Abstract Recent years have witnessed more attention paid to the health effects of the natural radionuclide 226Ra, and a series of research carried out on the detection methods of 226Ra at home and abroad. The common 226Ra detection methods are emanation scintillation, gamma spectrometry, liquid scintillation counting, alpha spectrometry and alpha counting. Emanation scintillation is mature enough as a classical method, while gamma spectrometry and liquid scintillation counting proceed fast. Due to the radiation of 226Ra, these detection methods still have the problems such as the requirement for large samples, long detection periods, complicated steps, high detection limits and low recovery rates. This paper reviews the five methods above and summarize their advantages and disadvantages, so as to provide the reference for selecting and optimizing the detection methods for different samples as well as perfecting the standard method in China.

OBJECTIVETo observe depot medroxyprogesterone acetate (DMPA) and testosterone undecanoate (TU) injected at 8-week intervals for the suppression of spermatogenesis in healthy Chinese men.

METHODSAfter screening, 30 healthy volunteers were enrolled and randomly assigned to 3 dosage-groups (n = 10/group): 1000 mg TU (Group A), 1000 mg TU plus 150 mg DMPA (Group B), 1000 mg TU plus 300 mg DMPA (Group C). All dosages were given as intramuscular injections at 8-week intervals. The study consisted of an 8-week control (baseline) period, a 24-week treatment period and a 24-week recovery period.

RESULTSConsistent azoospermia or severe oligozoospermia was achieved and maintained in all the volunteers during the treatment period, except 2 in the mere TU group who experienced a "rebound" in sperm concentrations. An 8-week regimen of TU plus DMPA at both tested combination dosages effectively suppressed spermatogenesis to azoospermia. All volunteers tolerated the injections; no serious adverse effects were reported.

CONCLUSIONThe lower combined dosage is recommended for further testing in an expanded clinical trial or contraceptive efficacy study.

Adult ; Androgens ; pharmacology ; China ; Gonadotropin-Releasing Hormone ; biosynthesis ; Humans ; Hypothalamo-Hypophyseal System ; metabolism ; Male ; Medroxyprogesterone Acetate ; pharmacology ; Prospective Studies ; Sperm Count ; Spermatogenesis ; drug effects ; Testosterone ; analogs & derivatives ; pharmacology

Excellent lead compounds have a profound influence on drug development and can improve the success rate of product launch. It is expensive and time-consuming to discover lead compounds by traditional methods, yet artificial intelligence (AI) can discover good lead compounds efficiently.This article systematically summarizes the research progress of obtaining lead compounds through the screening and generation models of AI, classifies different models according to the type of information input, focuses on drug repurposing by screening model and multi-objective drug design by generation model, and discusses the development prospect of AI in the research field of lead compounds, aiming to provide new research ideas for the application of AI in lead compounds.