bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of isometric handgrip testing on left ventricular twist mechanics
Authors: Weiner Rory B. , Weyman Arthur E. , Kim Jonathan H. , Wang Thomas J. , Picard Michael H. , Baggish Aaron L.
Published: August 2012

Key points

Left ventricular twist (LVT) results from rotation of the LV apex and base in opposite directions.

Although LVT is altered in various cardiac diseases, physiological factors that affect LVT remain incompletely understood.

In an experimental model involving healthy humans, isometric handgrip testing (IHGT) was performed to produce a clinically relevant form of LV afterload increase. The impact of IHGT on LV twist mechanics was assessed using speckle‐tracking echocardiography.

IHGT produced significant increase in systemic blood pressure and acute reduction in LV stroke volume. In this setting, LV apical rotation and LVT significantly decreased.

Impairment of LV twist mechanics may in part underlie the LV dysfunction that can occur in the clinical context of acute increase in afterload.

Abstract  Left ventricular (LV) rotation occurs due to contraction of obliquely oriented myocardial fibres. Left ventricular twist (LVT) results from rotation of the apex and base in opposite directions. Although LVT is altered in various cardiac diseases, physiological factors that affect LVT remain incompletely understood. Isometric handgrip testing (IHGT), a well‐established laboratory‐based technique to increase LV afterload, was performed for 3 min at 40% maximum force generation in healthy human subjects (n= 18, mean age 29.7 ± 2.7 years). Speckle‐tracking echocardiography was used to measure LV volumes, LV apical and basal rotation, peak systolic LVT and peak early diastolic untwisting rate (UTR) at rest and at peak IHGT. IHGT led to significant increase in systemic blood pressure (systolic, 120.6 ± 9.7 vs. 155.6 ± 14.5 mmHg, P < 0.001; diastolic, 67.5 ± 6.4 vs. 94.1 ± 21.1 mmHg, P < 0.001) and LV end‐systolic volume (44.2 ± 7.8 vs. 50.5 ± 10.8 ml, P= 0.005), as well as a significant increase in heart rate (62.8 ± 11.7 vs. 84.7 ± 13.8 beats min−1; P < 0.001). IHGT produced a significant acute reduction in LV stroke volume (63.9 ± 12.0 vs. 49.4 ± 7.8 ml, P < 0.001). In this setting, there was a significant decrease in peak systolic apical rotation (11.9 ± 3.0 vs. 8.6 ± 2.2 deg, P < 0.001) and a resultant 25% decrease in peak systolic LVT (16.6 ± 2.8 vs. 12.5 ± 2.8 deg, P < 0.001). The magnitude of peak early diastolic UTR did not change (−114.5 ± 26.4 vs. −110.6 ± 39.8 deg s−1, P= 0.71). Peak systolic apical rotation and LVT decrease during IHGT in healthy humans. This impairment of LV twist mechanics may in part underlie the LV dysfunction that can occur in the clinical context of acute increase in afterload.
Cortical inhibition, pH and cell excitability in epilepsy: what are optimal targets for antiepileptic interventions?
Authors: Pavlov Ivan , Kaila Kai , Kullmann Dimitri M. , Miles Richard
Published: August 2012

Abstract  Epilepsy is characterised by the propensity of the brain to generate spontaneous recurrent bursts of excessive neuronal activity, seizures. GABA‐mediated inhibition is critical for restraining neuronal excitation in the brain, and therefore potentiation of GABAergic neurotransmission is commonly used to prevent seizures. However, data obtained in animal models of epilepsy and from human epileptic tissue suggest that GABA‐mediated signalling contributes to interictal and ictal activity. Prolonged activation of GABAA receptors during epileptiform bursts may even initiate a shift in GABAergic neurotransmission from inhibitory to excitatory and so have a proconvulsant action. Direct targeting of the membrane mechanisms that reduce spiking in glutamatergic neurons may better control neuronal excitability in epileptic tissue. Manipulation of brain pH may be a promising approach and recent advances in gene therapy and optogenetics seem likely to provide further routes to effective therapeutic intervention.
Mammalian prestin is a weak Cl−/HCO3− electrogenic antiporter
Authors: Mistrík P. , Daudet N. , Morandell K. , Ashmore J. F.
Published: August 2012

Key points

Outer hair cells of the mammalian cochlea are cells which amplify the incoming sound using mechanisms based on prestin, a molecular actuator related to a family of chloride–bicarbonate exchangers.

It has not been clear so far whether prestin has any bicarbonate–chloride exchange properties, often being described as an ‘incomplete transporter’.

Here we show, using a pH probe linked to prestin in an expression system, that prestin can transport bicarbonate at low rates and acts as an electrogenic transporter for chloride.

The high expression level of prestin in mammalian outer hair cells thus accounts for a number of previous observations of the cells’ internal pH regulation, and may indicate an additional role for prestin in homeostatic regulation of cochlear amplification.

Abstract  The lateral membrane of mammalian cochlear outer hair cells contains prestin, a protein which can act as a fast voltage‐driven actuator responsible for electromotility and enhanced sensitivity to sound. The protein belongs to the SLC26 family of transporters whose members are characterised as able to exchange halides for SO42− or HCO3− yet previous analyses of mammalian prestin have suggested that such exchange functions were minimal. Here anion transport is investigated both in guinea‐pig outer hair cells (OHCs) and in an expression system where we employ a sensitive intracellular pH (pHi) probe, pHluorin, to report HCO3− transport and to monitor the small pHi changes observable in the cells. In the presence of extracellular HCO3−, pHi recovered from an acid load 4 times faster in prestin‐transfected cells. The acceleration required a chloride gradient established by reducing extracellular chloride to 2 mm. Similar results were also shown using BCECF as an alternative pHi sensor, but with recovery only found in those cells expressing prestin. Simultaneous electrophysiological recording of the transfected cells during bicarbonate exposure produced a shift in the reversal potential to more negative potentials, consistent with electrogenic transport. These data therefore suggest that prestin can act as a weak Cl−/HCO3− antiporter and it is proposed that, in addition to participating in wide band cochlear sound amplification, prestin may also be involved in the slow time scale (>10 s) phenomena where changes in cell stiffness and internal pressure have been implicated. The results show the importance of considering the effects of the endogenous bicarbonate buffering system in evaluating the function of prestin in cochlear outer hair cells.
Reversibility of Functional and Structural Changes of Lysozyme Subjected to Hydrodynamic Flow
Authors: Türköz Burcu Kaplan , Zakhariouta Anastassia , Sesen Muhsincan , Taralp Alpay , Koşar Ali
Published: August 2012

In this initial study, the effect of hydrodynamic flow on lysozyme structure and function was investigated using a microchannel device. Protein was subjected to bubbly cavitation as well as noncavitating flow conditions at pH 4.8 and 25 °C. Interestingly, time course analyses indicated that the secondary structure content, the hydrodynamic diameter, and enzymatic activity of lysozyme were unaffected by cavitation. However, noncavitating flow conditions did induce a decrease of the hydrodynamic diameter. The corresponding structural change was subtle to the extent that bioactivity was marginally suppressed. Moreover, native diameter and bioactivity could be fully restored following a brief period of ultrasonication. The findings encouraged further study of various hydrodynamic flow conditions in order to better ascertain the potential risks and benefits of invasive hydrodynamic cavitation in medicine. The results also served to highlight the counter-intuitive notion that proteins need not necessarily be denatured in high-shear media, risks that typically correlate well with forcefully agitated solutions.
The Effect of Particle Size and Film Cooling on Nozzle Guide Vane Deposition
Authors: Bonilla C. , Webb J. , Clum C. , Casaday B. , Brewer E. , Bons J. P.
Published: August 2012

An accelerated deposition test facility is used to study the effect of particle size and film cooling on deposit roughness, spatial distribution, and thickness. Tests were run at gas turbine representative inlet Mach numbers (0.08) and temperatures (1080 °C). Deposits were created from a subbituminous coal fly ash with mass median diameters from 4 to 16 micron (Stokes numbers ranging from 0.1 to 1.9). Two CFM56-5B nozzle guide vane doublets comprising three full passages and two half passages of flow were utilized as the test articles. Tests were run with three levels of film cooling. The addition of film cooling to the vanes was shown to decrease the deposit capture efficiency by as much as a factor of 3 and shift the primary location of deposit buildup to the leading edge, coincident with an increased region of positive cooling backflow margin. Video taken during the tests noted that film cooling holes with a negative backflow margin were primary areas of deposit formation, regardless of the film cooling percentage. The Stokes number was shown to have a marked effect on the vane capture efficiency, with the largest Stokes number ash (St = 1.9) approximately 3 times as likely to stick to the vane as the smallest Stokes number ash (St = 0.1). Posttest observations on the deposit thickness were made using a coordinate measurement machine. The deposit thickness was noted to be reduced with a decreasing Stokes number and an increased film cooling percentage. The deposit surface roughness falls with particle size but is only weakly dependent on the cooling level.
A Metal Mesh Foil Bearing and a Bump-Type Foil Bearing: Comparison of Performance for Two Similar Size Gas Bearings
Authors: San Andrés Luis , Abraham Chirathadam Thomas
Published: August 2012

Gas bearings in oil-free microturbomachinery for gas process applications and power generation (<400 kW) must be reliable and inexpensive, ensuring low drag power and thermal stability. Bump-type foil bearings (BFBs) and overleaf-type foil bearings are in use in specialized applications, though their development time (design and prototyping), exotic materials, and excessive manufacturing cost still prevent their widespread usage. Metal mesh foil bearings (MMFBs), on the other hand, are an inexpensive alternative that use common materials and no restrictions on intellectual property. Laboratory testing shows that prototype MMFBs perform similarly as typical BFBs, but offer significantly larger damping to dissipate mechanical energy due to rotor vibrations. This paper details a one-to-one comparison of the static and dynamic forced performance characteristics of a MMFB against a BFB of similar size and showcases the advantages and disadvantages of MMFBs. The bearings for comparison are a generation I BFB and a MMFB, both with a slenderness ratio L/D = 1.04. Measurements of rotor lift-off speed and drag friction at start-up and airborne conditions were conducted for rotor speeds to 70 krpm and under identical specific loads (W/LD = 0.06 to 0.26 bar). Static load versus bearing elastic deflection tests evidence a typical hardening nonlinearity with mechanical hysteresis, the MMFB showing two to three times more material damping than the BFB. The MMFB exhibits larger drag torques during rotor start-up, and shut-down tests though bearing lift-off happens at lower rotor speeds (∼15 krpm). As the rotor becomes airborne, both bearings offer very low drag friction coefficients, ∼0.03 for the MMFB and ∼0.04 for the BFB in the speed range 20–40 krpm. With the bearings floating on a journal spinning at 50 krpm, the MMFB dynamic direct force coefficients show little frequency dependency, while the BFB stiffness and damping increases with frequency (200–400 Hz). The BFB has a much larger stiffness and viscous damping coefficients than the MMFB. However, the MMFB material loss factor is at least twice as large as that in the BFB. The experiments show that the MMFB, when compared to the BFB, has a lower drag power and earlier lift-off speed and with dynamic force coefficients having a lesser dependency on whirl frequency excitation.
Cu film thermal stability on plasma cleaned polycrystalline Ru
Authors: Liu Xin , Zhu Chiyu , Eller Brianna S. , Sun Tianyin , Jezewski Christopher J. , King Sean W. , Nemanich Robert J.
Published: August 2012

The first part of this study examined oxide stability and cleaning of Ru surfaces. The surface reactions during H2 plasma exposure of Ru polycrystalline films were studied using x-ray photoelectron spectroscopy (XPS). The ∼2 monolayer native Ru oxide was reduced after H-plasma processing. However, absorbed oxygen, presumably in the grain boundaries, remains after processing. A vacuum thermal anneal at 150 °C substantially removes both surface oxide and absorbed oxygen which is attributed to a reduction by carbon contamination. The second part of the study examined the thermal stability of Cu on a Ru layer. The thermal stability or islanding of the Cu film on the Ru substrate was characterized by in situ XPS. After plasma cleaning of the Ru adhesion layer, the deposited Cu exhibited full coverage. In contrast, for Cu deposition on the Ru native oxide substrate, Cu islanding was detected and was described in terms of grain boundary grooving and surface and interface energies. The oxygen in the grain boundary has a negligible contribution to the surface energy and does not contribute to Cu islanding.
Simulation study of cleaning induced extreme ultraviolet reflectivity loss mechanisms on mask blanks
Authors: Upadhyaya Mihir , Denbeaux Gregory , Kadaksham Arun John , Jindal Vibhu , Jones Jenah Harris , Lee Byunghoon , Goodwin Frank
Published: August 2012

It is widely recognized in the semiconductor industry that getting to defect-free extreme ultraviolet (EUV) mask blanks is critical in achieving high volume chip manufacturing yield beyond the 22 nm half-pitch node. Finished mask blanks are normally subjected to a cleaning process to get rid of the loosely adhered particles on the top. It is important that this cleaning process does not degrade the properties of the multilayer blank or introduce additional particles or pits during the process. However, standard cleaning processes used to clean multilayer blanks can result in EUV reflectivity loss, loss of uniformity in reflectivity, increased roughness, and add pits and particles on mask blanks. The standard cleaning process consists of multiple steps, each of which may cause the oxidation of the ruthenium capping layer, as well as the underlying bilayers, etching of the multilayer stack, and increased roughness of the bilayers, thus leading to a loss in EUV reflectivity. It is a challenging task to experimentally correlate the processing steps to the resulting damage and to quantify the reflectivity loss. Further, due to the high cost of materials we have not been able to perform extensive experiments to determine the root cause of problems. In this work, we have combined mask blank cleaning using standard processes, x-ray photoelectron spectroscopy, transmission electron microscope cross section, and atomic force microscope studies with simulations to quantify the impact of the multilayer oxidation, etching, and roughness on the EUV reflectivity loss and mask blank degradation.
Interference with the PTEN-MAST2 Interaction by a Viral Protein Leads to Cellular Relocalization of PTEN
Authors: Terrien Elouan , Chaffotte Alain , Lafage Mireille , Khan Zakir , Préhaud Christophe , Cordier Florence , Simenel Catherine , Delepierre Muriel , Buc Henri , Lafon Monique , Wolff Nicolas
Published: August 2012

The G protein of rabies virus manipulates the cellular localization of PTEN, which may promote cell survival.
L-Type Calcium Channels: On the Fast Track to Nuclear Signaling
Authors: D’Arco Marianna , Dolphin Annette C.
Published: August 2012

In excitation-transcription coupling, some calcium signals are more efficient than others.
Elimination by Extrusion
Authors: Gough Nancy R.
Published: August 2012

An AMPK homolog and its upstream activators are necessary for cell death by cell shedding in
Caenorhabditis elegans
.
Cancer-Fighting Vanilloids
Authors: VanHook Annalisa M.
Published: August 2012

Endogenous vanilloids produced by neural precursor cells inhibit the growth of malignant gliomas.
A Caspase for Phagosomal-Lysosomal Fusion
Authors: Foley John F.
Published: August 2012

Clearance of phagosomes containing pathogenic bacteria depends on caspase-11.
Phosphoinositide Contributions
Authors: Ray L. Bryan
Published: August 2012

The phospholipid phosphatidylinositol 4-phosphate defines important physical properties of the cell membrane.
Differential Modulation of Intracellular Survival of Cytosolic and Vacuolar Pathogens by Curcumin
Authors: Marathe Sandhya A. , Sen Minakshi , Dasgupta Ishani , Chakravortty Dipshikha
Published: August 2012

Curcumin, a principal component of turmeric, acts as an immunomodulator regulating the host defenses in response to a diseased condition. The role of curcumin in controlling certain infectious diseases is highly controversial. It is known to alleviate symptoms of
Helicobacter pylori
infection and exacerbate that of
Leishmania
infection. We have evaluated the role of curcumin in modulating the fate of various intracellular bacterial pathogens. We show that pretreatment of macrophages with curcumin attenuates the infections caused by
Shigella flexneri
(clinical isolates) and
Listeria monocytogenes
and aggravates those caused by
Salmonella enterica
serovar Typhi CT18 (a clinical isolate),
Salmonella enterica
serovar Typhimurium,
Staphylococcus aureus
, and
Yersinia enterocolitica
. Thus, the antimicrobial nature of curcumin is not a general phenomenon. It modulated the intracellular survival of cytosolic (
S. flexneri
and
L. monocytogenes
) and vacuolar (
Salmonella
spp.,
Y. enterocolitica
, and
S. aureus
) bacteria in distinct ways. Through colocalization experiments, we demonstrated that curcumin prevented the active phagosomal escape of cytosolic pathogens and enhanced the active inhibition of lysosomal fusion by vacuolar pathogens. A chloroquine resistance assay confirmed that curcumin retarded the escape of the cytosolic pathogens, thus reducing their inter- and intracellular spread. We have demonstrated that the membrane-stabilizing activity of curcumin is crucial for its differential effect on the virulence of the bacteria.
Utilization of Omeprazole To Augment Subtherapeutic Voriconazole Concentrations for Treatment of Aspergillus Infections
Authors: Boyd Natalie K. , Zoellner Cindy L. , Swancutt Mark A. , Bhavan Kavita P.
Published: August 2012

Voriconazole is the preferred antifungal agent for
Aspergillus
infections. Therapeutic drug monitoring is recommended to achieve target concentrations and prevent toxicity. However, variable pharmacokinetics, cytochrome P450 polymorphisms, and extensive drug-drug interactions can contribute to subtherapeutic concentrations. We report a voriconazole “boosting” effect of omeprazole to achieve target concentrations for the treatment of
Aspergillus
in a patient who had persistently subtherapeutic trough concentrations.
Multicenter Study of Posaconazole Therapeutic Drug Monitoring: Exposure-Response Relationship and Factors Affecting Concentration
Authors: Dolton Michael J. , Ray John E. , Chen Sharon C.-A. , Ng Kingsley , Pont Lisa , McLachlan Andrew J.
Published: August 2012

Posaconazole has an important role in the prophylaxis and salvage treatment of invasive fungal infections (IFIs), although poor and variable bioavailability remains an important clinical concern. Therapeutic drug monitoring of posaconazole concentrations has remained contentious, with the use of relatively small patient cohorts in previous studies hindering the assessment of exposure-response relationships. This multicenter retrospective study aimed to investigate relationships between posaconazole concentration and clinical outcomes and adverse events and to assess clinical factors and drug interactions that may affect posaconazole concentrations. Medical records were reviewed for patients who received posaconazole and had ≥1 concentration measured at six hospitals in Australia. Data from 86 patients with 541 posaconazole concentrations were included in the study. Among 72 patients taking posaconazole for prophylaxis against IFIs, 12 patients (17%) developed a breakthrough fungal infection; median posaconazole concentrations were significantly lower than in those who did not develop fungal infection (median [range], 289 [50 to 471] ng/ml versus 485 [0 to 2,035] ng/ml;
P
< 0.01). The median posaconazole concentration was a significant predictor of breakthrough fungal infection via binary logistic regression (
P
< 0.05). A multiple linear regression analysis identified a number of significant drug interactions associated with reduced posaconazole exposure, including coadministration with proton pump inhibitors, metoclopramide, phenytoin or rifampin, and the H
2
antagonist ranitidine (
P
< 0.01). Clinical factors such as mucositis, diarrhea, and the early posttransplant period in hematopoietic stem cell transplant recipients were also associated with reduced posaconazole exposure (
P
< 0.01). Low posaconazole concentrations are common and are associated with breakthrough fungal infection, supporting the utility of monitoring posaconazole concentrations to ensure optimal systemic exposure.
Clinical Prediction of Failure of Lamivudine Prophylaxis for Hepatitis B Virus-Infected Patients Undergoing Cytotoxic Chemotherapy for Malignancy
Authors: Kim In Kyoung , Kim Byeong Gwan , Kim Won , Kim Donghee , Kim Yoon Jun , Yoon Jung-Hwan , Lee Hyo Suk
Published: August 2012

Although lamivudine (LAM) prophylaxis is recommended for patients infected with hepatitis B virus (HBV) undergoing chemotherapy for malignant disease, HBV reactivation sometimes occurs during or after LAM administration. The aim of this study was to determine predictors of LAM prophylactic failure in patients with malignancies. Patients with malignancies were routinely screened for serum hepatitis B surface antigen (HBsAg) from June 2002 to August 2008. All consecutive, HBsAg-positive patients received LAM prophylaxis during and after completion of chemotherapy. We assessed risk factors for virologic breakthrough and withdrawal hepatitis. Death without HBV reactivation was regarded as a competing risk event, which was adjusted by Fine and Gray's model. A total of 110 patients were included in this study. They received LAM prophylaxis for a median of 9.2 months. Virologic breakthrough occurred in 15 patients at a median of 10.9 months from the initiation of LAM prophylaxis. Withdrawal hepatitis occurred in 15 patients at a median of 2.4 months after cessation of LAM prophylaxis. Multivariable analysis showed that high baseline HBV DNA titer (≥2,000 IU/ml) (hazard ratio [HR], 9.94;
P
= 0.0063) and the use of rituximab (HR, 3.19;
P
= 0.027) were significant predictors of virologic breakthrough and that high baseline HBV DNA titer (HR, 5.90;
P
= 0.007), liver cirrhosis (HR, 10.4;
P
= 0.002), and distant metastasis (HR, 5.14;
P
= 0.008) were independent risk factors for withdrawal hepatitis. Patients with high viremia, liver cirrhosis, rituximab treatment, and distant metastasis are at high risk of prophylactic failure and need antiviral agents with a greater barrier to resistance.
Telavancin in Therapy of Experimental Aortic Valve Endocarditis in Rabbits Due to Daptomycin-Nonsusceptible Methicillin-Resistant Staphylococcus aureus
Authors: Xiong Yan Q. , Hady Wessam Abdel , Bayer Arnold S. , Chen Liang , Kreiswirth Barry N. , Yang Soo-Jin
Published: August 2012

A number of cases of both methicillin-susceptible
Staphylococcus aureus
(MSSA) and methicillin-resistant
S. aureus
(MRSA) strains that have developed daptomycin resistance (DAP-R) have been reported. Telavancin (TLV) is a lipoglycopeptide agent with a dual mechanism of activity (cell wall synthesis inhibition plus depolarization of the bacterial cell membrane). Five recent daptomycin-susceptible (DAP-S)/DAP-R MRSA isogenic strain pairs were evaluated for
in vitro
TLV susceptibility. All five DAP-R strains (DAP MICs ranging from 2 to 4 μg/ml) were susceptible to TLV (MICs of ≤0.38 μg/ml).
In vitro
time-kill analyses also revealed that several TLV concentrations (1-, 2-, and 4-fold MICs) caused rapid killing against the DAP-R strains. Moreover, for 3 of 5 DAP-R strains (REF2145, A215, and B
2.0
), supra-MICs of TLV were effective at preventing regrowth at 24 h of incubation. Further, the combination of TLV plus oxacillin (at 0.25× or 0.50× MIC for each agent) increased killing of DAP-R MRSA strains REF2145 and A215 at 24 h (∼2-log and 5-log reductions versus TLV and oxacillin alone, respectively). Finally, using a rabbit model of aortic valve endocarditis caused by DAP-R strain REF2145, TLV therapy produced a mean reduction of >4.5 log
10
CFU/g in vegetations, kidneys, and spleen compared to untreated or DAP-treated rabbits. Moreover, TLV-treated rabbits had a significantly higher percentage of sterile tissue cultures (87% in vegetations and 100% in kidney and spleen) than all other treatment groups (
P
< 0.0001). Together, these results demonstrate that TLV has potent bactericidal activity
in vitro
and
in vivo
against DAP-R MRSA isolates.
Antibacterial Activity of Joint Fluid in Cemented Total-Knee Arthroplasty: an
In Vivo
Comparative Study of Polymethylmethacrylate with and without Antibiotic Loading
Authors: Ueng Steve W. N. , Hsieh Pang-Hsin , Shih Hsin-Nung , Chan Yi-Shan , Lee Mel S. , Chang Yuhan
Published: August 2012

The objective of this study was to evaluate the antibacterial activities of joint fluids of patients undergoing total-knee arthroplasty (TKA). Thirty patients who were scheduled for primary cemented TKA were enrolled in the study. The patients were grouped on the basis of whether the cement was without antibiotic loading (control group) or loaded with oxacillin (oxacillin group) or vancomycin (vancomycin group). Cefazolin was administered to every patient as the perioperative prophylactic antibiotic. Samples of joint fluids were collected from the knee joints at 8, 16, 24, 32, 40, and 48 h after prosthesis implantation. We assessed the bioactivities of the joint fluids against methicillin-susceptible
Staphylococcus aureus
(MSSA) and methicillin-resistant
S. aureus
(MRSA). The antibiotic contents of the joint fluid samples were further evaluated by using high-performance liquid chromatography. Against MSSA, all joint fluid samples exhibited at least 24 h of bacterial inhibition activity. The oxacillin (43.2 h ± 2 h) and vancomycin (40.8 h ± 1.8 h) groups exhibited significantly longer durations of antibacterial activities than the control group (28 h ± 1.3 h;
P
< 0.05). However, antibacterial activity against MRSA was observed only in the vancomycin group. In conclusion, cefazolin, which was administered as a prophylactic antibiotic in TKA, exhibited good ability for knee joint penetration and was sufficient to inhibit MSSA during its administration. The use of antibiotic-loaded cement can prolong the antibacterial activity of joint fluid in TKA. Further, vancomycin-loaded cement had antibacterial activity against MRSA superior to that of cement loaded with oxacillin or without antibiotic loading.
Risk Factors for Infection or Colonization with CTX-M Extended-Spectrum-β-Lactamase-Positive Escherichia coli
Authors: Han Jennifer H. , Kasahara Kei , Edelstein Paul H. , Bilker Warren B. , Lautenbach Ebbing
Published: August 2012

There has been a significant increase in the prevalence of
Enterobacteriaceae
that produce CTX-M-type extended-spectrum β-lactamases. The objective of this study was to evaluate risk factors for infection or colonization with CTX-M-positive
Escherichia coli
. A case-control study was conducted within a university system from 1 January 2007 to 31 December 2008. All patients with clinical cultures with
E. coli
demonstrating resistance to extended-spectrum cephalosporins were included. Case patients were designated as those with cultures positive for CTX-M-positive
E. coli
, and control patients were designated as those with non-CTX-M-producing
E. coli
. Multivariable logistic regression analyses were performed to evaluate risk factors for CTX-M-positive isolates. A total of 83 (56.8%) of a total of 146 patients had cultures with CTX-M-positive
E. coli
. On multivariable analyses, there was a significant association between infection or colonization with CTX-M-type β-lactamase-positive
E. coli
and receipt of piperacillin-tazobactam in the 30 days prior to the culture date (odds ratio [OR], 7.36; 95% confidence interval [CI], 1.61 to 33.8;
P
= 0.01) and a urinary culture source (OR, 0.36; 95% CI, 0.17 to 0.77;
P
= 0.008). The rates of resistance to fluoroquinolones were significantly higher in isolates from case patients than in isolates from control patients (90.4 and 50.8%, respectively;
P
< 0.001). We found that nonurinary sources of clinical cultures and the recent use of piperacillin-tazobactam conferred an increased risk of colonization or infection with CTX-M-positive
E. coli
. Future studies will need to focus on outcomes associated with infections due to CTX-M-positive
E. coli
, as well as infection control strategies to limit the spread of these increasingly common organisms.
Prevalence and Significance of HIV-1 Drug Resistance Mutations among Patients on Antiretroviral Therapy with Detectable Low-Level Viremia
Authors: Li Jonathan Z. , Gallien Sebastien , Do Tri D. , Martin Jeffrey N. , Deeks Steven , Kuritzkes Daniel R. , Hatano Hiroyu
Published: August 2012

HIV-1 resistance testing was performed in 47 antiretroviral (ARV)-treated subjects with low-level viremia (LLV) of <1,000 copies/ml. The median viral load was 267 copies/ml. In those with ≥2 LLV episodes, 44% accumulated additional resistance mutations. Fewer active ARVs and longer elapsed time were associated with an increased risk of resistance accumulation after controlling for adherence and viral load. Virologic failure followed 16% of LLV time points. Strategies for early intervention after LLV episodes should be further studied.
Macrolides and β-Lactam Antibiotics Enhance C3b Deposition on the Surface of Multidrug-Resistant Streptococcus pneumoniae Strains by a LytA Autolysin-Dependent Mechanism
Authors: Ramos-Sevillano Elisa , Rodríguez-Sosa Cinthya , Díez-Martínez Roberto , Giménez María-José , Olmedillas Eduardo , García Pedro , García Ernesto , Aguilar Lorenzo , Yuste Jose
Published: August 2012

The emergence of
Streptococcus pneumoniae
strains displaying high levels of multidrug resistance is of great concern worldwide and a serious threat for the outcome of the infection. Modifications of the bacterial envelope by antibiotics may assist the recognition and clearance of the pathogen by the host immune system. Recognition of
S. pneumoniae
resistant strains by the complement component C3b was increased in the presence of specific anti-pneumococcal antibodies and subinhibitory concentrations of different macrolides and β-lactam antibiotics for all the strains investigated. However, C3b levels were unchanged in the presence of serum containing specific antibodies and sub-MICs of levofloxacin. To investigate whether LytA, the main cell wall hydrolase of
S. pneumoniae
, might be involved in this process,
lytA
-deficient mutants were constructed. In the presence of antibiotics, loss of LytA was not associated with enhanced C3b deposition on the pneumococcal surface, which confirms the importance of LytA in this interaction. The results of this study offer new insights into the development of novel therapeutic strategies using certain antibiotics by increasing the efficacy of the host immune response to efficiently recognize pneumococcal resistant strains.
The Toll Interleukin-1 Receptor (IL-1R) 8/Single Ig Domain IL-1R-Related Molecule Modulates the Renal Response to Bacterial Infection
Authors: Leemans Jaklien C. , Butter Loes M. , Teske Gwendoline J. D. , Stroo Ingrid , Pulskens Wilco P. , Florquin Sandrine
Published: August 2012

Our immune system has to constantly strike a balance between activation and inhibition of an inflammatory response to combat invading pathogens and avoid inflammation-induced collateral tissue damage. Toll interleukin-1 receptor 8 (IL-1R-8)/single Ig domain IL-1R-related molecule (TIR8/SIGIRR) is an inhibitor of Toll-like receptor (TLR)/IL-1R signaling, which is predominantly expressed in the kidney. The biological role of renal TIR8 during infection is, however, unknown. We therefore evaluated renal TIR8 expression duringEscherichia colipyelonephritis and explored its role in host defense using TIR8−/−versus TIR8+/+mice. We found that TIR8 protein is abundantly present in the majority of cortical tubular epithelial cells. Pyelonephritis resulted in a significant downregulation of TIR8 mRNA in kidneys of TIR8+/+mice. TIR8 inhibited an effective host response againstE. coli, as indicated by diminished renal bacterial outgrowth and dysfunction in TIR8−/−mice. This correlated with increased amounts of circulating and intrarenal neutrophils at the early phase of infection. TIR8−/−tubular epithelial cells had increased cytokine/chemokine production when stimulated with lipopolysaccharide (LPS) or heat-killedE. coli, suggesting that TIR8 played an anti-inflammatory role during pathogen stimulation by inhibiting LPS signaling. These data suggest that TIR8 is an important negative regulator of an LPS-mediated inflammatory response in tubular epithelial cells and dampens an effective antibacterial host response during pyelonephritis caused by uropathogenicE. coli.
Uptake and Persistence of Mycobacterium avium subsp. paratuberculosis in Human Monocytes
Authors: Keown Dayle A. , Collings David A. , Keenan Jacqueline I.
Published: August 2012

Mycobacterium avium
subsp.
paratuberculosis
is a bacterium sometimes found in human blood and tissue samples that may have a role in the etiology of Crohn's disease in humans. To date, however, there have been few studies examining the interactions of these bacteria with human cells. Using the THP-1 human monocytic cell line, this study shows that the uptake and trafficking of
M. avium
subsp.
paratuberculosis
in human cells are cholesterol dependent and that these bacteria localize to cholesterol-rich compartments that are slow to acidify.
M. avium
subsp.
paratuberculosis
bacteria containing phagosomes stain for the late endosomal marker Rab7, but recruitment of the Rab7-interacting lysosomal protein that regulates the fusion of bacterium-containing phagosomes with lysosomal compartments and facilitates subsequent bacterial clearance is significantly reduced. Disruption of phagosome acidification via this mechanism may contribute to
M. avium
subsp.
paratuberculosis
persistence in human cells, but there was no evidence that internalized
M. avium
subsp.
paratuberculosis
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Observing earth’s sodium and atomic oxygen dayglow emissions 1This article is part of a Special Issue that honours the work of Dr. Donald M. Hunten FRSC who passed away in December 2010 after a very illustrious career.
Authors: Shepherd Gordon G.
Published: August 2012

The observation of sodium emission in the twilight upper atmosphere was the leading edge of the study of metals in the upper atmosphere, and its quantitative measurement and analysis were pioneered by Donald M. Hunten. He extended these early observations into the daytime, the sodium dayglow, including rocket observations of this phenomenon. More than fifty years later the amount of information on this subject has grown enormously through LIDAR observations, laboratory measurements, and extensive modeling. The author’s participation in those early measurements inspired him to undertake observations of the atomic oxygen dayglow, first from the ground, and then from orbit with the WINDII instrument on NASA’s Upper Atmosphere Research Satellite. The parallels between the Na and O dayglows are described and reviewed, including in particular the methods of observation. Very recent results on the atomic oxygen O(1S) dayglow are presented, showing the influence of the DE3 nonmigrating tide reaching from the troposphere to 250 km altitude in the thermosphere.
Re-evaluation of thermosphere heating by solar EUV and UV radiation 1This article is part of a Special issue that honours the work of Dr. Donald M. Hunten FRSC who passed away in December 2010 after a very illustrious career.
Authors: Richards P.G.
Published: August 2012

This paper presents a new calculation of neutral gas heating by solar extreme ultraviolet and ultraviolet radiation with updated solar irradiances and photochemistry. It is found that the heating rate of the neutral gas is significantly different from some previous determinations. Neutral gas heating arises from the many exothermic chemical reactions that take place from the ions and excited species created by energetic electrons. The calculations show that less than half the energy initially deposited ends up heating the neutral gases. The rest is radiated or lost in the dissociation of O2 because the O atoms do not recombine in the thermosphere above 100 km. At high altitudes, the heating rates are sensitive to the thermal electron density and long-lived species. The calculations show that, while most of the energy is deposited at low altitudes, the heating per neutral particle is greatest at high altitudes. This paper also examines the consequences of different thermal electron cooling rates to O2 vibration and O fine structure. Although there are large differences between the individual rates, the overall cooling rates have similar magnitudes and there is little effect on the calculated electron temperature. The concept of the neutral gas heating efficiency is a useful way of capturing the flow of energy in the thermosphere and was used in early global models to reduce computation. It is defined at a particular altitude as the rate of energy transferred to the neutral gas divided by the energy deposited rate at that altitude. The heating efficiency peaks at about 0.5 just below 200 km altitude. The heating efficiency is relatively insensitive to the solar input and thermosphere conditions when plotted against pressure rather than altitude coordinates and when thermal electron heating is calculated separately.
Excited oxygen states in the Venus nightglow 1This article is part of a Special Issue that honours the work of Dr. Donald M. Hunten FRSC who passed away in December 2010 after a very illustrious career.
Authors: Slanger T.G.
Published: August 2012

In the absence of solar radiation, the most common photoexcitation process in the terrestrial planets results from atom recombination. Thus, in the Mars and Venus atmospheres recombination of O(3P) + O(3P) and O(3P) + N(4S) leads to emissions of excited states of O2 and NO, respectively. However, in the Earth’s atmosphere there are ionospheric emissions that depend on interactions of charged species, for example, the oxygen red and green lines arising from dissociative recombination (DR) of [Formula: see text]. In the case of the CO2 planets, the predominant ionospheric ion is also [Formula: see text], so that in principle DR is important in that environment, where the markers would also be the red and green lines. Whether these can be detected depends on DR rates and the radiating efficiencies of these species. In this report we discuss the history of green line detection in the Venus nightglow as well as the observations of excited O2 molecules, and the lack of appearance of the O2 (b–X) Atmospheric 0–0 band.
Carl Størmer’s auroral discoveries 1This article is part of a Special Issue that honours the work of Dr. Donald M. Hunten FRSC who passed away in December 2010 after a very illustrious career.
Authors: Egeland Alv , Burke William J.
Published: August 2012

In the first half of the 20th century Professor Carl Størmer took aurora research to new heights, devoting all of his energy to solving the riddle of this fascinating natural phenomenon. He began his pioneering research by calculating the trajectories allowed to energetic charged particles. Because the equations of motion did not have analytic solutions, he was forced to invent new numerical methods to follow each particle’s path, step by step. Through a series of treatises he presented now classic solutions to the trajectory problem. To explain the large scale motion of the auroral zone, he was first to introduce the concept of a ring current in 1911. His theoretical work also provided the basis for understanding later discoveries of cosmic rays and the radiation belts. Størmer contributed many important scientific achievements to space physics. In 1909 he constructed the first useful auroral camera needed to make precise space–time mappings of auroral characteristics. Over the course of four sunspot cycles he took more than 100 000 auroral photographs with his network of stations spread across southern Norway. These parallactic auroral photographs gave not only the heights of individual auroral features, but also their occurrence rates, locations, and orientations. He classified the different auroral forms by publishing the first Auroral Atlas (Størmer. Photographic Atlas of Auroral Forms. Brøggers Boktrykkeri, Oslo. 1930.). Among Størmer’s other fascinating discoveries was his identification of sunlit aurorae and descriptions of their remarkable properties.
Hydrogen and methane in Titan’s atmosphere: chemistry, diffusion, escape, and the Hunten limiting flux principle 1This article is part of a Special Issue that honours the work of Dr. Donald M. Hunten FRSC who passed away in December 2010 after a very illustrious career.
Authors: Strobel Darrell F.
Published: August 2012

One of Professor Donald M. Hunten’s lasting contributions to the field of planetary atmospheres was the principle of the (Hunten) limiting flux, where the escape of light species is limited by the rate at which they can diffuse through the atmosphere. While his limiting flux expression has been well tested for hydrogen’s escape from the Earth’s atmosphere (e.g., Hunten and Strobel (J. Atmos. Sci. 31, 305 (1974)); Hunten and Donahue (Ann. Rev. Earth Planet Sci. 4, 265 (1976))), it has not been tested for Titan’s atmosphere, which was the original motivation for the principle. The Cassini–Huygens mission has provided sufficient data on the variation of the H2 mole fraction with altitude to test its applicability and validity. Only in the vicinity of the homopause does the limiting flux expression yield the actual H2 escape flux, because the mole fraction varies with altitude. This paper deals also with our current understanding of the three major constituents of Titan’s atmosphere (N2, CH4, and H2) from the various measurements by instruments on the Cassini orbiter and the Huygens probe. Specific problems addressed are additional required sources of H2, the CH4 escape rate, and the possible role of energetic electron and ion precipitation from Saturn’s magnetosphere.
Vibrational populations of near-ultraviolet O2 band systems in the night airglow 1This article is part of a Special issue that honours the work of Dr. Donald M. Hunten FRSC who passed away in December 2010 after a very illustrious career.
Authors: Gattinger R.L. , McDade I.C. , Broadfoot A.L. , Evans W.F.J. , Stegman J. , Llewellyn E.J.
Published: August 2012

Observations of the limb night airglow spectrum from 250 to 475 nm, emitted from the upper mesosphere and lower thermosphere, are compared with model spectra. Data from the Arizona GLO-1 imaging spectrograph and the OSIRIS spectrograph are combined to form the observed mean airglow spectrum; a tabulated version of this spectrum is included. Model spectra of the individual O2 Herzberg I, II, and III, Chamberlain, and Slanger band systems are combined to simulate the observed mean spectrum. Franck–Condon relative band intensities are used to form a series of basis functions for the upper vibrational levels in each band system. These functions are fitted to the observed airglow spectrum with a least-squares method, the relative vibrational populations are derived and discussed.
SYSTEMATIC ENUMERATION OF CONFIGURATION CLASSES FOR ENTROPIC SAMPLING OF ISING MODELS
Authors: LOURENÇO BRUNO JEFERSON , DICKMAN RONALD
Published: August 2012

We describe a systematic method for complete enumeration of configuration classes (CCs) of the spin-1/2 Ising model in the energy-magnetization plane. This technique is applied to the antiferromagnetic (AF) Ising model in an external magnetic field on the square lattice, which is simulated using the tomographic entropic sampling (TES) algorithm. We estimate the number of configurations, Ω(E,m,L), and related microcanonical averages, for all allowed energies E and magnetizations m for L = 10 to 30, with ΔL = 2. With prior knowledge of the CCs, we can be sure that all allowed classes are sampled during the simulation. Complete enumeration of CCs also enables us to use the final estimate of Ω(E,m,L) to obtain good initial estimates, Ω0(E,m,L′), for successive system sizes (L′ > L) through a two-dimensional interpolation. Using these results we calculate canonical averages of the thermodynamic quantities of interest as continuous functions of temperature T and external field h. In addition, we determine the critical line in the h-T plane using finite-size scaling analysis, and compare these results with several approximate theoretical expressions.
The Inhibitory Effect of Rheum palmatum Against Coxsackievirus B3in Vitro and in Vivo
Authors: Xiong Hai-Rong , Shen Yuan-Ying , Lu Li , Hou Wei , Luo Fan , Xiao Hong , Yang Zhan-Qiu
Published: August 2012

Coxsackievirus B3(CVB3) infection is the major cause of viral myocarditis, as well as dilated cardiomypathy. Rhubarb is one of the oldest and best-known traditional Chinese medicines. We initiated this study to determine the antiviral effect of an ethanol extract from the roots and rhizoma of Rheum palmatum (R. palmatum, one of the Chinese Rhubarbs), against CVB3 in tissue culture cells and in a mouse model. The ethanol extract from R. palmatum showed significant inhibitory activity against CVB3 on HEp-2 cells when added after infection, with IC50 of 4 μg/ml, TI of 10. The medicated mouse serum still contained the pharmaceutical compound 24 h after intraperitoneal injection, and exhibited an antiviral effect on CVB3-infected cells, especially in the 0.3 and 0.5 g/kg/day treatment groups. Furthermore, the CVB3-infected mice were treated with the extract solution with dosages of 0.3 g/kg/day beginning 24 h post-CVB3 exposures. The ethanol extract treated mice showed alleviated clinical signs, better survival rate, prolonged MTD and decreased viral titers compared to the virus control group. Our results indicate that the ethanol extract from R. palmatum has the anti-CVB3 activity in vitro and in vivo and thus provides a re-evaluation of this old remedy with a broad therapeutic potential.
RECENT RESULTS FROM ATLAS AND CMS ON HIGGS, SUPERSYMMETRY AND PHYSICS BEYOND THE STANDARD MODEL SEARCHES
Authors: NAHN STEVE , TSYBYCHEV DMITRI
Published: August 2012

This article has been retracted. A statement of retraction is published in Int. J. Mod. Phys. A, Volume 28, Issue 16 (2013) http://dx.doi.org/10.1142/S0217751X13930019.

A new version of this article will be published in Int. J. Mod. Phys. A, Volume 28, Issue 16 (2013) Article No. 1330026, DOI: S0217751X13300263.
NOVEL NANOPHOTOLYSIS TECHNIQUE FOR BREAST CANCER THERAPY
Authors: ASHIQ M. G. B. , IBRAHIM NOORDDIN , SHAHID M. , TAHIR B. A. , SAEED M. A.
Published: August 2012

The aim of this study is to investigate the effects of gold nanoparticles on breast cancer tumor. A theoretical approach has been adopted to probe the nanophotolysis technique using short pulse laser. The influences of various parameters including number of ions, shock front, energy distribution function, laser fluence are discussed in detail. Computational results suggest that spherical gold nanoparticles provides a promising platform for selective killing of abnormal cells in breast cancer tumor.