Surface-confined Ullmann coupling of thiophene substituted porphyrins.

The covalent coupling of (5,10,15,20-tetrabromothien-2-ylporphyrinato)zinc(II) (TBrThP) molecules on the Ag(111) surface has been investigated under ultra-high-vacuum conditions, using scanning tunnelling microscopy and x-ray photoelectron spectroscopy. The findings provide atomic-level insight into surface-confined Ullmann coupling of thiophene substituted porphyrins, analyzing the progression of organometallic intermediate to final coupled state. Adsorption of the TBrThP molecules on the Ag(111) surface at room temperature is found to result in the reductive dehalogenation of the bromothienyl substituents and the subsequent formation of single strand and crosslinked coordination networks. The coordinated substrate atoms bridge the proximal thienyl groups of the organometallic intermediate, while the cleaved bromine atoms are bound on the adjacent Ag(111) surface. The intermediate complex displays a thermal lability at ∼423 K that results in the dissociation of the proximal thienyl groups with the concomitant loss of the surface bound bromine. At the thermally induced dissociation of the intermediate complex the resultant thienylporphyrin derivatives covalently couple, leading to the formation of a polymeric network of thiophene linked and meso-meso fused porphyrins.

The antimicrobial effects of helium and helium-air plasma on Staphylococcus aureus and Clostridium difficile.

UNLABELLED: Healthcare-associated infections (HCAI) affect 5-10% of acute hospital admissions. Environmental decontamination is an important component of all strategies to prevent HCAI as many bacterial causes survive and persist in the environment, which serve as ongoing reservoirs of infection. Current approaches such as cleaning with detergents and the use of chemical disinfectant are suboptimal. We assessed the efficacy of helium and helium-air plasma in killing Staphylococcus aureus and Clostridium difficile on a glass surface and studied the impact on bacterial cells using atomic force microscopy (AFM). Both plasma types exhibited bactericidal effects on Staph. aureus (log3·6 - >log7), with increased activity against methicillin-resistant strains, but had a negligible effect on Cl. difficile spores (<1log). AFM demonstrated cell surface disruption. The addition of air increased the microbicidal activity of the plasma and decreased the exposure time required for an equivalent log reduction. Further evaluation of cold plasma systems is warranted with, for example, different bacteria and on surfaces more reminiscent of the health care environment as this approach has potential as an effective decontaminant. SIGNIFICANCE AND IMPACT OF THE STUDY: Many bacterial causes of healthcare infection can survive in the inanimate environment for lengthy periods and be transmitted to patients. Furthermore, current methods of environmental decontamination such as detergents, chemical disinfectants or gaseous fumigation are suboptimal for a variety of reasons. We assessed the efficacy of helium and helium-air plasma as a decontaminant and demonstrated a significant reduction in bacterial counts of Staphylococcus aureus on a glass surface. Atomic force microscopy morphologically confirmed the impact on bacterial cells. This approach warrants further study as an alternative to current options for hospital hygiene.

Control of the axial coordination of a surface-confined manganese (III) porphyrin complex.

The organization and thermal lability of chloro(5,10,15,20-tetraphenyl porphyrinato)manganese(III) (Cl-MnTPP) molecules on the Ag(111) surface have been investigated under ultra-high vacuum conditions, using scanning tunnelling microscopy, low energy electron diffraction and x-ray photoelectron spectroscopy. The findings reveal the epitaxial nature of the molecule-substrate interface, and moreover, offer a valuable insight into the latent coordination properties of surface-confined metalloporphyrins. The Cl-MnTPP molecules are found to self-assemble on the Ag(111) surface at room temperature, forming an ordered molecular overlayer described by a square unit cell. In accordance with the threefold symmetry of the Ag(111) surface, three rotationally equivalent domains of the molecular overlayer are observed. The primitive lattice vectors of the Cl-MnTPP overlayer show an azimuthal rotation of ±15° relative to those of the Ag(111) surface, while the principal molecular axes of the individual molecules are found to be aligned with the substrate (0(-)11) and ((-)211) crystallographic directions. The axial chloride (Cl) ligand is found to be orientated away from the Ag(111) surface, whereby the average plane of the porphyrin macrocycle lies parallel to that of the substrate. When adsorbed on the Ag(111) surface, the Cl-MnTPP molecules display a latent thermal lability resulting in the dissociation of the axial Cl ligand at ~423 K. The thermally induced dissociation of the Cl ligand leaves the porphyrin complex otherwise intact, giving rise to the coordinatively unsaturated Mn(III) derivative. Consistent with the surface conformation of the Cl-MnTPP precursor, the resulting (5,10,15,20-tetraphenyl porphyrinato)manganese(III) (MnTPP) molecules display the same lattice structure and registry with the Ag(111) surface.

Ni(II) porphine nanolines grown on a Ag(111) surface at room temperature.

The room temperature growth and ordering of (porphyrinato)nickel (II) (or nickel (II) porphine, NiP) molecules on a Ag(111) surface have been investigated using scanning tunnelling microscopy and low-energy electron diffraction (LEED). At a coverage of one monolayer, NiP molecules form a well-ordered molecular layer, having a hexagonal structure, on the Ag(111) surface. Porphyrin molecules have a flat orientation in this overlayer with the molecular plane lying parallel to the substrate. LEED data obtained from one monolayer of the NiP on the Ag(111) surface show the formation of two mirror domains each rotated either clockwise or anticlockwise by 6 degrees with respect to the substrate. NiP molecules forming a second layer self-assemble into well-ordered and uniformly separated nanolines at room temperature. These nanolines consist of hexagonally ordered NiP molecules and are found to be 1-4 molecules wide, depending on the molecular coverage. The completed second monolayer preserves the same planarity and hexagonal ordering as the first molecular layer but with a 4% lateral relaxation which produces a periodic modulation of approximately 5 nm.

An x-ray absorption and photoemission study of the electronic structure of Ni porphyrins and Ni N-confused porphyrin.

Investigations of chemical bonding and electronic structure features for polycrystalline (porphyrinato)nickel (II) (NiP, the simplest Ni porphyrin), (5,10,15,20-tetraphenylporphyrinato)nickel (II) (NiTPP) and (2-aza-21-carba-5,10,15,20-tetraphenylporphyrinato)nickel (II) (N-confused NiTPP, NiNCTPP) have been performed by means of high-resolution soft x-ray absorption and x-ray photoemission spectroscopy. The Ni 2p(3/2) x-ray absorption spectra show strong π-back-bonding in these compounds leading to a high-energy shift (1.2 eV for the NiP and NiTPP) of the entire absorption structure compared to Ni metal. It has been found that the main absorption line of the Ni 2p(3/2) spectrum of the NiNCTPP is shifted by an additional 0.5 eV to higher energies in comparison with those for other nickel porphyrins. This shift is evidence of stronger back-donation (metal-to-ligand charge transfer) and a smaller effective number of 3d electrons on the central Ni atom in the NiNCTPP as compared to other Ni porphyrins. The confused N atom in the NiNCTPP is of pyrrolic type (protonated nitrogen), which was confirmed by the N 1s absorption and core-level photoemission spectra.

Synthesis of armchair graphene nanoribbons from the 10,10'-dibromo-9,9'-bianthracene molecules on Ag(111): the role of organometallic intermediates.

We investigate the bottom-up growth of N = 7 armchair graphene nanoribbons (7-AGNRs) from the 10,10'-dibromo-9,9'-bianthracene (DBBA) molecules on Ag(111) with the focus on the role of the organometallic (OM) intermediates. It is demonstrated that DBBA molecules on Ag(111) are partially debrominated at room temperature and lose all bromine atoms at elevated temperatures. Similar to DBBA on Cu(111), debrominated molecules form OM chains on Ag(111). Nevertheless, in contrast with the Cu(111) substrate, formation of polyanthracene chains from OM intermediates via an Ullmann-type reaction is feasible on Ag(111). Cleavage of C-Ag bonds occurs before the thermal threshold for the surface-catalyzed activation of C-H bonds on Ag(111) is reached, while on Cu(111) activation of C-H bonds occurs in parallel with the cleavage of the stronger C-Cu bonds. Consequently, while OM intermediates obstruct the Ullmann reaction between DBBA molecules on the Cu(111) substrate, they are required for the formation of polyanthracene chains on Ag(111). If the Ullmann-type reaction on Ag(111) is inhibited, heating of the OM chains produces nanographenes instead. Heating of the polyanthracene chains produces 7-AGNRs, while heating of nanographenes causes the formation of the disordered structures with the possible admixture of short GNRs.

Effect of folic acid and vitamin C supplementation on folate status and homocysteine level: a randomised controlled trial in Italian smoker-blood donors.

BACKGROUND: This trial sought to examine the effects of high dosage of folic acid and vitamin C supplementation on red blood cell folate (RCF), serum folate (SF) and homocysteine (Hcy) levels in subjects who smoke more than 15 cigarettes per day. METHODS: A prospective study of 100 Italian repeat blood donors was undertaken to measure RCF, SF and Hcy levels before and after 45 days of vitamin supplementation. All subjects were randomised into four groups: [A] folic acid (FA) 5 mg/day, [B] vitamin C 500 mg/day, [C] FA 5 mg/day plus vitamin C 500 mg/day [D] no supplementation. RESULTS: Before supplementation the median RCF, SF and Hcy levels were similar in the four groups; 32 (40%) subjects had an RCF level below 340 nmol/l, 15 (18.8%) had an SF level below 6.8 nmol/l and 21 (26.3%) had an Hcy level above 16 micromol/l. After 45 days the median RCF and SF levels were significantly (P<0.01) increased in all supplemented subjects. The median Hcy level was significantly (P=0.008) reduced in subjects supplemented with FA and significantly (P=0.01) increased in those supplemented with vitamin C alone. CONCLUSION: The supplementation with 5 FA mg/day is able to increase significantly both RCF and SF levels and reduce Hcy level in Italian smoker-blood donors.

The dominant role of adsorbed fluid layers on the polar surfaces of ZnO in ambient atmospheric conditions.

Polar ZnO surfaces with O- and Zn-termination were studied with atomic and lateral force microscopy and force curves. Adsorbed fluid layers on both surfaces are found to dominate their adhesion properties in air. The hydrophilic O-surface has a substantially thicker adsorbed layer and larger residual particle densities. Our data suggest that different preparation is required for the two surfaces before use in epitaxy, and may resolve some contradictions in the literature. The data also indicate that adsorbed fluid layers may be important in the growth of certain ZnO nanostructures.

Recombinant interferon alpha-2 modulates hairy cell phenotype "in vitro".

The "in vitro" effect of IFN-alpha on the phenotypic profile of atypical cells from 5 hairy cell leukemia patients was investigated in a 72 hr culture assay. Cytochemical investigations revealed a dramatic decrease in the cytoplasmic content of acid phosphatase and tartrate resistant acid phosphatase in the absence of any apparent morphological modification. Flow cytometry showed that IFN-alpha markedly reduced the density of surface Ig without modifying the original isotype pattern. The expression of the receptor for the Fc fragment of IgG was also reduced. The class II MHC antigen recognized by the monoclonal antibody 12 remained essentially unchanged. Hairy cells were negative for OKT10 and PCA-1 and remained so after IFN-alpha incubation. Present data indicate that IFN-alpha is able to consistently and selectively affect membrane and cytoplasmic features of hairy cells in a short term period. The possibility is envisaged that these changes may be related to the therapeutic efficacy of IFN-alpha.

The alpha 2 (r) interferon in the treatment of hairy cell leukemia: progressive report of 25 cases.

Twenty-five patients with Hairy Cell Leukemia (HCL), eleven in post-splenectomy progressive disease, have been treated as out-patients with alpha 2 (r) Interferon (IFN) for twelve months. Eighteen patients completed the treatment: four achieved Complete Response (CR), twelve Partial Response (PR) and two Minor Response (MR). The response to IFN has been CR or PR in 89% of cases and MR in 11%. Even if the IFN effective dose and the length of treatment remain to be determined, IFN at relatively low dose seems to become the first treatment of choice in HCL patients. The remaining seven patients, still under treatment, already achieved PR at least.

In vitro effects of human recombinant alpha-2b interferon on Ph1+ chronic myelogenous leukemia cells maintained in long term marrow cultures: a functional and morphological analysis.

In this study in vitro results obtained with hu rec IFN-alpha 2b on Ph1+ stem cells from patients with chronic myelogenous leukemia in chronic phase (CML in CP) will be discussed: cells were incubated with different IFN concentrations (100, 1000, 10000 IU/ml) for different times (24, 96 hrs, 8, 15, days) and maintained in long term marrow cultures (LTMC); CFU-GM assay, cytochemistry and cytogenetic analyses were performed weekly. A high sensitivity of CML cells to the in vitro treatment with IFN was observed. Cell count in LTMC showed a progressive reduction inversely proportional to time of incubation and concentration of IFN; a marked decrease in colony growth was observed at the end of incubations and during the course of LTMC. Low concentrations of IFN permitted a morphological maturation and the expression of alkaline phosphatase. Cytogenetic analyses showed a marked reduction of mytoses in cultures treated with high concentrations of IFN as result of a combined cytostatic and cytolitic effect; the persistance of 100% Ph1+ cells in LTMC and in CFU-GM colonies might be related, as opposed to in vivo results, to different IFN exposure conditions or might be influenced by other factors.

Hairy cell leukemia: preliminary results with alpha 2 (r) interferon.

Ten patients with hairy cell leukemia are being treated at our institution with a therapeutic schedule of alpha 2(r) interferon (2 X 10(6) IU/m2 s.c. three times per week). Five patients underwent splenectomy from 4 to 108 months before treatment; nonsplenectomized patients had spleens palpable 6 to 12 cm UCM. According to Quesada's response criteria, at the sixth month of therapy, one patient was considered a complete responder, 8 partial responders and one a minor responder, with no differences between splenectomized and nonsplenectomized patients. In nonsplenectomized patients the spleen returned to normal. Our data confirm that interferon, even at low dosages, is a very effective approach for hairy cell leukemia. No evidence was found to contraindicate such therapy.

Growth and ordering of Ni(II) diphenylporphyrin monolayers on Ag(111) and Ag/Si(111) studied by STM and LEED.

The room temperature self-assembly and ordering of (5,15-diphenylporphyrinato)nickel(II) (NiDPP) on the Ag(111) and Ag/Si(111)-(√3 × âˆš3)R30° surfaces have been investigated using scanning tunnelling microscopy and low-energy electron diffraction. The self-assembled structures and lattice parameters of the NiDPP monolayer are shown to be extremely dependent on the reactivity of the substrate, and probable molecular binding sites are proposed. The NiDPP overlayer on Ag(111) grows from the substrate step edges, which results in a single-domain structure. This close-packed structure has an oblique unit cell and consists of molecular rows. The molecules in adjacent rows are rotated by approximately 17° with respect to each other. In turn, the NiDPP molecules form three equivalent domains on the Ag/Si(111)-(√3 × âˆš3)R30° surface, which follow the three-fold symmetry of the substrate. The molecules adopt one of three equivalent orientations on the surface, acting as nucleation sites for these domains, due to the stronger molecule-substrate interaction compared to the case of the Ag(111). The results are explained in terms of the substrate reactivity and the lattice mismatch between the substrate and the molecular overlayer.

"Zeus" a new oral anticoagulant therapy dosing algorithm: a cohort study.

The demand for oral anticoagulant therapy (OAT) has constantly increased during the last ten years with an extended use of computer assistance. Many mathematical algorithms have been projected to suggest doses and time to next visit for patients on OAT. We designed a new algorithm: "Zeus". A "before-after" study was planned to compare the efficacy and safety of this algorithm dosing OAT with manual dosage decided by the same expert physicians according to the target of International Normalized Ratio (INR). The study analysed data of 1876 patients managed with each of the two modalities for eight months, with an interval of two years between them. The aim was to verify the increased quality of therapy by time spent in INR target and efficiency and safety of Zeus algorithm. Time in therapeutic range (TTR) was significantly (p < 0.0001) higher during the algorithm dosing period in comparison with the TTR during manual management period (62.3% vs 50.3%). The number of PT/INR tests above 5 was significantly (p < 0.001) reduced by algorithm suggested prescriptions in comparison with manual those (254 vs 537 times). The anticoagulant drug amount prescribed according to the algorithm suggestions was significantly (p < 0.0001) lower than that of the manual method. The number of clinical events observed in patients during the algorithm management time was significantly (p < 0.05) lower than that in those managed with the manual dosage. This study confirms the clinical utility of the computer-assisted OAT and shows the efficacy and safety of the Zeus algorithm.

Protein pattern transfer for biosensor applications.

This paper presents a very simple, industrially scalable method for transferring a high-resolution, biologically active protein pattern from one substrate to another. We demonstrate the transfer of a protein pattern formed initially by microcontact printing from a silicon surface (to which this form of printing is applicable) onto a glass or polymer substrate, almost independently of the surface/bulk properties of the second substrate. A very thin, spin-coated layer of a sugar is used to preserve the structure and organization of proteins during the subsequent plasma deposition of a siloxane polymer, after which the protein pattern could simply be peeled off the silicon substrate and glued onto any other desired substrate.

Reactive amine surfaces for biosensor applications, prepared by plasma-enhanced chemical vapour modification of polyolefin materials.

Here we have demonstrated a solventless plasma-based process that integrates low-cost, high throughput, high reproducibility and ecofriendly process for the functionalization of the next-generation point-of-care device platforms. Amine functionalities were deposited by plasma-enhanced chemical vapour deposition (PECVD) using a new precursor. The influence of the plasma RF power and the deposition time on surfacial properties, as well as their effect on the reactivity and content of amino groups was investigated. The key process determinants were to have a sufficient power in the plasma to activate and partially fragment the monomer but not too much as to lose the reactive amine functionality, and sufficient deposition time to develop a reactive layer but not to consume or erode the amine reactivity. An immunoassay performed using human immunoglobulin (IgG) as a model analyte showed an improvement of the detection limit by two orders of magnitude beyond that obtained using devices activated by liquid-phase reaction.

Rapid liver failure related to chronic C hepatitis in an HIV seropositive hemophilic patient with severe immunodepression.

We report the case of a young HIV seropositive patient with severe hemophilia A who presented rapid liver failure related to his chronic C hepatitis. The patient had been receiving factor VIII:C clotting factor concentrates (mean 60,000 U/year) since 1975. In 1984 alanine aminotransferase presented abnormal levels. The CD4 lymphocyte count in 1991 was normal and ultrasonographic scan showed normal liver morphology. In 1991 the patient were found to be seropositive for HCV antibodies as detected by the ELISA method and confirmed by the RIBA method. One year later, a progressive increase in policlonal gamma-globulin and a decrease in the CD4+ lymphocyte count to below 500/muL were detected in concomitance with ultrasonographic evidence of a progressive increase in the longitudinal diameters of the liver and spleen and signs of liver inhomogeneity. A significant inverse correlation was observed between the increase in the longitudinal diameter of the liver and the decline in albumin levels, and between the increase in the longitudinal diameter of the liver and the drop in platelet count. Elevated levels of ammonemia, gamma-glutamyl transpeptidase, alkaline phosphatase and IgA were detected. Moreover, decreased levels of the C4 and C3 complement fractions were documented. At this time (1994), esophagogram and esophagogastroscopy evidenced varicosities in the lower esophageal section (stage F1). The patient died in 1995 March at the age of 29 years of sudden septic shock related to Pseudomonas aeruginosa infection.

Lymphocyte T subsets and natural killer cells in Italian and Philippino blood donors.

BACKGROUND AND OBJECTIVES: The characterization of lymphocyte subsets in blood donors has been utilized to determine the normal ranges that can be related to race. A study was performed in blood donors from two racial groups - Caucasian (Italians) and Asian (Philippinos) - to define respective T-lymphocyte subsets and levels of cytokines. MATERIALS AND METHODS: Ninety-two blood donors (46 Italians and 46 Philippinos) were enrolled. Blood count and immunophenotyping of lymphocytes by flow cytometry were carried out, and cytokine production was tested in six blood donors of each group. RESULTS: Philippino blood donors showed a significantly higher mean value of leucocytes (P = 0.01) and lymphocytes (P < 0.001) than Italians. The mean absolute count of lymphocyte subsets CD3- CD16+ CD56+ and CD3+ CD8+ were both significantly higher in Philippino than in Italian subjects, respectively, P < 0.01 and P < 0.0001. Philippinos showed a statistically significant higher frequency of lymphocytes producing interferon-gamma (IFN-gamma) compared to Italians (P = 0.02). CONCLUSIONS: T-lymphocyte subsets in Italian and Philippino blood donors seem to be correlated to ethnic background. The higher levels of CD3+ CD8+ T cells, natural killer (NK) cells and IFN-gamma-producing cells found in Philippinos suggest leucoreduction in Asian blood donors.

Terminal transferase positive acute myeloid leukemia: immunophenotypic characterization and response to induction therapy.

A quantitative evaluation of terminal deoxynucleotidyl transferase (TdT) was performed using a highly sensitive enzyme immunoassay (EIA) in 72 previously untreated patients with acute myeloid leukemia (AML). Biological analysis of the leukemic cells included in all cases cytochemistry, search for Ph' chromosome and immunophenotyping with both anti-lymphoid and anti-myeloid monoclonal antibodies (MoAbs). Thirteen AML cases (18 per cent) were considered TdT+ by EIA. According to the FAB classification, almost all of them (12 out of 13) were within the M1 and M2 subgroups. A mixed lymphoid-myeloid phenotype was observed in one of the 13 TdT+ cases, while in none of the others were lymphoid features detected. Nine of the 10 EIA TdT+ cases studied in parallel were TdT positive with the conventional immunofluorescence assay. All patients received standard protocol chemotherapy and in 61 (13 TdT+, 48 TdT--) the response to induction treatment was analysable. Only 3/13 TdT+ patients (23 per cent) achieved a complete remission (CR), while in the TdT- group 38 patients had a CR (79 per cent) and 10 were resistant (p less than 0.01). It is suggested that the incidence, biological interest and prognostic significance of TdT+ AML should encourage the routine and more accurate search for this marker in all patients with AML.