Forming Weakly Interacting Multilayers of Graphene Using Atomic Force Microscope Tip Scanning and Evidence of Competition between Inner and Outer Raman Scattering Processes Piloted by Structural Defects

We report on an alternative route based on nanomechanical folding induced by an AFM tip to obtain weakly interacting multilayer graphene (wi-MLG) from a chemical vapor deposition (CVD)-grown single-layer graphene (SLG). The tip first cuts and then pushes and folds graphene during zigzag movements. The pushed graphene has been analyzed using various Raman microscopy plots- A_D/ A_G × E_L⁴ vs Γ_G, ω_2D vs Γ_2D, Γ_2D vs Γ_G, ω_2D+/- vs Γ_2D+/-, and A_2D-/ A_2D+ vs A_2D/ A_G. We show that the SLG in-plane properties are maintained under the folding process and that a few tens of graphene layers are stacked, with a limited number of structural defects. A blue shift of about 20 cm^-1 of the 2D band is observed. The relative intensity of the 2D_- and 2D₊ bands have been related to structural defects, giving evidence of their role in the inner and outer processes at play close to the Dirac cone.

Combined SERS/DFT studies of push–pull chromophore self-assembled monolayers: insights into their surface orientation

Having clear and deep information on the surface/interface of deposited molecules is of crucial importance for the development of efficient optoelectronic devices.

A randomized comparison of two prophylaxis regimens and a paired comparison of on-demand and prophylaxis treatments in hemophilia A management

BACKGROUND

Prophylaxis with factor (F)VIII is considered the optimal treatment for managing hemophilia A patients without inhibitors.

OBJECTIVES

To compare the efficacy of two prophylaxis regimens (primary outcome) and of on-demand and prophylaxis treatments (secondary outcome), and to continue the evaluation of immunogenicity and overall safety of the ADVATE Antihemophilic Factor (Recombinant), Plasma/Albumin Free Method (rAHF-PFM).

PATIENTS/METHODS

Previously on-demand-treated patients aged 7-59 years (n = 66) with FVIII levels ≤ 2% received 6 months of on-demand treatment and then were randomized to 12 months of either standard (20-40 IU kg(-1) every other day) or pharmacokinetic (PK)-tailored (20-80 IU kg(-1) every third day) prophylaxis, both regimens intended to maintain FVIII trough levels at or above 1%. Efficacy was evaluated in terms of annualized bleeding rates (ABRs). As subjects were first treated on-demand and then on prophylaxis, statistical comparisons between these treatments were paired.

RESULTS

Twenty-two (33.3%) subjects on prophylaxis experienced no bleeding episodes, whereas none treated on-demand were free from an episode of bleeding. ABRs for the two prophylaxis regimens were comparable, whereas differences between on-demand and either prophylaxis were statistically significant (P < 0.0001): median (interquartile range [IQR]) ABRs were 43.9 (21.9), 1.0 (3.5), 2.0 (6.9) and 1.1 (4.9) during on-demand treatment, standard, PK-tailored and any prophylaxis, respectively. There were no differences in FVIII consumption or adverse event rates between prophylaxis regimens. No subject developed FVIII inhibitors.

CONCLUSIONS

The present study demonstrates comparable safety and effectiveness for two prophylaxis regimens and that prophylaxis significantly reduces bleeding compared with on-demand treatment. PK-tailored prophylaxis offers an alternative to standard prophylaxis for the prevention of bleeding.

Mechanics of multi walled Carbon nanotubes probed by AFM

Using the AFM tip, nanotubes are caught on a raw sample then deposited on a clean surface with an absolute precision better than 500nm. A nanostructured surface made of smooth Germanium dots on flat silicon was used as deposition sample. Nanotube mechanics is probed by AFM tip induced displacement. Nanotubes are shown to be blocked by Ge dots: it is impossible to induce a controlled displacement of the nanotube over a Ge dot when it is pushed against the dot. Elastic energy due to the bending of the nanotube is at the root of that behavior.

Pulsed Laser Deposition of Si Nanocluster Films

Reactive laser ablation of Si targets by ArF* excimer laser (wavelength 193 nm, pulse width 15 ns (FWHM)) was performed in He, Ar or O2 0.05-1 Torr atmospheres and led to Si-SiOx nanocluster thin film formation within laser-induced plasma plume. Optical spectroscopy and optical Time-of-Flight (TOF) measurements were carried out during ablation-deposition experiments. A number of large weak emission bands in blue and green-yellow spectral branches were observed both in inert gases and in oxygen ambient atmospheres and attributed to the emission from excited nanoparticles in the plasma plume. TOF measurements proved a different spatio-temporal evolution of this emission compare to the emission of monoatomic particles. The films exhibit photoluminescence bands in the UV region (around 290 nm and between 310-370 nm), in the blue (between 420 and 500 nm), and in the green-yellow (at 520-560 nm). The relative intensities of the luminescence bands depend on the average cluster size, which is determined by preparation conditions (nature and pressure of the ambient gas, laser fluence).

Comparative pharmacokinetics of plasma- and albumin-free recombinant factor VIII in children and adults: the influence of blood sampling schedule on observed age-related differences and implications for dose tailoring

BACKGROUND

Dose tailoring of coagulation factors requires reliably estimated and reproducible pharmacokinetics (PK) in the individual patient.

OBJECTIVES

To investigate the contribution of both biological and methodological factors to the observed variability of factor VIII (FVIII) PK, with the focus on differences between children and adults, and to examine the implications for dosing.

PATIENTS

Data from 52 1-6-year-old and 100 10-65-year-old patients with hemophilia A (FVIII < or = 2 IU dL(-1)) in three clinical studies were included.

RESULTS

In vivo recovery was lower, weight-adjusted clearance was higher and FVIII half-life was on average shorter in children than in adults. However, a reduced blood sampling schedule for children was estimated to account for up to one half of the total observed differences. Intrapatient variance in PK was smaller than interpatient variance in 10-65-year-olds. Age and ratio of actual to ideal weight only showed weak relationships with PK parameters. Variance in PK caused large variance in the calculated dose required to maintain a target FVIII trough level during prophylactic treatment.

CONCLUSION

Differences in blood sampling schedules should be taken into account when results from different PK studies are compared. However, even with this consideration, PK cannot be predicted from observable patient characteristics but must be determined for the individual. Because the influence of reducing the blood sampling was minor in comparison to the true variance between patients, a reduced blood sampling protocol can be used. Low intrapatient variability supports the use of PK measurements for dose tailoring of FVIII.

Surface enhanced Raman spectroscopy of organic molecules deposited on gold sputtered substrates

Aggregates of Au nanoparticles have been extremely easily obtained on glass substrates by physical sputtering under primary vacuum. With such a protocol, we demonstrate that it is possible to control the surface plasmon band absorption. Surface enhanced Raman spectroscopy (SERS) experiments were performed with methylene blue, zinc octacarboxyphthalocyanine, 4-aminothiophenol and cysteamine. The correlation between the absorption band and the wavelength giving the highest SERS intensity is clearly observed for methylene blue, in accordance with the electromagnetic enhancement theory. For the other molecules, effects of the chemical enhancement are also observed. In addition, we noticed a strong influence of the nature of the adsorbed molecule on the enhancement factor for a given wavelength. The origin of this feature is discussed in terms of resonant effects or multipolar surface plasmon modes.

Evidence of the key role of metal-molecule bonding in metal-molecule-metal transport experiments

The transport properties of two oligothiophene derivatives, that differ only by the chemical group coupling to gold, are compared. It is shown that the role of the coupling group in the transport properties can be decoupled from that of the conjugated body of the molecules and that Se is a better electronic coupling group than S. These results are accounted for semiquantitatively within the frame of the scattering theory of transport, using results from ultraviolet photoemission spectroscopy experiments as inputs for the position in energy of the molecular orbitals with respect to the Fermi level of the electrodes.

An essential octamer motif in the mb-1 (Igalpha) promoter

The mb-1 (Igalpha) gene is B cell-specific and expressed throughout B cell maturation. In combination with B29 (Igbeta) and surface immunoglobulin mb-1 comprises the B cell receptor complex (BCR). The murine mb-1 promoter has been characterized to depend on the trans-acting transcription factors; Sp1, ets, lkaros, and EBF for full promoter activity. These trans-acting factors are also involved in the regulation of mb-1's closely related heterodimeric partner, B29. However, octamer transcription factors 1 and 2 (Oct-1 and Oct-2) are also necessary for full B29 promoter activity while they are not known to be required for mb-1 promoter activity. Here, we show that the octamer transcription factors bind a degenerate octamer consensus sequence within the mb-1 promoter. Like B29, the mb-1 octamer-binding, motif interacted with both ubiquitously expressed Oct-1 and the B cell-specific Oct-2 transcription factors. Furthermore, the interaction of Oct-1 and Oct-2 contributed to the regulation of the mb-1 promoter as site-directed mutations within the octamer motif substantially reduced its activity. These data confirm that octamer factor interactions and function contribute to the full transcriptional activity of the mb-1 promoter.

An upstream Oct-1- and Oct-2-binding silencer governs B29 (Ig beta) gene expression

The B cell-specific B29 (Igbeta) gene is activated in the earliest B cell precursors and is expressed throughout B cell development. Tissue-specific expression of the murine B29 gene is controlled by a B cell-specific promoter whose activity is governed by a cassette of upstream transcriptional silencers. This study describes a potent new silencer that is located 5' of the previously identified B29 silencer elements, FROG and TOAD. Like these known elements, the new B29 silencer is not restricted to the B29 promoter. Nuclear proteins from all cell lines tested interacted with this A+T-rich sequence, which closely resembled a noncanonical octamer binding motif and also conformed to the consensus sequence for nuclear matrix attachment regions. Interaction of Oct-1 and Oct-2 with the B29 A+T-rich sequence was confirmed using octamer-specific Abs. Oct-1/Oct-2 binding was required for the inhibitory activity of this sequence because mutations that blocked Oct-1/Oct-2 binding also eliminated inhibition of the B29 promoter. This B29 A+T-rich sequence specifically interacted with isolated nuclear matrix proteins in vitro, suggesting that it may also function as a matrix attachment region element. Maintenance of the level of B29 gene expression through the interaction of the minimal promoter and the upstream silencer elements FROG, TOAD, and the A+T-rich Oct-1/Oct-2 binding motif may be essential for normal B cell development and/or function.

Expression of the integrin subunit alpha 9 in the murine embryo

The alpha 9 integrin subunit is expressed in adult skeletal muscle, visceral smooth muscle, hepatocytes, squamous epithelium, and airway epithelium. The in vivo function of this protein is unknown. Thus far, only a single alpha 9-containing integrin has been identified (alpha 9 beta 1) and only a single ligand (tenascin) has been found for this integrin. In order to gain insight into the potential function of alpha 9 integrin(s), we examined the spatiotemporal distribution of the alpha 9 subunit and tenascin during murine embryogenesis. In all tissues where alpha 9 was expressed, its appearance was associated with other evidence of cell differentiation. In developing airway, visceral, and vascular smooth muscles, the onset of alpha 9 expression either coincided with or immediately followed the expression of alpha-SM actin. Expression of alpha 9 in epithelia was restricted to the choroid plexus and the basal cell layer of squamous epithelia where its appearance coincided with the development of stratification. alpha 9 immunostaining was first detected in developing skeletal musculature when skeletal myotubes formed. Tenascin expression was detected in many, but not all tissues found to express alpha 9. For example, the hair germs of maturing hair follicles exhibited high levels of alpha 9 staining, but no tenascin immunoreactivity was detected either within the hair germ themselves or in the adjacent dermis. In some tissues where tenascin expression colocalized with alpha 9, expression patterns were not synchronous. Although alpha 9 expression was associated with the onset of tissue differentiation, its expression was not limited to terminally differentiated cells. In fact, in the skin, alpha 9 expression appeared restricted to cells known to retain the capacity to proliferate, i.e., basal cells and hair germs. Thus, alpha 9 integrin(s) are not likely to contribute to the early steps in organ formation, but probably play a role in the maturation and/or maintenance of a variety of differentiated tissues. The expression of alpha 9 without its only known ligand, tenascin, suggests the existence of additional ligands.

Interleukin-2-responsive wound-infiltrating lymphocytes in surgical adjuvant cancer immunotherapy

Wound-infiltrating lymphocytes (WIL) were assessed in murine models of localized sarcoma and carcinoma to evaluate the role of interleukin-2 (IL-2)-responsive lymphocytes in adjuvant immunotherapy. Following tumor resection, IL-2 or diluent was injected at the surgical site for 6 days. Surgical site tissues were harvested and digested in a triple enzyme mixture, and single cell suspensions were prepared. Thy 1.2+ lymphocytes were isolated by incubating cells with monoclonal anti-Thy 1.2 antibody-coated magnetic beads. Lymphocyte-bead complexes were extracted with a magnet and cultured in medium containing IL-2 (100 units/ml) for 1-3 weeks. Perioperative IL-2 immunotherapy led to a three- to four-fold increase in WIL yield. WIL from IL-2-treated mice also demonstrated enhanced cytolysis of the autologous tumor and bound to activated endothelial cells with greater avidity than did the controls. We conclude that perioperative IL-2 therapy augments the yield, as well as the cytolytic and adhesive properties, of wound-infiltrating lymphocytes.

Intratumoral interleukin-2 immunotherapy: activation of tumor-infiltrating and splenic lymphocytes in vivo

Direct intratumoral injection of interleukin-2 (IL-2) was evaluated in a murine model. Balb/c mice received 5 x 10(4) Line 1 alveolar carcinoma cells (L1C2) by subcutaneous injection. On the third day following tumor implantation, mice received injections of IL-2 (5 x 10(3)-5 x 10(4) units) or diluent twice daily, either by i.p. or intratumoral injection, 5 days/week for 3 weeks. Intratumoral injection of 5 x 10(4) units IL-2 significantly reduced tumor volume (P < 0.05 versus control), increased median survival time (P = 0.0001), and resulted in a 23.5% cure rate (P = 0.008). There were no long-term survivors in the other treatment groups. Both tumor-infiltrating lymphocytes (TIL) and splenic lymphocytes isolated directly from IL-2-treated mice demonstrated enhanced cytolytic activity compared to diluent-treated controls. To determine whether non-T-cell-mediated antitumor responses were active in our model, intratumoral immunotherapy was evaluated in athymic Balb/c nu/nu mice. In order to decrease the recruitment of lymphocyte precursors, nude mice were splenectomized and received cyclophosphamide prior to tumor injection and IL-2 therapy. Intratumoral IL-2 immunotherapy also significantly decreased tumor volume in these immunodeficient mice (P < 0.02), but did not lead to long-term survival. We conclude that both TIL and splenic lymphocytes are activated in vivo in response to intratumoral IL-2 immunotherapy, suggesting that intratumoral therapy with IL-2 activates both local and systemic antitumor responses.