Development of a micro-electrochemical machining nanosecond pulse power supply.

Micro-electrochemical machining (micro-ECM) has been widely used for microscale and nanoscale processing of materials. The performance of the nanosecond pulse power supply is directly related to the precision of micro-ECM, which is one of the core technologies for micro-ECM. In this work, a nanosecond pulse power supply, with adjustable pulse frequency, duty cycle, and voltage, was designed with an STM32F103VET6 single-chip microcomputer as the control core and a metal-oxide-semiconductor field-effect transistor as the chopper switch component. The performance test has shown that the power supply can produce a continuous pulse with the highest frequency of 8 MHz, the shortest pulse width of 50 ns, the maximum peak current of 12 A, and the maximum voltage of 10 V. As compared with the power supply reported in the literature, the present power supply demonstrated the enhanced output current and improved waveform of the nanosecond pulse output, which could result in better machining accuracy and efficiency for micro-ECM.

[Studies on efficacy of a bioabsorbable steroid-eluting sinus stent in the frontal sinus opening of chronic rhinosinusitis with nasal polyps].

Objective: To assess the efficacy of a bioabsorbable steroid-eluting sinus stent in improving surgical outcomes when placed in the frontal sinus ostium (FSO) following full endoscopic sinus surgery (ESS) in patients with whole group chronic rhinosinusitis with nasal polyps (CRSwNP). Methods: Patients with whole group CRSwNP who had similar lesions on bilateral sinus between September 2019 and March 2020 in Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Changhai Hospital were chosen. Patients with CRSwNP who underwent extended ESS were randomly assigned to receive a steroid-eluting sinus stent in one FSO whereas the contralateral side received surgery alone. Endoscopic evaluations recorded at 30, 90 days postoperative were graded by an independent assessment panel to assess the need for interventions in the FSO. Semi-quantitative data with CT and endoscopic score were performed by rank sum test. The need for postoperative intervention and the patency rate of FSO were analyzed using the McNemar test. Results: Thirty-one patients with whole group CRSwNP met all eligible criteria, including 17 males and 14 females, with the age of (44.5±11.8) years(x¯±s). Stents were successfully placed in one FSO of all patients. At 30 days post-ESS, the assessment panel reported that steroid-eluting stents reduced the need for postoperative interventions by 41.0% (χ2=5.314,P=0.021), the need for oral steroid interventions by 40.0% (χ2=4.133,P=0.042) and the need for surgical interventions by 74.8% (χ2=4.292,P=0.038) compared to control sinuses with no stents. Clinical surgeons also reported greater diameter of FSO compared to control sinuses at 30 days post-ESS (74.2% vs 48.4%, χ2=4.351, P=0.037). These results at 90 days post-ESS were consistent with those at 30 days post-ESS. Conclusion: Bioabsorbable steroid-eluting sinus stents in the FSO can reduce polyp formation, adhesion, and the need for postoperative interventions in FSO of CRSwNP patients and improve the early postoperative outcomes.

[The role of neutrophil density in neutrophils-mediated inflammatory response induced by monosodium urate crystals].

Objective: To study the role of neutrophil density and molecular mechanism in neutrophils-mediated inflammatory response induced by monosodium urate (MSU) crystals. Methods: Polymorphonuclear neutrophils (PMNs) isolated from healthy human peripheral blood were treated with MSU crystals at different density (5×10(6)/ml, 20×10(6)/ml, 100×10(6)/ml) in vitro. The mean fluorescence intensity (MFI) of PMNs and production of reactive oxygen species (ROS) were detected by flow cytometry. The distribution of MSU crystals was observed by polarized light microscopy. The neutrophil extracellular traps (NETs) formation was detected by immune fluorescence. The cytokines in cell supernatant were measured by beads assay including interleukin 1ß (IL-1ß) , tumor necrosis factor α (TNFα) , interleukin 8 (IL-8) , interferon inducible protein 10 (IP-10) , macrophage inflammatory protein 1 (MIP-1) , monokine induced by interferon-γ (MIG) , macrophage inflammatory protein 1α (MIP-1α) , macrophage inflammatory protein 1ß (MIP-1ß) . Results: (1) After MSU crystal intervention, the side scatters (SSC) of neutrophils with medium-cell density (20×10(6)/ml) and high-cell density (100×10(6)/ml) were 128±13 and 93±9 respectively, both significantly lower than 170±19 in low-cell density (5×10(6)/ml) group.(2) Similarly, compared with low-cell density group, the MFI (lucifer yellow) of PMNs with high-cell density was 1.8±0.2, also significantly decreased (P<0.05). When co-treated with oxygenated adenosine triphosphate (oxATP), MFI of PMNs were all enhanced consistently. (3) In MSU crystals stimulated PMNs, after adding 2',7'-dichlorodihydrofluorescein diacetate, the MFI values were 0.85±0.32, 2.49±0.78, 4.54±1.02 in low cell density groups, medium cell density groups, and high cell density groups respectively, indicating that the generation of ROS was positively correlated with the increase of PMN density (P<0.05). After the intervention of oxATP, the ROS production was significantly reduced. (4) MSU crystal induced NETs formation, especially at high cell density. NETs formation promotes MSU crystal aggregation, which could be partially overcome by oxATP pretreatment. (5) The expression of cytokines were all significantly decreased in the supernatant of PMNs at high cell density exposed to MSU crystals compared with PMNs at medium cell density (P<0.05) . Conclusion: The PMN-mediated inflammation induced by MSU crystals is cell density dependent, and ATP may play a role in partially overcoming the process.

[Preliminary study of whole-tumor volume analysis of mono-exponential and intravoxel incoherent motion models in the preoperative histologic grading of hepatocellular carcinoma].

Objective: To investigate the diagnostic performance of whole-tumor volume analysis of mono-exponential and intravoxel incoherent motion (IVIM)parameters in the preoperative grading of hepatocellular carcinoma (HCC). Methods: A total of 106 patients who undewent parital hepatectomy were prospectively enrolled and underwent with routine MR and IVIM examination.112 HCCs were confirmed by the surgical pathology.The original images of IVIM were imported into the GE AW 4.6 workstation.Two independent radiologist who were blinded to the histopathological results analyzed the data.Freehand ROI was used to cover the whole tumor volume, ADC, ADC(slow), ADC(fast) and f was calculated.Intra-class correlation coefficient (ICC) was used to evaluate the inter-observer agreement, One-way ANOVA and Kruskal-Wallis sign rank test were used to evaluate the difference of these parameters in grading HCC, Spearman correlation analysis was used to determine the correlation between these parameters and histologic grade, receiver operating characteristics (ROC) curves were performed to evaluate the diagnostic performance. Results: ICC value of ADC, ADC(slow), ADC(fast) and f were 0.948, 0.966, 0.901 and 0.940, respectively.Statistical significances were obtained from the ADC(slow)(R1: χ(2)=74.403, P<0.001; R2: F=44.973, P<0.001) and ADC (R1: χ(2)=52.987, P<0.001; R2: F=30.851, P<0.001) in grading HCC.Between the multiple-comparison in grading HCC, the ADC(slow) and ADC (except for E-S 3 and 4, R1: P=0.134; R2: P=0.069) also demonstrated a statistical significant difference (all P<0.05). Area under curve (AUC) value of two radiologists for ADC(slow) were 0.905 and 0.917, for ADC were 0.831 and 0.829, a negative correlation was obtained from the ADC and ADC(slow) (all P<0.05). Conclusion: Mono-exponential and intravoxel incoherent motion (IVIM) model can be used to evaluate the pathological differentiated grade of HCC, ADC and ADC(slow) value entailed the highest diagnostic performance.

An instrument for measuring scintillators efficiently based on silicon photomultipliers.

An instrument used for measuring multiple scintillators' light output and energy resolution was developed. The instrument consisted of a light sensor array which was composed of 64 discrete SiPMs (Silicon Photomultipliers), a corresponding individual channel readout electronics system, and a data processing algorithm. A Teflon grid and a large interval between adjacent SiPMs were employed to eliminate the optical cross talk among scintillators. The scintillators' light output was obtained by comparing with a reference sample with known light output. Given the SiPM temperature dependency and the difference among each SiPM, a temperature offset correction algorithm and a non-uniformity correction algorithm were added to the instrument. A positioning algorithm, based on nine points, was designed to evaluate the performance of a scintillator array. Tests were performed to evaluate the instrument's performance. The uniformity of 64 channels for light output measurement was better than 98%, the stability was better than 98% when temperature varied from 15 °C to 40 °C, and the nonlinearity under 511 keV was better than 2%. This instrument was capable of selecting scintillators and evaluating the packaging technology of scintillator arrays with high efficiency and accuracy.

Central administrations of hemopressin and related peptides inhibit gastrointestinal motility in mice.

BACKGROUND: Hemopressin was identified as an endogenous inverse agonist/antagonist of CB1 receptor, whereas VD-hemopressin(α) [VD-Hpα] and VD-hemopressin(ß) [VD-Hpß] were found as the novel endogenous peptidic agonists of cannabinoid receptors. As cannabinoids are potent modulators of gastrointestinal (GI) motility, our aim was to characterize the effects of hemopressin and related peptides on GI motility in vivo. METHODS: The responses of intracerebroventricular (i.c.v.) administration of the reference compound WIN55,212-2, hemopressin, and related peptides to GI motility were investigated by measuring upper GI transit, colonic bead expulsion, and whole gut transit in mice. KEY RESULTS: Central administration of the classical cannabinoid receptor agonist WIN55,212-2 dose-dependently slowed upper GI transit, colonic expulsion, and whole gut transit via CB1 receptor. Similarly, Hpα, VD-Hpα, and VD-Hpß delayed upper GI transit and colonic expulsion after i.c.v. administration. At the high doses, Hpα and VD-Hpß inhibited whole gut transit, whereas VD-Hpα had no effect on whole gut transit. In addition, the effects of these three peptides on GI transit were antagonized by the CB1 receptor selective antagonist AM251, but not by the CB2 receptor selective antagonist AM630. CONCLUSION & INFERENCES: The endogenous cannabinoid peptide ligands hemopressin, VD-Hpα, and VD-Hpß inhibited GI transit through the activation of CB1 , but not CB2 cannabinoid receptors. The lower potencies of the hemopressin and related peptides in GI transit assays may be important for the future development of cannabinoid peptides as the therapeutic analgesics with limited GI side effects.

Triple therapy for neovascular age-related macular degeneration using single-session photodynamic therapy combined with intravitreal bevacizumab and triamcinolone.

AIM: To evaluate the efficacy and safety of triple therapy consisting single-session photodynamic therapy (PDT), intravitreal bevacizumab (IVB) and intravitreal triamcinolone (IVTA) for treatment of neovascular age-related macular degeneration (AMD) METHODS: Consecutive patients with subfoveal choroidal neovascularisation (CNV) secondary to AMD were treated with PDT using a standard protocol immediately followed by 1.25 mg of IVB and 4 mg of IVTA. 1.25 mg of IVB was given at 3 months for residual leakage. Best-corrected Snellen visual acuity (BCVA) and fluorescein angiography (FA) were performed prior to treatment. BCVA, intraocular pressure (IOP) and presence of vitritis were documented at 1 and 6 weeks, 3 and 6 months. FA was repeated at 3 and 6 months. Outcome measures included visual improvement measured by logMAR equivalent, angiographic evident of leakage and safety profile. RESULTS: 36 eyes of 33 patients, aged 76.4 (SD 10.5) years with mean follow-up of 14.7 (6.9-19.2) months were analysed. Baseline logMAR acuity was 1.22 (0.71). The mean logMAR acuity was 1.14 (0.62) and 1.18 (0.63) at 3 and 6 months respectively. At 6 months, 61.1% (22/36) showed stable or gaining vision, and 27.8% (10/36) gained three or more lines. Twenty-eight eyes (77.8%) achieved CNV resolution by single session of triple therapy. One eye lost more than six lines due to retinal pigment epithelium rip, three eyes showed a significant cataract requiring surgery, and two showed persistent raised IOP at 6 months. None resulted in endophthalmitis or reported thromboembolic event. CONCLUSIONS: Short-term results of single session triple therapy suggested that it might be a useful treatment option for neovascular AMD based on its low retreatment rates, sustainable CNV eradication result and visual gain achievement. However, the risk and benefits of using intravitreal triamcinolone in addition to combined PDT and IVB warrant further evaluation.

The role of three-dimensional ultrasonographic images in ovarian measurement.

OBJECTIVE: To determine whether three-dimensional ultrasonography can increase the ability to evaluate the ovary and follicles, especially in women with polycystic ovary disease (PCOD). DESIGN: Prospective clinical study. SETTING: University hospital endocrine and infertility center. PATIENT(S): Sixty-six patients undergoing routine gynecologic evaluation were divided into two groups: the normal control group consisted of 22 patients, and there were 44 patients with PCOD. INTERVENTION(S): Three-dimensional ultrasonography was performed to store and document whole volumes of the ovaries for evaluation. MAIN OUTCOME MEASURE(S): Three perpendicular planes of bilateral ovaries are rotatable to obtain the largest dimensions. The three-dimensional volume was measured using the trapezoid formula. RESULT(S): The ovaries of the patients with PCOD were larger in size, area, and volume than those of normal controls. CONCLUSION(S): Stroma and volume determinations can be obtained more accurately by three-dimensional images than by traditional ultrasonography. Three-dimensional ultrasonography not only facilitates noninvasive evaluation and volume calculation but also completes the examination in a short time without increasing patient discomfort.

The determination of vasoactive substances during autonomic dysreflexia.

Urinary bladder percussion induced autonomic dysreflexia (AD) was observed in spinal cord injured patients with a complete neurological lesion, the upper level being above T5. To document the pathology and study the etiology of autonomic dysreflexia to further investigate its mechanism, this paper presents some clinical data on the determination of vasoactive substances such as norepinephrine (NE), epinephrine (E), renin (R), angiotensin II (AII) and atrial natriuretic polypeptide (ANP) before and during bladder percussion in 30 patients with a thoracolumbar or cervical spine and spinal cord injury. It is demonstrated that tapping the urinary bladder of such patients can cause AD. Changes of some of the vasoactive substances in the plasma were also observed, which might indicate that autonomic dysreflexia result from excitation of the sympathetic nervous system. Overactivity of the sympathetic nervous system was antagonized by excitation of the vegetative nerve system. There was no correlation between changes of blood pressure and adrenal function as well as the change of R-A II system; during autonomic dysreflexia, the inclement of ANP secretion played an important role in recovering homeostasis.

Coagulopathy during ascites reinfusion: prevention by antiplatelet therapy.

The development of disseminated intravascular coagulation (DIC) during a controlled IV infusion of concentrated ascitic fluid was studied in a group of patients with cirrhosis and refractory ascites. Nine studies were performed on patients who had not received prophylactic antiplatelet therapy. All developed laboratory evidence of DIC. The total collagen infused, estimated by ascitic hydroxyproline concentration, correlated significantly with both the prolongation of the partial thromboplastin time with kaolin (r = 0.8628; P less than 0.005) and the decrease in platelet count (r = 0.5674; P less than 0.05). The changes in the coagulation profile were reversible on ceasing the infusion, returning to baseline levels within 12 hours. There were no changes in the coagulation profiles of four patients studied 48 hours after beginning antiplatelet therapy with aspirin and dipyridamole. It is concluded that the infusion of concentrated ascitic fluid into a peripheral vein of patients with cirrhosis results in DIC, the severity of which correlates with the amount of collagen infused and which is completely prevented by inhibiting collagen-induced platelet aggregation. The results support the hypothesis that the DIC that complicates ascites infusion into the systemic circulation is largely related to ascitic fluid collagen.