefixime and ceftriaxone contained a nearly identical
penA
mosaic allele and previously described polymorphisms in
mtrR
(a single nucleotide [A] deletion in the promoter),
penB
(mutations in
porB1b
encoding loop 3 of PorB1b), and
ponA
(
ponA1
polymorphism). The remaining seven Cef
i
isolates (39%), which had somewhat lower MICs of cefixime and ceftriaxone, contained an aspartic acid insertion (Asp-345a) in PBP 2 in conjunction with alterations of 4 to 10 amino acid residues in the C-terminal region of the transpeptidase domain of
penA
. In conclusion, an unambiguous association between
penA
mosaic alleles, in conjunction with genetic polymorphisms in
mtrR
,
porB1b
, and
ponA
, and greater reduced susceptibility to cefixime and ceftriaxone was identified.
Identification of a Novel Two-Partner Secretion Locus in
Moraxella catarrhalis
Authors: Plamondon Pascale , Luke Nicole R. , Campagnari Anthony A.
Published: April 2007

Although
Moraxella catarrhalis
continues to be a significant cause of disease in both children and adults, the steps involved in pathogenesis remain poorly understood. We have identified three open reading frames in the
M. catarrhalis
genome that encode homologues of the two-partner secretion system (TPS). The sequenced
M. catarrhalis
hemagglutinin-like locus of strain 7169 has a unique gene organization composed in the order of
mchA1
,
mchB
, and
mchA2
, where
mchA1
is divergent. MchA1 and MchA2 are 74% identical at the amino acid level and diverge only in the C-terminal regions. The TPS motif identified in the common N-terminal regions of MchA1 and MchA2 was found to be homologous to the filamentous hemagglutinin of
Bordetella pertussis
, and MchB has homology to other TpsB transporters. The presence of MchA1 and MchA2 in outer membrane protein preparations and concentrated culture supernatants (CCSs) of strain 7169 was confirmed by immunoblotting using specific antisera. Nanoscale liquid chromatography-tandem mass spectrometry peptide sequencing of the antibody-reactive bands from the CCSs was performed and demonstrated that 13 different peptides mapped to identical regions of MchA1 and MchA2. Quantitative adherence assays revealed a decrease of binding to primary normal human bronchial epithelial cells by the
mch
mutants 7169mchB and 7169mchA1A2B compared to that by the wild-type strain. These studies show that MchA1, MchA2, and MchB are components of a novel TPS identified in
M. catarrhalis
and suggest that these proteins may be involved in colonization.