ABSTRACT
Development of high-performance cutting tool materials is one of the critical parameters enhancing the surface finishing of high-speed machined products. Ti(C,N)-based cermets reinforced with and without different contents of silicon nitride were designed and evaluated to satisfy the requirements. In fact, the effect of silicon nitride addition to Ti(C,N)-based cermet remains unclear. The purpose of this study is to investigate the influence of Si3N4 additive on microstructure, mechanical properties, and thermal stability of Ti(C,N)-based cermet cutting tools. In the present work, α-Si3N4 "grade SN-E10" was utilized with various fractions up to 6 wt.% in the designed cermets. A two-step reactive sintering process under vacuum was carried out for the green compact of Ti(C,N)-based cermet samples. The samples with 4 wt.% Si3N4 have an apparent solid density of about 6.75 g/cm3 (relative density of about 98 %); however, the cermet samples with 2 wt.% Si3N4 exhibit a superior fracture toughness of 10.82 MPa.m1/2 and a traverse rupture strength of 1425.8 MPa. With an increase in the contents of Si3N4, the Vickers hardness and fracture toughness of Ti(C,N)-based cermets have an inverse behavior trend. The influence of Si3N4 addition on thermal stability is clarified to better understand the relationship between thermal stability and mechanical properties of Ti(C,N)-based cermets.
ABSTRACT
The present study reports a patient case with a 17α-hydroxylase deficiency accompanied by triple X syndrome. A 17α-hydroxylase deficiency leads to a very low 17α-hydroxylated steroid synthesis as well as a non-feedback increase in the adrenocorticotropic hormone level. Meanwhile, the progesterone level increases the 17α-hydroxyprogesterone level and decreases the dehydroepiandrosterone sulfate level. The patient is characterized by intractable hypokalemia, high urinary potassium, hyperaldosteronemia, hyporeninemia, hypocortisolemia, hypertension, gonadal and secondary sexual dysplasia, a decreased estrogen level, primary amenorrhea, and infertility. The imaging findings indicate a presence of multiple bilateral adrenal gland adenomas, and the sequencing indicates a missense CYP17A1-E7 gene pathogenic variant. The karyotype is a 47, XXX [3]/46, XX [47] low-level chimeric karyotype. The patient's parents are cousins. To our knowledge, this patient is the first case diagnosed with congenital adrenal hyperplasia caused by hydroxylase deficiency and triple X syndrome. The uniqueness of this case is that this patient has two very rare genetic diseases, probably due to the marriage of close relatives.
ABSTRACT
OBJECTIVE: This study aimed to investigate the association of the glycated albumin (GA)/glycosylated hemoglobin (HbA1c) ratio with the mean amplitude of glycemic excursion (MAGE) in type 2 diabetes mellitus (T2DM). METHODS: A total of 102 patients with T2DM who were first treated in Jinjiang Hospital of Fujian Province were enrolled in this study. The patients' general clinical data, including HbA1c, GA, fasting blood glucose, and fasting and peak C-peptide values upon diagnosis and after one year of follow-up, were collected, and their MAGE was calculated. RESULTS: With the increase of the GA/HbA1c ratio at baseline, the patients' fasting and peak C-peptide values decreased gradually from baseline to follow-up, while their MAGE, HbA1c, and fasting blood glucose increased gradually. A regression analysis demonstrated that the baseline MAGE was independently positively correlated with the GA/HbA1c ratio. A Cox regression analysis demonstrated that a baseline GA/HbA1c ratio of >2.78 was an independent risk factor for poor fasting blood glucose and HbA1c. CONCLUSION: The GA/HbA1c ratio is closely related to the MAGE and islet function in patients with T2DM.
