The half-life of the first metastable state in 90Nb

1969 ◽  
Vol 47 (8) ◽  
pp. 949-951 ◽  
Author(s):  
J. S. Geiger ◽  
R. L. Graham ◽  
M. W. Johns
Keyword(s):  
Metastable State ◽  
Half Life ◽  
Published Data ◽  
Proton Bombardment ◽  
Tentative Assignment

A delayed γ activity, Eγ = 122.2 ± 0.2 keV, t1/2 = 18.82 ± 0.09 s, is observed following 10 MeV proton bombardment of targets of natural Zr and of natural Hf in which Zr is present as a contaminant. The present results taken together with other recently published data show that this activity arises from 90Zr(p,n)90Nbm. The tentative assignment of this 122 keV γ activity to 179Ta, which we proposed in an earlier publication, is withdrawn.

scholarly journals A psychrometric model to assess the biological decay of the SARS-CoV-2 virus in aerosols

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11024
Author(s):  
Clive B. Beggs ◽  
Eldad J. Avital
Keyword(s):  
Air Temperature ◽  
Vapour Pressure ◽  
Half Life ◽  
Analytical Study ◽  
Decay Constant ◽  
Meteorological Data ◽  
Environmental Parameters ◽  
Published Data ◽  
Reasonable Accuracy ◽  
The Impact

There is increasing evidence that the 2020 COVID-19 pandemic has been influenced by variations in air temperature and humidity. However, the impact that these environmental parameters have on survival of the SARS-CoV-2 virus has not been fully characterised. Therefore, an analytical study was undertaken using published data to develop a psychrometric model to assess the biological decay rate of the virus in aerosols. This revealed that it is possible to describe with reasonable accuracy (R2 = 0.718, p < 0.001) the biological decay constant for the SARS-CoV-2 virus using a regression model with enthalpy, vapour pressure and specific volume as predictors. Applying this to historical meteorological data from London, Paris and Milan over the pandemic period, produced results which indicate that the average half-life of the virus in aerosols outdoors was in the region 13–22 times longer in March 2020, when the outbreak was accelerating, than it was in August 2020 when epidemic in Europe was at its nadir. However, indoors, this variation is likely to be much less. As such, this suggests that changes in virus survivability due the variations in the psychrometric qualities of the air might influence the transmission of SARS-CoV-2.

DISCOVERY OF Pr137

1958 ◽  
Vol 36 (11) ◽  
pp. 1483-1486 ◽  
Author(s):  
Carl Dahlstrom ◽  
J. S. Foster ◽  
A. L. Thompson
Keyword(s):  
Gamma Rays ◽  
Half Life ◽  
Chemical Separation ◽  
Mass Determination ◽  
Proton Bombardment ◽  
End Point ◽  
Neutron Deficient Isotope ◽  
Positron Spectrum

The neutron-deficient isotope Pr137 has been discovered by proton bombardment of natural cerium, chemical separation, and mass determination. Its half-life is 1.5 ± 0.1 hours and the end point of its positron spectrum is 1.7 ± 0.1 Mev. No gamma rays were observed.

Increased Clearance Explains the Ultra-Large Multimers in Von Willebrand Disease Type 2M Vicenza; Lessons from Recombinant VWF Vicenza and Modeling of Multimer Catabolism.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3669-3669 ◽  
Author(s):  
András Gézsi ◽  
Gábor Balázsi ◽  
Krisztina Sallai ◽  
Adrienn Mohl ◽  
Eszter Nagy ◽  
...  
Keyword(s):  
Half Life ◽  
Time Course ◽  
Plasma Concentrations ◽  
Von Willebrand Disease ◽  
Published Data ◽  
Primary Defect ◽  
Fixed Rate ◽  
Normal Platelet ◽  
Von Willebrand ◽  
Plasma Half Life

Abstract The pathogenesis of VWD Vicenza has remained elusive. VWD Vicenza is characterized by low plasma but normal platelet VWF concentration, the presence of ultra-large plasma multimers, and a heterozygous R1205H mutation. VWF Vicenza is reported to have a decreased half-life in the circulation. When we expressed rVWF Vicenza R1205H in 293T cells, it was secreted with wild type efficiency and multimer distribution, suggesting that the primary defect is accelerated clearance. To evaluate this hypothesis, we developed a pharmacokinetic model of VWF multimer catabolism. The initial assumptions are: 1. Secretion occurs at a fixed rate with the initial “ultra-large” multimer distribution seen in platelet alpha granules. 2. Cleavage of multimers occurs with a probability p that increases with increasing multimer size. 3. Clearance occurs with a time constant determined by the plasma half life and is independent of multimer size. Modeled multimer distributions were compared to those determined experimentally for patient plasma samples. The effects of DDAVP infusion also were modeled and compared to published data (Casonato et al, Blood2002; 99:180). For p = 7.5 x 10−4 min−1 and a half life of 12 h, the modeled multimer patterns were comparable to the observed steady-state distribution of normal VWF. Decreasing the half life to 2 hours produces a low plasma concentration of “ultra-large” multimers typical of VWD Vicenza without a change in any other parameter. Conversely, increasing the probability of cleavage by only thirty percent produces typical VWD 2A multimer distributions. The model also reproduces the triplet patterns of normal and type 2A VWF. Finally, the DDAVP simulations reproduced the time course of VWF plasma concentrations and multimer distributions of DDAVP-treated patients. We conclude that increased clearance alone can explain the ultra-large multimer distribution of VWD Vicenza. Similar modeling should allow the estimation of VWF cleavage and clearance rates in other variants of VWD and in other clinical situations including thrombotic thrombocytopenic purpura. Figure Figure Figure Figure

Differences in the distribution of methotrexate into high grade gliomas following intravenous administration, as monitored by microdialysis, are associated with blood brain barrier integrity

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 1548-1548 ◽  
Author(s):  
J. J. Olson ◽  
J. O. Blakeley ◽  
S. A. Grossman ◽  
J. Weingart ◽  
A. Rashid ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Blood Brain Barrier ◽  
Half Life ◽  
Extracellular Fluid ◽  
Brain Barrier ◽  
Published Data ◽  
High Grade ◽  
Blood Brain ◽  
Drug Concentrations ◽  
High Grade Gliomas

1548 Background: Microdialysis (MD) is an accepted technique to monitor neurochemicals in pts with traumatic brain injury. This study was conducted to evaluate the use of MD to define the time course of intratumoral drug concentrations in pts with high grade gliomas (HGG) receiving systemic chemotherapy. Methods: MD catheters were placed in residual HGG following tumor debulking and infused with Ringer’s solution at 1 μL/min. MD probe location and integrity of the blood brain barrier (BBB) in adjacent tissue were determined by fused MRI/CT. Highdose (12g/m2) methotrexate (MTX), was given as a 4 h iv infusion the next day. MTX was measured in plasma and dialysate samples, collected at 30 min intervals from 1 h before to 24 h after dosing, with an LC/MS assay. Results: Six pts have been enrolled without any adverse events attributed to the MD catheter. Adequate pharmacokinetics (PK) were obtained in 4/6pts. MTX plasma pharmacokinetics (PK) were very consistent between the 4 evaluable pts and similar to published data. Time courses of the uncorrected MTX concentration in extracellular fluid (CECF) exhibited two distinctly different kinetic profiles. For 2pts in whom the MD probe resided within contrast enhancing tumor, CECF increased and decreased in parallel with drug levels in plasma, with a peak CECF of 189 ± 6 μM, an apparent elimination half-life in ECF of 4.44 ± 0.07 h, and an ECF/plasma AUCratio of 0.13 ± 0.01. The other 2pts had a much lower peak CECF (10.4 ± 0.4 μM) and AUC ratio (0.028 ± 0.020), with a more prolonged ECF half-life (11.4 ± 4.5 h). Fused images from 2 of these pts showed that the MD probe was located in nonenhancing tissue. Conclusions: MD is a clinically practical technique to monitor the distribution of systemically administered drugs to brain tumors in pts. It has the capability to elucidate variations in kinetic behavior that are consistent with regional differences in BBB integrity. Appropriate interpretation of data from MD studies to evaluate the distribution of investigational new drugs into brain tumors necessarily requires radiographic determination of the region of the tumor into which the probe has been placed. No significant financial relationships to disclose.

scholarly journals Intramuscular injection of testosterone undecanoate for the treatment of male hypogonadism: phase I studies

1999 ◽  
pp. 414-419 ◽  
Author(s):  
HM Behre ◽  
K Abshagen ◽  
M Oettel ◽  
D Hubler ◽  
E Nieschlag
Keyword(s):  
Half Life ◽  
Castor Oil ◽  
Seed Oil ◽  
Serum Levels ◽  
Published Data ◽  
Male Hypogonadism ◽  
Substitution Therapy ◽  
Testosterone Undecanoate ◽  
Tea Seed Oil ◽  
Long Acting

OBJECTIVE: In the search for long-acting testosterone preparations suited for substitution therapy of hypogonadal men, testosterone undecanoate (TU) dissolved in either tea seed oil or castor oil was investigated. DESIGN: In study I, 1000 mg TU in tea seed oil (125 mg/ml) were injected in equal parts into the gluteal muscles of seven hypogonadal men. In study II, 1000 mg TU in castor oil (250 mg/ml) were injected into one gluteal muscle of 14 patients. RESULTS: In comparison with published data on testosterone enanthate, most widely used for i.m. injections, the kinetic profiles of both TU preparations showed extended half-lives and serum levels not exceeding the upper limit of normal. The castor oil preparation had a longer half-life than TU in tea seed oil (33.9+/-4.9 vs 20.9+/-6.0 days (mean pm S.E.M.)). CONCLUSION: The longer half-life and the smaller injection volume make TU in castor oil a strong candidate for further applications in substitution therapy and in trials for male contraception.

scholarly journals DELAYED PROTONS FOLLOWING THE DECAY OF ARGON-33

1965 ◽  
Vol 43 (3) ◽  
pp. 418-421 ◽  
Author(s):  
J. C. Hardy ◽  
R. I. Verrall
Keyword(s):  
Lithium Chloride ◽  
Half Life ◽  
Proton Spectrum ◽  
Proton Bombardment

The delayed-proton precursor 33Ar has been produced by proton bombardment of a lithium chloride target in the internal beam of the McGill synchrocyclotron. The half-life of 33Ar was measured to be (178 ± 10) msec. To explain the delayed proton spectrum, two new levels, at 5.55 and 7.55 MeV, in 33Cl are proposed. It is also proposed that the former is the expected first T = 3/2 state in that nucleus.

LOW MOLECULAR WEIGHT INTRACELLULAR IODOCOMPOUNDS WITH LONG INTRATHYROIDAL HALF-LIFE: REMNANTS OF THYROGLOBULIN HYDROLYSIS?

1979 ◽  
Vol 92 (1) ◽  
pp. 105-118 ◽  
Author(s):  
A. Haeberli ◽  
H. Engler ◽  
C. von Grünigen ◽  
H. Kohler ◽  
H. Studer
Keyword(s):  
Molecular Weight ◽  
Half Life ◽  
Intracellular Localization ◽  
Iodine Intake ◽  
Published Data ◽  
Low Molecular Weight ◽  
Total Iodine ◽  
Hydrolysis Of

ABSTRACT in this paper additional information on low molecular weight, soluble, intrathyroidal iodocompounds with slow metabolic rate is provided. These compounds have previously been localized autoradiographically within the follicular cells. Radioiodide was administered to rats on a normal iodine intake (6–7 μg/day) for 80 days to approach isotopic equilibration of the intrathyroidal iodine with the dietary radioiodide. When the isotope was omitted from the diet the intrathyroidal radioiodine was released with an apparent half-life of approximately 12 days. When the individual soluble components carrying radioiodine were analyzed after separation on Sephadex G-200, different apparent half-lives were found, the half-life of thyroglobulin (Tgb) being roughly 10 days and that of the low molecular weight iodocomounds being in the order of 60 to 100 days or more. In addition to the soluble low molecular weight iodocompounds, the radioactivity in the particulate fraction increased by 100 % during the tracer washout when compared to Tgb and the total soluble fraction. The soluble slow turnover iodocompounds contained a higher percentage of carbohydrate and total iodine than Tgb, while the relative amounts of each sugar analyzed (hexoses, fucose, hexosamine and sialic acid) were close to those in Tgb. Sephadex G-25 chromatography of the low molecular weight iodocompounds obtained after Sephadex G-200 separation resulted in the separation of 4 peaks. Two peaks identified as iodopeptides could be further analyzed. The carbohydrate composition of these peptides was similar to that of 2 glycopeptides obtained after in vitro enzymatic hydrolysis of purified Tgb with pronase. Slow equilibration with radioiodine, long apparent intrathyroidal half-life and carbohydrate content similar to that of Tgb, taken together with previously published data on intracellular localization of soluble intrathyroidal iodocompounds, suggest that the low molecular weight iodocompounds are products of in vivo hydrolysis of engulfed Tgb droplets.

A Metastable State of Half-Life about10−6Second inRe187

1947 ◽  
Vol 71 (6) ◽  
pp. 380-381 ◽  
Author(s):  
S. de Benedetti ◽  
F. K. McGowan
Keyword(s):  
Metastable State ◽  
Half Life

scholarly journals A Novel Method for Calculating Mean Erythrocyte Age Using Erythrocyte Creatine

2019 ◽  
Author(s):  
Masashi Kameyama ◽  
Masafumi Koga ◽  
Toshika Okumiya
Keyword(s):  
Hemolytic Anemia ◽  
Half Life ◽  
Published Data ◽  
Exponential Relationship ◽  
Practical Applications ◽  
Novel Method ◽  
Erythrocyte Age

AbstractBackgroundsErythrocyte creatine (EC) decreases reflecting erythrocyte age.MethodsWe developed an EC model, which showed a bi- or mono-exponential relationship between mean erythrocyte age (MRBC) andEC. We reanalyzed the previously published data of 21 patients with hemolytic anemia which includedECand51Cr half-life.ResultsMRBCand logeECshowed excellent significant linearity (r= −0.9475,p <0.001), showing that it can be treated as a mono-exponential relationship within the studied range (EC: 1.45 – 11.76µmol/g Hb). We established an equation to obtainMRBC(days) fromEC(µmol/g Hb),MRBC= −22.84 logeEC+ 65.83.ConclusionThis equation allows calculation ofMRBCbased on EC which has practical applications such as the diagnosis of anemia.

A phase I and pharmacokinetic study of continuous infusion EMD 121974 (EMD), an antiangiogenic αvβ3 and αvβ5 integrin antagonist, in patients with advanced solid malignancy

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 3052-3052 ◽  
Author(s):  
S. D. Undevia ◽  
L. Janisch ◽  
W. M. Stadler ◽  
S. M. Wittemer ◽  
M. J. Ratain
Keyword(s):  
Phase I ◽  
Continuous Infusion ◽  
Dose Level ◽  
Half Life ◽  
Karnofsky Performance Status ◽  
Performance Status ◽  
Pharmacokinetic Analysis ◽  
Published Data ◽  
Pharmacokinetic Studies ◽  
Dose Levels

3052 Background: Integrins αvβ3 and αvβ5 are cell-surface receptors that play a significant role in angiogenesis by mediating the ligation signal that allows endothelial cells to attach to the extracellular matrix. These integrins share the binding epitope Arg-Gly-Asp (RGD). EMD is an RGD-containing cyclic pentapeptide. In clinical studies to date, EMD has been administered in an intermittent fashion. However, EMD has a short half-life of 3–5 hours with no evidence of drug accumulation. These data prompted the initiation of this phase I study of continuous infusion EMD. Methods: EMD was administered as a continuous infusion without break in 4-week cycles. Plasma samples for pharmacokinetic studies were obtained weekly in cycle 1 immediately prior to and 2 hours after infusion bag change. Results: To date 21 patients (15 male/6 female, median age 56, median Karnofsky performance status 90%) have been treated at the following dose levels: 1, 2, 4, 8, 12, 18, and 27 mg/h. Hematologic toxicities have been limited to grade 2 anemia and grade 3 lymphopenia. Non-hematologic toxicities have been limited to grade ≤ 2 and include alopecia, anorexia, diarrhea, fatigue, hypokalemia, hyponatremia, hypophosphatemia, insomnia, mucositis, nail changes, nausea, and transaminase elevation. One patient treated at 27 m/h experienced an unobserved death of unknown cause after two weeks of therapy. Pharmacokinetic analysis has been completed for patients treated at the 12 mg/h dose level and below. Mean values for half-life, clearance, and volume of distribution were comparable across dose levels, and steady-state concentration increased proportionally to dose. Conclusions: EMD can be safely administered as a continuous infusion at doses of up to at least 18 mg/h. No single toxicity has been consistently observed. A patient death in cycle 1 has resulted in the expansion of the 27 mg/h dose level. The pharmacokinetics of continuous infusion EMD were predictable and in general agreement with the published data of twice weekly infusion. Study enrollment is ongoing. [Table: see text]

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