Near-Temperature-Independent Electron Transport Well beyond Expected Quantum Tunneling Range via Bacteriorhodopsin Multilayers

A key conundrum of biomolecular electronics is efficient electron transport (ETp) through solid-state junctions up to 10 nm, often without temperature activation. Such behavior challenges known charge transport mechanisms, especially via nonconjugated molecules such as proteins. Single-step, coherent quantum-mechanical tunneling proposed for ETp across small protein, 2-3 nm wide junctions, but it is problematic for larger proteins. Here we exploit the ability of bacteriorhodopsin (bR), a well-studied, 4-5 nm long membrane protein, to assemble into well-defined single and multiple bilayers, from ∼9 to 60 nm thick, to investigate ETp limits as a function of junction width. To ensure sufficient signal/noise, we use large area (∼10-3 cm2) Au-protein-Si junctions. Photoemission spectra indicate a wide energy separation between electrode Fermi and the nearest protein-energy levels, as expected for a polymer of mostly saturated components. Junction currents decreased exponentially with increasing junction width, with uniquely low length-decay constants (0.05-0.5 nm-1). Remarkably, even for the widest junctions, currents are nearly temperature-independent, completely so below 160 K. While, among other things, the lack of temperature-dependence excludes, hopping as a plausible mechanism, coherent quantum-mechanical tunneling over 60 nm is physically implausible. The results may be understood if ETp is limited by injection into one of the contacts, followed by more efficient charge propagation across the protein. Still, the electrostatics of the protein films further limit the number of charge carriers injected into the protein film. How electron transport across dozens of nanometers of protein layers is more efficient than injection defines a riddle, requiring further study.

Volumetric assessment of the nose after primary unilateral cleft rhinoplasty using Laberge's technique

BACKGROUND

There is a lack of standardized surgery for cleft rhinoplasty. We felt that the technique described by Dr Louise Caouette Laberge is an ideal way to approach this problem, thus we tried to quantify the outcome of surgery by volumetric assessment.

MATERIAL AND METHOD

We recorded 3D images using an Artec scanner and performed volume calculations of the cleft side and noncleft side of the nose. These readings were taken once in the preoperative and then 2 weeks postoperative. Another scan of the face was performed 2 years after the surgery to compare the volumes of the cleft and noncleft side nostril.

RESULTS

Of the 31 patients with unilateral cleft lip operated on (mean age 3-8 months), we found a significant increase in the cleft side volume at 3 weeks postoperative from 3.95 mm3 to 5.65 mm3 (p < 0.001 on paired t-test). A repeat scan done on the study population at 2 years postoperative found that the mean volume of the cleft side was 30.43 mm3 (standard deviation [SD], 2.49) and that of the normal side was 30.82 mm3 (SD, 2.51). An independent t-test found that there was no significant difference between the two volumes (p > 0.05) CONCLUSION: The use of volumetric data in the evaluation of postoperative outcomes provides an objective criterion for assessing the aesthetics as well as the growth. Our study concludes that the Laberge technique provides a good aesthetic outcome with minimal scarring for the management of cleft nose and lip with the anterior palate.

Biotin Binding Hardly Affects Electron Transport Efficiency across Streptavidin Solid-State Junctions

The electron transport (ETp) efficiency of solid-state protein-mediated junctions is highly influenced by the presence of electron-rich organic cofactors or transition metal ions. Hence, we chose to investigate an interesting cofactor-free non-redox protein, streptavidin (STV), which has unmatched strong binding affinity for an organic small-molecule ligand, biotin, which lacks any electron-rich features. We describe for the first time meso-scale ETp via electrical junctions of STV monolayers and focus on the question of whether the rate of ETp across both native and thiolated STV monolayers is influenced by ligand binding, a process that we show to cause some structural conformation changes in the STV monolayers. Au nanowire-electrode-protein monolayer-microelectrode junctions, fabricated by modifying an earlier procedure to improve the yields of usable junctions, were employed for ETp measurements. Our results on compactly integrated, dense, uniform, ∼3 nm thick STV monolayers indicate that, notwithstanding the slight structural changes in the STV monolayers upon biotin binding, there is no statistically significant conductance change between the free STV and that bound to biotin. The ETp temperature (T) dependence over the 80-300 K range is very small but with an unusual, slightly negative (metallic-like) dependence toward room temperature. Such dependence can be accounted for by the reversible structural shrinkage of the STV at temperatures below 160 K.

Analysis of clinical and patient-reported outcomes in post-ELAPE perineal reconstruction with IGAP flap – A 5-year review

Background: Extralevator abdominoperineal excisions (ELAPE) are now the accepted treatment option for low rectal cancers, which result in large perineal defects necessitating reconstruction. The aim of our study was to assess the clinical outcomes as well as the quality-of-life parameters (QOLP) following these reconstructions. Methods: A series of 27 patients who underwent ELAPE and immediate reconstruction with inferior gluteal artery perforator flaps (IGAP) between December 2013 to December 2018 were retrospectively analysed on patient demographics, disease and treatment, complications, and QOLP. Results: With a mean age of 71.6 years, all patients had low rectal cancers and underwent ELAPE (24 open, 3 lap-assisted) and immediate IGAP flap reconstruction. The follow-up period was 1 year. The overall perineal early minor complication rate was 25.9% and the early major complication rate of 14.8%. QOLP, such as tolerance to sit, perineal pain, perineal aesthetics, showed high patient satisfaction of 77.7%, 40.74%, and 66.6%, respectively at 1 year. The perineal hernia rate was 14.8% with all patients being female (p 0.0407; significant). Conclusion: IGAP flaps are a reliable option for reconstructing post-ELAPE defects with good patient satisfaction and outcomes.

Molecularly resolved, label-free nucleic acid sensing at solid-liquid interface using non-ionic DNA analogues

Nucleic acid-based biosensors, where the capture probe is a nucleic acid, e.g., DNA or its synthetic analogue xeno nucleic acid (XNA), offer interesting ways of eliciting clinically relevant information from hybridization/dehybridization signals. In this respect, the application of XNA probes is attractive since the drawbacks of DNA probes might be overcome. Within the XNA probe repertoire, peptide nucleic acid (PNA) and morpholino (MO) are promising since their backbones are non-ionic. Therefore, in the absence of electrostatic charge repulsion between the capture probe and the target nucleic acid, a stable duplex can be formed. In addition, these are nuclease-resistant probes. Herein, we have tested the molecularly resolved nucleic acid sensing capacity of PNA and MO capture probes using a fluorescent label-free single molecule force spectroscopy approach. As far as single nucleobase mismatch discrimination is concerned, both PNA and MO performed better than DNA, while the performance of the MO probe was the best. We propose that the conformationally more rigid backbone of MO, compared to the conformationally flexible PNA, is an advantage for MO, since the probe orientation can be made more upright on the surface and therefore MO can be more effectively accessed by the target sequences. The performance of the XNA probes has been compared to that of the DNA probe, using fixed nucleobase sequences, so that the effect of backbone variation could be investigated. To our knowledge, this is the first report on molecularly resolved nucleic acid sensing by non-ionic capture probes, here, MO and PNA.

Improved nucleic acid sensing in terms of single nucleobase mismatch discrimination, as achieved by the surface-confined non-ionic PNA and MO capture probes, is exemplified by single molecule force spectroscopy.

Ulnar-Basilic Arteriovenous Fistula for Hemodialysis Access: Utility as the "Second Procedure" after Radio Cephalic Fistula

Objectives: As per standard guidelines, the recommended order of arteriovenous fistula (AVF) creation for hemodialysis (HD) access is radiocephalic (RC), followed by proximal elbow fistulas and arteriovenous graft. Although ulnar-basilic (UB) fistula has been an alternative to RC-AVF, still this procedure searches clear recommendations. We present here our experience on UB-AVF as the preferred “second procedure” instead of proximal fistula after the RC-AVF.

Methods: Forty-two UB-AVF were created in nonfeasible and failed RC-AVF cases between 2016 and 2018. They were reviewed retrospectively and outcomes were compared with 480 RC-AVF constructed within the same period.

Results: The primary patency at 18 months was 73.8%, 69.6% and mean maturation time was 33.7±6.6 days, 32.1±4.7 days for UB-AVF and RC-AVF respectively (p>0.05).

Conclusion: Our altered order of preference enabled us to create all the first-time fistula in the distal forearm, providing all the advantages of distal fistula like RC-AVF and avoiding proximal fistula, improved patient convenience and short-term benefit. In an inference that may be used for references and needs support from a larger sample and longer duration study from other centers, UB-AVF may be considered as the second option after RC-AVF depending on the clinical scenario.

Lower Extremity Marjolin's Ulcer Reconstruction With Free Anterolateral Thigh Flap: A Case Series of 11 Patients

Background

Marjolin’s ulcer (MU) of lower extremities usually presents with scar contracture and functional disability. They often follow an aggressive course and poor outcome, and require early radical removal. Split-thickness skin grafts, local flaps, or amputation are commonly practiced surgical options for MU. Though free flaps are gaining popularity for various oncoplastic reconstruction, they are not frequently used for MU. A free anterolateral thigh (ALT) flap may have a beneficial role as it provides simultaneous coverage for a large defect after radical tumor and scar excision.

Methods

Between January 2015 and December 2018, 11 patients with lower limb MU reconstructed with free ALT flap were reviewed retrospectively for the surgical procedure, recurrences, and functional outcomes.

Results

Mean dimensions of the defect and flaps were 8 cm × 6 cm and 18.91 cm × 11 cm, respectively, and total flap coverage was obtained in nine cases. Marginal flap loss was noted in one and residual contracture in two cases. Functional improvement of the limb was achieved in all cases. Recurrence or disease-related mortality was not seen in any patient after a mean follow-up of 35.82 months.

Conclusions

Free ALT flap reconstruction of MU of extremity facilitates most radical tumor and scar-contracture removal and thus reduces the chances of re-ulceration. It facilitates local radiotherapy protocol with the provision of immediate durable coverage. Thus, it has a beneficial role other than a secondary reconstructive procedure. Moreover, an added benefit may be obtained with a “flow-through’ flap” to avoid amputation and improve functional outcomes.

The Oxylipin Signaling Pathway Is Required for Increased Aphid Attraction and Retention on Virus-Infected Plants

Many studies have shown that virus infection alters phytohormone signaling and insect vector contact with hosts. Increased vector contact and movement among plants should increase virus survival and host range. In this study we examine the role of virus-induced changes in phytohormone signaling in plant-aphid interactions, using Pea enation mosaic virus (PEMV), pea aphids (Acyrthosiphon pisum), and pea (Pisum sativum) as a model. We observed that feeding by aphids carrying PEMV increases salicylic acid and jasmonic acid accumulation in pea plants compared to feeding by virus-free aphids. To determine if induction of the oxylipin jasmonic acid is critical for aphid settling, attraction, and retention on PEMV-infected plants, we conducted insect bioassays using virus-induced gene silencing (VIGS), an oxylipin signaling inducer, methyl jasmonate (MeJA), and a chemical inhibitor of oxylipin signaling, phenidone. Surprisingly, there was no impact of phenidone treatment on jasmonic acid or salicylic acid levels in virus-infected plants, though aphid attraction and retention were altered. These results suggest that the observed impacts of phenidone on aphid attraction to and retention on PEMV-infected plants are independent of the jasmonic acid and salicylic acid pathway but may be mediated by another component of the oxylipin signaling pathway. These results shed light on the complexity of viral manipulation of phytohormone signaling and vector-plant interactions.

Structural and Optical Properties of GaN Film on Copper and Graphene/Copper Metal Foils Grown by Laser Molecular Beam Epitaxy

We report the direct growth of crystalline GaN on bare copper (Cu) and monolayer-graphene/Cu metal foils using laser molecular beam epitaxy technique at growth temperature of 700 °C. The surface morphology investigated with field emission scanning electron microscopy revealed that the size of GaN grains for film grown on bare Cu falls in range of 90 to 160 nm whereas large grains with size of ˜200 to 600 nm was obtained for GaN grown on graphene/Cu foil under similar growth condition. The transverse optical mode of cubic GaN and E₂ (high) phonon mode for wurtzite GaN phases were obtained on the GaN film grown on Cu and graphene/Cu metal foils as deduced by Raman spectroscopy. The photoluminescence (PL) spectroscopy studies showed that the near band edge emission peaks for GaN on Cu and graphene/Cu consist two major peaks at 3.26 and 3.4 eV, corresponding to cubic and wurtzite GaN, respectively. The Raman and PL studies disclosed that the mixed phase growth of GaN occurs on these foils and better structural and optical quality for GaN on graphene/Cu foil. The direct growth of GaN on two dimensional graphene on polycrystalline metal foils is beneficial various transferrable and flexible opto-electronics device applications.

The Revolving Door Flap: Revisiting an Elegant but Forgotten Flap for Ear Defect Reconstruction

Background  The revolving door flap, although well described in the literature, is not widely used in general plastic surgery practice. The flap has been used for anterior auricular and conchal defects and is considered elegant for its unique flap design and peculiarity of flap harvest. However, due to its use for a very specific purpose and unique flap harvest technique that may be difficult to grasp, the flap is not very popular in reconstructive practice.

Objectives  This study aims to evaluate the understanding and learning curve of the revolving door flap, assess surgical outcome, and reemphasize its utility and elegance in reconstruction of ear defects.

Methodology  This is a case series of nine surgeries performed between January 2014 and 2018. Three cases were performed by the senior author and six cases by two junior authors. Patients were observed for complications and aesthetic outcomes.

Results  The mean dimension of the flaps was 27.22 mm × 22.78 mm. The mean operative time was 56.56 minutes (standard deviation 22.50, standard error of the mean 7.5). Flap congestion was noted in three cases postoperatively which resolved completely by the second week. Major “pinning” of the ear was noted in four cases.

Conclusion  Though infrequently performed, the revolving door flap has an easy learning curve once the proper harvest technique and flap movement has been grasped. The flap harvest is convenient, safe, and yields predictable results. Not only is total or partial flap loss extremely rare, the flap is sensate, color match is good, auricular contour is maintained, and the donor site can be closed primarily and remains well hidden.

Sorting Fermionization from Crystallization in Many-Boson Wavefunctions

Fermionization is what happens to the state of strongly interacting repulsive bosons interacting with contact interactions in one spatial dimension. Crystallization is what happens for sufficiently strongly interacting repulsive bosons with dipolar interactions in one spatial dimension. Crystallization and fermionization resemble each other: in both cases - due to their repulsion - the bosons try to minimize their spatial overlap. We trace these two hallmark phases of strongly correlated one-dimensional bosonic systems by exploring their ground state properties using the one- and two-body density matrix. We solve the N-body Schrödinger equation accurately and from first principles using the multiconfigurational time-dependent Hartree for bosons (MCTDHB) and for fermions (MCTDHF) methods. Using the one- and two-body density, fermionization can be distinguished from crystallization in position space. For N interacting bosons, a splitting into an N-fold pattern in the one-body and two-body density is a unique feature of both, fermionization and crystallization. We demonstrate that this splitting is incomplete for fermionized bosons and restricted by the confinement potential. This incomplete splitting is a consequence of the convergence of the energy in the limit of infinite repulsion and is in agreement with complementary results that we obtain for fermions using MCTDHF. For crystalline bosons, in contrast, the splitting is complete: the interaction energy is capable of overcoming the confinement potential. Our results suggest that the spreading of the density as a function of the dipolar interaction strength diverges as a power law. We describe how to distinguish fermionization from crystallization experimentally from measurements of the one- and two-body density.

Electron Transport in Muscle Protein Collagen

In recent times, collagen, which is one of the most abundant proteins in animals, has appeared to be an attractive candidate for biomaterial applications, for example, in medical implants and wearable electronics. This is because collagen is water-insoluble, biocompatible, and nontoxic. In addition, films of different sizes and shapes can be made using this protein as it is malleable and elastic in nature. However, its electron transport capacity or its absence has remained largely untested so far. Therefore, in this work, the electron transport behavior of collagen has been studied in both film and single-fiber states in a local probe configuration using current-sensing atomic force spectroscopy (CSAFS). From the CSAFS analyses, the electronic (transport) band gap of collagen has been estimated. It has been found that collagen behaves as a wide band gap semiconductor (near-insulating) in a variety of experimental conditions. The transition to a semiconducting material with a low electronic band gap and a nearly 1000-fold enhancement of current (picoampere to nanoampere level) occurs by metal ion treatment (here, Fe³⁺) of the native collagen. To the best of our knowledge, this is the first report of a molecular level study of the electron transport behavior of collagen proteins and estimation of transport band gap values of collagen and metalated collagen.

Negative Differential Resistance Behavior of the Iron Storage Protein Ferritin

Realization of useful nanometer length scale devices in which metalloproteins are junction-confined in a distinct molecular arrangement for generating practical electronic signals (e.g., in bioelectronic switch configuration) is elusive till date. This is mostly due to difficulties in observing an electronically appropriate signal (i.e., reproducible and controllable), when studied under junction-assembled condition. A useful "ON"-"OFF" behavior, based on the negative differential resistance (NDR) peak characteristics in the current-voltage response curves, acquired using metal-insulator-metal (MIM) configuration, has been observed only in the case of a few proteins, namely, azurin, cytochrome c, bacteriorhodopsin, so far. The case of NDR in ferritin, an iron storage protein having a semiconducting iron core consisting of few thousands of iron atoms connected in an oxide network, has not been studied in the MIM configuration where single (or a few) molecule(s) are junction-trapped, for example, as in the case of local probe configuration of scanning probe microscopy. The present study by scanning tunneling microscopy (STM), using the naturally occurring iron-containing ferritin (human liver), as well as different iron-loaded ferritins, provides clear indication of the capability of ferritins to be NDR capable, at varying sweep conditions. As ferritin can be tailor-made in a structurally conserved manner, metal core-reconstituted ferritins, that is, Mn(III)-ferritin, Cu(II)-ferritin, and Ag-ferritin, were prepared. A correlation between the NDR peak signatures, as observed in the respective current-voltage response curves of these reconstituted ferritins, and the nature of the metal core is demonstrated. In support of our earlier proposition, here, we affirm that the ferritin protein behaves as a conductor-insulator (metal core-polypeptide shell) composite, where the overall electronic structure of the material can alter as a function of the nature of the conducting filler placed inside the insulated matrix.

Single crystal Er3+ : YAG fibers with tailored refractive index profiles

Erbium-doped yttrium aluminum garnet (Er³⁺:YAG) rods were inserted inside undoped tubes and grown into single-crystal fibers of a diameter of 300 μm using the laser-heated pedestal growth technique. Growth at various rates resulted in radially graded distributions of Er³⁺ dopant ions, as observed using laser-induced fluorescence imaging. Profiles of the refractive index were measured using cross-sectional reflectometry in a microscope. Dopant distributions and the corresponding index profiles were compared with thermal diffusion theory to determine the inter-diffusion coefficient of Y³⁺ and Er³⁺ ions at 2000°C, yielding an estimated value of D=(9.10±0.8)×10^-11  m²/s. This work constitutes a step toward controlled growth of fibers with high thermal conductivities, low Brillouin gain, and waveguiding properties required for high-power optical amplifier and laser applications.

Nanoscale On-Silico Electron Transport via Ferritins

Silicon is a solid-state semiconducting material that has long been recognized as a technologically useful one, especially in electronics industry. However, its application in the next-generation metalloprotein-based electronics approaches has been limited. In this work, the applicability of silicon as a solid support for anchoring the iron-storage protein ferritin, which has a semiconducting iron nanocore, and probing electron transport via the ferritin molecules trapped between silicon substrate and a conductive scanning probe has been investigated. Ferritin protein is an attractive bioelectronic material because its size (X-ray crystallographic diameter ∼12 nm) should allow it to fit well in the larger tunnel gaps (>5 nm), fabrication of which is relatively more established, than the smaller ones. The electron transport events occurring through the ferritin molecules that are covalently anchored onto the MPTMS-modified silicon surface could be detected at the molecular level by current-sensing atomic force spectroscopy (CSAFS). Importantly, the distinct electronic signatures of the metal types (i.e., Fe, Mn, Ni, and Au) within the ferritin nanocore could be distinguished from each other using the transport band gap analyses. The CSAFS measurements on holoferritin, apoferritin, and the metal core reconstituted ferritins reveal that some of these ferritins behave like n-type semiconductors, while the others behave as p-type semiconductors. The band gaps for the different ferritins are found to be within 0.8 to 2.6 eV, a range that is valid for the standard semiconductor technology (e.g., diodes based on p-n junction). The present work indicates effective on-silico integration of the ferritin protein, as it remains functionally viable after silicon binding and its electron transport activities can be detected. Potential use of the ferritin-silicon nanohybrids may therefore be envisaged in applications other than bioelectronics, too, as ferritin is a versatile nanocore-containing biomaterial (for storage/transport of metals and drugs) and silicon can be a versatile nanoscale solid support (for its biocompatible nature).

Fast Bayesian inference of optical trap stiffness and particle diffusion

Bayesian inference provides a principled way of estimating the parameters of a stochastic process that is observed discretely in time. The overdamped Brownian motion of a particle confined in an optical trap is generally modelled by the Ornstein-Uhlenbeck process and can be observed directly in experiment. Here we present Bayesian methods for inferring the parameters of this process, the trap stiffness and the particle diffusion coefficient, that use exact likelihoods and sufficient statistics to arrive at simple expressions for the maximum a posteriori estimates. This obviates the need for Monte Carlo sampling and yields methods that are both fast and accurate. We apply these to experimental data and demonstrate their advantage over commonly used non-Bayesian fitting methods.

Density of states in graphene with vacancies: midgap power law and frozen multifractality

The density of states ϱ(E) of graphene is investigated numerically and within the self-consistent T-matrix approximation in the presence of vacancies within the tight binding model. The focus is on compensated disorder, where the concentration of vacancies n(A) and n(B) in both sublattices is the same. Formally, this model belongs to the chiral symmetry class BDI. The onlinear sigma model predicts for BDI a Gade-type singularity ϱ(E)∼|E|(-1)exp[-|log(E)|(-1/x)]. Our numerical data are comparable to this result in a preasymptotic regime that gives way, however, at even lower energies to ϱ(E)∼E(-1)|log(E)|(-x̃), 1≤x̃<2. We take this finding as evidence that, similar to the case of dirty d-wave superconductors, generic bipartite random hopping models may also exhibit unconventional (strong-coupling) fixed points for certain kinds of randomly placed scatterers if these are strong enough. Our research suggests that graphene with (effective) vacancy disorder is a physical representative of such systems.

The effects of selenium and the GPx-1 selenoprotein on the phosphorylation of H2AX

BACKGROUND

Significant data supports the health benefits of selenium although supplementation trials have yielded mixed results. GPx-1, whose levels are responsive to selenium availability, is implicated in cancer etiology by human genetic data. Selenium's ability to alter the phosphorylation of the H2AX, a histone protein that functions in the reduction of DNA damage by recruiting repair proteins to the damage site, following exposure to ionizing radiation and bleomycin was investigated.

METHODS

Human cell lines that were either exposed to selenium or were transfected with a GPx-1 expression construct were exposed to ionizing radiation or bleomycin. Phosphorylation of histone H2AX was quantified by flow cytometry and survival by the MTT assay. Phosphorylation of the Chk1 and Chk2 checkpoint proteins was quantified by western blotting.

RESULTS

In colon-derived cells, selenium increases GPx-1 and attenuated H2AX phosphorylation following genotoxic exposures while the viability of these cells was unaffected. MCF-7 cells and transfectants that express high GPx-1 levels were exposed to ionizing radiation and bleomycin, and H2AX phosphorylation and cell viability were assessed. GPx-1 increased H2AX phosphorylation and viability following the induction of DNA damage while enhancing the levels of activated Chk1 and Chk2.

CONCLUSIONS

Exposure of mammalian cells to selenium can alter the DNA damage response and do so by mechanisms that are dependent and independent of its effect on GPx-1.

GENERAL SIGNIFICANCE

Selenium and GPx-1 may stimulate the repair of genotoxic DNA damage and this may account for some of the benefits attributed to selenium intake and elevated GPx-1 activity.

Diffusion and criticality in undoped graphene with resonant scatterers

A general theory is developed to describe graphene with an arbitrary number of isolated impurities. The theory provides a basis for an efficient numerical analysis of the charge transport and is applied to calculate the Dirac-point conductivity σ of graphene with resonant scatterers. In the case of smooth resonant impurities the symmetry class is identified as DIII and σ grows logarithmically with increasing impurity concentration. For vacancies (or strong on-site potential impurities, class BDI) σ saturates at a constant value that depends on the vacancy distribution among two sublattices.

Molecular characterization of tumor associated glyceraldehyde-3-phosphate dehydrogenase

Here we describe the purification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from normal leukocytes of healthy subjects and leukocytes of chronic myeloid leukemia (CML) patients and from normal mouse muscle and sarcoma tissue. The data indicate that some properties of GAPDH of leukocytes of CML patients and sarcoma tissues are similar and also similar to those of EAC (Ehrlich ascites carcinoma) cellular GAPDH but distinctly different from those of the normal cellular GAPDH. Polyclonal antiserum raised against the 54 kDa subunit of EAC cell GAPDH strongly reacted with GAPDH of leukocytes of CML patients and sarcoma tissue GAPDH only and weakly reacted with GAPDH of normal leukocyte and normal muscle and a variety of other tissues of normal rats. Both the subunits of GAPDH of sarcoma tissues were partially sequenced from the N-terminus and compared with the known sequences of GAPDH. The altered properties of GAPDH of three different malignant sources might be common feature of all malignant cells, which is discussed in relation to glycolysis and malignant aberrations.

Optimization study of the femtosecond laser-induced forward-transfer process with thin aluminum films

The parameters for an effective laser-induced forward-transfer (LIFT) process of aluminum thin films using a femtosecond laser are studied. Deposited feature size as a function of laser fluence, donor film thickness, quality of focus, and the pulse duration are varied, providing a metric of the most desirable conditions for femtosecond LIFT with thin aluminum films.

Microstructures of a Pt/Ni/C multilayer system: an X-ray reflectivity and ion scattering study

Microstructural characterization of a synthetic periodic and graded Pt/Ni/C multilayer system by X-ray reflectivity and ion scattering techniques is presented. The experimental reflectivity data are fitted with a theoretical multi-trilayer model with graded periodicity which increases from substrate to film surface along the surface normal direction. The increase in periodicity is found to be due to a linear increase in C-layer thickness from the bottom to the top, with a change of slope nearly at the middle of the multilayer stack. The thicknesses of Pt and Ni layers, the variation of C-layer thickness with depth, interface roughness of Pt/Ni, Ni/C, C/Pt interfaces are determined from the analysis of the reflectivity data. Rutherford backscattering spectrometry measurements were also made on the same sample. Simulated Rutherford back scattering spectrometry data using the parameters obtained from the analysis of the X-ray reflectivity data agree well with the measured Rutherford backscattering spectrum.

Probing atomic migration in nanostructured multilayers: application of X-ray standing wave fields

X-ray standing wave fields, excited in periodic nanostructured multilayers during Bragg diffraction, have been used to probe atomic migration in multilayers. Ion beam induced migration of Fe impurity atoms from the C layers to the Pt layers in a Pt(Fe)/C(Fe) multilayer, where each layer is about 2 nm thick, has been detected. With a depth resolution better than 0.2 nm of this technique, the direction of Fe migration (here outward) and the change of Fe concentration in C (also Pt) layers have been determined. The results of such measurements are important for understanding the properties of multilayers, for example, the evolution of ferromagnetism in the present example [Dev, Microelectron. Eng. 83, 1721 (2006)10.1016/j.mee.2006.01.230].

Development of a femtosecond micromachining workstation by use of spectral interferometry

A workstation that permits real-time measurement of ablation depth while micromachining with femtosecond laser pulses is demonstrated. This method incorporates the unamplified pulse train that is available in a chirped-pulse amplification system as the probe in an arrangement that uses spectral interferometry to measure the ablation depth while cutting with the amplified pulse in thin metal films.

Substituted hydrophobic and hydrophilic residues at methionine-68 influence the chaperone-like function of alphaB-crystallin

Amino acid residues 57-69 in alphaB-crystallin have been implicated as a target protein binding site. Moreover, a direct correlation between the extent of alpha-crystallin hydrophobicity and chaperone-like activity has been demonstrated. The purpose of this study was to mutate a moderately hydrophobic residue Met-68 (M-68) in the above region to strongly hydrophobic and hydrophilic residues and show whether chaperoning ability is affected with or without structural changes. Mutation of M-68 to Val, Ile or Thr did not result in significant changes in molecular mass and secondary and tertiary structures. However, the Val and Ile mutants showed significant improvement and the Thr mutant showed substantial loss in chaperone activity. Differences in chaperone function in the absence of any structural changes confirmed that the hydrophobicity or hydrophilicity of the substituted amino acid in the putative target protein binding site was the only contributing factor.

Substituted hydrophobic and hydrophilic residues at methionine-68 influence the chaperone-like function of alphaB-crystallin

Amino acid residues 57-69 in alphaB-crystallin have been implicated as a target protein binding site. Moreover, a direct correlation between the extent of alpha-crystallin hydrophobicity and chaperone-like activity has been demonstrated. The purpose of this study was to mutate a moderately hydrophobic residue Met-68 (M-68) in the above region to strongly hydrophobic and hydrophilic residues and show whether chaperoning ability is affected with or without structural changes. Mutation of M-68 to Val, Ile or Thr did not result in significant changes in molecular mass and secondary and tertiary structures. However, the Val and Ile mutants showed significant improvement and the Thr mutant showed substantial loss in chaperone activity. Differences in chaperone function in the absence of any structural changes confirmed that the hydrophobicity or hydrophilicity of the substituted amino acid in the putative target protein binding site was the only contributing factor.

The effect of glutathione upon chaperone activity of alpha-crystallin is probably mediated through target modulation

We studied the effect of the presence of glutathione, both reduced (GSH) and oxidized (GSSG), on the chaperone activity of alpha-crystallin towards thermal aggregation of gamma 2-crystallin. Results showed that while GSH enhanced the chaperone activity of alpha-crystallin, GSSG appeared to diminish it to some extent. When, however, the effect of the presence of glutathione was studied in the absence of alpha-crystallin, the nature of their action was found to be almost similar to that observed in its presence. These results suggest that glutathiones probably modulate the target protein which ultimately influences the chaperone activity of alpha-crystallin.

Mutation of R116C results in highly oligomerized alpha A-crystallin with modified structure and defective chaperone-like function

An autosomal dominant congenital cataract in human is associated with mutation of Arg-116 to Cys (R116C) in alpha A-crystallin. To investigate the molecular basis of cataract formation, rat alpha A-crystallin cDNA was cloned into pET-23d(+), and the site-directed mutants S142C (similar to wild-type human alpha A) and R116C/S142C or R116C (similar to human R116C variant) were generated. These were expressed in E. coli and the recombinant alpha A-crystallins purified by Sephacryl size-exclusion chromatography. The chaperone-like function of mutant R116C determined at 37 degrees C with insulin and alcohol dehydrogenase as target proteins was about 40% lower than those of wild-type and mutant S142C. Based on size-exclusion chromatography data, the oligomeric size of the R116C mutant was about 2000 kDa at 25 degrees C, 1400 kDa at 37 degrees C, and 900 kDa at 45 degrees C. In comparison, alpha A-wild-type and alpha A-S142C ranged from 477 to 581 kDa. Heat stability studies corroborated the effect of temperature on the dynamic quaternary structure of the R116C mutant. Circular dichroism spectra showed secondary and tertiary structural changes, and ANS fluorescence spectra showed loss of surface hydrophobicity in the R116C mutant. These findings suggest that the molecular basis for the congenital cataract with the alpha A-R116C mutation is due to the generation of a highly oligomerized alpha A-crystallin having a modified structure and decreased chaperone-like function.

Synthesis and antiviral studies of unsaturated analogues of isomeric dideoxynucleosides

Novel isomeric dideoxynucleosides with unsaturation in the carbohydrate moiety have been synthesized. For example, isod4A was synthesized through a rearrangement reaction involving a cyclonucleoside. Support for the structures of both purine and pyrimidine d4 compounds came from UV, NMR, HRMS and single crystal X-ray data. Interestingly, the single crystal X-ray data for isod4C shows that the base is almost orthogonal to the carbon-carbon double bond of the sugar moiety. Consistent with this is the observation that the UV data of this compound does not show a bathochromic shift compared to the saturated compound implying that the pi-bond is not in conjugation with the pyrimidine base.

Synthesis of novel isomeric dideoxydidehydronucleosides

Methodologies for the synthesis of novel isomeric dideoxynucleosides with unsaturation in the carbohydrate moiety have been developed. An example of the synthesis (Isod4A) is presented. Antiviral studies are in progress.

Small-area analysis: targeting high-risk areas for adolescent pregnancy prevention programs

CONTEXT

Traditional methods of identifying areas in need of adolescent pregnancy prevention programs may miss small localities with high levels of adolescent childbearing.

METHODS

Birthrates for 15-17-year-olds were computed for all California zip codes, and the zip codes with birthrates in the 75th percentile were identified. Panels of local experts in adolescent pregnancy reviewed these "hot spots" for accuracy and grouped them into potential project areas, based on their demographics, geography and political infrastructure.

RESULTS

In all, 415 zip codes exceeded the 75th-percentile cut-off point of 62.8 births per 1,000, and 210 of them differed significantly from the state average of 44.5 per 1,000 for 15-17-year-olds. While all had high adolescent birthrates, they varied greatly in racial and ethnic mix, poverty and educational attainment, and certain perinatal measures such as inadequate prenatal care and repeat pregnancy.

CONCLUSIONS

The use of zip code-level data holds promise for more effective program planning and intervention.

Behavioral and experiential patterns of avoidantly and securely attached women across adulthood: a 31-year longitudinal perspective

Attachment patterns of women avoidantly or securely attached at age 52 were studied using a 31-year longitudinal design and multiple perspectives, including life outcomes, observer descriptions of behavioral and personality characteristics, and self-reports of working models collected at ages 21, 27, 43, and 52. Findings from these diverse data sources provide evidence for the continuity of the behavioral and experiential patterns associated with attachment styles across adulthood. Avoidant compared with secure participants (a) experienced diverging relationship trajectories that were less happy and less steady, (b) showed a consistent pattern of behavioral and personality characteristics, including interpersonal distance, defensiveness, and vulnerability, as assessed by observers, (c) reported distinct and longitudinal consistent internal working models characterized by distrustful self-reliance and interpersonal and emotional distance, and (d) had childhood environments that afforded fewer opportunities for developing close interpersonal ties.

Interaction of H(+)-ions with alpha-crystallin: solvent accessibility of ionizable side chains and surface charge

Interaction of H(+)-ions with alpha-crystallin from goat lens has been studied at three different ionic strengths using the potentiometric titration method. Titrations have also been carried out in the presence of 1.5 M and 6 M GuHCl (guanidine hydrochloride). The isoionic pH of the protein in water and the effect of KCl on it have been determined. Titration curves have been found to be reversible between pH 3 to 9.25 at all ionic strengths. To aid in the data analyses, the reactivities of alpha-crystallin lysine residues to trinitrobenzenesulfonic acid have been determined in this work. For alpha-crystallin aggregate, 130 +/- 2 histidine side chains out of a total of 300 and about 134 +/- 4 lysine side chains out of 310 have been found to be inaccessible to the solvent in the native condition. The remaining titratable side chains determine the surface charge of the native protein. In 1.5 M GuHC1, however, the nontitratable histidine side chains are found to be available for titration as are the nontitratable lysine and tyrosine side chains in 6M GuHC1. The theoretical titration curve computed on the basis of Linderstrøm-Lang model is found to fit quite comfortably with the experimental one between pH 4.6 and 9.25. The pKint value for beta gamma-carboxyl side chains has been found to be 5.18 which is somewhat higher than usual indicating that the carboxyl groups in the protein are probably in some constrained condition which is released in the presence of a denaturant. Below pH 4.6, there begins a conformational change in the alpha-crystallin aggregate as is corroborated from the circular dichroism studies. The value of electrostatic interaction factor w which remains more or less constant between pH 4.6 and 9.25 is also found to gradually fall off below pH 4.6.

Behavioral and experiential patterns of avoidantly and securely attached women across adulthood: a 31-year longitudinal perspective

Attachment patterns of women avoidantly or securely attached at age 52 were studied using a 31-year longitudinal design and multiple perspectives, including life outcomes, observer descriptions of behavioral and personality characteristics, and self-reports of working models collected at ages 21, 27, 43, and 52. Findings from these diverse data sources provide evidence for the continuity of the behavioral and experiential patterns associated with attachment styles across adulthood. Avoidant compared with secure participants (a) experienced diverging relationship trajectories that were less happy and less steady, (b) showed a consistent pattern of behavioral and personality characteristics, including interpersonal distance, defensiveness, and vulnerability, as assessed by observers, (c) reported distinct and longitudinal consistent internal working models characterized by distrustful self-reliance and interpersonal and emotional distance, and (d) had childhood environments that afforded fewer opportunities for developing close interpersonal ties.

Chemical modifications and dissociation characteristics of tyrosine and tryptophan residues in alpha-crystallin

A quantitative estimation of surface accessibility of aromatic residues in alpha-crystallin from goat lens has been accomplished by chemical modifications using different specific reagents having varying sizes. Results of modification of tyrosine residues with N-acetylimidazole and tetranitromethane when combined with those of ionization studies carried out with hydroxyl ions having the smallest size reveal different classes of tyrosine residues in the native protein: 78 +/- 2 residues have been found to be easily available for modification; among the rest, 94 +/- 2 residues appear to be comparatively less exposed to the reagents while 28 +/- 2 residues are found to be completely unavailable for modification in the native protein and are modified only when the protein is denatured. Modification of tryptophan residues with H2O2 also indicates different classes of these residues available for oxidation at different concentrations of the oxidant. 34 +/- 2 residues of tryptophan are found to be easily oxidized at a lower concentration of H2O2 during the first phase of the reaction. The remaining tryptophan residues appear to be less exposed to the reagent. This is also corroborated from the studies of reactivities of these residues towards another specific but bulkier reagent, 2-hydroxy-5-nitrobenzyl bromide. These surface exposed aromatic residues in alpha-crystallin may be considered to be vulnerable to in vivo oxidative modifications forming insoluble aggregates which may finally contribute to the formation of cataract.