Capacitive storage at nitrogen doped amorphous carbon electrodes: structural and chemical effects of nitrogen incorporation

Nitrogen incorporated carbon materials play an important role in electrochemical energy conversion technologies from fuel cells to capacitive storage devices. This work investigates the effects of nitrogen incorporation on capacitance, work function and semiconductor properties of amorphous carbon thin film electrodes. Nitrogenated electrodes (a-C:N) electrodes were synthesized via magnetron sputtering and characterized using X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy (UPS), Raman spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). EIS was carried in both aqueous (0.1 M KCl) and organic (0.1 M TBAPF₆/acetonitrile) electrolytes to discriminate between pseudocapacitive contributions and changes to semiconductor properties of the materials arising from structural and chemical disruption of the graphitic carbon scaffold. Raman and UPS spectroscopy both suggest that nitrogen incorporation increases the metallic character of the disordered carbon matrix at low-intermediate concentrations, whereas further nitrogen incorporation results in significantly more defective carbon with small graphitic cluster size. EIS studies in 0.1 M KCl indicate that the capacitance of a-C:N electrodes increases relative to nitrogen-free a-C electrodes due to a combination of microroughness and pseudocapacitive contributions in parallel to those of the double layer capacitance. Results in 0.1 M TBAPF₆ in acetonitrile which are dominated by the interfacial capacitance, show that initial nitrogen incorporation into the disordered carbon scaffold compensates for p-type properties in the disordered carbon matrix, resulting in an increase in metallic character. Greater levels of nitrogenation, are instead disruptive and increase defect density while decreasing the double layer capacitance.

Nitrogen incorporation into carbon increases metallic character and capacitance, however high concentrations are instead disruptive and decrease interfacial capacitance.

Nanoplasmonic Sensing at the Carbon-Bio Interface: Study of Protein Adsorption at Graphitic and Hydrogenated Carbon Surfaces

Various forms of carbon are known to perform well as biomaterials in a variety of applications and an improved understanding of their interactions with biomolecules, cells, and tissues is of interest for improving and tailoring their performance. Nanoplasmonic sensing (NPS) has emerged as a powerful technique for studying the thermodynamics and kinetics of interfacial reactions. In this work, the in situ adsorption of two proteins, bovine serum albumin and fibrinogen, were studied at carbon surfaces with differing chemical and optical properties using nanoplasmonic sensors. The carbon material was deposited as a thin film onto NPS surfaces consisting of 100 nm Au nanodisks with a localized plasmon absorption peak in the visible region. Carbon films were fully characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and spectroscopic ellipsometry. Two types of material were investigated: amorphous carbon (a-C), with high graphitic content and high optical absorptivity, and hydrogenated amorphous carbon (a-C:H), with low graphitic content and high optical transparency. The optical response of the Au/carbon NPS elements was modeled using the finite difference time domain (FDTD) method, yielding simulated analytical sensitivities that compare well with those observed experimentally at the two carbon surfaces. Protein adsorption was investigated on a-C and a-C:H, and the protein layer thicknesses were obtained from FDTD simulations of the expected response, yielding values in the 1.8-3.3 nm range. A comparison of the results at a-C and a-C:H indicates that in both cases fibrinogen layers are thicker than those formed by albumin by up to 80%.

Modulation of Protein Fouling and Interfacial Properties at Carbon Surfaces via Immobilization of Glycans Using Aryldiazonium Chemistry

Carbon materials and nanomaterials are of great interest for biological applications such as implantable devices and nanoparticle vectors, however, to realize their potential it is critical to control formation and composition of the protein corona in biological media. In this work, protein adsorption studies were carried out at carbon surfaces functionalized with aryldiazonium layers bearing mono- and di-saccharide glycosides. Surface IR reflectance absorption spectroscopy and quartz crystal microbalance were used to study adsorption of albumin, lysozyme and fibrinogen. Protein adsorption was found to decrease by 30–90% with respect to bare carbon surfaces; notably, enhanced rejection was observed in the case of the tested di-saccharide vs. simple mono-saccharides for near-physiological protein concentration values. ζ-potential measurements revealed that aryldiazonium chemistry results in the immobilization of phenylglycosides without a change in surface charge density, which is known to be important for protein adsorption. Multisolvent contact angle measurements were used to calculate surface free energy and acid-base polar components of bare and modified surfaces based on the van Oss-Chaudhury-Good model: results indicate that protein resistance in these phenylglycoside layers correlates positively with wetting behavior and Lewis basicity.

[Cryptorchidism and fertility: evaluation in adult age]

Impairment of fertility rate has been found to be associated with cryptorchidism. In this study we assessed the fertility of 172 adult subjects with unilateral and bilateral cryptorchidism who underwent surgical correction in pediatric age. Fertility has been evaluated by sperm analysis. Moreover test of function of spermatozoa membrane (swelling-test) and the research of antisperm antibodies (spermmar test) were carried out. The report presents data demonstrating that the fertility rate in patients with bilateral cryptorchidism is markedly reduced if compared with subjects affected by unilateral cryptorchidism. Azoospermia is present in 18% of bilateral cryptorchidism. The timing of surgery and the anatomical position of the cryptorchid testes do not seem to affect the fertility rate.

Fertility rates after successful correction of varicocele in adolescence and adulthood

Vast epidemiologic studies have shown that varicocele becomes manifest at the beginning of sexual maturation and its incidence gradually increases in patients between 10-16 years. This percentage is 16-18% in adolescents and is comparable to that of the adult male population. Since varicocele first appears in early adolescence and its gonadotoxic effect increases with age, the possibility of improved fertility rate with early varicocelectomy has been suggested. We report the results of a comparative follow-up study to value the efficacy of surgical correction in two groups of adolescent and adult patients. Our study shows that early recognition and treatment of a severe varicocele provide a higher fertility rate and can prevent the reduced fertility rate associated with delayed varicocelectomy.

[Cryptorchidism and fertility: an assessment in adulthood]

Impairment of fertility rate has been found to be associated with cryptorchidism. In this study we assessed the fertility of 172 adult subjects with unilateral and bilateral cryptorchidism who underwent surgical correction in pediatric age. Fertility has been evaluated by sperm analysis. Moreover test of function of spermatozoa membrane (swelling-test) and the research of antisperm antibodies (spermmar test) were carried out. The report presents data demonstrating that the fertility rate in patients with bilateral cryptorchidism is markedly reduced if compared with subjects affected by unilateral cryptorchidism. Azoospermia is present in 18% of bilateral cryptorchids. The timing of surgery and the anatomical position of the cryptorchid testes do not seem to affect the fertility rate.

[Small size breast cancer conservative surgical therapy and subsequent radiotherapy]

From february 1980 to december 1985, 115 breast carcinomas were treated with QU.A.RT. with limited surgery and following radiotherapy. Median age was 51 years (range 25 to 75). Surgical approach was quadrantectomy with axillary nodes dissection. Irradiation of residual breast was performed by an anterior high energy electron beam. 50 Gy in 25 fractions was the minimal dose to whole breast. In pN+ patients systemic adjuvant therapy was done. Local control was obtained in 111 cases. Local recurrence appeared in 4: 1 menopausal pT1 pNO and 3 premenopausal (1 pT1 pNO and 2 pT1 pN+) at respectively 31, 19, 22 months from diagnosis. Distant metastases appeared in 10 patients. 7 died for cancer and 3 are still alive. Cosmetic results were scored as good in 52, better than mastectomy in 26, unsatisfactory in 3, and not stated in 34. Our results are comparable to those of other Centers. Youth, axillary metastases and delay between surgery and radiotherapy appears to influence the risk of recurrence also in our series.

[Diagnostic aspects of aneurysm of the splenic artery (description of a case)]

A case of splenic artery aneurysm with ultrasonic examination discovered is reported and analyzed. The aneurysm pas asymptomatic and founded as incidental finding during standard x-ray. Arteriography was required to confirm the diagnosis and indicate the correct surgical treatment.

[Primary carcinoma of the gallbladder: ultrasonic features (remarks on 8 cases)]

The authors illustrate the ultrasound features of gallbladder carcinoma after reviewing literature and basing upon their own experience. The diagnosis of this neoplasia is formulated more frequently today by introduction of scanning means, but it remains very difficult on initial phase because of its precocious lymphatic and hilar infiltration.

[Hepatic angioma: a bothersome presence during staging of neoplasms of the digestive system]

On reviewing a consecutive series of 1,200 ultrasonic tomographies of the liver to assess the incidence of liver angiomas, the authors describe their sonographic, tomodensitometric and angiographic characteristics. They emphasise the fact that such lesions, though usually not constituting a serious clinical or diagnostic problem, as a simple sonographic follow-up will suffice to clarify the situation, may nevertheless, in certain particular clinical situations such as in the course of tumour staging of the digestive apparatus, require full diagnostic investigation using all the techniques available (ultrasonic tomography, CAT, liver arteriography, sonographically guided thin-needle biopsy.

[Leiomyosarcoma of the duodenum (description of a case and review of the literature)]

The Authors report on a case of duodenal leiomyosarcoma of small dimensions in a paravaterian site and presenting a low degree of histological malignity. They summarize the main anatomoclinical features of the neoplasm and conclude by indicating less aggressive surgical therapy as adequate in such cases, accompanied, however, by a protracted post-operative follow-up.

[Epidemiology and monitoring of closed abdominal injuries]

The authors review the epidemiological and aetiopathogenetic characteristics of abdominal blunt injuries (118 cases) monitored in a homogeneous manner. The relatively young age of the patients, the diagnostic difficulties encountered and the frequent presence of associated lesions call for the rigorous application of a predetermined clinico-diagnostic protocol.

[Ductal adenoma of the breast: correlations between clinico-radiologic and histo-pathologic aspects (considerations on a case)]

The authors report on a case of ductal adenoma of the breast, pointing out that routine clinico-instrumental diagnostic signs, though suggesting a picture of malignancy, may actually relate to this rare benign form of tumor. In the presence of cases of this type, we therefore advise a cautions approach to surgery, in that oncological radicality is subordinate to confirmation in the form of a traditional histological preparation, as freezer examinations are unable to provide wholly reliable responses.

[Clinico-diagnostic aspects of aggressive angiomyxoma of the pelvis and perineum]

The authors report on a case of aggressive angiomyxoma of the pelvis and perineum in a 46-year-old female patient. After reviewing the cases described in the literature, they examine the clinical characteristics of this rare form of neoplasia, which tends to occur more frequently in patients of female sex and in the young to middle-aged age bracket and is characterized by slow growth, non-infiltration of adjacent organs and a tendency to recur owing to incomplete excision. Metastases have never been reported. Failure to recognize the tumor at first approach may be due to the fact that it is easy to confuse it clinically with other more common diseases of the perineum. The authors conclude by advising systematic anatomicopathological identification of all perineal tumors, even when apparently benign.

["Wandering spleen": preoperative diagnosis by echotomography of the abdomen (review of the literature and report of a case)]

Splenic wandering is a rare condition of upset position of spleen, due to congenital fault or to excessive looseness of the supporting apparatus of this organ. The literature reports about 180 cases thereof, few of which recognized as such before operation. Ultimate investigations, in this limited number of preoperative diagnoses, resulted angiography and hepato-splenic scintigraphy; only three times the diagnosis was correctly placed through ultra-sounds. The authors show a case, confirmed by the operative report, where the ultrasonic test allowed to place the diagnosis with certainty, and, due to a particular lot of circumstances, proved to be better than TAC.

Neuropathy in Tangier disease: A clinicopathologic study and a review of the literature

A new case of Tangier disease is described. It is the 33rd case in world literature and only the 2nd in Italy. A 52-year-old man showed a widely spread neuropathy with facial diplegia, bilateral wasting of hand muscles and dissociated loss of pain and temperature sensation sparing the distal parts of the lower limbs. Clinical and laboratory data were typical of Tangier disease. A histological and ultrastructural study of the patient's superficial peroneal nerve and brevis peroneus muscle was carried out. A revision of the clinical and neuropathological aspects of the neuropathy of Tangier disease allowed our case to be included within a particular neurological description. Four patients with similar clinical characteristics had been noted previously. Clinical, morphological and biochemical data suggest the hypothesis that there are two different neuropathic forms of Tangier disease.

Metabolic effects of physical training in subjects with oral glucose intolerance

A group of normal weight subjects with oral glucose intolerance was studied for 4 months before, during, and after a physical training program (8 km/day/run). There were no significant differences in weight, basal blood glucose, lactate, and total cholesterol during and after training as compared with before training. Serum triglycerides significantly (P less than 0.05) decreased during the training period, and cholesterol-HDL significantly (P less than 0.01) increased during and after the physical program. Our data show that in previously inactive subjects with oral glucose intolerance physical training improves serum lipid patterns and thereby reduces atherosclerotic risk.

Maturation-related change of the protein kinase activity in the rabbit red blood cells

The protein kinase activity of rabbit reticulocyte and erythrocyte hemolysate is due to multiple forms (casein kinases and histone kinases) which have been partially purified by Sepharose 6B filtration followed by phosphocellulose chromatography in the presence of 0.2% Triton X-100. The casein kinase activity is resolved by such a procedure into two forms differing in catalytic properties: i.e. the casein kinase TS phosphorylates both serine and threonine residues of casein, while the casein kinase S phosphorylates only serine residues. The comparative results indicate that during differentiation and maturation of rabbit red blood cells multiple cytosol protein kinase activities markedly decrease, while the casein kinase S does not change significantly.

Acid-base balance on peritoneal dialysis

Forty studies of acid-base balance during intermittent peritoneal dialysis (IPD) and during continuous ambulatory peritoneal dialysis (CAPD) were performed on 20 patients who were receiving IPD with acetate buffer (5 patients), IPD with lactate buffer (5 patients), CAPD with acetate buffer (5 patients) and CAPD with lactate buffer (5 patients). Measurements of acetate, lactate and pyruvate levels in blood and dialyzate were taken at different times during dialysis; blood samples for blood gas analysis were drawn at the same times. Calculations of the kinetics of acetate, lactate and bicarbonate during IPD and CAPD were carried out according to the method of Tolchin [1977] but modified for PD. Thus it was possible to quantify the balance of the buffers, their mass transfer rates, bicarbonate generation and the percentage of buffer converted to HCO3. IPD kinetics of acetate and lactate were found to be similar, the main difference being a lower and significant percentage conversion of lactate to bicarbonate (45%) compared to that of acetate to bicarbonate (71%) (P < 0.005). On CAPD the kinetics of the two buffers was quite different: while the serum lactate level was always low (mean 0.97 +/- 0.33 mM/l), the acetate level was always high (mean 5.12 +/- 3.34 mM/l). Thus the utilization of the two buffers during "acute intermittent" treatment (IPD) and "continuous" treatment (CAPD) is different. On IPD there are no important differences between the two buffers, whilst on CAPD lactate seems to be better and safer than acetate; for instance, serum HCO3 values are relatively constant with lactate (27.7 +/- 2.13 mM/l) while with acetate there is a trend to exceed physiological values (29.5 +/- 1.7 mM/l). When acetate is used in the dialyzate for CAPD the concentration must be less than 38.5 mM/l.

Correlation of plasma gonadotrophins and ovarian steroids pattern with symptomatic changes in cervical mucus during the menstrual cycle in normal cycling women

27 healthy young Italian women were studied to evaluate their ability to identify symptomatically the potentially fertile phase of the menstrual cycle by self observation of their cervical mucus pattern as described in the Ovulation Method Billings. The women's observations were correlated with daily plasma levels of FSH, LH, estradiol-17 beta and progesterone. Ovulation was considered to occur on the day following the LH peak. The hormonal assays revealed that 2 of the 34 cycles studied were anovulatory. 24 of the 27 subjects in the study group demonstrated their ability to recognize the onset of the mucus discharge and the peak symptom from the first cycle after teaching, another two from the second cycle. The only other subject contributed an anovulatory cycle in which the hormonal assay confirmed the accuracy of her mucus observations. In the study, the mean interval between the time of ovulation as assessed and the peak symptom recorded by the subjects was 0.0 days, with a range from -2 to +1 days. The mean time interval from the first recorded symptom to the estimated day of ovulation was 6.0 days, with a range from 3 to 10 days. The study shows that young Italian women can be taught to recognize their cervical mucus pattern as described in the Ovulation Method Billings. The accuracy of their observations is demonstrated by the hormonal assays. The study also confirms the conclusion reached in earlier similar studies that there is a direct correlation between the cervical mucus symptom and the potentially fertile phase of the cycle. Research is currently being conducted on a larger number of couples employing the Ovulation Method Billings to actually regulate their fertility.

Subcellular localization of renin and kallikrein in rat kidney

The subcellular localization of renin and kallikrein in rat kidney cortex homogenate was investigated using both differential and density gradient centrifugation techniques. Highest specific activity of renin was found in the heavy mitochondrial fraction. Mitochondrial localization of renin was further supported by the behaviour of succinic dehydrogenase. By differential centrifugation, highest specific activity of kallikrein was found in the light mitochondrial fraction, while by density gradient centrifugation kallikrein was almost completely recovered in the lysosomal fraction. Lysosomal localization of kallikrein is further supported by the behaviour of acid phosphatase. The different subcellular localizations of renin and kallikrein are confirmed and the suggestion that kallikrein is located in the lysosomes is advanced.