Corrigendum: Controlling hybrid nonlinearities in transparent conducting oxides via two-colour excitation.

This corrects the article DOI: 10.1038/ncomms15829.

Controlling hybrid nonlinearities in transparent conducting oxides via two-colour excitation.

Nanophotonics and metamaterials have revolutionized the way we think about optical space (ɛ,µ), enabling us to engineer the refractive index almost at will, to confine light to the smallest of the volumes, and to manipulate optical signals with extremely small footprints and energy requirements. Significant efforts are now devoted to finding suitable materials and strategies for the dynamic control of the optical properties. Transparent conductive oxides exhibit large ultrafast nonlinearities under both interband and intraband excitations. Here we show that combining these two effects in aluminium-doped zinc oxide via a two-colour laser field discloses new material functionalities. Owing to the independence of the two nonlinearities, the ultrafast temporal dynamics of the material permittivity can be designed by acting on the amplitude and delay of the two fields. We demonstrate the potential applications of this novel degree of freedom by dynamically addressing the modulation bandwidth and optical spectral tuning of a probe optical pulse.

Optically induced metal-to-dielectric transition in Epsilon-Near-Zero metamaterials.

Epsilon-Near-Zero materials exhibit a transition in the real part of the dielectric permittivity from positive to negative value as a function of wavelength. Here we study metal-dielectric layered metamaterials in the homogenised regime (each layer has strongly subwavelength thickness) with zero real part of the permittivity in the near-infrared region. By optically pumping the metamaterial we experimentally show that close to the Epsilon-Near-Zero (ENZ) wavelength the permittivity exhibits a marked transition from metallic (negative permittivity) to dielectric (positive permittivity) as a function of the optical power. Remarkably, this transition is linear as a function of pump power and occurs on time scales of the order of the 100 fs pump pulse that need not be tuned to a specific wavelength. The linearity of the permittivity increase allows us to express the response of the metamaterial in terms of a standard third order optical nonlinearity: this shows a clear inversion of the roles of the real and imaginary parts in crossing the ENZ wavelength, further supporting an optically induced change in the physical behaviour of the metamaterial.

Enhanced Nonlinear Refractive Index in ε-Near-Zero Materials.

New propagation regimes for light arise from the ability to tune the dielectric permittivity to extremely low values. Here, we demonstrate a universal approach based on the low linear permittivity values attained in the ε-near-zero (ENZ) regime for enhancing the nonlinear refractive index, which enables remarkable light-induced changes of the material properties. Experiments performed on Al-doped ZnO (AZO) thin films show a sixfold increase of the Kerr nonlinear refractive index (n_{2}) at the ENZ wavelength, located in the 1300 nm region. This in turn leads to ultrafast light-induced refractive index changes of the order of unity, thus representing a new paradigm for nonlinear optics.

Complete energy conversion by autoresonant three-wave mixing in nonuniform media.

Resonant three-wave interactions appear in many fields of physics e.g. nonlinear optics, plasma physics, acoustics and hydrodynamics. A general theory of autoresonant three-wave mixing in a nonuniform media is derived analytically and demonstrated numerically. It is shown that due to the medium nonuniformity, a stable phase-locked evolution is automatically established. For a weak nonuniformity, the efficiency of the energy conversion between the interacting waves can reach almost 100%. One of the potential applications of our theory is the design of highly-efficient optical parametric amplifiers.

Kidney instant monitoring (K.IN.G): a new analyzer to monitor kidney function.

AIM: The key role of the kidney in the regulation of body fluids and acid-base status is well known. Nonetheless, urine analysis has not received great attention in critically ill patients, likely due to the common practice of only analyzing 24-hour collected specimens. We hypothesized that the kidney may react more rapidly to minimal hemodynamic and acid-base status variations than can be assessed by a 24-hour analysis. Accordingly, we developed and tested a urine analyzer, allowing quasi-continuous urinary analysis. METHODS: A novel analyzer (Kidney INstant monitorinG--K.IN.G) was developed that allows non-invasive, quasi-continuous analysis of urine pH, sodium, chloride, potassium and ammonium levels. Analytic measurement accuracy was calculated for urine samples of patients admitted to ICUs as well as medical staff, using standard techniques as references. For clinical investigation, approximately 200 patients were connected to the analyzer after ICU admission until discharge. Clinically relevant parameters were recorded. Here, three cases are presented. RESULTS: For each analytic parameter, the accuracy of measurements obtained with the K.IN.G analyzer appeared to be acceptable as compared to those of the reference techniques. In case 1, urine analysis revealed increased urinary sodium and chloride excretion strictly in parallel with mean arterial pressure, and increased ammonium excretion which was associated with moderate hypercapnia. Case 2 showed increases in urinary pH and sodium and chloride levels following awakening after sedation suspension. In case 3, urine analysis revealed an impairment of renal concentrative power, which was associated with hypovolemia. CONCLUSION: The K.IN.G analyzer, allowing quasi-continuous monitoring of urinary pH and principal electrolyte levels, may represent a novel tool for clinical and research purposes.

X entanglement: the nonfactorable spatiotemporal structure of biphoton correlation.

We investigate the spatiotemporal structure of the biphoton entanglement in parametric down-conversion (PDC) and we demonstrate its nonfactorable X-shaped geometry. Such a structure gives access to the ultrabroad bandwidth of PDC, and can be exploited to achieve a biphoton temporal localization in the femtosecond range. This extreme localization is connected to our ability to resolve the photon positions in the source near field. The nonfactorability opens the possibility of tailoring the temporal entanglement by acting on the spatial degrees of freedom of twin photons.

Candidosis in the intensive care unit: a 20-year survey.

Deep-seated candidosis is a major problem in critically ill patients. Colonization with candida has been identified as an important independent risk factor for the development of candidaemia. Since the 1980s routine surveillance cultures have been performed on patients admitted for six or more days to the 'E. Vecla' intensive care unit (ICU) of the IRCCS Ospedale Maggiore di Milano. Colonization was observed on admission to the ICU in 59 of 117 (50%) patients in 2000 and 10 others developed colonization during their stay on the unit. A similar colonization rate was found in a survey performed 16 years earlier. The incidence of non-albicans Candida species, however, increased in 2000. In particular, 24 patients were culture positive for Candida glabrata at some point during their hospital stay, whereas this species was isolated from only one patient in 1983-1984. Antifungal susceptibility testing performed by Sensititre Yeast One revealed no resistance among 19 C. albicans strains tested. In contrast, fluconazole resistance was observed in two of 39 (5%) C. glabrata isolates from 23 patients. In the period 1983-2002, 28 candida bloodstream infections were identified and 12 were considered to be ICU-acquired (2.6/1000 hospitalized patients; 0.33/1000 patient days). The low rate of ICU-acquired candidaemia despite the inclusion of severely compromised patients in this study confirms the usefulness of routine mycological surveillance in preventing deep-seated candidosis.

A blunt complex abdominal trauma: total hepatectomy and liver transplantation.

A victim of a motor accident was referred to the Emergency Department. He was unconscious, breathing was rapid and shallow, and had a mean arterial pressure of 60 mmHg with a distended abdomen. A peritoneal lavage was positive for blood. An immediate laparotomy showed a massive hepatic injury with bilobar disruptions. After an unsuccessful hepatorrhaphy an extensive perhepatic gauze packing was done. During the operation the patient was massively transfused and high doses of dopamine were used. At the end a relative stability was reached, but a few hours later, due to the high risk of sepsis and abdominal compartment syndrome, a second laparotomy was performed. Despite efforts to reach a good hemostasis, it was decided to perform a total hepatectomy and portocaval shunt. The patient was put on the waiting list for a compatible liver. After 36 h in this anhepatic state, the patient received the new graft. The graft showed immediate recovery. In cases of severe and complex liver trauma, performing a total hepatectomy followed by liver transplantation is justified.

Simultaneous kidney and pancreas transplantation at the San Raffaele Scientific Institute: clinical experience and results.

Pancreas and kidney transplantation is performed in uremic IDDM patients to cure end-stage renal failure and diabetes. Seventy-two simultaneous kidney-pancreas transplantations were performed at our Institution between July 1985 and November 1994. All transplants were performed using heart-beating cadaver donors. The first 25 patients received 26 segmental pancreas according to Dubernard (KPS), whereas the last 46 patients received a whole, bladder-drained pancrea according to Sollinger (KPW). Mean pancreas cold and warm ischemia times were 294 +/- 14 and 44 +/- 2 minutes, respectively, in the KPS group and 660 +/- 37 and 40 +/- 8 minutes, respectively, in the KPW group. Twelve (48%) KPS patients and 19 (41%) KPW patients had postoperative pancreas surgical complications: vascular thrombosis led to graft failure in 5 KPS patients (20%) and 2 KPW patients (4%) (p = 0.01). Pancreatic fistula, hemorrhagic complications, and duodenum-bladder leakage were the surgical complications observed more frequently. Six KPS patients (24%) and 8 KPW patients (17%) underwent reintervention as a consequence of surgical complications. Fifteen KPS patients (60%) and 30 KPW patients (65%) experienced an acute kidney rejection episode, which was steroid-resistant in 14 KPW and 2 KPS patients. The actuarial survival rates for simultaneous kidney-pancreas recipients at one and 4 years were 92% and 84%, respectively, for KPS recipients, and 95% and 88%, respectively, for KPW patients. Kidney actuarial survival rates at one and 4 years were 96% and 76% respectively, for group KPS, and 93% and 89%, respectively, for KPW patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Deranged platelet calcium homeostasis in poorly controlled IDDM patients.

OBJECTIVE: Platelet hyperfunction frequently occurs in IDDM. As in many other cellular systems, cytosolic free Ca plays a key role in platelet activation. RESEARCH DESIGN AND METHODS: We measured cytosolic free Ca concentration ([Ca2+]i) by means of the fluorescent probe fura-2 in 60 IDDM patients (mean age 30.8 yr, range 18-50 yr) and in 31 age-matched healthy control subjects. Platelets were studied in both resting conditions and after stimulation with thrombin at 0.05, 0.1, and 0.5 U/ml. RESULTS: No differences were noted between control subjects and diabetic patients, as a whole. Patients with a poor metabolic control (HbA1c > 8%) had significantly (P < 0.01 and P < 0.03) higher [Ca2+]i in resting platelets. The presence or absence of retinopathy did not modify resting platelet [Ca2+]i. After stimulation with thrombin, a significantly (P < 0.009) higher rise of platelet [Ca2+]i was observed only in those patients who were both free from complications and had good metabolic control. A highly significant (P < 0.001) correlation was found between resting [Ca2+]i and both blood cholesterol and HbA1c in the diabetic patients. Platelets from 10 young healthy subjects also were studied after in vitro incubation with various glucose concentrations (from 1.68 to 56 mM): resting and thrombin-stimulated platelet [Ca2+]i and thrombin-induced aggregation were not modified. CONCLUSIONS: These data confirm that platelet hyperfunction is present in IDDM patients who have unsatisfactory metabolic control, and give evidence that such an activation involves Ca homeostasis. Acute variations of blood glucose concentration are probably not influent, in this respect.