Photocycle of point defects in highly- and weakly-germanium doped silica revealed by transient absorption measurements with femtosecond tunable pump.

We report pump-probe transient absorption measurements addressing the photocycle of the Germanium lone pair center (GLPC) point defect with an unprecedented time resolution. The GLPC is a model point defect with a simple and well-understood electronic structure, highly relevant for several applications. Therefore, a full explanation of its photocycle is fundamental to understand the relaxation mechanisms of such molecular-like systems in solid state. The experiment, carried out exciting the sample resonantly with the ultraviolet (UV) GLPC absorption band peaked at 5.1 eV, gave us the possibility to follow the defect excitation-relaxation dynamics from the femto-picosecond to the nanosecond timescale in the UV-visible range. Moreover, the transient absorption signal was studied as a function of the excitation photon energy and comparative experiments were conducted on highly- and weakly-germanium doped silica glasses. The results offer a comprehensive picture of the relaxation dynamics of GLPC and allow observing the interplay between electronic transitions localized on the defect and those related to bandgap transitions, providing a clear evidence that the role of dopant high concentration is not negligible in the earliest dynamics.

Photoinduced charge separation in functional carbon-silver nanohybrids.

In recent times, nanoscience is devoting growing interest to the easy assembly of well-established nanomaterials into hybrid nanostructures displaying new emerging features. Here, we study the photophysicochemical response of binary nanohybrids obtained by the spontaneous coupling of luminescent carbon dots to silver nanoparticles with controlled surface charge. Evidence of the successful coupling is obtained by steady-state and time resolved optical measurements and further confirmed by direct imaging. We demonstrate strong interactions within nanohybrids, which can be modelled in terms of a sub-picosecond electron transfer from photoexcited carbon dots to silver nanoparticles. Accordingly, newly designed nanohybrids display significant photocatalytic performance demonstrated by the photodegradation of methylene blue under ultraviolet-visible light. Our results provide an exhaustive picture of the optical response of these self-assembled carbon-silver nanohybrids and show their promise as a new class of eco-friendly materials for light-driven catalytic applications.

Intra-bundle contractions enable extensile properties of active actin networks.

The cellular cortex is a dynamic and contractile actomyosin network modulated by actin-binding proteins. We reconstituted a minimal cortex adhered to a model cell membrane mimicking two processes mediated by the motor protein myosin: contractility and high turnover of actin monomers. Myosin reorganized these networks by extensile intra­bundle contractions leading to an altered growth mechanism. Hereby, stress within tethered bundles induced nicking of filaments followed by repair via incorporation of free monomers. This mechanism was able to break the symmetry of the previously disordered network resulting in the generation of extensile clusters, reminiscent of structures found within cells.

UV photobleaching of carbon nanodots investigated by in situ optical methods.

Carbon dots are a family of optically-active nanoparticles displaying a combination of useful properties that make them attractive for many applications in photonics and photochemistry. Despite the initial claims of high photostability of carbon dots even under prolonged illuminations, several recent studies have evidenced their photobleaching (PB) under UV light, detrimental for some applications. A study of the mechanism and dynamics of carbon dot PB can be considered a useful route to gather relevant information on the underlying photophysics of these nanoparticles, which is still widely debated. Here we report a study of the PB of carbon dots under UV light, conducted through optical experiments under well-controlled illumination conditions. In particular, the use of a laser as an irradiation source allows a precise control of the irradiated volume, and provides accurate estimates and control of the administered energy. Besides, our setup allows spectroscopic measurements to be carried out in situ at the irradiated site, thus allowing us to investigate in real time the progress of photobleaching effects through a time-resolved approach. Therefore, our experiments allow the precise kinetics of the undergoing PB process to be captured which is found to be significantly affected by disorder and photoselection effects. Furthermore, our study discloses several pieces of information on the nature of the main blue chromophore absorbing at 340 nm and emitting at 430 nm, and on its PB mechanism. We propose that the emissive units consist in small molecular-like chromophores adsorbed on carbon dot surfaces and are in a dynamical equilibrium with free diffusing molecules in solution. Their photobleaching proceeds in two distinct steps: in the first phase, linear absorption of UV photons rapidly converts the molecular surface chromophores into a non-emissive form, likely through an isomerization, causing the disappearance of the fluorescence properties but almost no changes in the optical absorption spectra. At higher fluences, a complete destruction of the optically-active centers is observed, which completely wipes out all the absorption features of surface chromophores and only leaves a fully carbonized, yet non-fluorescent, dot core.

The dynamics of actin network turnover is self-organized by a growth-depletion feedback.

The dynamics of actin networks is modulated by a machinery consisting of actin binding proteins that control the turnover of filaments in space and time. To study this complex orchestration, in vitro reconstitution approaches strive to project actin dynamics in ideal, minimal systems. To this extent we reconstitute a self-supplying, dense network of globally treadmilling filaments. In this system we analyze growth and intrinsic turnover by means of FRAP measurements and thereby demonstrate how the depletion of monomers and actin binding partners modulate the dynamics in active actin networks. The described effects occur only in dense networks, as single filament dynamics are unable to produce depletion effects to this extent. Furthermore, we demonstrate a synergistic relationship between the nucleators formin and Arp2/3 when branched networks and formin-induced networks are colocalized. As a result, the formin-enhanced filament turnover depletes cofilin at the surface and thus protects the dense, Arp2/3 polymerized network from debranching. Ultimately, these results may be key for understanding the maintenance of the two contradicting requirements of network stability and dynamics in cells.

Cardiotoxicity of environmental contaminant tributyltin involves myocyte oxidative stress and abnormal Ca2+ handling.

Tributyltin (TBT) is an organotin environmental pollutant widely used as an agricultural and wood biocide and in antifouling paints. Countries began restricting TBT use in the 2000s, but their use continues in some agroindustrial processes. We studied the acute effect of TBT on cardiac function by analyzing myocardial contractility and Ca2+ handling. Cardiac contractility was evaluated in isolated papillary muscle and whole heart upon TBT exposure. Isolated ventricular myocytes were used to measure calcium (Ca2+) transients, sarcoplasmic reticulum (SR) Ca2+ content and SR Ca2+ leak (as Ca2+ sparks). Reactive oxygen species (ROS), as superoxide anion (O2•-) was detected at intracellular and mitochondrial myocardium. TBT depressed cardiac contractility and relaxation in papillary muscle and intact whole heart. TBT increased cytosolic, mitochondrial ROS production and decreased mitochondrial membrane potential. In isolated cardiomyocytes TBT decreased both Ca2+ transients and SR Ca2+ content and increased diastolic SR Ca2+ leak. Decay of twitch and caffeine-induced Ca2+ transients were slowed by the presence of TBT. Dantrolene prevented and Tiron limited the reduction in SR Ca2+ content and transients. The environmental contaminant TBT causes cardiotoxicity within minutes, and may be considered hazardous to the mammalian heart. TBT acutely induced a negative inotropic effect in isolated papillary muscle and whole heart, increased arrhythmogenic SR Ca2+ leak leading to reduced SR Ca2+ content and reduced Ca2+ transients. TBT-induced myocardial ROS production, may destabilize the SR Ca2+ release channel RyR2 and reduce SR Ca2+ pump activity as key factors in the TBT-induced negative inotropic and lusitropic effects.

Multimodal Approach of Pulmonary Artery Intimal Sarcoma: A Single-Institution Experience.

INTRODUCTION: Pulmonary artery sarcoma (PAS) is a rare tumor, whose therapeutic approach is mainly based on surgery, either pneumonectomy or pulmonary endarterectomy (PEA). The prognosis reported in published series is very poor, with survival of 1.5 months without any kind of treatment. PATIENTS AND METHODS: From January 2010 to January 2016, 1027 patients were referred to our hospital for symptoms of acute or chronic pulmonary thromboembolic disease. Twelve patients having a confirmed diagnosis of PAS underwent PEA. Median age was 64.5 years. Most patients had a long history of symptoms, having a median time of 7.5 months from onset of symptoms to surgery. RESULTS: Following PEA and cardiopulmonary rehabilitation, 10 patients received conventional chemotherapy with doxorubicin and ifosfamide, starting at a median of 42 days from surgery. Four patients also received radiotherapy. Four patients have died due to disease progression, while 7 are still alive, with 5 being disease-free at 4-55+ months from diagnosis. CONCLUSIONS: In patients with PAS, a multimodal approach including PEA, CT, and RT is feasible but it should be evaluated individually, according to the tumor extension and the patient's clinical condition. Apart from improving quality of life mainly by reducing or delaying symptoms due to PH, it may improve life expectancy.

Different natures of surface electronic transitions of carbon nanoparticles.

The photoluminescence behaviour of carbon-based nanodots is still debated. Both core and surface structures are involved in the emission mechanism, and the electronic transitions can be modified by external agents such as metal ions or pH, but the general relation between the structure and the optical function is poorly understood. Here, we report a comparative study on the effects of these variables, changing the core structure from crystalline to amorphous, and modifying the surface structure by different passivation procedures. Our results highlight that the emission mechanism of the tunable visible fluorescence is identical for crystalline and amorphous samples, indicating the independence of the emission from the core structure. Furthermore, surface functionalization weakly influences the emission peak position, but has large consequences on their interaction with different metal ions. This suggests the involvement of quasi-degenerate electronic states originating from the high density of different interacting groups on the surface. Finally, we report the presence of an unusual ultraviolet emission band for the amorphous sample, likely involving localized molecular-type chromophores with carboxyl ends. Our findings provide new information on the emission mechanisms of CDs and can be used to engineer sub-types of CDs displaying very similar emission features, but specifically tailored for different sensing applications.

The interaction of photoexcited carbon nanodots with metal ions disclosed down to the femtosecond scale.

Fluorescent carbon nanodots are a novel family of carbon-based nanoscale materials endowed with an outstanding combination of properties that make them very appealing for applications in nanosensing, photonics, solar energy harvesting and photocatalysis. One of the remarkable properties of carbon dots is their strong sensitivity to the local environment, especially to metal ions in solution. These interactions provide a testing ground for their marked photochemical properties, highlighted by many studies, and frequently driven by charge transfer events. Here we combine several optical techniques, down to femtosecond time resolution, to understand the interplay between carbon nanodots and aqueous metal ions such as Cu2+ and Zn2+. We find that copper inhibits the fluorescence of carbon dots through static and diffusional quenching mechanisms, and our measurements allow discriminating between the two. Ultrafast optical methods are then used to address the dynamics of copper-dot complexes, wherein static quenching takes place, and unveil the underlying complexity of their photocycle. We propose an initial increase of electronic charge on the surface of the dot, upon photo-excitation, followed by a partial electron transfer to the nearby ion, with 0.2 ps and 1.9 ps time constants, and finally a very fast (≪1 ps) non-radiative electron-hole recombination which brings the system back to the ground state. Notably, we find that the electron transfer stage is governed by an ultrafast water rearrangement around photo-excited dots, pointing out the key role of solvent interactions in the photo-physics of these systems.

Ectopic prolactinoma in the clivus: a case report.

We report the case of an ectopic pituitary adenoma in a 65-year-old man with an empty sella who initially presented with right ptosis and eyelid edema and headache. Neuroimaging studies revealed a large tumoral process at the height of the clivus, with partial destruction of surrounding bone structure. He underwent transphenoidal surgery and histopathologic examination, including immunohistochemical studies, revealed a prolactin-producing pituitary adenoma. A careful review of the literature was done.

Breast core biopsy of a rare case of unknown primary large cell neuroendocrine carcinoma metastatic to the breast.

Metastases to the breast from extramammary neoplasms are very rare. Correct diagnosis of breast malignancy is important for establishing appropriate management. Here we report a 57-year old male patient with breast metastasis from large cell neuroendocrine carcinoma (LCNEC) which was diagnosed with ultrasonography-guided-core-biopsy.

Emphysematous cholecystitis: Imaging findings.

We report a case of emphysematous cholecystitis. We also offer a review of the literature, emphasizing the clinical features, pathogenesis, imaging features and treatment of this surgical condition. Early recognition and surgical consultation are vital in these patients. The significance of plain abdominal radiographs, ultrasonography, CT and RM studies is discussed. Diagnostic problems are mentioned to help understand this rare clinical condition.

[Adrenal incidentaloma: case report and synthesis of indication and thresholds of surgery therapy]. / Un caso di incidentaloma surrenalico: sintesi delle indicazioni e limiti della terapia chirurgica.

With the term of incidental mass, any mass is identified, occasionally discovered with imaging techniques, in the absence of specific symptoms. In 1982, the term "incidentaloma" was introduced to indicate lesions detected on adrenal regions, found unexpectedly. The incidence percentages vary from 0.6%-3% in CT followed by other indications , to 10% and 25% in all patients who underwent an ultrasound, CT or MRI. An appropriate diagnostic protocol is mandatory to identify and to choose the proper treatment for the functioning lesions, as well as the malignant or potentially malignant lesions (1, 2). Incidentalomas with diameters under 1 cm seem to not have a pathologic significance, and are considered like manifestation of the gland involution in advanced-age subjects, and can remain unseen for a long time. The use of diagnostic imaging techniques has made it possible to identify these masses, even those of small size, in the course of diagnostic surveys done under various guidelines. The mass dimensions are a fundamental parameter used to distinguish benign lesions from malign ones (2, 3). Most Authors suspect malignity in masses above 5-6 cm, while considering those with a diameter under 3 cm to be benign. Whereas the rest remain undefined, thereby valued and treated according to criteria not perfectly established.

[The role of the intraoperative manometry in the esophageal achalasia surgical treatment]. / Il ruolo della manometria intraoperatoria nel trattamento chirurgico dell'acalasia esofagea.

INTRODUCTION: The authors report their experience about the intraoperative manometry in the achalasia surgical treatment. PATIENTS AND METHODS: We have considered 239 patients with achalasia observed from 1994 to 2006; only 79 continued the path diagnostic therapeutic and 31 underwent Heller longitudinal miotomy, with Dor anti-reflux plastic in 25 patients and in 6 Nissen anti-reflux plastic. In 24 we performed the intraoperative manometry (MI) recording the high pressure areas. RESULTS: The patients underwent Heller's procedure with manometric check of the gastric muscular fibre sectioned areas reported the disappearance of the dysphagia. Three of the operated ones without using the MI complained about the persistence of mild dysphagia and it did not depend from the antireflux surgical procedure used. CONCLUSIONS: Our findings confirm that the extramucosal miotomy is the treatment of choice for the achalasia and suggest that by MI a complete miotomy is allowed mostly on the gastric side where the muscular fibres get an important role in the maintenance of the high pressure areas.

[Infected pancreatic pseudocysts: technical notes]. / Pseudocisti pancreatiche infette: note di tecnica.

INTRODUCTION: Starting from the observation of 9 cases of giant infected pancreatic cysts, which occurred from 1994 to 2004 at the Department of Oncological and Surgical Studies, the Authors' aim has been to evaluate whether a more thorough necrosectomy, carried-out under video-endoscopic control, associated with a nose-gastro-cavity tube, which ensures a continuous cleansing of the newly-formed cavity, and an appropriate positioning of the drainages, could reduce the morbidity and allow a shorter recovery of the infected pseudocysts. PATIENTS AND METHODS: Of 73 cases of acute pancreatitis, observed from 1994 to 2004, 9 showed severe and acute pancreatitis, which included giant pseudocysts, as revealed by the abdomen angio-TC. Our nine septic patients underwent cysto-gastro-anastomosis, necrosectomy, intraoperative cleansing of the cavity with an antibiotic solution and positioning of multiple drainages. Three of these patients also underwent a thorough and targeted necrosectomy, assisted by a trans-anastomotic video-endoscopy. A nose-gastro-cavity tube has been placed in all the patients. RESULTS: The disappearance of the septic state in our three patients who underwent a targeted video-assisted necrosectomy occurred after three days of treatment; moreover, the abdomen angio-TC on the 5th postoperative day showed the disappearance of the necrotic areas. The recovery of these three patients was significantly shorter, compared to those undergoing traditional treatment (cysto-gastro-anastomosis, standard necrosectomy and positioning of abdominal drainages). CONCLUSIONS: Our surgical video-assisted technique demonstrated that, with a slight increase in the operative time, a better control over sepsis may be accomplished, as well as a reduction of the post-operative morbidity, which leads to shorter hospitalisation of patients with infected pancreatic pseudocysts.

Can losartan improve cardiac performance during the treadmill exercise test in hypertensive subjects?

Systolic blood pressure (SBP) normally increases during exercise. This increase is frequently exaggerated in hypertensive individuals. The aim of our study was to evaluate the antihypertensive effects of losartan at peak exercise and on cardiac performance during the treadmill test in individuals with essential hypertension. Forty subjects with a mean age of 44.2 +/- 12.4 years and with mild-to-moderate essential hypertension were enrolled. After a 14-day washout period, all selected subjects were given a treadmill exercise test using the modified Bruce protocol for exercise. The test was performed at the end of the washout period (step 0), again after 1 month (step 1), after 3 months (step 2) and after 6 months (step 3) of losartan administration (50 mg/daily per oral). Heart rate, SBP and diastolic blood pressure (DBP) were measured at rest and at maximal exercise. Exercise duration and double product were also recorded. In all patients who completed the study, a significant reduction from baseline in SBP at rest was found at 3 and 6 months (p < 0.05). No significant reduction from baseline in SBP at peak exercise was observed. No significant changes from baseline were found in double product, DBP, heart rate or exercise time. The results of our study suggest that losartan is effective in reducing blood pressure only at rest but is unable to improve exercise BP response or cardiac performance in subjects with mild-to-moderate essential hypertension.

Dizziness and vertigo in a department of emergency medicine.

Dizziness is a common and vexing diagnostic problem in emergency departments. The term is rather undefinite and often misused, but can in practice be classified into four categories: fainting, disequilibrium, vertigo and miscellaneous syndromes. Vertigo is the most common category of dizziness. Classification of vertigo can be based either on chronological criteria (acute, recurrent or chronic vertigo) or on topographical criteria (peripheral or central vertigo). Physicians working in emergency departments must be able to rapidly identify patients with potentially serious forms of vertigo, which could cause death or disability, and patients with mild conditions, that can be effectively treated. Previous studies and the experience of the authors have shown that reliable diagnostic hypotheses can be generated by taking a proper clinical history (focused on the onset and duration of the disease, the circumstances causing the vertigo and associated otological or neurological symptoms) and performing an accurate physical examination (evaluation of neurological defects and spontaneous or provoked nystagmus), supplemented by few laboratory tests and diagnostic procedures. Therapy of vertigo in emergency settings is mainly symptomatic and based on sedation and use of vestibulosuppressant drugs (antihistamines, phenothiazines).

The efficacy of administering blood transfusions at home to terminally ill cancer patients.

Comfort care for cancer patients in the terminal stage has been the goal of hospice programs since their inception. Among the many treatment modalities available to homebound patients, transfusions have been little studied for their effects on advanced disease symptoms, particularly for those in the terminal phase. Our work in a hospital-based home care program established in 1978 led us to believe that blood transfusions neither slowed the progress of symptoms nor relieved their severity. Our hypothesis being that transfusions do not improve or significantly change the quality of life of terminally ill patients, we studied 24 men and women with various forms of advanced cancer. The only significant clinical difference between pre- and post-transfusion variables was in hematocrit. In the subjective testing, the only significant difference was in the quality of life index completed by the patient. This result could be interpreted as a positive psychological benefit from blood transfusions. The results of other subjective tests, although statistically less significant, also showed a trend toward psychological benefit from transfusions. It would be necessary to carry out studies with a larger sample to conclude that this is indeed the case.

A comparative assessment of home versus hospital comprehensive treatment for advanced cancer patients.

A prospective comparative analysis of home and hospital comprehensive treatment for advanced non-ambulatory cancer patients was conducted. Patients were assigned to hospital (group A) and home (group B) treatment groups based on geographic location. Home treatment was provided by the Don Monti Home Oncology Medical Extension (HOME) program. A multidisciplinary health team, including an oncologist, oncology nurse, social worker, dietitian, and medical technologist, was transported to the home in a medically equipped van. Services included physical examinations, pain control, psychosocial interventions, chemotherapy and blood transfusions, nutrition consultation, and bereavement counseling. One hundred seventy-four patients were treated at home and 44 in the hospital. Pretreatment characteristics were similar for both groups, with the exception that age under 50 years was more frequent in the hospital group, and home patients were more likely to have gastrointestinal (GI) cancer. Medical benefits for home treatment included decreased narcotic analgesic requirements, decreased hospitalization and length of stay, and improved measurements of fat stores for female patients. Improved survival for home patients was related to Karnofsky performance status, since there was no difference in survival for sicker patients with lower performance status whether they received home or hospital treatment. Patient and family acceptance of home treatment was excellent. Comprehensive home treatment provided by a multispecialty oncology team is an effective alternative to hospitalization for terminal cancer patients.

Comparative cost analysis of home and hospital treatment.

A comparative study evaluating home and hospital treatment for terminal cancer patients is reported. Home care was provided by a comprehensive home care program, the Don Monti Home Oncology Medical Extension (H.O.M.E.). A multispecialty team including an oncologist, oncology nurse, social worker, dietitian and technologist is transported to the home in a medically-equipped van to render treatment. Services provided include physical assessments, pain control, chemotherapy and transfusion administration, psychosocial support, nutrition education and bereavement counseling. Two-hundred eighteen patients were entered of which 174 were treated at home and 44 in the hospital. Patients were comparable in age, diagnosis, sites of metastases, prior treatment and Karnofsky status. Both groups received similar supportive care either at home or in the hospital. Cost analysis of home and hospital care revealed a per diem cost benefit of $256.00 for home treatment. Comprehensive home treatment provided by a multi-specialty team can deliver effective care with medical and financial benefits to terminal cancer patients.