Search Results - (Author, Cooperation:L. Levin)

2011-08-27

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2013-07-06

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2018-01-05

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Geosciences

Computer Science

Medicine

Natural Sciences in General

Physics

Geochemistry, Geophysics, Online Only

2018-02-16

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Geosciences

Computer Science

Medicine

Natural Sciences in General

Physics

Editorials

2018-07-05

American Association for the Advancement of Science (AAAS)

2375-2548

Natural Sciences in General

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A novel fiber optic velocity interferometer for velocity measurements of moving surfaces has been developed and tested. The interferometer is based on optical fibers or fiber coupled components only and therefore is compact, portable, easy to align, and enables measurements in hard to reach locations. It also does not require a source of long coherence length (only a few wavelengths, regardless of the optical path difference or the surface displacement). This interferometer removes the directional ambiguity of the acceleration using a [3×3] optical coupler. © 1996 American Institute of Physics.

Electronic Resource

1525-1438

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Twelve patients were given 31 courses of carboplatin using a glomerular filtration rate (GFR)-based area under the curve (AUC) dose schedule, and nine patients were given 35 cycles at a body surface area (BSA) dose of 350 mg m−2 every 3 weeks. The GFR was determined using technetium-99m-DTPA. The dose given was calculated according to AUC, 5 for previously treated and 7 for previously untreated patients × GFR + 25. Patients treated using the GFR had a 22% lower projected dose intensity (DI) and a 15% lower received DI compared with controls. The percentage difference between the received and projected DI was not different between the two groups of patients. In 11 of 12 patients treated according to the GFR, if the BSA calculation dose had been used it would have resulted in a higher dose of carboplatin. Twenty per cent (six of 30 courses) of GFR-based doses were delayed compared to 29% (10 of 35) of the BSA-calculated control groups. We conclude that giving a dose according to a BSA of 350 mg m−2 leads to a higher DI and total dose and does not substantially effect toxicity. It is also cost effective as it eliminates the need for unnecessary radiometric GFR determination.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The evolution of the interface between two mutually insoluble metallic phases, under the influence of a strong electric field is examined. A slight perturbation of the interface away from a plane y=h(x) leads to a component of the electric field along the interface. This creates a diffusion flux of the individual atoms along the interface which, in turn, leads to an increase in the amplitude of the initial perturbation and thus to an interfacial profile instability. The processes is expected to be controlled by interface diffusion in response to three distinct driving forces: the electric field, internal stresses (which arise due to the accumulation or depletion of matter at the interface), and the interfacial curvature. The stress distribution along the interface was found from a self-consistent solution of the elastic problem. For the instability to occur, differences in effective atomic charges, elastic moduli and/or atomic mobilities of the two constituent metals are required. Small sinusoidal corrugations are shown to grow with time for a range of wavelengths. The corrugations can grow monotonically or vary in oscillatory manner, depending on their wavelength. © 1996 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

We have studied morphological changes of an interface in a strong electric field which is normal to the initially planar interface. Electromigration along the interface in a two phase metallic system A-B of the immiscible components has been considered. The stresses arising during electromigration of the components were taken into account. A nonlinear equation has been derived for the interface evolution in the electric field, allowing for curvature of the interface. It was shown that the interface diffusion in an electric field leads to the formation of a periodic corrugation on the interface if the components are distinguished by their electric charges. The corrugation increases with time and is transformed into a channel-hillock-like structure. The nonlinear equation was analyzed numerically for the steady-state case. The shape and the growth rate of hillocks on the interface have been calculated. © 1995 American Institute of Physics.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Cell-free extracts of autologous ovarian cancer cells evoked a delayed hypersensitivity response (DHR) in skin in four out of six patients in remission from disease and none of seven patients in relapse. These initial results appear to be consistent with in vitro blastogenic assay using the same autologous extracts. To assess whether diminished tumour-associated immunity was due to impaired cellmediated immunocompetence, blastogenic responses to purified protein derivative of tuberculin (PPD), a secondary recall antigen, and phytohaemagglutinin (PHA) were assessed. Impaired responses to PHA were seen in the relapse group of patients, but responses to PPD did not appear to be impaired in this group.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We report results of photoemission from metal cathodes. The photon source was a pulsed XeCl laser of 10 ns width (FWHM). We obtained a photocurrent density of 600 A/cm2, a quantum efficiency of 8×10−5, and a calculated brightness of 1×108 A/(cm2 rad2) for a uranium cathode and a photocurrent of 60 A/cm2, a quantum efficiency of 8×10−6 and brightness of 1×107 A/(cm2 rad2) for a magnesium cathode. Space charge limited and emission limited photoelectrons were studied using high and low energy laser pulses, respectively. The uranium cathode was operated for over 50 h with no reduction of the photocurrent.

Electronic Resource

1600-0595

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract – Alendronate (ALN) is a third generation bisphosphonate with demonstrated osteoclast inhibitory activity that may slow down the resorptive process after severe traumatic injuries. Eighty-two premolar roots of five mongrel dogs were endodontically treated and restored, extracted and treated as follows: 70 roots were bench dried for either 40 or 60 min. Thirty-eight of these roots were then soaked for 5 min in a 1 mM solution of ALN in Hanks’ Balanced Salt Solution (HBSS) and replanted. Thirty-two roots were soaked for 5 min in HBSS and replanted. In the remaining 12 roots which were not exposed to the bench drying procedure, a 0.5 mM deep lingual mid-root cemental defect was made. Six of these roots were soaked in a 1 mM solution of ALN in HBSS for 5 min and replanted. The other six roots were soaked for 5 min in HBSS and replanted. Historical negative and positive controls were used from similarly treated teeth in our previous studies. After 4 months the dogs were killed and the roots prepared for histological evaluation. Five-μm-thick cross-sections of the root and surrounding tissue taken every 70 μm were evaluated for healing according to the criteria of Andreasen. In the 12 roots with cemental defects, healing with cementum of the damaged root surface was evaluated. In addition, residual root mass was also measured to determine the extent of root structure loss for each soaking method. Cemental healing took place in all 12 artificially damaged roots, indicating that these soaking media did not inhibit cementogenesis. The alendronate-soaked roots had statistically significantly more healing than the roots soaked in HBSS without alendronate. This improvement in healing was seen in all dogs except one and in all teeth except the first premolar. Soaking in alendronate also resulted in significantly less loss in root mass due to resorption compared to those teeth soaked in HBSS without alendronate.

Electronic Resource

1600-0595

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract – This study compared the ability of the TACT system of imaging and conventional D-speed film to detect simulated resorptive defects in cadaver teeth and jaws. Mandibular human jaw blocks were prepared and then split through the teeth in a mesial to distal direction so that the mandibular halves could be opened and reassembled when necessary. One half of each of 42 teeth was extracted, and areas on the tooth and corresponding bone identified to be studied. The jaws were opened and reassembled after no defects or after defects of different sizes (0.25, 0.5, 1.0, 2.0 mm) were placed in the tooth and the corresponding bone at predetermined evaluation areas. The teeth were imaged after each stage with conventional D-speed film using a standard paralleling technique, and with a modified orthopantomograph OP100 machine using a Schick #2 size CCD sensor as the image receptor. The source images were registered and TACT slices were generated using TACT Workbench Software. Three observers were asked to identify the presence of resorptive defects in the conventional film group and the TACT image group using specific criteria. TACT imaging was statistically superior to conventional radiographs in detecting defects that were present (Wilcoxon matched pairs signed ranks test P=0.003). This was true for all sizes of defects examined. There was no difference between the two modalities when a defect was not present.

Electronic Resource

1089-7666

AIP Digital Archive

Physics

Several types of edge plasma perturbations in the TUMAN-3 tokamak [Proceedings of the 13th International Atomic Energy Agency Conference on Plasma Physics and Controlled Nuclear Fusion Research, 1990 (International Atomic Energy Agency, Vienna, 1991), Vol. 1, p. 509] have been demonstrated to trigger the Ohmic H-mode transition. It is shown that three different methods, (1) radial electric field of either sign imposed by an electrode biased up to 500 V, (2) perturbation of the edge plasma density by strong gas puffing, and (3) LiD pellet injection, bring about the Ohmic H mode. In biasing experiments, the degree of improvement of particle and energy confinement depends on the polarity of the electric field and is higher for negative biasing. The evaporation of a LiD pellet (V∼150 m/sec, size ∼0.3 mm, density perturbation∼50%) in the peripheral region of the plasma column can also lead to the H-mode transition. Experimental results are shown to be in reasonable agreement with the theory of radial electric fields in tokamaks.

Electronic Resource

1600-0595

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract  – Minocycline is available as a locally administered tetracycline derivative antibiotic (Arestin™, OraPharma, Inc., Warminster, PA, USA) which demonstrated antibacterial activity and anti-inflammatory action that may slow down resorptive processes after severe traumatic injuries to the dentition. A total of 48 premolar roots of six mongrel dogs were instrumented in an aseptic fashion with rotary nickel-titanium files and obturated with vertically condensed warm gutta percha. All accesses were sealed with glass ionomer, the roots extracted and then allowed to bench dry for 60 min. Group 1 consisted of 15 roots that were coated with minocycline and replanted and nine roots that were replanted without minocycline. Group 2 consisted of 24 roots, all of which were prepared with a uniform cemental defect down to sound dentin along the lateral aspect of the root, with a high-speed bur following the 60-min dry time. Half of the roots (12) were then coated with minocycline and replanted, and the other 12 roots were replanted without minocycline. After 4 months, the dogs were killed and the roots prepared for histological evaluation. About 5-µm thick cross-sections of the root and surrounding tissue taken every 90 µm were evaluated for healing. In addition, residual root mass was also measured in the roots of group 1 to determine the extent of root structure loss for each treatment method. The roots with and without minocycline treatment showed no significant differences between the remaining root mass or the percentage of favorably healed root surfaces. The use of minocycline is not currently recommended for prevention or attenuation of external root resorption following avulsion in a dog trauma model.

Electronic Resource

1600-0595

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract   –  Ledermix Paste® is a paste containing triamcinolone and demeclocycline with demonstrated anti-inflammatory activity that may slow down resorptive processes after severe traumatic injuries to the dentition. A total of 29 premolar roots of six mongrel dogs were extracted and instrumented with rotary nickel titanium files. Fifteen of these roots were then filled with a calcium hydroxide (Ca(OH)2) slurry and 14 roots were filled with Ledermix Paste® paste. All accesses were sealed with glass ionomer and the roots replanted after an extraoral dry time of 60 min. After 4 months, the dogs were killed and the roots prepared for histological evaluation. Five-micrometer thick cross-sections of the root and surrounding tissue taken every 90 µm were evaluated for healing. In addition, residual root mass was also measured to determine the extent of root structure loss for each treatment method. The Ledermix Paste®-treated roots had statistically significantly more healing and less resorption than the roots treated with Ca(OH)2. Root filling with Ledermix Paste® also resulted in significantly less loss in root mass due to resorption compared to those roots filled with Ca(OH)2. Immediate intracanal placement of Ledermix Paste® at the emergency visit after an avulsion injury appears to decrease resorption and increase favorable healing.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Two groups each of approximately 100 Moenkhausia dichroua, a schooling characid, showed a long–lasting, constant–oriented swimming when placed in a light–centred circular channel. This apparatus consists of a 1–m diameter circular channel illuminated by either a central or a peripheral light system, so that the light angle is constant all around the channel. With the central light at a fixed angle, fish swam for several months in one direction and reversed direction at a certain date. When the light angle was increased by 10° every other day between 0° (horizontal) and 90° (vertical), swimming direction was reversed at a particular angle in each experiment. This response to artificial light suggests that this small schooling fish uses the sun as an orientation clue in its seasonal migrations.

Electronic Resource

1600-0668

Blackwell Publishing Journal Backfiles 1879-2005

Architecture, Civil Engineering, Surveying

Medicine

Electronic Resource

1600-0714

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Several types of human papilloma viruses (HPV) have been associated with benign and malignant squamous cell tumours of mucosal epithelium. To identify HPV in erosive oral lichen planus (OLPe), considered as a premalignant lesion, tissues from 20 patients were examined by Southern blot hybridization with 32P-labeled HPV DNA probes. Type 11 was found in 6 of the lesions while HPV types 6, 16 and 18 were not detected in any of the tissues examined. Using a type-specific polymerase chain reaction (PCR) assay for HPV-6, 11, 16 and 18, HPV-11 was detected in 8 of the samples (all of those positive by Southern blot), and, in addition, HPV-6 was found in 5 samples and HPV-16 in 3 samples. Overall, by the more sensitive PCR assay, 65% of samples were positive for HPV DNA. The finding of HPV DNA in many of the samples using two different techniques indicates a high prevalence of HPV in the OLPe afflicted oral mucosa. However, the role of HPV in the pathogenesis of OLPe has yet to be determined.

Electronic Resource

0026-7937

Linguistics and Literary Studies

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