bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of cuticular abrasion and recovery on water loss rates in queens of the desert harvester ant Messor pergandei
Authors: Johnson Robert A. , Kaiser Alexander , Quinlan Michael , Sharp William
Published: September 2011

Factors that affect water loss rates (WLRs) are poorly known for organisms in natural habitats. Seed-harvester ant queens provide an ideal system for examining such factors because WLRs for mated queens excavated from their incipient nests are twofold to threefold higher than those of alate queens. Indirect data suggest that this increase results from soil particles abrading the cuticle during nest excavation. This study provides direct support for the cuticle abrasion hypothesis by measuring total mass-specific WLRs, cuticular abrasion, cuticular transpiration, respiratory water loss and metabolic rate for queens of the ant Messor pergandei at three stages: unmated alate queens, newly mated dealate queens (undug foundresses) and mated queens excavated from their incipient nest (dug foundresses); in addition we examined these processes in artificially abraded alate queens. Alate queens had low WLRs and low levels of cuticle abrasion, whereas dug foundresses had high WLRs and high levels of cuticle abrasion. Total WLR and cuticular transpiration were lowest for alate queens, intermediate for undug foundresses and highest for dug foundresses. Respiratory water loss contributed ∼10% of the total WLR and was lower for alate queens and undug foundresses than for dug foundresses. Metabolic rate did not vary across stages. Total WLR and cuticular transpiration of artificially abraded alate queens increased, whereas respiratory water loss and metabolic rate were unaffected. Overall, increased cuticular transpiration accounted for essentially all the increased total water loss in undug and dug foundresses and artificially abraded queens. Artificially abraded queens and dug foundresses showed partial recovery after 14 days.
Cues to body size in the formant spacing of male koala (Phascolarctos cinereus) bellows: honesty in an exaggerated trait
Authors: Charlton Benjamin D. , Ellis William A. H. , McKinnon Allan J. , Cowin Gary J. , Brumm Jacqui , Nilsson Karen , Fitch W. Tecumseh
Published: September 2011

Determining the information content of vocal signals and understanding morphological modifications of vocal anatomy are key steps towards revealing the selection pressures acting on a given species' vocal communication system. Here, we used a combination of acoustic and anatomical data to investigate whether male koala bellows provide reliable information on the caller's body size, and to confirm whether male koalas have a permanently descended larynx. Our results indicate that the spectral prominences of male koala bellows are formants (vocal tract resonances), and show that larger males have lower formant spacing. In contrast, no relationship between body size and the fundamental frequency was found. Anatomical investigations revealed that male koalas have a permanently descended larynx: the first example of this in a marsupial. Furthermore, we found a deeply anchored sternothyroid muscle that could allow male koalas to retract their larynx into the thorax. While this would explain the low formant spacing of the exhalation and initial inhalation phases of male bellows, further research will be required to reveal the anatomical basis for the formant spacing of the later inhalation phases, which is predictive of vocal tract lengths of around 50 cm (nearly the length of an adult koala's body). Taken together, these findings show that the formant spacing of male koala bellows has the potential to provide receivers with reliable information on the caller's body size, and reveal that vocal adaptations allowing callers to exaggerate (or maximise) the acoustic impression of their size have evolved independently in marsupials and placental mammals.
Images of health care
Authors: Light Kate , Harden Melissa , Light Kate , Stirk Lisa
Published: September 2011

‘A picture is worth a thousand words’ captures the idea that well chosen images can increase the successful dissemination of health care messages. This edition of ‘What's on the web’ explores sites that host images suitable for use in presentations and teaching. We have focused on sites that provide images that are in the public domain or have a creative commons license which generally allows non-commercial use. It is important to be careful, however, and it is recommended that you check the copyright situation before using any image from these sites.

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Sonographic Diagnosis of Infected Chronic Uterine Inversion at 12 Weeks Postpartum
Authors: Chauhan N , Sharma Y
Published: September 2011

Puerperal uterine inversion is an uncommon but potentially life-threatening obstetric emergency. We report a case of an infected chronic uterine inversion which presented 12 weeks after the vaginal delivery. The diagnosis was made on ultrasound and resulted in timely therapeutic intervention. The greyscale and Doppler findings are discussed.
Endovascular repair of the half aortic arch in pigs with an improved, single-branched stent graft system for the brachiocephalic trunk
Authors: Lin Chen , Lu Qingsheng , Liao Mingfang , Guo Mingjin , Gong Jing , Jing Zaiping
Published: September 2011

The objective of this study was to evaluate the feasibility of endovascular repair of half of the aortic arch in pigs using an improved, integrated, single-branched stent graft for the ascending aorta and brachiocephalic trunk (BCT). We designed an improved stent graft in an integrated fashion and deployed the stent grafts into the ascending aortas and BCT of eight pigs. The feasibility of the stent graft deployments was evaluated three months after the procedures using arteriography, computed tomography angiography (CTA) and animal autopsy. The stent grafts were successfully deployed in eight pigs. All animals survived for at least three months. Arteriography, CTA and animal necropsy revealed good stent fixation in eight cases. Their head CT scans found no evidence of cerebral infarction. In conclusion, endovascular repair of the half aortic arch with the integrated single-branched stent graft system appears to be safe and feasible in pigs.
The endovascular management of splenic artery aneurysms and pseudoaneurysms
Authors: Xin Jia , Xiao-ping Liu , Wei Guo , Jiang Xiong , Hong-peng Zhang , Xiao-hui Ma , Xin Du , Min-hong Zhang
Published: September 2011

The purpose of this study was to evaluate outcomes of the endovascular treatment of splenic artery aneurysms (SAAs) and pseudoaneurysms (SAPAs). From April 2003 to December 2009, 12 patients (mean age 46.8 years, range 29–58) with SAAs ( n = 9) or SAPAs ( n = 3) underwent endovascular treatment. Four patients were asymptomatic and three had ruptured aneurysms. Lesions were in the proximal splenic artery ( n = 3), intermediate splenic artery ( n = 3) and distal splenic artery ( n = 6). Endovascular procedures included embolization by sac packing ( n = 5), sandwich occlusion of the splenic artery ( n = 4) or stent graft deployment ( n = 3). Computed tomography (CT) was done before the operation, 3 and 12 months after the operation, then yearly. Endovascular treatment was successful at the first attempt in all 12 (100%) patients, with complete angiographic exclusion of the aneurysm at the end of the operation. The mean amount of contrast medium used was 165 mL (range 100–230), and the mean total procedure time was 92 minutes (range 55–160). No major complications occurred. Postoperational CT scans showed splenic multisegmental infarcts in eight patients (66.7%, 8/12) and among them postembolization syndrome developed in six patients, manifesting as abdominal pain and fever. The mean follow-up was 32 months (range 9–51). No patient demonstrated gross evidence of aneurysm sac growth, and no significant decrease in aneurysm sac size postintervention was noted on follow-up. The endovascular management of SAAs and SAPAs is safe and effective and may induce less mortality than open surgery. Regardless of the etiology, endovascular treatment can provide excellent mid-term results.
Patient-reported symptoms are independent of disease severity in patients with primary varicose veins
Authors: Conway A M , Nordon I M , Hinchliffe R J , Thompson M M , Loftus I M
Published: September 2011

The objective of this paper is to explore patterns of incompetence and disease distribution in patients with chronic venous disorders and to correlate this with CEAP (Clinical, Etiologic, Anatomic and Pathologic) classification and presenting symptoms to determine which features of chronic venous disorder (CVD) could be used to guide a patient pathway for referral and treatment. Consecutive patients attending a one-stop venous clinic at a university teaching hospital were recruited over a 12-month period. Patients were clinically assessed, assigned CEAP scores, duplex-scanned and categorized. Data were analyzed to identify associations between symptomatology and disease. Four hundred twenty-four limbs were divided into groups A (C2–3) (339) and B (C4–6) (85). The number of men, mean patient age, varicose vein diameter and quality-of-life score (Aberdeen Varicose Vein Questionnaire – AVVS) were significantly higher in group B ( P < 0.01). Ache occurred more commonly in group A and in women ( P < 0.01). Ache and pain were seen more frequently with saphenofemoral junction reflux ( P < 0.05). Group A women were more likely to be offered surgical intervention while men were managed conservatively ( P < 0.05). In conclusion, CVD symptoms are independent of disease severity assessed by CEAP score. Advanced disease is associated with larger venous diameters, older age and corresponds to a poorer quality of life. Objective markers such as CEAP, Venous Clinical Severity Score and AVVS should be used in determining a patient pathway for referral and treatment of CVD.
Mechanism for gene control by a natural allosteric group I ribozyme
Authors: Chen Andy G.Y. , Sudarsan Narasimhan , Breaker Ronald R.
Published: September 2011

An allosteric ribozyme consisting of a metabolite-sensing riboswitch and a group I self-splicing ribozyme was recently found in the pathogenic bacterium Clostridium difficile. The riboswitch senses the bacterial second messenger c-di-GMP, thereby controlling 5′-splice site choice by the downstream ribozyme. The proximity of this allosteric ribozyme to the open reading frame (ORF) for CD3246 suggests that coenzyme-mediated regulation of splicing controls expression of this putative virulence gene. In the presence of c-di-GMP, the allosteric ribozyme in the CD3246 precursor transcript generates a spliced transcript that retains the riboswitch aptamer. In the absence of c-di-GMP, the ribozyme mediates an alternative GTP attack that results in a truncated transcript (alternative GTP-attack product). Using reporter assays in Escherichia coli, we investigated the difference in gene expression between the spliced product and the alternative GTP-attack product. We provide evidence that CD3246 gene expression is activated if allosteric ribozyme splicing creates a ribosome binding site (RBS) for translation from a UUG start codon. In addition, biochemical and genetic analyses reveal that the riboswitch may further control CD3246 expression by revealing or occluding this newly formed RBS. Therefore, this architecture provides the riboswitch with a mechanism for extended regulation after splicing has occurred or as a backup mechanism for suppression of translation in the event of misregulated splicing.
Cryo-electron microscopy structure of the 30S subunit in complex with the YjeQ biogenesis factor
Authors: Jomaa Ahmad , Stewart Geordie , Mears Jason A. , Kireeva Inga , Brown Eric D. , Ortega Joaquin
Published: September 2011

YjeQ is a protein broadly conserved in bacteria containing an N-terminal oligonucleotide/oligosaccharide fold (OB-fold) domain, a central GTPase domain, and a C-terminal zinc-finger domain. YjeQ binds tightly and stoichiometrically to the 30S subunit, which stimulates its GTPase activity by 160-fold. Despite growing evidence for the involvement of the YjeQ protein in bacterial 30S subunit assembly, the specific function and mechanism of this protein remain unclear. Here, we report the costructure of YjeQ with the 30S subunit obtained by cryo-electron microscopy. The costructure revealed that YjeQ interacts simultaneously with helix 44, the head and the platform of the 30S subunit. This binding location of YjeQ in the 30S subunit suggests a chaperone role in processing of the 3′ end of the rRNA as well as in mediating the correct orientation of the main domains of the 30S subunit. In addition, the YjeQ binding site partially overlaps with the interaction site of initiation factors 2 and 3, and upon binding, YjeQ covers three inter-subunit bridges that are important for the association of the 30S and 50S subunits. Hence, our structure suggests that YjeQ may assist in ribosome maturation by preventing premature formation of the translation initiation complex and association with the 50S subunit. Together, these results support a role for YjeQ in the late stages of 30S maturation.
Regret from Postpurchase Discovery of Lower Market Prices: Do Price Refunds Help?
Authors: Dutta Sujay , Biswas Abhijit , Grewal Dhruv
Published: September 2011

Consumer regret can result in unfavorable outcomes for marketers. To prevent regret, many retailers promise to refund money to consumers who discover lower prices after purchase. The authors show that a refund's effect on felt regret depends on how consumers view these promises. If consumers mainly view them as protective tools (i.e., adopt a protection focus), postrefund regret is minimal. If consumers primarily view such promises as sources of information about the retailer's price status (i.e., adopt an information focus), regret persists even after refund. The authors show that regret persists with these consumers because finding a lower price results in a perception of trust violation. They find that subject to boundary conditions, using a disclaimer that states that the retailer does not claim to offer the lowest prices helps avoid this negative outcome for information-focused consumers. The authors contribute to the literature on outcome reversibility and regret by showing that outcome reversal does not necessarily obviate regret. In addition, they show that regulatory focus serves as the motivational basis for how consumers view refund promises.
The Aha! Experience: Insight and Discontinuous Learning in Product Usage
Authors: Lakshmanan Arun , Krishnan H. Shanker
Published: September 2011

Success of many products depends on how consumers learn to use them. This research suggests that initial product trial may lead to jumps in consumer learning. Such discontinuities in learning co-occur with the experience of insight—namely, a better conceptual understanding of how to use the product. Notably, such learning also positively affects downstream outcomes such as affect and usage intentions. Whereas exploration during initial trial facilitates insight-based learning, usage instructions seem to limit this type of learning. The implication for marketing managers is to structure initial trials in a manner conducive to exploration, thus leading to insight-driven learning and the associated positive outcomes.
Reference change values
Authors: Fraser Callum G.
Published: September 2011

Reference change values (RCV) provide objective tools for assessment of the significance of differences in serial results from an individual. The concept is simple and the calculation easy, since all laboratories know their analytical imprecision (CV
Neural Correlates of Interindividual Differences in Children's Audiovisual Speech Perception
Authors: Nath Audrey R. , Fava Eswen E. , Beauchamp Michael S.
Published: September 2011

Children use information from both the auditory and visual modalities to aid in understanding speech. A dramatic illustration of this multisensory integration is the McGurk effect, an illusion in which an auditory syllable is perceived differently when it is paired with an incongruent mouth movement. However, there are significant interindividual differences in McGurk perception: some children never perceive the illusion, while others always do. Because converging evidence suggests that the posterior superior temporal sulcus (STS) is a critical site for multisensory integration, we hypothesized that activity within the STS would predict susceptibility to the McGurk effect. To test this idea, we used BOLD fMRI in 17 children aged 6–12 years to measure brain responses to the following three audiovisual stimulus categories: McGurk incongruent, non-McGurk incongruent, and congruent syllables. Two separate analysis approaches, one using independent functional localizers and another using whole-brain voxel-based regression, showed differences in the left STS between perceivers and nonperceivers. The STS of McGurk perceivers responded significantly more than that of nonperceivers to McGurk syllables, but not to other stimuli, and perceivers' hemodynamic responses in the STS were significantly prolonged. In addition to the STS, weaker differences between perceivers and nonperceivers were observed in the fusiform face area and extrastriate visual cortex. These results suggest that the STS is an important source of interindividual variability in children's audiovisual speech perception.
Modulation of Fgfr1a Signaling in Zebrafish Reveals a Genetic Basis for the Aggression–Boldness Syndrome
Authors: Norton William H. J. , Stumpenhorst Katharina , Faus-Kessler Theresa , Folchert Anja , Rohner Nicolas , Harris Matthew P. , Callebert Jacques , Bally-Cuif Laure
Published: September 2011

Behavioral syndromes are suites of two or more behaviors that correlate across environmental contexts. The aggression–boldness syndrome links aggression, boldness, and exploratory activity in a novel environment. Although aggression–boldness has been described in many animals, the mechanism linking its behavioral components is not known. Here we show that mutation of the gene encoding fibroblast growth factor receptor 1a (fgfr1a) simultaneously increases aggression, boldness, and exploration in adult zebrafish. We demonstrate that altered Fgf signaling also results in reduced brain histamine levels in mutants. Pharmacological increase of histamine signaling is sufficient to rescue the behavioral phenotype offgfr1amutants. Together, we show that a single genetic locus can underlie the aggression–boldness behavioral syndrome. We also identify one of the neurotransmitter pathways that may mediate clustering of these behaviors.
Synaptic and Extrasynaptic NMDA Receptors Differentially Modulate Neuronal Cyclooxygenase-2 Function, Lipid Peroxidation, and Neuroprotection
Authors: Stark David T. , Bazan Nicolas G.
Published: September 2011

Stimulation of synaptic NMDA receptors (NMDARs) induces neuroprotection, while extrasynaptic NMDARs promote excitotoxic cell death. Neuronal expression of cyclooxygenase-2 (COX-2) is enhanced by synaptic NMDARs, and although this enzyme mediates neuronal functions, COX-2 is also regarded as a key modulator of neuroinflammation and is thought to exacerbate excitotoxicity via overproduction of prostaglandins. This raises an apparent paradox: synaptic NMDARs are pro-survival yet are essential for robust neuronal COX-2 expression. We hypothesized that stimulation of extrasynaptic NMDARs converts COX-2 signaling from a physiological to a potentially pathological process. We combined HPLC-electrospray ionization-tandem MS-based mediator lipidomics and unbiased image analysis in mouse dissociated and organotypic cortical cultures to uncover that synaptic and extrasynaptic NMDARs differentially modulate neuronal COX-2 expression and activity. We show that synaptic NMDARs enhance neuronal COX-2 expression, while sustained synaptic stimulation limits COX-2 activity by suppressing cellular levels of the primary COX-2 substrate, arachidonic acid (AA). In contrast, extrasynaptic NMDARs suppress COX-2 expression while activating phospholipase A2, which enhances AA levels by hydrolysis of membrane phospholipids. Thus, sequential activation of synaptic then extrasynaptic NMDARs maximizes COX-2-dependent prostaglandin synthesis. We also show that excitotoxic events only drive induction of COX-2 expression through abnormal synaptic network excitability. Finally, we show that nonenzymatic lipid peroxidation of arachidonic and other polyunsaturated fatty acids is a function of network activity history. A new paradigm emerges from our results suggesting that pathological COX-2 signaling associated with models of stroke, epilepsy, and neurodegeneration requires specific spatiotemporal NMDAR stimulation.
Thermochemistry and Kinetics for 2-Butanone-3yl Radical (CH3C(=O)CH•CH3) Reactions with O2
Authors: Sebbar Nadia , Bozzelli Joseph W. , Bockhorn Henning
Published: September 2011

Thermochemistry and chemical activation kinetics for the reaction of the secondary radical of 2-butanone, 2-butanone-3yl, with 3O2 are reported. Thermochemical and kinetic parameters are determined for reactants, transition states structures and intermediates. Standard enthalpies and kinetic parameters are evaluated using ab initio (G3MP2B3 and G3), density functional (B3LYP/6-311g(d,p)) calculations and group additivity (GA). The C–H bond energies are determined for the three carbons of the 2-butanone, showing that the C–H bond energy (BE) on the secondary carbon is low at 90.5 kcal mol−1. The CH3C(=O)CH•CH3 radical + O2 association results in chemically-activated peroxy radical with 26 kcal mol−1 excess of energy. The chemically activated adduct can dissociate to butanone-oxy radical + O, react back to butanone-yl + O2, form cyclic ethers or lactones, eliminate HO2 to form an olefinic ketone, or undergo rearrangement via intramolecular abstraction of hydrogen to form hydroperoxide and/or OH radicals. The hydroperoxide-alkyl radical intermediates can undergo further reactions forming cyclic ethers (lactones) and OH radicals. Quantum RRK analysis is used to calculate k(E) and master equation analysis is used for evaluation of pressure fall-off in these chemical activated reaction systems.
Cortisol, estradiol-17β, and progesterone secretion within the first hour after awakening in women with regular menstrual cycles
Authors: Ahn Ryun S , Choi Jee H , Choi Bum C , Kim Jung H , Lee Sung H , Sung Simon S
Published: September 2011

Cortisol concentration in both serum and saliva sharply increases and reaches a peak within the first hour after waking in the morning. This phenomenon is known as the cortisol awakening response (CAR) and is used as an index of hypothalamus–pituitary–adrenal (HPA) axis function. We examined whether ovarian steroid concentrations increased after awakening as with the CAR in the HPA axis. To do this, cortisol, estradiol-17β (E2), and progesterone (P4) concentrations were determined in saliva samples collected immediately upon awakening and 30 and 60 min after awakening in women with regular menstrual cycles and postmenopausal women. We found that both E2and P4concentrations increased during the post-awakening period in women with regular menstrual cycles, but these phenomena were not seen in any postmenopausal women. The area under the E2and P4curve from the time interval immediately after awakening to 60 min after awakening (i.e. E2auc and P4auc) in women with regular menstrual cycles were greater than those in the postmenopausal women. E2and P4secretory activity during the post-awakening period was influenced by the phase of the menstrual cycle. E2auc in the peri-ovulatory phase and P4auc in the early to mid-luteal phase were greater than in the menstrual phase. Meanwhile, cortisol secretory activity during the post-awakening period was not influenced by menstrual status or the phase of menstrual cycle. These findings indicate that, as with the CAR in the HPA axis function, ovarian steroidogenic activity increased after awakening and is closely associated with menstrual status and phase of menstrual cycle.
Topics In Neonatal Informatics
Authors: Palma Jonathan P. , Van Eaton Erik G. , Longhurst Christopher A.
Published: September 2011

Communication failures during physician handoffs represent a significant source of preventable adverse events. Computerized sign-out tools linked to hospital electronic medical record (EMR) systems and customized for neonatal care can facilitate standardization of the handoff process and access to clinical information, thereby improving communication and reducing adverse events. It is important to note, however, that adoption of technological tools alone is not sufficient to remedy flawed communication processes.
Cerebral Palsy: Prevalence, Predictability, and Parental Counseling
Authors: McAdams Ryan M. , Juul Sandra E.
Published: September 2011

Cerebral palsy (CP) is the most common cause of severe physical disability in childhood, occurring in approximately 2 in 1,000 liveborn infants. Although the prevalence of CP appears to have stabilized in the past 2 decades, recent studies suggest that severe CP may be decreasing. Neuroimaging studies help identify abnormal neuroanatomic findings, which are found in most affected children. Neuropathology identified by magnetic resonance imaging (MRI) corresponds well to clinical descriptions of motor impairment in children who have CP. Clinical risk factors, combined with imaging studies, can help identify a subpopulation of infants who are at high risk for poor neurodevelopmental outcome. Counseling caregivers on future adverse developmental risks can be challenging for the clinician in the neonatal intensive care unit (NICU), especially because the cause of CP remains unexplained in most cases and is typically diagnosed outside the neonatal period. Early counseling of families of at-risk neonates may function as the starting point for parental adaptation to a lifelong condition that requires ongoing services and adjustments to promote the overall health and well-being of their child.
Damage of concrete subjected to simultaneous fatigue load and thermal effect
Authors: Li Wenting , Sun Wei , Jiang Jinyang
Published: September 2011

Physical loads and environmental actions have simultaneous effects on concrete in nature. An analytical method is proposed to detect the damage to concrete subjected to four-point flexure fatigue load and thermal hysteresis in freeze–thaw. The interaction of the two kinds of loads on the combined damage, in terms of a coefficient fD(T), is defined to characterise quantification. Damage is aggravated by the combined loads when fD(N)>1 as compared to isolated loading. The results show that increasing fD(N) is always seen in the freezing stage, since damage as a result of tensile stress only is being considered here. Moreover, a critical point above which the damage is aggravated by the combined loads is found by extrapolating the maximum values of fD(N) until fD(N)=1 at N = 380 000, that is close to the average life (N = 348 310) obtained from the experiments. This work provides a framework to explore the coupled effects on damage from physical loads and environmental actions.
Tissue Integration of a New Titanium–Zirconium Dental Implant: A Comparative Histologic and Radiographic Study in the Canine
Authors: Thoma Daniel S. , Jones Archie A. , Dard Michel , Grize Leticia , Obrecht Marcel , Cochran David L.
Published: September 2011

Background: This study evaluates a newly developed titanium–zirconium implant (TiZr), comparing it to a commercially available pure titanium (Ti) implant subjected to the same surface treatment.

Methods: In nine dogs, 12 implants (six TiZr and six Ti) were randomly placed in the mandible with the implant shoulder at the bone crest and subjected to submerged healing. Standardized radiographs were taken after implantation, and at the sacrifice of 2 weeks (three dogs), 4 weeks (three dogs), and 8 weeks (three dogs). Histologic and histomorphometric measurements were performed on non‐decalcified histologic sections. The main outcome measures included the first bone–implant contact (fBIC) and BIC over time. For statistical analysis, Wilcoxon signed‐rank test and mixed model regressions were applied.

Results: From baseline to 8 weeks, a mean bone loss of 0.09 ± 0.33 mm for TiZr and a gain of 0.02 ± 0.33 mm for Ti were calculated radiographically. The number of implants with the fBIC coronal to the reference point (implant shoulder) gradually increased over time, reaching 39% of all TiZr implants and 50% of all Ti implants at 8 weeks. The mean fBIC values for Ti and TiZr were 0.29 ± 0.42 mm and 0.26 ± 0.32 mm (2 weeks), −0.01 ± 0.20 mm and 0.10 ± 0.28 mm (4 weeks), and −0.06 ± 0.22 mm and 0.08 ± 0.30 mm (8 weeks), respectively. The mean BIC values peaked at 86.9% ± 6.8% (8 weeks) for TiZr and at 83.4% ± 5.9% (4 weeks) for Ti. No statistically significant differences were observed at any time point.

Conclusion: TiZr and Ti bone level implants with chemically‐modified, sandblasted, and acid‐etched surfaces performed similarly in regards to osseointegration in this unloaded canine study.
Practical application of the head dependent gradient method for water distribution networks
Authors: Siew Calvin , Tanyimboh Tiku T.
Published: September 2011

Critical pressure-deficient operating conditions frequently occur in water distribution networks. Head driven analysis (HDA) of water distribution networks allows for the pressure-dependent nature of nodal flows and, therefore, yields the actual nodal flows and heads for both normal and subnormal pressure conditions. Hence, HDA simulation models are more practical than demand driven analysis models that assume that all demands are satisfied in full even under pressure-deficient conditions. This paper describes an approach in which a new pressure-dependent demand function that has no discontinuities has been incorporated in the Gradient Method. The procedure has been tested extensively and demonstrated to be capable of effectively simulating both normal and pressure-deficient operating conditions. The algorithm's convergence is smooth and rapid thanks to a line search and backtracking procedure that ensures progress towards the solution in each iteration. The results presented herein would appear to confirm that the proposed method is robust and efficient. Results for a real network are also included.
A survey of ancient Minoan water technologies
Authors: Gorokhovich Yuri , Mays Larry , Ullmann Lee
Published: September 2011

A survey is presented of water technologies used by the ancient Minoan civilization during the Bronze Age. This survey considers eleven Minoan settlements on the eastern part of Crete and is based upon a field assessment of the water technologies. While water systems had a monumental role in the life of the Minoans there has been little understanding of these ancient systems. Partially this can be explained by the multiple levels of modifications to the original structures since the demise of the Minoan civilization. In addition, post-excavation activities on archaeological sites obscure and mask features of the ancient structures making it difficult to discern their original purposes. Today, Minoan water technologies can serve as models for sustainable water management and adaptation to climatic fluctuations. Our present day practice of designing water systems in many developed parts of the world has forgotten the more sustainable practices, based upon traditional knowledge, such as rainfall water harvesting, particularly in arid and semi-arid regions. In many developing parts of the world people overlook the technologies and know how that was used thousands of years ago by ancient civilizations, such as the Minoans. How do we overcome these modern day shortcomings and strive for water resources sustainability? Possibly one way is to study the past.
Biological aspects of slow sand filtration: past, present and future
Authors: Haig S. J. , Collins G. , Davies R. L. , Dorea C. C. , Quince C.
Published: September 2011

For over 200 years, slow sand filtration (SSF) has been an effective means of treating water for the control of microbiological contaminants in both small and large community water supplies. However, such systems lost popularity to rapid sand filters mainly due to smaller land requirements and less sensitivity to water quality variations. SSF is still a particularly attractive process because its operation does not require chemicals or electricity. It can achieve a high level of treatment, which is mainly attributed to naturally-occurring, biochemical processes in the filter. Several microbiologically-mediated purification mechanisms (e.g. predation, scavenging, adsorption and bio-oxidation) have been hypothesised or assumed to occur in the biofilm that forms in the filter but these have not yet been comprehensively verified. Thus, SSFs are operated as ‘black boxes’ and knowledge gaps pertaining to the underlying ecology and ecophysiology limit the design and optimisation of the technology. The objective of this review is to outline the biological aspects of SSF in to the context of recent developments in molecular microbial ecology.
A GIS-based water distribution model for Zhengzhou city, China
Authors: Yu-Kun Hou , Chun-Hui Zhao , Yu-Chung Huang
Published: September 2011

Many water companies in China are developing GIS as a computer-based tool, for mapping and analyzing objects and events that happen on a water distribution network. However, only a few companies have taken a further step to develop a hydraulic model based on GIS, and Zhengzhou Water Supply Corporation is one of them. The WaterGEMS V8 XM from Bentley is used to develop the hydraulic model for the water distribution network in Zhengzhou city, which has a population of over 3 million. During establishment of the model, some of the data extracted from GIS are missing, abnormal, and redundant and require careful screening, searching, and judging. Model calibration is performed after a sensitivity analysis. Peaking factor and pipe roughness coefficient are key model parameters to calibrate. In calibrating peaking factors, the distribution system is divided into 5 operation districts with different types of water usage. To calibrate pipe roughness coefficients, the system was divided into 4 water supply districts with different attributes of pipelines. Finally, a case study of pipe layout evaluation it shows the hydraulic model to be a powerful tool for water supply management.
An Analysis of Authority Issues within National Response Framework ESF #6 ‐ Mass Care, Housing and Human Services Policy
Authors: Smith Steven L.
Published: September 2011

This policy analysis reviews the shared authority provisions between the American Red Cross and FEMA in ESF‐6 of the U.S. National Response Framework (NRF), which covers mass care, housing, and human services. The shared authority base in place prior to Hurricane Katrina contributed to confusion during the response in 2005. FEMA rewrote ESF‐6 in 2008; the role of FEMA and the American Red Cross under this policy continues to be reviewed at the federal level. This study evaluates policy options related to ESF‐6 authority issues using Patton and Sawicki's (1993) policy analysis framework.
A Newspaper Content Analysis of HIV/AIDS and Food Insecurity in Sub‐Saharan Africa
Authors: MacPherson Jennifer L. , Wadsworth Laurie A.
Published: September 2011

This study sought to identify media links presented between food insecurity and the HIV pandemic in sub‐Saharan Africa through description of commonly portrayed frames found in high visibility Western and African print media sources. An episodic sampling process during the summer of 2006 found articles that tied food security to the HIV pandemic. Content analysis employed a mixed methodology grounded in naturalistic inquiry. Included were interpretative thematic analyses of text and images along with a frequency content coding instrument as a means of triangulation. Several themes emerged during analysis of the sample, including a biomedical frame, war and competition imagery, economic threats, food insecurity as a contributing factor for HIV infection, and hopeful action. Differences noted within Western and African print media framing of food security within the HIV pandemic consisted of an overall Western portrayal that was less actionable and more hopeless in nature than African portrayals. The potential of integrating existing frames and working towards newer frames is discussed as a method to improve citizen‐level action on global issues and further the agenda‐setting process necessary for policy development.
Changing the Risk Paradigms can be Good for Our Health: J-Shaped, Linear and Threshold Dose-Response Models
Authors: Ricci P. F. , Straja S. R. , Cox A. L.
Published: September 2011

Both the linear (at low doses)-no-threshold (LNT) and the threshold models ( S-shapes) dose-response lead to no benefit from low exposure. We propose three new models that allow and include, but do not require – unlike LNT and S-shaped models — this strong assumption. We also provide the means to calculate benefits associated with bi-phasic biological behaviors, when they occur and propose:

Three hormetic (phasic) models: the J-shaped, inverse J-shaped, the min-max, and Method for calculating the direct benefits associated with the J and inverse J-shaped models.

The J-shaped and min-max models for mutagens and carcinogenic agents include an experimentally justified repair stage for toxic and carcinogenic damage. We link these to stochastic transition models for cancer and show how abrupt transitions in cancer hazard rates, as functions of exposure concentrations and durations, can emerge naturally in large cell populations even when the rates of cell-level events increase smoothly (e.g., proportionally) with concentration. In this very general family of models, J-shaped dose-response curves emerge. These results are universal, i.e., independent of specific biological details represented by the stochastic transition networks. Thus, using them suggests a more complete and realistic way to assess risks at low doses or dose-rates.
Dose Response of MTLN3 Cells to Serial Dilutions of Arsenic Trioxide and Ionizing Radiation
Authors: Raja Waseem Khan , Satti Jahangir , Liu Gang , Castracane James
Published: September 2011

MTLn3 cells derived from mouse mammary epithelium are known to be highly malignant and are resistant to both radio- and chemo-therapy. We exposed MTLn3 cells to various doses of inorganic Arsenic trioxide (As2O3) in combination with ionizing radiation. Cells were treated with a series of As2O3 concentrations ranging from 20 μM to 1.22 nM for 8 hour, 24 hour and 48 hour periods. Post-treated cell proliferation was quantified by measuring mitochondrial activity and DNA analysis. Cells exposed to radiation and As2O3 at concentration greater than 1.25 μM showed apoptosis and radiations alone treated cells were statistically not different from the control. Hormesis was observed for As2O3 concentrations in the range of 0.078 μM to 0.625 μM while the combined chemo and radiation treatments of the cells did not affect the hormetic effect. We have demonstrated that As2O3 (in the presence and absence of ionizing radiation) in specific low concentrations induced apoptosis in the otherwise chemoresistant cancer cells. This low concentration-mediated cell death is immediately followed by a surge in cell survival. Low dosing dosimetry is highly desirable in metronomic therapy however, it has a narrow window since necrosis, hormesis, apoptosis and other dose-dependent biological processes take place in this region. Further quantifiable dosimetry is highly desired for routine clinical practice.
Association of Pretransplant Serum Phosphorus with Posttransplant Outcomes
Authors: Sampaio Marcelo S. , Molnar Miklos Z. , Kovesdy Csaba P. , Mehrotra Rajnish , Mucsi Istvan , Sim John J. , Krishnan Mahesh , Nissenson Allen R. , Kalantar-Zadeh Kamyar
Published: September 2011

Background and objectives

Serum phosphorus levels are associated with mortality, cardiovascular disease, and renal function loss in individuals with and without chronic kidney disease. The association of pretransplant serum phosphorus levels with transplant outcomes is not clear.

Design, setting, participants, & measurements

Data of the Scientific Registry of Transplant Recipients (SRTR) up to June 2007 were linked to the database (2001 through 2006) of one of the U.S.-based large dialysis organizations (DaVita). The selected 9384 primary kidney recipients were divided into five groups according to pretransplant serum phosphorus levels (mg/dl): <3.5, 3.5 to <5.5 (reference group), 5.5 to <7.5, 7.5 to <9.5, and ≥9.5. Unadjusted and multivariate adjusted risks for transplant outcomes were compared.

Results

Patients were 48 ± 14 years old and included 37% women and 27% African Americans. After multivariate adjustment, all-cause and cardiovascular death hazard ratios were 2.44 (95% confidence interval: 1.28 to 4.65) and 3.63 (1.13 to 11.64), respectively, in recipients in the ≥9.5 group; allograft loss hazard ratios were 1.42 (1.04 to 1.95) and 2.36 (1.33 to 4.17) in recipients with 7.5 to >9.5 and ≥9.5, respectively. No significant association with delayed graft function was found.

Conclusions

Pretransplant phosphorus levels 7.5 to <9.5 mg/dl and ≥9.5 mg/dl were associated with increased risk of functional graft failure and increased risk of all-cause and cardiovascular deaths, respectively, when compared with 3.5 to <5.5 mg/dl. Additional studies are needed to examine whether more aggressive control of pretransplant serum phosphorus may improve posttransplant outcomes.
Accuracy of the freehand technique for 3 fixation methods in the C-2 vertebrae
Authors: Helgeson Melvin D. , Lehman Ronald A. , Dmitriev Anton E. , Kang Daniel G. , Sasso Rick C. , Tannoury Chadi , Riew K. Daniel
Published: September 2011

Object

Intraoperative imaging often does not provide adequate visualization to ensure safe placement of screws. Therefore, the authors investigated the accuracy of a freehand technique for placement of pars, pedicle, and intralaminar screws in C-2.

Methods

Sixteen cadaveric specimens were instrumented freehand by 2 experienced cervical spine surgeons with either a pars or pedicle screw, and bilateral intralaminar screws. The technique was based on anatomical starting points and published screw trajectories. A pedicle finder was used to establish the trajectory, followed by tapping, palpation, and screw placement. After placement of all screws (16 pars screws, 16 pedicle screws, and 32 intralaminar screws), the C-2 segments were disarticulated, radiographed in anteroposterior, lateral, and axial planes, and meticulously inspected by another spine surgeon to determine the nature and presence of any defects.

Results

A total of 64 screws were evaluated in this study. Pars screws exhibited 2 critical defects (1 in the foramen transversarium and 1 in the C2–3 facet) and an insignificant dorsal cortex breech, for an overall accuracy rate of 81.3%. Pedicle screws demonstrated only 1 insignificant violation (inferior facet/medial cortex intrusion of 1 mm) with an accuracy rate of 93.8%, and intralaminar screws demonstrated 3 insignificant violations (2 in the ventral canal, 1 in the caudad lamina breech) for an accuracy rate of 90.6%. Pars screws had significantly more critical violations than intralaminar screws (p = 0.041).

Conclusions

Instrumentation of the C-2 vertebrae using the freehand technique for insertion of pedicle and intralaminar screws showed a high success rate with no critical violations. Pars screw insertion was not as reliable, with 2 critical violations from a total of 16 placements. The freehand technique appears to be a safe and reliable method for insertion of C-2 pedicle and intralaminar screws.
Diagnostic pitfalls in spine surgery: masqueraders of surgical spine disease
Authors: Walcott Brian P. , Coumans Jean-Valery C. E. , Kahle Kristopher T.
Published: September 2011

Disorders of the spine are common in clinical medicine, and spine surgery is being performed with increasing frequency in the US. Although many patients with an established diagnosis of a true surgically treatable lesion are referred to a neurosurgeon, the evaluation of patients with spinal disorders can be complex and fraught with diagnostic pitfalls. While “common conditions are common,” astute clinical acumen and vigilance are necessary to identify lesions that masquerade as surgically treatable spine disease that can lead to erroneous diagnosis and treatment. In this review, the authors discuss musculoskeletal, peripheral nerve, metabolic, infectious, inflammatory, and vascular conditions that mimic the syndromes produced by surgical lesions. It is possible that nonsurgical and surgical conditions coexist at times, complicating treatment plans and natural histories. Awareness of these diagnoses can help reduce diagnostic error, thereby avoiding the morbidity and expense associated with an unnecessary operation.
Pedicle screw loosening in dynamic stabilization: incidence, risk, and outcome in 126 patients
Authors: Wu Jau-Ching , Huang Wen-Cheng , Tsai Hsiao-Wen , Ko Chin-Chu , Wu Ching-Lan , Tu Tsung-Hsi , Cheng Henrich
Published: September 2011

Object

The long-term outcome of lumbar dynamic stabilization is uncertain. This study aimed to investigate the incidence, risk factors, and outcomes associated with screw loosening in a dynamic stabilization system.

Methods

The authors conducted a retrospective review of medical records, radiological studies, and clinical evaluations obtained in consecutive patients who underwent 1- or 2-level lumbar dynamic stabilization and were followed up for more than 24 months. Loosening of screws was determined on radiography and CT scanning. Radiographic and standardized clinical outcomes, including the visual analog scale (VAS) and Oswestry Disability Index (ODI) scores, were analyzed with a focus on cases in which screw loosening occurred.

Results

The authors analyzed 658 screws in 126 patients, including 54 women (42.9%) and 72 men (57.1%) (mean age 60.4 ± 11.8 years). During the mean clinical follow-up period of 37.0 ± 7.1 months, 31 screws (4.7%) in 25 patients (19.8%) were shown to have loosened. The mean age of patients with screw loosening was significantly higher than those without loosening (64.8 ± 8.8 vs 59.3 ± 12.2, respectively; p = 0.036). Patients with diabetes mellitus had a significantly higher rate of screw loosening compared with those without diabetes (36.0% vs 15.8%, respectively; p = 0.024). Diabetic patients with well-controlled serum glucose (HbA1c ≤ 8.0%) had a significantly lower chance of screw loosening than those without well-controlled serum glucose (28.6% vs 71.4%, respectively; p = 0.021). Of the 25 patients with screw loosening, 22 cases (88%) were identified within 6.6 months of surgery; 18 patients (72%) had the loosened screws in the inferior portion of the spinal construct, whereas 7 (28%) had screw loosening in the superior portion of the construct. The overall clinical outcomes at 3, 12, and 24 months, measured by VAS for back pain, VAS for leg pain, and ODI scores, were significantly improved after surgery compared with before surgery (all p < 0.05). There were no significant differences between the patients with and without screw loosening at all evaluation time points (all p > 0.05). All 25 patients with screw loosening were asymptomatic, and in 6 (24%) osseous integration was demonstrated on later follow-up. Also, there were 3 broken screws (2.38% in 126 patients or 0.46% in 658 screws). To date, none of these loosened or broken screws have required revision surgery.

Conclusions

Screw loosening in dynamic stabilization systems is not uncommon (4.7% screws in 19.8% patients). Patients of older age or those with diabetes have higher rates of screw loosening. Screw loosening can be asymptomatic and presents opportunity for osseous integration on later follow-up. Although adverse effects on clinical outcomes are rare, longer-term follow-up is required in cases in which screws become loose.