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11.
This contribution discusses the ablation phenomena observed during laser treatment of carbon fiber-reinforced plastics (CFRPs) with pulsed lasers observed employing laser sources with wavelengths of 355 nm, 1064 nm and 10.6 µm and pulse durations from picoseconds (11 ps) to microseconds (14 µs) are analyzed and discussed. In particular, the threshold fluence of the matrix material epoxy (EP) and the damage threshold of CFRP were calculated. Moreover, two general surface pretreatment strategies are investigated, including selective matrix removal and structure generation through indentation (ablation of both, matrix material and fibers) with a cross-like morphology. The surfaces obtained after the laser treatment are characterized by means of optical and scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy is employed for the analysis of composite and constituent materials epoxy and carbon fibers. As a result, different ablation mechanisms, including evaporation and delamination are observed, depending on the employed laser wavelength and pulse duration. For both 355 nm and 1064 nm wavelength, the laser radiation produces only partial ablation of the carbon fibers due to their higher absorption coefficient compared to the epoxy matrix. Although a selective matrix removal without residues is achieved using the pulsed CO2 laser. Differently, both constituent materials are ablated with the nanosecond pulsed UV laser, producing indentations. The sum of the investigations has shown that existing theories of laser technology, such as the ablation threshold according to Liu et al., can be applied to composite materials only to a limited extent. Furthermore, it has been found that the pronounced heterogeneity of CFRP mostly leads to an inhomogeneous ablation result, both when creating grooves and during selective matrix removal, where the carbon fibers influence the ablation result by their thermal conductivity, depending on fiber direction. Finally, despite the material inhomogeneity, a scanning strategy has been developed to compensate the heterogeneous ablation results regarding structure depth, width and heat affected zone. 相似文献
12.
West SG Gebauer SK Kay CD Bagshaw DM Savastano DM Diefenbach C Kris-Etherton PM 《Hypertension》2012,60(1):58-63
Nut consumption reduces cardiovascular risk, and reductions in blood pressure and peripheral vascular resistance may be important mediators of this relationship. We evaluated effects of pistachios on flow-mediated dilation and blood pressure response to acute stress. Twenty-eight adults with dyslipidemia completed a randomized, crossover, controlled-feeding study. All of the meals were provided and calories were controlled. After 2 weeks on a typical Western diet (35% total fat and 11% saturated fat), test diets were presented in counterbalanced order for 4 weeks each, a low-fat control diet (25% total fat and 8% saturated fat), a diet containing 10% of energy from pistachios (on average, 1 serving per day; 30% total fat and 8% saturated fat), and a diet containing 20% of energy from pistachios (on average, 2 servings per day, 34% total fat and 8% saturated fat). None of the resting hemodynamic measures significantly differed from pretreatment values. When resting and stress levels were included in the repeated-measures analysis, average reductions in systolic blood pressure were greater after the diet containing 1 serving per day versus 2 servings per day of pistachios (mean change in systolic blood pressure, -4.8 vs -2.4 mm Hg, respectively; P<0.05). After the higher dose, there were significant reductions in peripheral resistance (-62.1 dyne · s × cm(-5)) and heart rate (-3 bpm) versus the control diet (P<0.0001). These changes were partially offset by increases in cardiac output. There was no effect of diet on fasting flow-mediated dilation. Reductions in peripheral vascular constriction and the resulting decrease in hemodynamic load may be important contributors to lower risk in nut consumers. 相似文献
13.
Gebauer Corinna Klotz Daniel Springer Skadi 《Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz》2018,61(8):952-959
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - In den letzten Jahren konnte der immense Vorteil der Muttermilchernährung für Frühgeborene belegt werden: in Bezug... 相似文献
14.
As is known from other reports, a rhabdomyoma or tumor metastasis may alter intracardiac electrical conduction, producing electrical phenomena like pseudopreexcitation or repolarization disturbances resembling ST‐elevation myocardial infarction or Brugada's syndrome. We present a newborn with a giant atrial rhabdomyoma and additionally multiple ventricular rhabdomyomas. He presented with several electrocardiogram (ECG) phenomena due to tumor‐caused atrial depolarization and repolarization disturbances. Except from the cardiac tumors, the physical status was within normal range. Initial ECG showed a rapid atrial tachycardia with a ventricular rate of 230 bpm, which was terminated by electrical cardioversion. Afterwards, the ECG showed atrial rhythm with frequent atrial premature contractions and deformation of the PR interval with large, broad P waves and loss of discret PR segment, imposing as pseudopreexcitation. The following QRS complex was normal, with seemingly abnormal ventricular repolarization resembeling ST‐elevation myocardial infarction. The atrial tumor was resected with consequent vast atrial reconstruction using patch plastic. The ventricular tumors were left without manipulation. After surgery, pseudopreexcitation and repolarization abnormalities vanished entirely and an alternans between sinus rhythm and ectopic atrial rhythm was present. These phenomena were supposably caused by isolated atrial depolarization disturbances due to tumor‐caused heterogenous endocardial activation. The seemingly abnormal ventricular repolarization is probably due to repolarization of the atrial mass, superimposed on the ventricular repolarization. Recognizably, the QRS complex before and after surgical resection of the rhabdomyoma is identical, underlining the atrial origin of the repolarization abnormalities before surgery. 相似文献
15.
The Australasian Psoriasis Collaboration view on methotrexate for psoriasis in the Australasian setting 下载免费PDF全文
Marius Rademaker Monisha Gupta Megan Andrews Katherine Armour Chris Baker Peter Foley Kurt Gebauer Jacob George Diana Rubel John Sullivan 《The Australasian journal of dermatology》2017,58(3):166-170
The Australasian Psoriasis Collaboration reviewed methotrexate (MTX) in the management of psoriasis in the Australian and New Zealand setting. The following comments are based on expert opinion and a literature review. Low‐dose MTX (< 0.4 mg/kg per week) has a slow onset of action and has moderate to good efficacy, together with an acceptable safety profile. The mechanism of action is anti‐inflammatory, rather than immunosuppressive. For pretreatment, consider testing full blood count (FBC), liver and renal function, non‐fasting lipids, hepatitis serology, HbA1c and glucose. Body mass index and abdominal circumference should also be measured. Optional investigations in at‐risk groups include an HIV test, a QuantiFERON‐TB Gold test and a chest X‐ray. In patients without complications, repeat the FBC at 2–4 weeks, then every 3–6 months and the liver/renal function test at 3 months and then every 6 months. There is little evidence that a MTX test dose is of value. Low‐dose MTX rarely causes clinically significant hepatotoxicity in psoriasis. Most treatment‐emergent liver toxicity is related to underlying metabolic syndrome and non‐alcoholic fatty liver disease or non‐alcoholic steatohepatitis. Alcohol itself is not contraindicated, but should be limited to < 20 gm/day. [Correction added on 6 January 2017, after first online publication: ‘20 mg/day’ has been corrected to ‘20 gm/day’.] Although MTX is a potential teratogen post‐conception, there is little evidence for this pre‐conception. MTX does not affect the quality of sperm. There is no evidence that MTX reduces healing, so there is no specific need to stop MTX peri‐surgery. MTX may be used in combination with cyclosporine, acitretin, prednisone and anti‐tumour necrosis factor biologics. 相似文献
16.
J. Beckmann R. Springorum E. Vettorazzi S. Bachmeier C. Lüring M. Tingart K. Püschel O. Stark J. Grifka T. Gehrke M. Amling M. Gebauer 《Journal of orthopaedic research》2011,29(11):1753-1758
The prevention of hip fractures is a desirable goal to reduce morbidity, mortality, and socio‐economic burden. We evaluated the influence on femoral strength of different clinically applicable cementing techniques as “femoroplasty.” Twenty‐eight human cadaveric femora were augmented by means of four clinically applicable percutaneous cementing techniques and then tested biomechanically against their native contralateral control to determine fracture strength in an established biomechanical model mimicking a fall on the greater trochanter. The energy applied until fracture could be significantly increased by two of the methods by 160% (53.1 Nm vs. 20.4 Nm, p < 0.001) and 164% (47.1 Nm vs. 17.8 Nm, p = 0.008), respectively. The peak load to failure was significantly increased by three of the methods by 23% (3818.3 N vs. 3095.7 N, p = 0.003), 35% (3698.4 N vs. 2737.5 N, p = 0.007), and 12% (3056.8 N vs. 2742.8 N, p = 0.005), respectively. The femora augmented with cemented double drill holes had a lower fracture strength than the single drilled ones. Experimental femoroplasty is a technically feasible procedure for the prophylactic reinforcement of the osteoporotic proximal femur and, hence, could be an auxiliary treatment option to protect the proximal femur against osteoporotic fractures. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1753–1758, 2011 相似文献
17.
Philip L Tong William A Walker Ross J Glancy Julian P Cooney Kurt Gebauer 《The Australasian journal of dermatology》2013,54(1):e12-e15
Primary localized cutaneous nodular amyloidosis (PLCNA) is a rare subtype of localized cutaneous amyloidosis and can be associated with various connective tissue disorders. It can be difficult to treat and past therapies include surgical excision, dermabrasion, electrodessication and curettage, cryotherapy and laser therapy. We present a case of a middle‐aged woman with PLCNA associated with CREST (calcinosis, Raynaud phenomenon, oesophageal motility disorders, sclerodactyly and telangiectasia) syndrome and Sjögren's syndrome responding to cyclophosphamide with no new amyloid deposits and resolution of skin ulceration after many years of resistance to drug therapy. It is important to monitor these patients for progression into systemic amyloidosis. 相似文献
18.
It was found that lectin-binding proteins (LB) from leguminosae seeds can serve as mitogens for B lymphocytes from athymic nu/nu mice. Most of the experiments were performed using a LB from Vicia faba as this was the most potent mitogen among all LB tested. When mixed B and T lymphocyte populations were stimulated by LB, a bell-shaped dose-response curve resulted which is also characteristic of the corresponding lectins; LB, however, act at much higher concentrations than the lectins. In control experiments, using lymphocytes from C3H/HeJ mice which have a genetic defect with respect to lipopolysaccharide responsiveness, the enhancement of DNA synthesis by LB was comparable to that observed with other strains. This indicates that stimulation by LB does not result from contamination by lipopolysaccharides. B lymphocytes from nu/nu mice were stimulated by LB as efficiently as mixed T and B lymphocyte populations whereas lectins per se had no effect on nu/nu lymphocytes. Cyclosporin A, a fungal metabolite, is known to specifically suppress T cell responses. Cyclosporin A did not influence the mitogenic activity of the LB from Vicia faba on unseparated spleen cells. Cell populations enriched for T cells (lymph node cells: nylon wool-passed or nylon wool-passed and anti-Ia plus complement-treated) responded poorly to LB, if at all, even in the presence of interleukin 2-containing supernatants. 相似文献
19.
Clinical utility of serial serum c-erbB-2 determinations in the follow-up of breast cancer patients 总被引:8,自引:0,他引:8
To evaluate the ability of serum c-erbB-2 protein to (1) indicate occult and manifest metastases and (2) reflect response to first-line therapy, serial serum c-erbB-2 measurements were performed in a retrospective series of 52 primary breast cancer patients who had developed metastatic disease during follow-up. The results were compared with CA 15-3. Preoperatively, 31% (16/52) of the primary breast cancer patients had elevated c-erbB-2 concentrations. The CA 15-3 positivity rate was 13% (7/52). After surgery, 10 of the 52 patients showed either stable but highly elevated or rising c-erbB-2 serum levels indicating serum c-erbB-2 producing minimal residual disease. Increasing CA 15-3 concentrations were seen in only three patients. Elevated serum c-erbB-2 levels predicted manifest metastases in 27 and 50% of the patients at 6 and 3 months, respectively, prior to clinical diagnosis. CA 15-3 was less sensitive. Only 16 and 32% of the patients had increased CA 15-3 serum concentrations at 6 and 3 months, respectively, prior to clinical detection. The positivity rates of c-erbB-2 and CA 15-3 were similar when metastases were clinically diagnosed. Elevated c-erbB-2 concentrations were found in 62% (32/52). The sensitivity of CA 15-3 was 56% (29/52). The association between serum profiles and response to first-line therapy was evaluated in detail for 45 patients. Serial c-erbB-2 and CA 15-3 measurements reflected disease course in 24 and 27 patients, respectively. The serum profiles of c-erbB-2 and CA 15-3 were similar in 17 patients. In summary, our results suggest that serial determinations of serum c-erbB-2 are useful to monitor breast cancer patients. 相似文献
20.