Investigation on the Surface Integrity of 40Cr Steel Machined by Rotary Ultrasonic Flank Milling.

Rotary Ultrasonic Machining (RUM) stands as a crucial method for machining hard and brittle materials. However, for machining hard-to-machine metal, it continues to face many challenges due to the complex vibration of the milling tool. Flank milling is an efficient method for machining complex parts, such as blisks and impellers, which have been widely used in aerospace field. However, current research is more focused on rotary ultrasonic end milling. In this context, we will study the surface integrity of rotary ultrasonic flank milling 40Cr steel using a self-developed RUM system. We delve into exploring the impacts of tool vibration on surface morphology, residual stress, and micro-hardness of the workpiece under various process parameters. The experimental findings reveal that rotary ultrasonic flank milling, in contrast to traditional flank milling techniques, significantly diminishes the surface roughness by about 40%. The reasons for the reduction of surface roughness are analyzed from the point of view of the cutting force. The surface roughness appears to be notably linked to both the average cutting force and the frequency domain characteristics. In addition, the experimental results indicate that rotary ultrasonic flank milling demonstrates the capacity to elevate the micro-hardness of the machined surface.

Towards understanding the cutting temperature in ultrasonic vibration-assisted drilling based on the dynamic contact characteristics between the cutting edge and workpiece.

Compared with conventional drilling (CD), ultrasonic vibration-assisted drilling(UVAD) is experimentally proven a promising method to reduce the cutting temperature. But sometimes cutting temperature also becomes higher in UVAD than in CD. To further make clear the cutting temperature mechanisms in UVAD, this study aims to study the effect of tool's ultrasonic vibration on the cutting heat generation and heat dissipation at a relatively micro level. Firstly, drilling experiments are designed to explore the variations of cutting heat under different ultrasonic vibrations. Then, to analyze the influence of ultrasonic vibration on the cutting heat theoretically, a kinematic model is developed to describe the dynamic contact between the cutting edge and workpiece in UVAD. Besides, a cutting heat analysis model based on the contact characteristics in UVAD is proposed to study and compare the variations of cutting heat generation. The effect of ultrasonic vibration on the cutting heat generation, heat dispassion, and the resultant cutting temperature under different machining in UVAD conditions are discussed. It is indicated from the theoretical analysis that more cutting heat tends to be produced due to the significantly increased sliding velocity on the cutting edge-workpiece interface when the ultrasonic vibration is applied. The analysis agrees with the experimental results that the cutting temperature in dry UVAD is higher than in dry CD. But on the other hand, ultrasonic vibration can also improve the lubrication and cooling effect under appropriate machining conditions, which is beneficial to the reduction in cutting temperature. The investigation shows the multifaceted influences of ultrasonic vibration on the cutting temperature in the drilling process in detail, which provides a reference for UVAD parameter optimization.

Analysis of the Mechanism and Safety of Bisphosphonates in Patients with Lung Cancer and Bone Metastases.

OBJECTIVE: To explore the mechanism and safety of bisphosphonates in patients with lung cancer and bone metastases. METHOD: A total of 104 patients with lung cancer and bone metastases in our hospital were selected and randomly divided into two groups: control group (n = 54) and research group (n = 50). Chemotherapy was given to the control group, and the research group was treated with bisphosphonate drugs. The quality of life, HAMA, HAMD score, VAS score, treatment effect, serum calcium and KPS score, inflammatory factor levels, and immune function were compared between the two groups. RESULT: The quality of life in both groups was significantly increased (P < 0.05). The HAMA and HAMD scores of the research group decreased significantly than those of the control group after treatment (P < 0.05). The VAS scores of the two groups were significantly reduced (P < 0.05). The effective rates of treatment in the control group and the research group were 81.5% and 96.0%, respectively. Serum calcium was significantly decreased, and KPS score was significantly increased at weeks 1 and 6 after treatment, and the change was more obvious in the research group (P < 0.05). The levels of inflammatory factors in the two groups were significantly reduced, and the immune indicators were significantly increased. CONCLUSION: Bisphosphonates have good effect on patients with lung cancer and bone metastases, which can improve anxiety and depression, reduce pain score, improve serum calcium level and immune function, and reduce inflammatory response. Therefore, bisphosphonate drug therapy is worth widely used.

Significance of highly phosphorylated insulin-like growth factor binding protein-1 and cervical length for prediction of preterm delivery in twin pregnancies.

BACKGROUND: A twin pregnancy can carry greater risks than singleton pregnancies. About 60 in 100 twin pregnancies result in spontaneous birth before 37 wk, which is associated with several complications in the premature babies. Clinical detection of biomarkers may help to predict the possibility of premature birth so that corresponding interventions can be given to the pregnant women in a timely manner, in order to reduce the risk of preterm birth and improve the outcomes of the newborn infants. AIM: To explore the clinical value of transvaginal ultrasound measurement of cervical length combined with insulin-like growth factor binding protein-1 (IGFBP-1) hyperphosphorylation in cervical secretions as predictors of preterm delivery in twin pregnancies. METHODS: A total of 254 pregnant women with twin pregnancies, who were admitted to Hainan General Hospital and underwent maternity examination, were selected as the study subjects from January 2015 to December 2018. All participants received transvaginal ultrasound measurement of cervical length and phosphorylated IGFBP-1 (phIGFBP-1) test between 24 and 34 wk gestation. The pregnancy outcomes were analyzed. RESULTS: Of the women with a positive phIGFBP-1 test result, preterm birth rate was higher in those with a cervical length ≤ 25 mm than those with a cervical length > 25 mm (all P < 0.05). Similarly, in women with a negative phIGFBP-1 test result, preterm birth rate was higher in those with a cervical length ≤ 25 mm than those with a cervical length > 25 mm (all P < 0.05). The sensitivity, specificity, and positive and negative predictive values of the phIGFBP-1 test combined with the cervical length test were 95.71%, 91.21%, 95.12% and 92.22%, respectively, for the prediction of preterm birth. CONCLUSION: Cervical length combined with phIGFBP-1 tests is of value for the prediction of outcomes of preterm delivery in twin pregnancies.

Modified Xiaochaihu Decoction () Promotes Collagen Degradation and Inhibits Pancreatic Fibrosis in Chronic Pancreatitis Rats / 中国结合医学杂志

OBJECTIVE@#To investigate the effect of Modified Xiaochaihu Decoction (MXD, ) on collagen degradation in rats with chronic pancreatitis (CP).@*METHODS@#Rats were injected dibutyltin dichloride (DBTC, 7 mg/kg of body weight) into the right caudal vein to induce CP model. Thirty heallhy male Wistar rats were randomly divided into three groups by a random number table: the control, the model and the treatment groups. Rats of treatment group were administered MXD (10 g/kg of body weight) orally once daily starting from the day post-model establishment. Pancreatic tissues were harvested after 28-day feeding and fibrosis was evaluated by picro-sirius red staining. The contents of collagen type I and III were detected using enzymelinked immunosorbent assay (ELISA), the expression of matrix metalloproteinase 13 (MMP13) and tissue inhibitor of metalloproteinase 1 (TIMP1) was analyzed by Western blot and real-time polymerase chain reaction (PCR).@*RESULTS@#The fibrosis scoring of pancreatic tissues, the concentrations of collagen type I and III, the expression levels of MMP13 and TIMP1 proteins and mRNA in the model group were all increased compared with the control group (P0.05).@*CONCLUSIONS@#MXD could promote collagen degradation and reverse pancreatic fibrosis in CP rats via a mechanism involve up-regulation of MMP13 expression.

Ultrasonically Assisted Single Point Diamond Turning of Optical Mold of Tungsten Carbide.

To realize high efficiency, low/no damage and high precision machining of tungsten carbide used for lens mold, a high frequency ultrasonic vibration cutting system was developed at first. Then, tungsten carbide was precisely machined with a polycrystalline diamond (PCD) tool assisted by the self-developed high frequency ultrasonic vibration cutting system. Tool wear mechanism was investigated in ductile regime machining of tungsten carbide. The cutter back-off phenomenon in the process was analyzed. The subsequent experimental results of ultra-precision machining with a single crystal diamond tool showed that: under the condition of high frequency ultrasonic vibration cutting, nano-scale surface roughness can be obtained by the diamond tool with smaller tip radius and no defects like those of ground surface were found on the machined surface. Tool wear mechanisms of the single crystal diamond tool are mainly abrasive wear and micro-chipping. To solve the problem, a method of inclined ultrasonic vibration cutting with negative rake angle was put forward according to force analysis, which can further reduce tool wear and roughness of the machined surface. The investigation was important to high efficiency and quality ultra-precision machining of tungsten carbide.

Filariae in vertebral canal, report of a case / 中华儿科杂志

<p><b>OBJECTIVE</b>To confirm diagnosis of a special case with chief complaints of abdominal pain and dyskinesia of lower extremities.</p><p><b>METHODS</b>The clinical symptoms, signs, MRI, pathological findings and the results of blood test for microfilaria were analyzed.</p><p><b>RESULTS</b>The patient was a 6-year old girl who had abdominal pain for 10 days dyskinesia of lower extremities for 6 days accompanied by difficulty in urination and defecation. There was tenderness on T7-9 spinous process, sensory dullness below the umbilicus. Babinski's and Oppenheim's sign were bilaterally positive, and ankle clonus was positive. MRI showed space occupying change in the vertebral canal at T7-9 level. The mass of 2 cm x 1 cm x 1 cm size was removed by surgical operation and histopathological study showed obvious fibrous tissue proliferation accompanied by eosinophil, lymphocyte and neutrophil infiltration around a worm-like structure. Night time blood test performed at 23:00 confirmed the presence of microfilaria.</p><p><b>CONCLUSION</b>The diagnosis of filariae in vertebral canal could be confirmed.</p>