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Impact and compression-after-impact (CAI) tests were carried out on [02/ ± 45]s carbon/epoxy samples to characterize the effect of z-pinning on the delamination resistance and damage tolerance properties of the laminate. Unpinned and z-pinned samples were subjected to impacts between 2 and 36 J to produce damage conditions that extend from barely visible impact damage (BVID) to complete penetration. The damage induced by impact and the damage modes leading to ultimate CAI failure were examined by X-radiography and by direct observations of the sample faces during CAI loading. The analyses indicate that the role of z-pins on the impact and CAI response of the laminate is dependent on the size and features of the damage. Z-pins do not modify the structural response to impact of the laminate, but they are effective in reducing the extent of damage for impact energies above a threshold value. Z-pinning is also effective in improving the CAI strength of the laminate for impact energies above this threshold value, even though it degrades the residual compressive strength for lower impact energies. Reductions in impact delamination size of up to 50% and improvements in CAI strength of about 20% were achieved by z-pinning for high-energy impacts. The mechanisms by which the z-pins affect the CAI response of the samples are illustrated and examined in detail for different impact damage severities.

In the past few decades, the need for efficient and reliable Structural Health Monitoring strategies has led to the development of several approaches for damage detection and characterization purposes. Among them, the Nonlinear Vibro-Acoustic Modulation (VAM) exploits the modulation arising from the interaction of two concurrently applied driving waves, namely the probe and the pump excitations, in the presence of nonlinear scatters such as cracks and defects. Therefore, the VAM provides information on the emergence of internal damage by extracting the nonlinear modulated components of the response of a damaged system. Originally proposed for granular media, the method has shown to be effective in detecting the presence of defects also in metals and composite materials. Nonetheless, its efficacy is highly affected by the excitation frequencies, which are usually chosen among the system resonances. The need for a preliminary modal analysis and, at once, the risk of selecting pump-probe frequency combinations with low sensitivity to damage may make the procedure time-consuming and not fully reliable, preventing the VAM technique from being widely accepted as a robust monitoring tool. To overcome these limitations, a broadband excitation may be used. This study assesses the effectiveness of the VAM technique when a combination of a frequency-swept pump excitation and a mono-harmonic probe wave is applied to drive the sample. Experimental tests were conducted on a composite laminated beam mounted on an electrodynamic shaker and tested in both pristine and damaged conditions. Low-profile surface-bonded piezoceramic transducers were used for both probe excitation and sensing. Barely visible impact damage (BVID) was introduced in the composite beam to examine the potential of the approach for the detection of very small, localized damage. The results show that the use of VAM with a broadband low-frequency excitation may be an effective option for identifying nonlinearities associated with typical damage occurring in composite structures.

Composite materials provide many advantages over more conventional materials. However, their susceptibility to impact damage can question their use in critical load-bearing structures, and efficient methods are needed for early damage detection. To this purpose, the nonlinear vibro-acoustic modulation (VAM) technique applies a low-frequency pump excitation and a high-frequency probe excitation to exploit the onset of harmonic components around the probe frequency of the damaged structural response. The VAM technique has been widely studied on structures instrumented with piezoceramic transducers used for both actuation and sensing, but few attempts have been made to use equipment typical of modal testing, such as shakers and accelerometers. In this study, the VAM technique is applied to a composite laminate beam by employing an electro-dynamic shaker to generate low-frequency flexural excitation, a low-profile piezoceramic transducer to introduce the probe wave, and a micro-accelerometer to sense the structural response. Three resonance low frequencies and two acoustic frequencies are considered in different testing scenarios, at increasing levels of excitation amplitude. The results show a general good performance of the technique with the adopted experimental setup, the choice of the probe frequency and the higher level of the pump excitation having a significant impact on its sensitivity.

Migration of natural reservoir fines mobilised by water production may cause significant well productivity decline. The aim of this work is long-term productivity forecast from the production history under fines migration. We derive an exact solution of the radial inflow problem for suspension with size-distributed particles. The exact solution allows for detailed analysis of the structure of the flow domain and for an implicit formulae for well impedance. Six model coefficients are determined from the history of well production and fines concentration in the produced fluid. 23 field cases have been matched by the analytical model. Close agreement between the field and modelling data and common variation intervals for the tuned model parameters validate the model proposed. The analytical model allows determining the size of the damaged zone during water production under fines migration, which is important for well stimulation planning and design.

In this study, the structural and fracture behavior of cementitious composite beams subjected to flexural loads is experimentally and numerically investigated. Six series of mortar specimens reinforced with steel mesh layer ware cast and tested in 4–point bending. Configurations with 2, 4 or 6 mesh layers were examined to characterize the flexural response of materials. A 3D FE model was developed in ABAQUS to predict the nonlinear behavior of the beams and to simulate the evolution of fracture patterns under an increasing load. The nonlinear cracking and crushing response of the mortar was implemented by using the Concrete Damage Plasticity model. For the steel reinforcement, an elasto-plastic model with isotropic hardening was adopted. The results of the numerical analysis are discussed. Comparisons between numerical and experimental results highlight a reasonably good agreement both in term of structural response and of damage growth.

Pseudoangiomatous stromal hyperplasia (PASH) is an uncommon benign mesenchymal breast lesion. There are extremely rare reports of PASH arising in accessory breast tissue. To date, in literature, fewer than 10 cases of PASH occurring in axillary region have been described. We report a case presenting as axillary lump in a young woman. A 20-year-old female presented to our surgical unit for a progressively growing and painful palpable mass of the right axilla for about a year. Before surgery an ultrasound was performed. The patient underwent local excision of the lesion under local anaesthesia. Through histological and immunohistochemical examination a pseudoangiomatous stromal hyperplasia (PASH) was diagnosed. At 6 months of followup the patient is free of disease. It is important to include PASH also in the differential diagnosis of axillary lumps. Histological examination of the surgical specimen and surgery represent, respectively, the mainstay for diagnosis and therapy.

The Investigations of this article focus on the response of an Al2O3:C radioluminescence (RL) prototype for medical dosimetry in a 6 MV photon beam. The prototype can be configured using two types of detectors coupled to fiber-optic cables - single crystal (1 x 1 x 2 mm(3)) and droplets (in two grain sizes, 38 and 4 mu m, molded in r =0.5 mm,1= 200 mu m). By using the appropriate filters in addition to time gating it is possible to remove disturbance present during irradiation: the stem effect. Pre -irradiation of the dosimeters to a dose of 300 Gy made the memory effects in Al2O3:C negligible, so as to not impair the dosimetric properties of the system. The key findings are that the system is suitable for small field beam dosimetry, while giving overall good dose response in other features (i.e., beam profile, dose rate - FF and FFF modes). The results show that our prototype can be used for real time dose rate assessment in medical photon dosimetry without many correction factors. The 41 mu m RL measurement results are in excellent agreement (i.e. below 1%) with the dose delivered according to standard beam data. (C) 2018 Elsevier B.V. All rights reserved.

The spread of infections from multi-resistant bacteria in hospitals around the world is raising at an alarming rate. With the increasing capacity of bacteria to develop resistance to traditional antibiotics that target a particular metabolic pathway inside the cell, the use of nanoparticles as therapeutic agents is gaining importance because of their ability to attack bacterial membranes without evoking resistance. We have synthesized the catanionic surfactants Coum12–Coum18, based on fluorescent lactose-derivative organic salts using low-cost starting materials. In water, they self-assemble spontaneously to form stable aggregates at a physiological pH. The antibacterial properties of Coum12–Coum18 were investigated towards multi-drug-resistant Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Compound Coum18 was found to have both a bacteriostatic and a bactericidal activity towards Gram-positive bacteria, although the values of both the MIC and MBC (32 μg mL−1) suggest only a topical use of the molecule. The valuable results that were found provide a challenging task for further investigation aimed at the development of this class of antibacterial drugs. In vitro fluorescence microscopy gave insight into the interaction between the aggregates and the cellular membranes on HeLa and CHO cells.

In this work, a multi-technical bulk and surface analytical approach was used to investigate the bioleaching of a pyrite and arsenopyrite flotation concentrate with a mixed microflora mainly consisting of Acidithiobacillus ferrooxidans. X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and X-ray-induced Auger electron spectroscopy mineral surfaces investigations, along with inductively coupled plasma-atomic emission spectroscopy and carbon, hydrogen, nitrogen and sulphur determination (CHNS) analyses, were carried out prior and after bioleaching. The flotation concentrate was a mixture of pyrite (FeS(2)) and arsenopyrite (FeAsS); after bioleaching, 95% of the initial content of pyrite and 85% of arsenopyrite were dissolved. The chemical state of the main elements (Fe, As and S) at the surface of the bioreactor feed particles and of the residue after bioleaching was investigated by X-ray photoelectron and X-ray excited Auger electron spectroscopy. After bioleaching, no signals of iron, arsenic and sulphur originating from pyrite and arsenopyrite were detected, confirming a strong oxidation and the dissolution of the particles. On the surfaces of the mineral residue particles, elemental sulphur as reaction intermediate of the leaching process and precipitated secondary phases (Fe-OOH and jarosite), together with adsorbed arsenates, was detected. Evidence of microbial cells adhesion at mineral surfaces was also produced: carbon and nitrogen were revealed by CHNS, and nitrogen was also detected on the bioleached surfaces by XPS. This was attributed to the deposition, on the mineral surfaces, of the remnants of a bio-film consisting of an extra-cellular polymer layer that had favoured the bacterial action.

In this work, the microbe-mediated oxidative dissolution of enargite surfaces (Cu(3)AsS(4)) was studied on powdered samples exposed to 9K nutrient solution (pH 2.3) inoculated by Acidithiobacillus ferrooxidans initially adapted to arsenopyrite. These conditions simulate the acid mine environment. The redox potential of the inoculated solutions increased up to +0.72 V vs normal hydrogen electrode (NHE), indicating the increase of the Fe(3+) to Fe(2+) ratio, and correspondingly the pH decreased to values as low as 1.9. In the sterile 9K control, the redox potential and pH remained constant at +0.52 V NHE and 2.34, respectively. Solution analyses showed that in inoculated medium Cu and As dissolved stoichiometrically with a dissolution rate of about three to five times higher compared to the sterile control. For the first time, X-ray photoelectron spectroscopy (XPS) was carried out on the bioleached enargite powder with the aim of clarifying the role of the microorganisms in the dissolution process. XPS results provide evidence of the formation of a thin oxidized layer on the mineral surface. Nitrogen was also detected on the bioleached surfaces and was attributed to the presence of an extracellular polymer substance layer supporting a mechanism of bacteria attachment via the formation of a biofilm a few nanometers thick, commonly known as nanobiofilm.

Photon beams produced by a cobalt-60 Unit and a 6 MV linear accelerator equipped with stereotactic collimators were used to investigate some dosimetric properties of a radioluminescent dosimeter based on a Ce-doped optical fibre. The stability of the signal with increasing the irradiation time, enabled a reliable and real-time measurement of the dose rate. The methods, recently developed, of optical coupling, light collection and signal processing allowed to achieve a satisfactory signal to noise ratio, a good reproducibility and a linear dose-response. The punctual dimension of the doped fibre diameter was exploited in the characterization of stereotactic fields, providing results in agreement with those obtained using a micro-ionization chamber. © 2008 Elsevier Ltd. All rights reserved.

Phosphorescence emitted by a new dosimetric system based on a SiO2 optical fibre doped with Ce3+ ions was investigated. The defects in the matrix that, acting as electron traps, originate the phosphorescence signal were studied by means of thermally stimulated luminescence in the temperature interval 313-533 K. A continuous trap distribution with activation energies extending from 0.8 to 1.5 eV was observed. On the basis of these findings, the temperature dependence of the shape of isothermal phosphorescence decay was analysed and the corresponding spectrum was compared with that of radioluminescence. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Background HCV infection beside chronic hepatitis can induce immunological disorders with different clinical expressions such as chronic arthritis. Aim To study the prevalence of arthritis in HCV-Ab positive patients and verify possible correlation with viral replication, hepatic damage and autoimmunity imbalance. Study design Three hundred and eighty patients (196 M and 184 F) affected by HCV infection were examined and 38 (10%) were selected according to the presence of arthritis. Eight of them were excluded because arthritis raised before HCV infection. Each patient, once undergone liver biopsy, was evaluated for: clinical examination (articular evolution), Rx examination, serum expression of hepatic damage (mainly ALT), viral replication, and involvement of autoimmunity (ANA, RF, crioglobulins, AKA, CCP). Results Data from patients [Lamprecht P, Gause A, Gross WL. Cryoglobulinemic vasculitis. Arthritis Rheum 1999; 42:2507–16.] with AKA and CCP positivity were not considered for statistical examination because the clear correlation between rheumatoid arthritis and these parameters. The remaining 20 patients showed hepatic damage 47%, viral replication in 74%, RF 42%, ANA 16%, crioglobulins 42% (RF positive). No correlation was evident between ANA serum concentrations and viral replication; furthermore a significant negative correlation between RF positivity and viral replication only in a subgroup of patients with serologic expression of hepatic damage was found. Conclusions These data support hypothesis that the onset of arthritis and presence of autoimmunity parameters ANA, RF are not related to the viral replication but others mechanism immunological induced by HCV might be considered.

A feasibility study for the use of a Ce3+-doped optical fibre as a radio luminescent dosimeter in radiotherapy was carried out. The prototype showed a satisfactory reproducibility (1.7%) and a good linearity over a clinically relevant dose range (from few cGy to approximately 10 Gy). Moreover, the device enabled a reliable evaluation of the absorbed dose, independently of the dose rate and of the orientation of the incoming radiation. A slight energy dependence of the response was observed when the system was irradiated with electron beams of different energies. The results indicate that the employment of this new system might be very promising both for quality control measurements and "in vivo" dosimetry. Some improvements are nevertheless still required in order to allow a real-time evaluation of the Cherenkov radiation produced by the irradiated portion of the passive optical fibre, which influences some of the dosimetric properties of the system. (c) 2006 Elsevier B.V. All rights reserved.

In this paper, errors and discrepancies in the subject paper [Cincotti et al. (2002)] are highlighted. A comment, concerning the axial resolution associated to the adopted processing procedure is also reported.

A novel series of 1-[2-(diarylmethoxy)ethyl]-2-methyl-5-nitroimidazole (DAMNI) analogues were synthesized and tested in cell-based assays and in enzyme assays against HIV-1 recombinant reverse transcriptase (RT). Preparation of the new derivatives was performed by reacting the appropriate benzhydrols or the corresponding bromides with 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole or the 3-hydroxypropyl homologue. Several compounds showed anti-HIV-1 activity in the submicromolar range. Structure-activity relationship studies suggested that meta substitution at one phenyl ring of the diarylmethane moiety strongly influences the antiviral activity. The 3,5-disubstitution at the same phenyl ring led to less potent derivatives. Molecular modeling and docking studies within the RT non-nucleoside binding site confirmed that DAMNIs, similar to other NNRTIs such as TNK-651 and delavirdine (BHAP U90152), assume a butterfly-like conformation that appears to be halfway between that of classical NNRTIs, such as nevirapine, HEPT, TBZ, TIBO, and DABOs, and the conformation of BHAPs. In particular, the diphenylmethane moiety mimics the wings whereas the 1-(2-methyl-5-nitroimidazolyl)ethane portion resembles the BHAP 5-methanesulfonamidoindole-2-carbonylpiperazine portion.

The synthesis and in vitro anti human immunodeficiency virus (HIV) and anti-hepatitis B virus (HBV) activities of some unnatural β- l -nucleoside enantiomers related to the anti-HIV compound 2′,3′-dideoxy-3′-fluoro-5-chlorouridine (β- d -3′Fdd5ClU) are reported. In contrast to β- d -3′Fdd5ClU, β- l -3′Fdd5ClU and the other l -congeners were devoid of significant anti-HIV effects, but β- l -2′,3′-dideoxy-5-chlorocytidine (β- l -dd5ClC) and β- l -2′,3′-dideoxy-3′-fluoro-cytidine (β- l -3′FddC) showed a distinct anti-HBV activity. Three mononucleoside phosphotriester derivatives with S -pivaloyl-2-thioethyl ( t- BuSATE) groups as biolabile phosphate protective groups were also synthesized. The bis( t -BuSATE) derivative of β- d -3′Fdd5ClU retained anti-HIV activity in thymidine kinase deficient (TK − ) CEM cells.

To the Editor: Streptococcus suis, a major swine pathogen worldwide, is emerging as a zoonotic agent capable of causing a variety of serious infections in swine as well as in persons exposed to pigs or to pork products. These infections include meningitis, septicemia, pneumonia, endocarditis, arthritis, and septic shock (1,2). Despite recent outbreaks among persons in China, S. suis disease in humans is a rare, probably underdiagnosed infection that usually occurs as sporadic cases (1,2). Persons in close occupational or accidental contact with pigs or pork products and those who eat uncooked or undercooked pork may be at higher risk than others. However, most infected persons are likely healthy carriers, and S. suis is believed to induce overt disease (especially meningitis) in only some circumstances (2). We describe a case of S. suis meningitis in a 68-year-old man from Sardinia, Italy, who had no reported contact with swine, other animals, or any animal products; the patient also had cancer, which was discovered incidentally during the workup. In November 2007, the patient was hospitalized with a 48-hour history of fever, headache, nausea, and general malaise. Physical examination showed impaired consciousness, nuchal rigidity, and a temperature of 39.5°C. Laboratory findings were 20,700 leukocytes/mm3 with 92% neutrophils, glucose 95 mg/dL, and C-reactive protein 375 mg/L. Cerebrospinal fluid (CSF) analysis demonstrated 240 leukocytes/μL with 80% polymorphonuclear cells, glucose 24 mg/dL, and protein 277 mg/dL. A computed tomography scan of the head showed no abnormal findings. Gram stain of CSF showed gram-positive cocci, mostly in pairs (Figure). Figure Gram-positive cocci, mostly in pairs, in cerebrospinal fluid from a 68-year-old man with Streptococcus suis meningitis. Magnification ×1,000. Empirical therapy consisted of intravenous ceftriaxone (2 g twice a day) and oral chloramphenicol (2 g once a day). On day 5, α-hemolytic streptococci were isolated from CSF on sheep blood agar and identified as S. suis by using APIStrep (bioMerieux, Marcy l’Etoile, France). Serotyping, performed by slide agglutination with specific antiserum (Statens Serum Institute, Copenhagen, Denmark), identified the isolate as serotype 2. Antimicrobial drug­­–susceptibility testing, performed according to guidelines of the Clinical and Laboratory Standards Institute (www.clsi.org), indicated susceptibility to penicillin, ceftriaxone, chloramphenicol, levofloxacin, and vancomycin and resistance to erythromycin (MIC >128 mg/L) and tetracycline (MIC 16 mg/L). Erythromycin resistance was constitutive and was mediated by the erm(B) determinant; tetracycline resistance was mediated by tet(W). Multilocus sequence typing (http://ssuis.mlst.net) assigned the S. suis isolate to sequence type (ST) 1. The patient, a retired welder, denied any recent occupational or even occasional contact with swine or other animals and had no history of eating raw or undercooked pork. The patient’s condition improved; chloramphenicol was discontinued on day 10, but the 14-day course of ceftriaxone was completed. On day 6, the patient became afebrile but had dizziness and deafness; a formal audiology evaluation on day 9 showed severe bilateral sensorineural high-frequency hearing loss (–80 dB) that improved after a short course of dexamethasone. However, the patient was not discharged because of the lung mass found on initial chest radiograph. Computed tomography scan, bronchoscopy, and histopathologic findings led to diagnosis of the mass as an advanced-stage squamous cell carcinoma. The meningitis had common and uncommon features. The common features were hearing loss, a typical outcome of S. suis meningitis independent of early antimicrobial drug administration (1,2); serotype 2, the most frequent and virulent serotype in swine and in humans (1,2); ST1, belonging to the ST1 complex, strongly associated with S. suis meningitis isolates (2,3); and erm(B)-mediated erythromycin resistance, widespread in this species (4). The uncommon features were tetracycline resistance mediated by tet(W), increasingly detected in gram-positive and in gram-negative bacteria (5) but never previously reported in S. suis or in other major streptococcal pathogens, where common determinants are tet(M) and tet(O); and lack of evidence for recent contact with swine, other animals, or swine (pork) products. Two previous cases of human S. suis meningitis in Italy (6,7) and other recent cases from Europe (8,9) were related to occupational exposure. However, the patient reported here also had cancer, and malignancy has been indicated as a predisposing factor for the development of severe S. suis disease in humans (2). These findings appear to be consistent with the recent suggestion of new epidemiologic patterns of infection caused by this organism (2). S. suis may become an opportunistic pathogen in persons who are under stress or who have immunodeficiency, and it has been increasingly isolated from mammalian species other than pigs, from birds, and from the environment. As also discussed in a recent survey (10), the possibility cannot be excluded that a patient with S. suis infection may be unaware or have no memory of previous exposure to animals. Alternatively, because asymptomatic carriage of S. suis has been documented in humans (2) and is believed to contribute to its transmission (10), the possibility should also be considered that the infection may be a reactivation, possibly favored by malignancy, of latently colonizing S. suis.

The Mycobacterium fortuitum group of rapidly growing nontuberculous mycobacteria is an uncommon cause of renal infection, particularly in otherwise healthy hosts. We describe a case of nephritis due to M. fortuitum in an immunocompetent woman with a clinical and radiological diagnosis of renal tuberculosis.

The synthesis and biological activity of selenophenfurin (5-beta-D-ribofuranosylselenophene-3-carboxamide, 1), the selenophene analogue of selenazofurin, are described. Glycosylation of ethyl selenophene-3-carboxylate (6) under stannic chloride-catalyzed conditions gave 2- and 5-glycosylated regioisomers, as a mixture of alpha- and beta-anomers, and the beta-2,5-diglycosylated derivative. Deprotected ethyl 5-beta-D-ribofuranosylselenophene-3-carboxylate (12 beta) was converted into selenophenfurin by ammonolysis. The structure of 12 beta was determined by 1H- and 13C-NMR, crystallographic, and computational studies. Selenophenfurin proved to be antiproliferative against a number of leukemia, lymphoma, and solid tumor cell lines at concentrations similar to those of selenazofurin but was more potent than the thiophene and thiazole analogues thiophenfurin and tiazofurin. Incubation of K562 cells with selenophenfurin resulted in inhibition of IMP dehydrogenase (IMPDH) (76%) and an increase in IMP pools (14.5-fold) with a concurrent decrease in GTP levels (58%). The results obtained confirm the hypothesis that the presence of heteroatoms such as S or Se in the heterocycle in position 2 with respect to the glycosidic bond is essential for both cytotoxicity and IMP dehydrogenase inhibitory activity in this type of C-nucleosides.

Among a series of unmodified phosphodiester (PO)-oligodeoxynucleotides (PO-ODNs) complementary to some of the human immunodeficiency virus type 1 (HIV-1) regulatory genes, several PO-ODN sequences complementary to the vpr gene (PO-ODNs-a-vpr, where a-vpr is the antisense vpr sequence) emerged as potent inhibitors (at concentrations of 0.8 to 3.3 microM) of HIV-1 multiplication in de novo infected MT-4 cells, while they showed no cytotoxicity for uninfected cells at concentrations up to 100 microM. Unlike phosphorothioate counterparts, PO-ODN-a-vpr sequences were not inhibitory to HIV-2 multiplication in de novo infected C8166 cells and neither prevented the fusion between chronically infected and bystander CD4+ cells nor inhibited the activity of the HIV-1 reverse transcriptase in enzyme assays. Moreover, they were not inhibitory to HIV-1 multiplication in chronically infected cells. Delayed addition experiments showed that PO-ODNs-a-vpr inhibit an event in the HIV-1 replication cycle following adsorption to the host cell, but preceding reverse transcription. Structure-activity relationship studies indicated that the antiviral activity of the test PO-ODN-a-vpr sequences is not related to an antisense mechanism but to the presence, within the active sequences, of contiguous guanine residues. Physical characterization of the test PO-ODNs suggested that the active structure is a tetramer stabilized by G quartets (i.e., four G residues connected by eight hydrogen bonds).

The decomposition pathways and kinetics in various biological media and the in vitro anti-HIV-1 and anti-HIV-2 activities of four derivatives of the 5'-mononucleotide of isoddA incorporating carboxylate esterase-labile transient phosphate protecting groups are reported and compared: namely, two mononucleoside aryl phosphoramidate derivatives 1a,b and two mononucleoside phosphotriester derivatives incorporating two S-acyl-2-thioethyl groups 2a,b. All four compounds show better antiviral activity, compared to the parent nucleoside analog isoddA. The results highlight that both types of compounds act as pronucleotides, i.e. they exert their antiviral effect via intracellular delivery of the 5'-mononucleotide of isoddA. The results may give insights for the design of new more efficient pronucleotides.

A new, simple extrapolation technique to enhance the lateral resolution of pulse-echo imaging systems is presented. The method attempts to build an image that could be obtained with a transducer aperture larger than that physically available, extrapolating the information contained in the image to be enhanced. The extrapolation process requires small hardware modifications of the standard echographic systems. The computational cost is very low compared with Fourier-based deconvolution approaches. The obtained computer simulations give very interesting and promising results.

Ultrasound beams propagating in biological tissues undergo distortions due to local inhomogeneities of the acoustic parameters and the nonlinearity of the medium. The spectral analysis of the radio-frequency (RF) backscattered signals may yield important clinical information in the field of tissue characterization, as well as enhancing the detectability of tissue parenchymal diseases. Here, the authors propose a new tissue spectral imaging technique based on the wavelet packets (WP) decomposition. In a conventional ultrasound imaging system, the received echo-signals are generally decimated to generate a medical image, with a loss of information. With the proposed approach, all the RF data are processed to generate a set of frequency subband images. The ultrasound echo signals are simultaneously frequency decomposed and decimated, by using two quadrature mirror filters, followed by a dyadic subsampling. In addition, to enhance the lesion detectability and the image quality, the authors apply a nonlinear filter to reduce noise in each subband image. The proposed method requires simple additional signal processing and it can be implemented on any real-time imaging system. The frequency subband images, which are available simultaneously, can be either used in a multispectral display or summed up together to reduce speckle noise. To localize the different frequency response in the tissues, the authors propose a multifrequency display method where 3 different subband images, chosen among those available, are encoded as red, green, and blue intensities (RGB) to create a false-colored RGB image. According to the clinical application, different choices can evidence different spectral proprieties in the biological tissue under investigation. To enhance the lesion contrast in a grey-level image, one of the possible methods is the summation of the images obtained from narrow frequency subbands, according to the frequency compounding technique. The authors show that by adding the denoised subband images created with the WP decomposition, the contrast-to-noise ratio in 2 phantom images is largely increased.

The study evaluated the performances of a commercial multiplex PCR assay, the Seegene Seeplex STI Master Panel 3, for Candida spp. identification. Eighty clinical strains of Candida spp. were identified with this system and a homemade multiplex PCR assay. The results were also compared with those obtained with two phenotypic methods. The study provided a preliminary evaluation of a multiplex assay from Seegene that uses capillary electrophoresis as the detection of amplified products. The Seeplex assay was found to be a rapid and useful method for identifying large numbers of yeast isolates in the clinical laboratory context.

The nominal 50 kg h −1 dry coal biodepyritization pilot plant was built at Porto Torres (Sassari, Italy) in the area of EniChem S.p.A. Chemical Works, with financial support of the Commission of European Communities and with the participation of the DMT of Essen (Germany), the Mining and Mineral Processing Department of the University of Cagliari (Italy), the Technical University of Delft (The Netherlands) and the Warren Spring Laboratory of Stevenage (UK). The plant went on stream in early September 1992. Test runs were carried in the range 6.5–41.5% solids concentration. For every solids concentration the steady state was attained in about 10 d. For all the test runs the assays showed that more than 90% pyrite removal is achieved in the first five bioreactors; for a pulp flow rate of 6.94 × 10 −2 dm 3 s −1 , (250 l h −1 ) and useful bioreactor volume of 7.5 m 3 , this corresponds to a residence time of 540 345 s, i.e., 6.254 d, and to a pyritic iron biosolubilization rate of 36 mg dm −3 h −1 . The pyrite biosolubilization rate constant is 1.53 × 10 −2 h −1 . The power input per bioreactor operating on a 40% solids pulp is 4 kW with cos Φ = 0.76. Hence, the power required for processing 100 kg h −1 coal at 40% solids in the bioreactor section is 4 × 5 = 20 kW h, i.e. 200 kW h per tonne dry coal.

Solids concentration is a critical technico-economic parameter in biohydrometallurgical processing since it decisively affects bioreactor size and therefore investment and operating costs. Researchers have repeatedly provided evidence, since the early times of biohydrometallurgy, that bioreactor leaching rates of metal sulphide concentrates drastically decrease whenever percent solids concentration exceeds 16–20. This limitation, should it hold also for coal biodepyritization processes, would place a serious constraint on their economics. The paper presents the results of an investigation carried out running in parallel three different types of laboratory reactors fed with the same pulp processed in the 7.5 m 3 stirred-tank reactors (STRs) installed in the Porto Torres coal biodepyritization pilot plant. Evidence is provided that biodepyritization performance of the reactors remains practically unchanged in the solids concentration range from 5% to 40%, whereas failure of pure pyrite bioleaching at 30% solids concentration is observed in the same reactors. This result seems to support the view that solids concentration influence on bioleaching performance is related to the proportion of oxidizable mineral present in the solid phase. Comparison of laboratory- and semi-commercial-scale STRs seems to show that scale-up imparts an improvement in machine performance.

Different particulate solids such as glass powder, various types of activated carbon and bentonite suspended in Thiobacillus ferrooxidans cultures produce very different effects on the oxidizing activity of the microorganism. The atmospheric oxygen uptake by Thiobacillus ferrooxidans in Warburg respirometer flasks containing 9K medium with ferrous sulfate as energy source and suspended bentonite is 2.8 times that in the absence of solids. The dissolution rate of pure pyrite in 250 cm 3 shake flasks containing 9K medium and bentonite is considerably enhanced over that where the only solid phase is pyrite. Conversely, the oxidizing ability of the microorganism seems to be inhibited by all the activated carbons tested. The effect of ground glass seems to be related to its particle size distribution. Implications for the bioleaching of sulfide ores and coal pyrite are discussed in the light of current knowledge on the adsorption of Thiobacillus ferrooxidans cells on solid surfaces.

The synthesis and the in vitro anti-HIV-1 activity of novel pyrrolo annulated benzothiadiazepine acetic acids and some related derivatives are reported. The new compounds share chemical features with pyrrolo[1,2-d][1,4]benzodiazepin-6-one 1 and Ro 5-3335 pyrrylbenzodiazepinone 4, two inhibitors of HIV-replication at the level of reverse transcriptase (RT) and transcriptional transactivation by Tat, respectively. Two derivatives, namely methyl 10,11-dihydropyrrolo[1,2-b][1,2,5]benzothiadiazepine-11-acetic-5,5 -dioxide (5a) and 1,12b-dihydro-2H-azeto[2,1-d]pyrrolo[1,2-b][1,2,5]benzoth iadiazepin-2-one 8,8-dioxide (7a), were found to exhibit a significant, although not very potent, activity against human immunodeficiency virus Type 1 (HIV-1).