Search Results - (Author, Cooperation:M. Greenfield)

2011-08-26

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Aedes/*microbiology/physiology/*virology ; Animals ; Dengue/microbiology/*prevention & control/*transmission/virology ; Dengue Virus/isolation & purification/*physiology ; Drosophila melanogaster/microbiology ; Female ; Humans ; Insect Vectors/microbiology/physiology/virology ; Male ; Pest Control, Biological/*methods ; Queensland ; Time Factors ; Wolbachia/isolation & purification/*physiology

1089-7550

AIP Digital Archive

Physics

Precise and reproducible correlations between environmental γ-ray count rates (GRR) with rain precipitation rates (RPR) and snow precipitation rates (SPR) have been measured to be 0.18±0.02 and 4.3±0.04 (counts/s)/(mm/h), respectively. The GRR, observed with two 12.3 cm3 NaI detectors, also exhibit a diurnal cycle (period of 1.01±0.03 day, maximum around sunrise and location dependent amplitude) and a seasonal cycle (smaller amplitude and maximum in mid-February). Increased GRR during precipitation have been observed at ground level, but the effects of the diurnal cycle and other noise are reduced by more than 20 at 15 m above ground. An improved signal-to-noise ratio, response time of less than one hour and precise correlations between the peaks in GRR and precipitation rates enable real-time determinations of RPR and SPR to better than 1 mm/h. The relative insensitivity of these correlations to other meteorological conditions enables GRR to serve as remote and environmentally stable sensors of RPR and SPR. The time-dependence of GRR is consistent with that expected from variations in the presence of radon and radon progeny in the atmosphere. Change in the amplitude of the diurnal cycle may serve as a monitor of radon concentration. A γ-ray detector integrates over a large volume with good time resolution and thus may be responsive to real-time changes in radon concentrations due to increased exhalation from tectonic activity. © 2002 American Institute of Physics.

Electronic Resource

0375-9474

Nuclear reaction

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

0375-9474

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

0301-0104

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Physics

Electronic Resource

1572-8889

Acrididae ; Ligurotettix coquilletti ; sound production ; broadcast area ; resource defence

Springer Online Journal Archives 1860-2000

Biology

Abstract Males of the desert clicker, Ligurotettix coquilletti (Acrididae: Orthoptera) defend a femalerequired resource, the creosote bush Larrea tridentata, in desert habitats of the southwestern United States. Males signal acoustically to each other as well as to searching females. The call is produced by tegminal/femoral stridulation where one or both legs are used for sound production. Sound pressure levels, measured laterally, are influenced by the intervening tegmen between the stridulating leg and the microphone. Differences in measured sound pressure levels between sides can vary up to 7 dB. When clicks are produced multiply,these multiple clicks may be 4 dB louder than single clicks. We examine the structure of the call and the effective broadcast area of single males by monitoring acoustic ascending neurons of the ventral nerve cord in the neck. By taking the neurophysiological preparation into the field, we were able to map the broadcast area of isolated males and also of males calling within aggregations. The distance over which the signal of isolated males could be detected was 8–14 m, whereas neural representation of the calls of males within aggregation were detectable within 4–6 m. The sound spectrum of the song, although having a major lower-frequency component around 10 kHz, has extensive power in the ultrasonic range. The tuning characteristics of the ascending auditory neuron matched the overall structure of the male call. The importance of the acoustic cue, as compared to visual cues, is discussed in relation to female attraction.

Electronic Resource

1420-9071

Grasshoppers ; herbivory ; homing behavior ; host plant chemistry ; landmark navigation ; Ligurotettix ; memory ; territoriality

Springer Online Journal Archives 1860-2000

Biology

Medicine

Summary Males ofLigurotettix spp. grasshoppers (Orthoptera, Acrididae, Gomphocerinae), territorial species that defend individual host plant shrubs, home to their territories by memorizing landmarks. Thus, the insects can navigate efficiently toward high quality shrubs which are chemically distinctive and recognizable via gustation, but indistinguishable from a distance.

Electronic Resource

1432-1904

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Natural Sciences in General

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Spectrum (a) shows the continuum emitted by collodion extending, left to right, from about 230 m.|x to about 470 ni(ji. The wave-length limits are set by the sensitivity of the photographic plate and not by the spectral energy distribution of the emitted light. Superimposed on the continuum are a ...

Electronic Resource

1432-0428

Hypertriglyceridaemia ; fasting hyperglycaemia ; insulin ; diabetic hypertriglyceridaemia ; glucose ; insulin-independent diabetes ; very low density lipoprotein secretion rate ; triglycerides ; insulindependent diabetes ; non-esterified fatty acids

Springer Online Journal Archives 1860-2000

Medicine

Summary Several aspects of lipid metabolism were studied to define the mechanism of hypertriglyceridaemia in insulin-independent diabetic patients with fasting hyperglycaemia. Patients with insulin-independent diabetes were more obese (p〈0.001) and had a significantly (p〈0.001) higher mean (± SEM) fasting plasma triglyceride concentration (387 ±66 mg/dl) than did either insulin-dependent diabetics (133±11 mg/dl) or normal (73±1 mg/dl) subjects. Very low density lipoprotein secretion rate was also significantly (p〈0.01 — 〈0.001) higher in patients with insulin-independent diabetes (14.65±1.37 mg/kg/h) as compared to 7.64±0.60 mg · kg/h and 9.86±0.75 mg/kg/h in normal subjects and patients with insulin-dependent diabetes, respectively. However, the relationship between plasma triglyceride concentration and very low density lipoprotein-triglyceride secretion was similar in diabetics and in normals. The diabetic groups had equivalent degrees of fasting and postprandial hyperglycaemia, and comparable elevations of fasting plasma nonesterified free fatty acid levels (insulin-independent = 0.72±0.07 mmol/L, insulin-dependent = 0.63±0.08 mmol/L). Postprandial plasma insulin concentrations, however, reached normal levels in insulin-independent diabetics and were higher (p〈0.001) than in insulin-dependent diabetics. Thus, hypertriglyceridaemia in insulin-independent diabetics with fasting hyperglycaemia was associated with increased hepatic very low density lipoprotein-triglyceride secretion, and normal plasma insulin levels. The lower triglyceride levels in the insulin-dependent diabetics is assumed to be due to their relative hypoinsulinaemia.

Electronic Resource

1432-1904

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Natural Sciences in General

Electronic Resource

1439-0973

Springer Online Journal Archives 1860-2000

Medicine

Zusammenfassung Zur Quantifizierung der Bakteriämie bei Laboratoriumstieren wurde eine Schnellmethode entwickelt. Durch Direktfärbung von Blutausstrichen mit Acridinorange und Bakterienzählung unter dem Fluoreszenzmikroskop ist es möglich,Haemophilus influenzae im Blut bei einer Bakteriendichte von 105–108 KBE/ml quantitativ zu bestimmen. Diese Technik erleichtert die Präzision bei Therapiestudien mit Infektionsmodellen bei Laboratoriumstieren.

Summary A rapid technique has been developed to quantitate the degree of bacteremia in laboratory animals. Direct staining of blood smears with acridine orange and enumeration using fluorescent microscopy allowed quantitation ofHaemophilus influenzae in blood at densities from 105 to 108 cfu/ml. This technique will facilitate the accuracy with which therapeutic trials are conducted in laboratory models of infection.

Electronic Resource

1439-0973

Springer Online Journal Archives 1860-2000

Medicine

Zusammenfassung Die Leptomeningitis durchHaemophilus influenzae Typ b kann bei jungen Ratten (bis zum Alter von drei Wochen) durch intranasale Inokulation und bei bis zu drei Monate alten Tieren durch intraperitoneale Inokulation hervorgerufen werden. Die Krankheit scheint bei Tierjungen eine mit der Säuglingsmeningitis vergleichbare Pathogenese zu haben. Aus immunologischen Studien ist anzunehmen, daß die gegen die Kapsel von Tyb b gerichteten (aktiv oder passiv erworbenen) Antikörper vor Bakteriämie und der nachfolgenden Meningitis schützen (unabhängig vom Inokulationsmodus). Jedoch schützen auch Antikörper gegen andere Oberflächenstrukturen vonH. influenzae b (allein oder zusammen mit Anti-Kapsel-Antikörpern) vor anhaltender Bakteriämie nach jeglicher Form der Inokulation. Infolge einer altersabhängigen Zunahme der Antibiotika-Clearance ergibt die Prüfung der Aktivität von antibiotika gegen diese Infektion bei Ratten keine zuverlässigen Werte. Es wird vorgeschlagen, bei Ratten eine Methode anzuwenden, mit der die Pharmakokinetik beim Menschen nachgeahmt wird. Das Rattenmodell eignet sich zum Studium derH. influenzae-Meningitis unter der Voraussetzung, daß bestimmte Einschränkungen berücksichtigt werden.

Summary Leptomeningitis due to type bHaemophilus influenzae can be produced in infant rats (up to three weeks of age) by intranasal inoculation, and in animals up to three months of age by intraperitoneal inoculation. In infant animals, the pathogenesis appears to mimic the disease in human infants. Immunologic experiments indicate that antibody directed against the type b capsule (actively or passively acquired) will protect against bacteremia (by any route of inoculation) and the subsequent development of meningitis. However, antibody directed against other surface structures ofH. influenzae b (alone or with anticapsular antibody) will protect against sustained bacteremia after any route of inoculation. Evaluation of antibiotic activity against this infection in rats is unreliable due to a marked age-dependent increase in antibiotic clearance. A means of mimicking human pharmacokinetics in rats is proposed. The rat model is useful for the study ofH. influenzae meningitis provided certain limitations are recognized.

Electronic Resource

1572-9567

entrainer ; FTIR ; hydrogen bonding ; supercritical

Springer Online Journal Archives 1860-2000

Physics

Abstract In chemical separation processes such as supercritical extraction the use of an entrainer cosolvent can dramatically improve selectivity and yield. Ideally, in an extraction process, an entrainer cosolvent should complex with only the desired solute, pulling it from the feed. But not all cosolvents are entrainers, and a cosolvent that is effective in one application may not be effective in others. Often, competing hydrogen bonding interactions limit the effectiveness of an entrainer cosolvent. In this paper FTIR spectroscopy is used to study hydrogen bonding competition in solute/solvent/entrainer cosolvent mixtures. The extent of hydrogen bonding is determined from analysis of hydrogen-bonded and non-hydrogen-bonded infrared absorption peaks. Since these peaks overlap, curvefitting and Fourier self-deconvolution techniques are used to resolve them. Concentrations of monomeric and hydrogen-bonded species are modeled using the associated perturbed anisotropic chain theory (APACT). Using APACT it is shown that the equilibrium constant, derived from activities, can be written as the product of a temperature-dependent term and the ratio of concentrations: K=(RT) vIIC i vi . This gives a statistical mechanical basis for the empirical observation that for hydrogen-bonding equilibria, the ratio of concentrations is approximately equal to the ratio of activities.

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