bluuebunny/crossref_metadata_2025 huggingface dataset:
Generalization of the Langmuir–Blodgett laws for a nonzero potential gradient
Authors: Sutherland Orson , Ankiewicz Adrian , Boswell Rod
Published: February 2005

The Langmuir–Blodgett laws for cylindrical and spherical diodes and the Child–Langmuir law for planar diodes repose on the assumption that the electric field at the emission surface is zero. In the case of ion beam extraction from a plasma, the Langmuir–Blodgett relations are the typical tools of study, however, their use under the above assumption can lead to significant error in the beam distribution functions. This is because the potential gradient at the sheath/beam interface is nonzero and attains, in most practical ion beam extractors, some hundreds of kilovolts per meter. In this paper generalizations to the standard analysis of the spherical and cylindrical diodes to incorporate this difference in boundary condition are presented and the results are compared to the familiar Langmuir–Blodgett relation.
Optoelectronically automated system for carbon nanotubes synthesis via arc-discharge in solution
Authors: Bera Debasis , Brinley Erik , Kuiry Suresh C. , McCutchen Matthew , Seal Sudipta , Heinrich Helge , Kabes Bradley
Published: February 2005

The method of arc discharge in the solution is unique and inexpensive route for synthesis of the carbon nanotubes (CNTs), carbon onions, and other carbon nanostructures. Such a method can be used for in situ synthesis of CNTs decorated with nanoparticles. Herein, we report a simple and inexpensive optoelectronically automated system for arc discharge in solution synthesis of CNTs. The optoelectronic system maintains a constant gap between the two electrodes allowing a continuous synthesis of the carbon nanostructures. The system operates in a feedback loop consisting of an electrode-gap detector and an analog electronic unit, as controller. This computerized feeding system of the anode was used for in situ nanoparticles incorporated CNTs. For example, we have successfully decorated CNTs with ceria, silica, and palladium nanoparticles. Characterizations of nanostructures are performed using high-resolution transmission electron microscopy, scanning transmission electron microscopy, energy dispersive spectroscopy, and scanning electron microscopy.
Bistability in a magnetic and nonmagnetic double-quantum-well structure mediated by the magnetic phase transition
Authors: Semenov Y. G. , Enaya H. , Kim K. W.
Published: February 2005

The hole distribution in a double-quantum-well (QW) structure consisting of a magnetic and a nonmagnetic semiconductor QW is investigated as a function of temperature, the energy shift between the QWs, and other relevant parameters. When the itinerant holes mediate the ferromagnetic ordering, it is shown that a bistable state can be formed through hole redistribution, resulting in a significant change in the properties of the constituting magnetic QW (i.e., the paramagnetic-ferromagnetic transition). The model calculation also indicates a large window in the system parameter space where bistability is possible. Hence, this structure could form the basis of a stable memory element that may be scaled down to a few-hole regime.
Modeling of high-current source-gated transistors in amorphous silicon
Authors: Balon F. , Shannon J. M. , Sealy B. J.
Published: February 2005

Compared with the field-effect transistor, the source-gated transistor has a much lower saturation voltage and higher output impedance. These features are investigated using computer modeling for amorphous silicon transistors operated at high currents when source barriers are low. In particular, it is shown that low saturation voltages are maintained at high current and are insensitive to source-drain separation. Furthermore, the output impedance is preserved even for submicron source-drain separations.
Concordant evolution of trichothecene 3-O-acetyltransferase and an rDNA species phylogeny of trichothecene-producing and non-producing fusaria and other ascomycetous fungi
Authors: Tokai Takeshi , Fujimura Makoto , Inoue Hirokazu , Aoki Takayuki , Ohta Kunihiro , Shibata Takehiko , Yamaguchi Isamu , Kimura Makoto
Published: February 2005

The cereal pathogenFusarium graminearumspecies complex (e.g.Fusarium asiaticum, previously referred to asF. graminearumlineage 6) produces the mycotoxin trichothecene in infected grains. The fungus has a gene for self-defence,Tri101, which is responsible for 3-O-acetylation of the trichothecene skeleton in the biosynthetic pathway. Recently, trichothecene non-producersFusarium oxysporumandFusarium fujikuroi(teleomorphGibberella fujikuroi) were shown to have both functional (Tri201) and non-functional (pseudo-Tri101) trichothecene 3-O-acetyltransferase genes in their genome. To gain insight into the evolution of the trichothecene genes inGibberellaspecies, the authors examined whether or not other (pseudo-)biosynthesis-related genes are found nearTri201. However, sequence analysis of a 12 kb region containingTri201did not result in identification of additional trichothecene (pseudo-)genes inF. oxysporum. In a further attempt to find other trichothecene (pseudo-)genes from the non-producer, the authors examined whether or not the non-trichothecene genes flanking the ends of the core trichothecene gene cluster (i.e. theTri5cluster) comprise a region of synteny inGibberellaspecies. However, it was not possible to isolate trichothecene (pseudo-)genes fromF. oxysporum(in addition to the previously identified pseudo-Tri101), because synteny was not observed for this region inF. asiaticumandF. oxysporum. In contrast to this unsuccessful identification of additional trichothecene (pseudo-)genes in the non-producer, a functional trichothecene 3-O-acetyltransferase gene could be identified in fusaria other thanGibberella:Fusarium decemcellulareandFusarium solani; and in an ascomycete from a different fungal genus,Magnaporthe grisea. Together with the recent functional identification ofSaccharomyces cerevisiae ScAYT1, these results are suggestive of a different evolutionary origin for the trichothecene 3-O-acetyltransferase gene from other biosynthesis pathway genes. The phylogeny of the 3-O-acetyltransferase was mostly concordant with the rDNA species phylogeny of these ascomycetous fungi.
A new insertion sequence, IS14999, from Corynebacterium glutamicum
Authors: Tsuge Yota , Ninomiya Kana , Suzuki Nobuaki , Inui Masayuki , Yukawa Hideaki
Published: February 2005

A new insertion sequence fromCorynebacterium glutamicumATCC 14999 was isolated and characterized. This IS element, designated IS14999, comprised a 1149 bp nucleotide sequence with 22 bp imperfect terminal inverted repeats. IS14999carries a single open reading frame of 345 amino acids encoding a putative transposase that appears to have partial homology to IS642, an IS630/Tc1superfamily element, at the C-terminal region in the amino acid sequence. This indicated that IS14999belonged to the IS630/Tc1superfamily, which was first identified inC. glutamicum. IS14999has a unique distance of 38 amino acid residues between the second and third amino acids in the DDE motif, which is well known as the catalytic centre of transposase. This suggested that IS14999constituted a new subfamily of the IS630/Tc1superfamily. A phylogenetic tree constructed on the basis of amino acid sequences of transposases revealed that this new transposable element was more similar to eukaryotic Tc1/marinerfamily elements than to prokaryotic IS630family elements. Added to the fact that IS14999was present in only a fewC. glutamicumstrains, this implies that IS14999was probably acquired by a recent lateral transfer event from eukaryotic cells. Analysis of the insertion site inC. glutamicumR revealed that IS14999appeared to transpose at random and always caused a target duplication of a 5′-TA-3′ dinucleotide upon insertion, like the other IS630/Tc1family elements. These findings indicated that IS14999could be a powerful tool for genetic manipulation of corynebacteria and related species.
Precursor and temperature modulation of fatty acid composition and growth of Listeria monocytogenes cold-sensitive mutants with transposon-interrupted branched-chain α-keto acid dehydrogenase
Authors: Zhu Kun , Bayles Darrell O. , Xiong Anming , Jayaswal R. K. , Wilkinson Brian J.
Published: February 2005

Branched-chain fatty acids (BCFAs) typically constitute more than 90 % of the fatty acids ofListeria monocytogenes. The authors have previously described two Tn917-induced, cold-sensitive, BCFA-deficient (<40 %)L. monocytogenesmutants (cld-1andcld-2) with lowered membrane fluidity. Sequence analyses revealed that Tn917was inserted into different genes of the branched-chainα-keto acid dehydrogenase cluster (bkd) in these two mutants. The cold-sensitivity and BCFA deficiency ofcld-1, in which Tn917was inserted intobkdB, were complementedin transby clonedbkdB. The growth and corresponding BCFA content of the mutants at 37 °C were stimulated by fatty acid precursors bypassing Bkd, 2-methylbutyrate (precursor for odd-numbered anteiso-fatty acids), isobutyrate (precursor for even-numbered iso-fatty acids) and isovalerate (precursor for odd-numbered iso-fatty acids). In contrast, the corresponding Bkd substrates,α-ketomethylvalerate,α-ketoisovalerate andα-ketoisocaproate, exhibited much poorer activity. At 26 °C, 2-methylbutyrate and isovalerate stimulated the growth of the mutants, and at 10 °C, only 2-methylbutyrate stimulated growth. Pyruvate depressed the BCFA content ofcld-2from 33 % to 27 %, which may be close to the minimum BCFA requirement forL. monocytogenes. The transcription ofbkdwas enhanced by Bkd substrates, but not by low temperature. When provided with the BCFA precursors,cld-2was able to increase its anteiso-C15 : 0fatty acid content at 10 °C compared to 37 °C, which is the characteristic response ofL. monocytogenesto low temperature. This implies that Bkd is not the major cold-regulation point of BCFA synthesis.
Increasing frequency of Gram‐positive bacteria in spontaneous bacterial peritonitis
Authors: Cholongitas Evangelos , Papatheodoridis George V. , Lahanas Alexandros , Xanthaki Anna , Kontou‐Kastellanou Chrysoula , Archimandritis Athanasios J.
Published: February 2005

Abstract: Aim: To evaluate the characteristics and possible recent changes of the microbial causes of spontaneous bacterial peritonitis (SBP) in cirrhotic patients.

Methods: We retrospectively evaluated 42 cirrhotic patients with positive ascitic fluid culture and without evidence of secondary peritonitis who were admitted consecutively to our Department between 1998 and 2002.

Results: Twenty (48%) of 42 patients with positive ascitic fluid culture were diagnosed during 1998–1999 (period A) and the remaining 22 (52%) patients during 2000–2002 (period B). Gram‐negative bacteria were the cause of SBP in 15 (75%) of the 20 patients during period A and in only nine (41%) of the 22 patients during period B (P=0.026). SBP patients with Gram‐positive bacteria compared with those with Gram‐negative bacteria were less frequently in Child class C (P=0.058) and had significantly higher ascitic fluid protein (P=0.014) and albumin concentrations (P=0.009) and lower ascitic fluid neutrophil count (P=0.008). Resistance to quinolones was detected significantly more frequently in the isolated Gram‐positive than Gram‐negative bacteria (P<0.001).

Conclusion: Culture‐positive SBP in cirrhotic patients are caused more frequently by Gram‐positive bacteria during the recent years, which are, in their vast majority, resistant to quinolones.
A Solution for Lightly Loaded Adhesive Rough Surfaces With Application to MEMS
Authors: Morrow Clint A. , Lovell Michael R.
Published: February 2005

The stiction forces that exist in microelectromechanical systems (MEMS) are characterized by surface energy and surface roughness. To simulate this contact condition, a three-dimensional fractal surface geometry and an adhesive contact model for a single asperity are used together to create a numerical adhesive rough surface solution methodology. This novel method of solution determines the characteristic adhesive contact type for each individual asperity uniquely at the time of load and area integration. Such a simulation more accurately represents the physics of the asperity-based contact. Numerical results for the adherence force are presented as a function of surface topography, interface compliance, and the work of adhesion for a MEMS interface. The magnitude of the force required to separate an adhesive rough surface interface is given in relation to a polysilicon system.
Spreading Characteristics of Monolayer Lubricant Films on Surfaces With Lube Textures
Authors: Zhang Hedong , Mitsuya Yasunaga , Fukuoka Natsuko , Fukuzawa Kenji
Published: February 2005

In this paper, we investigate the effect of lube textures from the viewpoint of lubricant spreading. Lube textures, designating a patterned distribution of bonding strength between lubricant molecules and disk surface, were formed by irradiating ultraviolet rays through a stripe-patterned mask onto a magnetic disk surface which was partially coated with one-monolayer film of perfluoropolyether. Surface characteristics of the lube textures were evaluated by surface energies ascertained from contact angle measurements. Spreading of the lubricant film was measured by scanning microellipsometry on the striped lube textures in the directions parallel and perpendicular to the stripes. The thickness-dependent diffusion coefficients extracted from the spreading profiles show that lubricant spreading in the regime of film thickness less than 0.2 nm is faster along the stripes, indicating the possibility of controlling the behavior of lubricant films with lube textures.
ON MULTIOBJECTIVE EVOLUTION MODEL
Authors: AHMED E. , ELETTREBY M. F.
Published: February 2005

Self-Organized Criticality (SOC) phenomena could have a significant effect on the dynamics of ecosystems. The Bak–Sneppen (BS) model is a simple and robust model of biological evolution that exhibits punctuated equilibrium behavior. Here, we will introduce random version of BS model. We also generalize the single objective BS model to a multiobjective one.
THE SELF-ORGANIZED MULTI-LATTICE MONTE CARLO SIMULATION
Authors: HORVÁTH DENIS , GMITRA MARTIN
Published: February 2005

Self-organized Monte Carlo simulations of 2D Ising ferromagnet on the square lattice are performed. The essence of the suggested simulation method is an artificial dynamics consisting of the well-known single-spin-flip Metropolis algorithm supplemented by a random walk on the temperature axis. The walk is biased towards the critical region through a feedback based on instantaneous energy and magnetization cumulants, which are updated at every Monte Carlo step and filtered through a special recursion algorithm. The simulations revealed the invariance of the temperature probability distribution function, once some self-organized critical steady regime is reached, which is called here noncanonical equilibrium. The mean value of this distribution approximates the pseudocritical temperature of canonical equilibrium. In order to suppress finite-size effects, the self-organized approach is extended to multi-lattice systems, where the feedback basis on pairs of instantaneous estimates of the fourth-order magnetization cumulant on two systems of different size. These replica-based simulations resemble, in Monte Carlo lattice systems, some of the invariant statistical distributions of standard self-organized critical systems.
EFFECT OF POSITIVE BACKGROUND ON THE FERROMAGNETIC PHASE OF 3D WIGNER ELECTRON CRYSTAL
Authors: PALANICHAMY R. RAJESWARA , IYAKUTTI K.
Published: February 2005

In the ferromagnetic phase of the 3D electron system, it is assumed that the spins of all the electrons are arranged in a parallel manner. The ferromagnetically ordered electrons are represented by the structure dependent Wannier functions. The ground state energies of the ferromagnetically ordered electron crystals corresponding to sc, bcc, fcc, diamond and perovskite structures are computed with Gaussian type and Yukawa type positive backgrounds. The stability of these structures is analyzed. In each case, the possibility of the Wigner electrons having cubic or spherical constant energy surface (the region of integration in momentum space) is considered for the range of rs values corresponding to low densities. The effect of correlation energy is suitably taken into account. The range of low density region favorable for Wigner crystallization is found to be at 6.0×1019/ cm 3. It is found that the ferromagnetically ordered electrons crystallize into fcc lattice in the low density limit with Yukawa type positive background.
ELECTRON SPIN RESONANCE STUDIES OF Mn2+ IN FRESHWATER SNAIL SHELLS: S. INGALLSIANA, P. AMPULLACEA, P. CANALICULATA LAMARCK AND FOSSILIZED SNAIL SHELL
Authors: MEEJOO S. , UDOMKAN N. , WINOTAI P. , CHAIMANEE Y.
Published: February 2005

We have studied paramagnetic Mn 2+ ions present in the shells of today's univalve freshwater snails, Sinotaia ingallsiana (FS), Pila ampullaceal (PA), Pomacea canaliculata lamarck (PCL) and the fossilized freshwater snail (FFS), Viviparus which are abundant in Thailand. The FS, PA and AG shells in our study were ground into fine powder. A set of seven samples was each then separately annealed for 2 hours in air atmosphere at 300°C, 400°C, 450°C, 500°C, 550°C, 600°C and 900°C, respectively, while the FFS powder was characterized as received. The FS, PA and PCL shells mainly consist of aragonite and a fraction of calcite. The heat treatments higher than 450°C of the FS, PA and PCL powder samples resulted in an irreversible phase transformation from aragonite to calcite. However, it is found that the FFS shell is mainly made of calcite, with a minor fraction of aragonite. The crystal structure of high temperature annealed FS, PA and PCL samples are quite similar to that of FFS, which indicates that the metamorphosis (aragonite → calcite) in the FFS shell had occurred but not yet completed, although they remained under the pressure and temperature of the Earth's crust over millions of years. Our detailed ESR spectral analyses of FS, PA, PCL and FFS show that Mn 2+ ions enter Ca 2+ sites during a biomineralization process. Typical simulated ESR parameters of FS-500 of Mn 2+ at a uniaxial site of calcite are gx=gy=2.078±0.001, gz=2.002±0.001, Ax=Ay=87.50±1.00 G , Az=89.00±1.00 G and D=115±1 G , respectively. It is surprising to find that the ratio of Mn 2+ concentration present in FFS to those in FS, PA and PCL shells evaluated from ESR spectra is as much as 10:1. It is thus possible to gain some insight of manganese incorporation into the freshwater shells during the biomineralization process.
SIMULATION OF TRAFFIC CONGESTION WITH SIR MODEL
Authors: WU JIANJUN , GAO ZIYOU , SUN HUIJUN
Published: February 2005

The spread of traffic congestion is related to the rate of infection and the recovery rate. In this paper, we describe the traffic congestion spread with SIR model of a complex network. From the point of the complex network, the spread of the traffic congestion with different parameters are simulated. By simulation, we find that the behavior of the traffic system is tightly related to the average rate of infection, the average recovery rate and the topological properties of traffic network.
On the extremal solutions of semilinear elliptic problems
Authors: Ben Chaabane Lamia
Published: February 2005

We investigate here the properties of extremal solutions for
semilinear elliptic equation −Δu = λf(u) posed on a bounded smooth domain of ℝn with Dirichlet boundary condition and with f exploding at a finite positive value a.
Quasilinear degenerate elliptic unilateral problems
Authors: Aharouch L. , Akdim Y. , Azroul E.
Published: February 2005

We will be concerned with the existence result of a degenerate elliptic unilateral problem of the form Au + H(x, u, ∇u) = f,
where A is a Leray‐Lions operator from W1,p(Ω, w) into its dual. On the nonlinear lower‐order term H(x, u, ∇u), we assume that it is a Carathéodory function having natural growth with
respect to |∇u|, but without assuming the sign condition. The right‐hand side f belongs to L1(Ω).
Continuous dependence on data for quasiautonomous nonlinear boundary value problems
Authors: Apreutesei N.
Published: February 2005

We devote this paper to quasiautonomous second‐order differential
equations in Hilbert spaces governed by maximal monotone operators. Some bilocal boundary conditions are associated. We discuss the continuous dependence of the solution both on the operator and on the boundary values. One uses the methods of
nonlinear analysis. Some applications to internal approximate schemes are given.
Diabetic Retinopathy Analysis
Authors: Sivakumar R. , Ravindran G. , Muthayya M. , Lakshminarayanan S. , Velmurughendran C. U.
Published: February 2005

Diabetic retinopathy is one of the common complications of diabetes. Unfortunately, in many cases the patient is not aware of any symptoms until it is too late for effective treatment. Through analysis of evoked potential response of the retina, the optical nerve, and the optical brain center, a way will be paved for early diagnosis of diabetic retinopathy and prognosis during the treatment process. In this paper, we present an artificial‐neural‐network‐based method to classify diabetic retinopathy subjects according to changes in visual evoked potential spectral components and an anatomically realistic computer model of the human eye under normal and retinopathy conditions in a virtual environment using 3D Max Studio and Windows Movie Maker.
Towards a Better Understanding of the Molecular Mechanisms Involved in Sunlight‐Induced Melanoma
Authors: Williams Mandy , Ouhtit Allal
Published: February 2005

Although much less prevalent than its nonmelanoma skin cancer counterparts, cutaneous malignant melanoma (CMM) is the most lethal human skin cancer. Epidemiological and biological studies have established a strong link between lifetime exposure to ultraviolet (UV) light, particularly sunburn in childhood, and the development of melanoma. However, the specific molecular targets of this environmental carcinogen are not known. Data obtained from genetic and molecular studies over the last few years have identified the INK4a/ARF locus as the “gatekeeper” melanoma suppressor, encoding two tumour suppressor proteins in human, p16INK4a and p14ARF. Recent developments in molecular biotechnology and research using laboratory animals have made a significant gene breakthrough identifying the components of the p16p16INK4a/Rb pathway as the principal and rate‐limiting targets of UV radiation actions in melanoma formation. This review summarizes the current knowledge of the molecular mechanisms involved in melanoma development and its relationship to sunlight UV radiation.
Comparison of Long-Term Perifused Pars intermedia of Anolis carolinensis, Rana pipiens and Hyla chrysoscelis: Their Responses to Dopamine
Authors: Barnawell Earl B. , Bargar Tom W.
Published: February 2005

Pituitary pars nervosa-pars intermedia of Anolis carolinensis, Rana pipiens and Hyla crysoscelis were perifused with synthetic medium 199 for up to 35 h. The pre- and post-perifused tissues were examined by electron microscopy. No neuronal endings were found in Anolis tissue, but both Rana and Hyla had occasional synaptic end bulbs, which remained visible in the post-perifused tissue, although the synaptic vesicles appeared to cluster in the center of the end bulbs. Exposure to dopamine HCl from 10–8 to10–5M had little effect on Anolis pituitary but inhibited Rana and Hyla pituitaries from releasing skin-darkening substances. The skin-darkening substances, presumably derivatives of the proopiomelanocortin molecule, were assayed on Anolis skin. No dose-dependent responses to dopamine were seen at the concentrations used. We saw the possibility of a short-loop feedback.
Polymorphism of the Interleukin-4, Interleukin-13, and Signal Transducer and Activator of Transcription 6 Genes in Indonesian Children with Minimal Change Nephrotic Syndrome
Authors: Acharya Bishnu , Shirakawa Toshiro , Pungky Ardanykusuma , Damanik Parlin , Massi Muh. Nasrum , Miyata Masahiro , Matsuo Masafumi , Gotoh Akinobu
Published: February 2005

Background/Aims: Minimal change nephrotic syndrome (MCNS) in children is frequently associated with allergy and immunoglobulin E (IgE) production. T-helper subtype 2 cytokines, such as interleukin (IL)-4 and IL-13, have been implicated in the regulation of IgE production. We investigated the associations of gene polymorphisms of IL-4, IL-13, and signal transducer and activator 6 (STAT6) in Indonesian children with MCNS (n = 84) and controls with neither allergic nor renal disease (n = 61). Methods: Polymerase chain reaction-restriction fragment length polymorphism was used to determine the IL-4 promoter gene polymorphism (–590C/T) and IL-13 gene polymorphism (4257G/A), and direct sequencing was used for the STAT6 3S untranslated region (2964G/A) polymorphism. Results: There was a significant difference between the MCNS group and the controls in the genotypic distribution of IL-4 and IL-13 gene polymorphism. In the case of the IL-4 promoter gene, the frequency of the CC homozygote was significantly lower in the MCNS group than in the controls, while, in the case of IL-13, the frequency of the GG homozygote was significantly lower in the MCNS group. However, there was no difference between the MCNS group and the controls in the STAT6 gene polymorphism. Conclusion: The genetic variations in the IL-4 and IL-13 genes may be associated with predisposition to MCNS.
Optimal Product Launch Times in a Duopoly: Balancing Life-Cycle Revenues with Product Cost
Authors: Savin Sergei , Terwiesch Christian
Published: February 2005

We present a model describing the demand dynamics of two new products competing for a limited target market. The demand trajectories of the two products are driven by a market saturation effect and an imitation effect reflecting the product experience of previous adopters. In this general setting, we provide analytical results for the sales trajectories and life-cycle sales of the competing products. We use these results to study the impact of launch time on overall life-cycle sales. We consider the perspective of one of the competing products and model the trade-off between the lost revenues resulting from a delayed launch and the lower unit-production costs. We find that the profit-maximizing launch time exhibits a counterintuitive behavior. In particular, we show that a firm facing a launch time delay from a competing product might benefit from accelerating its own product launch, as opposed to using the softened competitive situation to further improve its cost position. We identify conditions under which a marginal cost-benefit analysis leads to suboptimal launch-time decisions. Finally, we analyze the Nash equilibrium in launch-time decisions of the two competing products.
The Single-Product Lot-Sizing Problem with Constant Parameters and Backlogging: Exact Results, a New Solution, and All Parameter Stability Regions
Authors: Ganas Ioannis , Papachristos Sotirios
Published: February 2005

We consider the single-product lot-sizing problem over a finite planning horizon. Demand at each period is constant, and excess demand is completely backlogged. Holding and backlogging costs are proportional to the amount of inventory stocked or backlogged, while ordering cost is fixed, independent of the quantity ordered. The optimal policy targets to minimize the total relevant costs over the planning horizon. The key results of this paper are: (1) an explicit formula for the optimal total cost as a function of the model parameters and the number of cycles of the policy; (2) a new, polynomial-time algorithm which determines the overall optimal policy; and (3) stability regions for any solution considering simultaneous variations on all cost and demand parameters. The proposed algorithm is easy to implement and therefore is suitable for practical use.
A two‐step mechanism for the binding of the HIV‐1 MPER epitope by the 10E8 antibody onto biosensor‐supported lipid bilayers
Authors: García‐Porras Miguel , Torralba Johana , Insausti Sara , Valle Javier , Andreu David , Apellániz Beatriz , Nieva José L.
Published: February 2024

HIV‐1 antibodies targeting the carboxy‐terminal area of the membrane‐proximal external region (ctMPER) are close to exerting viral pan‐neutralization. Here, we reconstituted the ctMPER epitope as the N‐terminal extremity of the Env glycoprotein transmembrane domain helix and immobilized it onto biosensor‐supported lipid bilayers. We assessed the binding mechanism of anti‐MPER antibody 10E8 through Surface Plasmon Resonance, and found, through equilibrium and kinetic binding analyses as a function of bilayer thickness, peptide length, and paratope mutations, that 10E8 engages first with the epitope peptide (encounter), limited by ctMPER helix accessibility at the membrane surface, and then inserts into the lipid bilayer assisted by favorable Fab‐membrane interactions (docking). This mechanistic information may help in devising new strategies to develop more efficient MPER‐targeting vaccines.
AI4OPT: AI Institute for Advances in Optimization
Authors: Van Hentenryck Pascal , Dalmeijer Kevin
Published: February 2024

This article is a short introduction toAI4OPT, the NSF AI Institute for Advances in Optimization.AI4OPTfuses AI and optimization, inspired by societal challenges in supply chains, energy systems, chip design and manufacturing, and sustainable food systems. By combining machine learning and mathematical optimization,AI4OPTstrives to develop AI‐assisted optimization systems that bring orders of magnitude improvements in efficiency, perform accurate uncertainty quantification, and address challenges in resiliency and sustainability.AI4OPTalso applies its “teaching the teachers” philosophy to provide longitudinal educational pathways in AI for engineering.
Mitigated Oxygen Loss in Lithium‐Rich Manganese‐Based Cathode Enabled by Strong Zr–O Affinity
Authors: Wang Guan , Xie Chenghao , Wang Hong , Li Quan , Xia Fanjie , Zeng Weihao , Peng Haoyang , Van Tendeloo Gustaaf , Tan Gangjian , Tian Jinsai , Wu Jinsong
Published: February 2024

Oxygen loss is a serious problem of lithium‐rich layered oxide (LLO) cathodes, as the high capacity of LLO relies on reversible oxygen redox. Oxygen release can occur at the surface leading to the formation of spinel or rock salt structures. Also, the lattice oxygen will usually become unstable after long cycling, which remains a major roadblock in the application of LLO. Here, it is shown that Zr doping is an effective strategy to retain lattice oxygen in LLO due to the high affinity between Zr and O. A simple sol‐gel method is used to dope Zr4+into the LLOs to adjust the local electronic structure and inhibit the diffusion of oxygen anions to the surface during cycling. Compared with untreated LLOs, LLO–Zr cathodes exhibit a higher cycling stability, with 94% capacity retention after 100 cycles at 0.4 C, up to 223 mAh g−1at 1 C, and 88% capacity retention after 300 cycles. Theoretical calculations show that due to the strong Zr–O covalent bonding, the formation energy of oxygen vacancies has effectively increased and the loss of lattice oxygen under high voltage can be suppressed. This study provides a simple method for developing high‐capacity and cyclability Li‐rich cathode materials for lithium‐ion batteries.
A Self‐Powered Wound Dressing Based on “Lock‐ON/OFF” Drug Release Combined Electric Stimulus Therapy for Accelerated Infected Wound Healing
Authors: Sun Yani , Tang Yufei , He Yuxuan , Chen Lei , Wu Cong , Zhang Bo , Yan Fuxue , Zhao Kang , Wu Zixiang
Published: February 2024

To facilitate the on‐demand release of hydrophilic antibiotics for accelerated repair of infected wounds, a self‐powered wound dressing incorporating a “Lock‐ON/OFF” electric field (EF)‐driven drug release mechanism combined with electrical stimulation (ES) therapy is presented. When subjected to mechanical stress, the drug exhibits controlled, slow‐release behavior, achieving a remarkable cumulative release rate of 88.57%—89 times higher than the non‐mechanical stress group. Conversely, in the absence of mechanical stress, the drug remains unreleased, maintaining a 0% cumulative release rate in a fully closed state. The dressing utilizes its piezoelectric effect to establish an electric field, enabling precise control of hydrophilic drug release by regulating the electrostatic balance between the drug carrier and the drug. Moreover, the piezoelectric field acts as an exogenous electric field, remodeling the endogenous electric field of the wound, and accelerating wound closure. Combining EF‐driven drug release with ES result in a 1.26 fold improvement in wound healing compared to ES alone. This study addresses precision therapy limitations in fully automated diagnosis and treatment, paving the way for advancements in remote diagnosis, wireless therapy, and on‐demand precision medicine.
Optical Microlithography of Perovskite Quantum Dots/Organic Semiconductor Heterojunctions for Neuromorphic Photosensors
Authors: Wu Yue , Dai Shilei , Liu Xu , Guo Pu , Zhang Junyao , Sun Tongrui , Guo Ziyi , Xu Yutong , Liang Haixia , Xiong Lize , Hu Huawei , Huang Jia
Published: February 2024

Heterojunctions of perovskite quantum dots (QDs) and organic semiconductors (OSCs) can synergistically leverage the unique optoelectronic properties of different functional components to fabricate advanced optoelectronic devices, such as neuromorphic photosensors, by low‐cost solution processes. However, a long‐lasting challenge remains in micropatterning high‐density perovskite QDs/polymer OSCs heterojunction array with high yield and reliability due to the fragility of functional layers to organic solvents. High‐density and micro‐structure patterned organic neuromorphic photosensor arrays based on OSCs and QDs are thus rarely reported. Here, an effective cross‐linking microlithography strategy is reported to fabricate perovskite QDs/OSCs microstructure arrays. The fabricated CsPbBr3 QDs/(poly(2,5‐(2‐octyldodecyl)−3,6‐diketopyrrolopyrrole‐alt‐5,5‐(2,5‐di(thien‐2‐yl) thieno [3,2‐b] thiophene) (DPPDTT) planer heterojunctions phototransistor array presents minor device‐to‐device variation, high density (6500 devices cm−2), and high yield (almost 100%). The device array exhibits impressive merits as a neuromorphic photosensor, including a photosensitivity of 3.02 × 107, a responsivity up to 1.92 × 104 A W−1, a detectivity exceeding 1014 Jones, and a persistent photoconductivity. Moreover, an energy consumption as low as 27.9 aJ is achieved at an operating voltage of −0.0001 V. The potential application of the heterojunction neuromorphic photosensor array in motion perception is demonstrated in conjunction with a neural network.
TiO2 Nano‐Biopatterning Reveals Optimal Ligand Presentation for Cell–Matrix Adhesion Formation
Authors: Jain Kashish , Pandey Ashish , Wang Hao , Chung Taerin , Nemati Arash , Kanchanawong Pakorn , Sheetz Michael P. , Cai Haogang , Changede Rishita
Published: February 2024

Nanoscale organization of transmembrane receptors is critical for cellular functions, enabled by the nanoscale engineering of bioligand presentation. Previously, a spatial threshold of ≤60 nm for integrin binding ligands in cell–matrix adhesion is demonstrated using monoliganded gold nanoparticles. However, the ligand geometric arrangement is limited to hexagonal arrays of monoligands, while plasmonic quenching limits further investigation by fluorescence‐based high‐resolution imaging. Here, these limitations are overcome with dielectric TiO2 nanopatterns, eliminating fluorescence quenching, thus enabling super‐resolution fluorescence microscopy on nanopatterns. By dual‐color super‐resolution imaging, high precision and consistency among nanopatterns, bioligands, and integrin nanoclusters are observed, validating the high quality and integrity of both nanopattern functionalization and passivation. By screening TiO2 nanodiscs with various diameters, an increase in fibroblast cell adhesion, spreading area, and Yes‐associated protein (YAP) nuclear localization on 100 nm diameter compared with smaller diameters was observed. Focal adhesion kinase is identified as the regulatory signal. These findings explore the optimal ligand presentation when the minimal requirements are sufficiently fulfilled in the heterogenous extracellular matrix network of isolated binding regions with abundant ligands. Integration of high‐fidelity nano‐biopatterning with super‐resolution imaging allows precise quantitative studies to address early signaling events in response to receptor clustering and their nanoscale organization.
Bioresorbable Multilayer Organic–Inorganic Films for Bioelectronic Systems
Authors: Hu Ziying , Guo Hexia , An Dongqi , Wu Mingzheng , Kaura Anika , Oh Hannah , Wang Yue , Zhao Mengjia , Li Shuo , Yang Quansan , Ji Xudong , Li Shupeng , Wang Bo , Yoo Davin , Tran Phuong , Ghoreishi‐Haack Nayereh , Kozorovitskiy Yevgenia , Huang Yonggang , Li Rui , Rogers John A.
Published: February 2024

Bioresorbable electronic devices as temporary biomedical implants represent an emerging class of technology relevant to a range of patient conditions currently addressed with technologies that require surgical explantation after a desired period of use. Obtaining reliable performance and favorable degradation behavior demands materials that can serve as biofluid barriers in encapsulating structures that avoid premature degradation of active electronic components. Here, this work presents a materials design that addresses this need, with properties in water impermeability, mechanical flexibility, and processability that are superior to alternatives. The approach uses multilayer assemblies of alternating films of polyanhydride and silicon oxynitride formed by spin‐coating and plasma‐enhanced chemical vapor deposition , respectively. Experimental and theoretical studies investigate the effects of material composition and multilayer structure on water barrier performance, water distribution, and degradation behavior. Demonstrations with inductor‐capacitor circuits, wireless power transfer systems, and wireless optoelectronic devices illustrate the performance of this materials system as a bioresorbable encapsulating structure.
Mechanically Robust Self‐Organized Crack‐Free Nanocellular Graphene with Outstanding Electrochemical Properties in Sodium Ion Battery
Authors: Park Wong‐Young , Han Jiuhui , Moon Jongun , Joo Soo‐Hyun , Wada Takeshi , Ichikawa Yuji , Ogawa Kazuhiro , Kim Hyoung Seop , Chen Mingwei , Kato Hidemi
Published: February 2024

Crack‐free nanocellular graphenes are attractive materials with extraordinary mechanical and electrochemical properties, but their homogeneous synthesis on the centimeter scale is challenging. Here, a strong nanocellular graphene film achieved by the self‐organization of carbon atoms using liquid metal dealloying and employing a defect‐free amorphous precursor is reported. This study demonstrates that a Bi melt strongly catalyzes the self‐structuring of graphene layers at low processing temperatures. The robust nanoarchitectured graphene displays a high‐genus seamless framework and exhibits remarkable tensile strength (34.8 MPa) and high electrical conductivity (1.6 × 104 S m−1). This unique material has excellent potential for flexible and high‐rate sodium‐ion battery applications.
Capillary Manganese Halide Needle‐Like Array Scintillator with Isolated Light Crosstalk for Micro‐X‐Ray Imaging
Authors: Shao Wenyi , He Tengyue , Wang Lijie , Wang Jian‐Xin , Zhou Yang , Shao Bingyao , Ugur Esma , Wu Wentao , Zhang Zhenzhong , Liang Hongwei , De Wolf Stefaan , Bakr Osman M. , Mohammed Omar F.
Published: February 2024

The exacerbation of inherent light scattering with increasing scintillator thickness poses a major challenge for balancing the thickness‐dependent spatial resolution and scintillation brightness in X‐ray imaging scintillators. Herein, a thick pixelated needle‐like array scintillator capable of micrometer resolution is fabricated via waveguide structure engineering. Specifically, this involves integrating a straightforward low‐temperature melting process of manganese halide with an aluminum‐clad capillary template. In this waveguide structure, the oriented scintillation photons propagate along the well‐aligned scintillator and are confined within individual pixels by the aluminum reflective cladding, as substantiated from the comprehensive analysis including laser diffraction experiments. Consequently, thanks to isolated light‐crosstalk channels and robust light output due to increased thickness, ultrahigh spatial resolutions of 60.8 and 51.7 lp mm−1 at a modulation transfer function (MTF) of 0.2 are achieved on 0.5 mm and even 1 mm thick scintillators, respectively, which both exceed the pore diameter of the capillary arrays’ template (Φ = 10 µm). As far as it is known, these micrometer resolutions are among the highest reported metal halide scintillators and are never demonstrated on such thick scintillators. Here an avenue is presented to the demand for thick scintillators in high‐resolution X‐ray imaging across diverse scientific and practical fields.
Dynamic Optical Encryption Fueled via Tunable Mechanical Composite Micrograting Systems
Authors: Xin Yi‐Hang , Hu Kai‐Ming , Yin Hao‐Zhe , Deng Xin‐Lu , Dong Zhi‐Qi , Yan Shu‐Zhen , Jiang Xue‐Song , Meng Guang , Zhang Wen‐Ming
Published: February 2024

Optical grating devices based on micro/nanostructured functional surfaces are widely employed to precisely manipulate light propagation, which is significant for information technologies, optical data storage, and light sensors. However, the parameters of rigid periodic structures are difficult to tune after manufacturing, which seriously limits their capacity for in situ light manipulation. Here, a novel anti‐eavesdropping, anti‐damage, and anti‐tamper dynamic optical encryption strategy are reported via tunable mechanical composite wrinkle micrograting encryption systems (MCWGES). By mechanically composing multiple in‐situ tunable ordered wrinkle gratings, the dynamic keys with large space capacity are generated to obtain encrypted diffraction patterns, which can provide a higher level of security for the encrypted systems. Furthermore, a multiple grating cone diffraction model is proposed to reveal the dynamic optical encryption principle of MCWGES. Optical encryption communication using dynamic keys has the effect of preventing eavesdropping, damage, and tampering. This dynamic encryption method based on optical manipulation of wrinkle grating demonstrates the potential applications of micro/nanostructured functional surfaces in the field of information security.
Synthesis of Hierarchical Superhydrophilic/Superhydrophobic Nanostructured Surfaces for Oil/Water Separation
Authors: Kang Seung Min , Kim Kanghyun , Kim Suhyeon , Lee Dong Gyu , An Taechang , Kim Geon Hwee
Published: February 2024

Surface wetting, the phenomenon where a liquid spreads or adheres to a solid surface, plays a crucial role in both natural and technological fields. This study focuses on elucidating the relationship between surface properties and wetting behavior, emphasizing the significance of hierarchical structures. A 3D hierarchical structure is created by controlling shape and size through electroplating and chemical reactions, adjusted by current intensity, ammonium persulfate, and ammonium hydroxide concentrations. This modification is achieved by modifying the surface's chemical properties. This control directly impacted the surface wetting properties, providing a means to regulate wetting behavior by altering surface structure. Through control of surface chemistry, a superhydrophilic surface is able to successfully create with a contact angle of 0° and a superhydrophobic surface with a contact angle of  171.3.
Continuous Glycemic Monitoring Enabled by A Wi‐Fi Energy‐Harvesting Wearable Sweat‐Sensing Patch
Authors: Mirlou Fariborz , Abbasiasl Taher , Mirzajani Hadi , Istif Emin , Akhtar Muhammad Junaid , Cakır Cengiz , Beker Levent
Published: February 2024

Continuous monitoring of multiple physiological parameters, such as glucose levels, temperature, and heart rate variability (HRV) is crucial for effective diabetes management and mitigating the risks associated with hypoglycemic events. These events often occur without apparent symptoms, posing a challenge for diabetic patients in managing their condition. Therefore, a non‐invasive wearable device capable of continuously measuring multiple body signals to predict hypoglycemic events would be highly beneficial. In this study, a wearable patch that continuously measures glucose, temperature, and HRV is presented. The device uses a novel power harvesting system to convert radiofrequency (RF) signals with the frequency of 2.45 GHz to direct current (DC) signals to extend the battery life for further continuous monitoring. The patch is small and has a conformal structure that can easily fit onto different body parts. The screen‐printed glucose sensor demonstrates a sensitivity of 10.3 nA cm−2 µM−1, a limit of detection (LOD) of 8.9 µM, and a limit of quantification (LOQ) of 27 µM. The device employs a photoplethysmography (PPG) module with a peak‐finding algorithm to calculate the HRV values. In vivo experiments demonstrate the validation of the device's proper operation in glucose, HRV, and temperature measurement.
AI‐Assisted Multimodal Breath Sensing System with Semiconductive Polymers for Accurate Monitoring of Ammonia Biomarkers
Authors: Weisbecker Hannah , Shanahan Jordan , Liu Yihan , Zhang Lin , Xie Wanrong , McDow Samuel , Lambert Noah , Huang Amber , Sopp Stephen , You Wei , Bai Wubin
Published: February 2024

Breath ammonia is an essential biomarker for patients with many chronic illnesses, such as chronic kidney disease (CKD), chronic liver disease (CLD), urea cycle disorders (UCD), and hepatic encephalopathy. However, existing breath ammonia sensors fail to compensate for the impact of breath humidity and complex breathing motions associated with a human breath sample. Here, a multimodal breath sensing system is presented that integrates an ammonia sensor based on a thermally cleaved conjugated polymer, a humidity sensor based on reduced graphene oxide (rGO), and a breath dynamics sensor based on a 3D folded strain‐responsive mesostructure. The miniaturized construction and module‐based configuration offer flexible integration with a broad range of masks. Experimental results present the capabilities of the system in continuously detecting diagnostic ranges of breath ammonia under real, humid breath conditions with sufficient sensing accuracy and selectivity over 3 weeks. A machine‐learning algorithm based on K‐means clustering decodes multimodal signals collected from the breath sensor to differentiate between healthy and diseased breath concentrations of ammonia. The on‐body test highlights the operational simplicity and practicality of the system for noninvasively tracing ammonia biomarkers.
Sequential Deposition Processing to Control Vertical Composition Distribution toward High‐Performance and Stable Inverted Organic Solar Cells
Authors: Qiu Yi , Shi Jingyu , Peng Ruixiang , Li Xiyun , Ge Ziyi
Published: February 2024

Sequential deposition (SD) is widely applied in the fabrication of high‐performance organic solar cells (OSCs). Nevertheless, the feasibility of SD in inverted photovoltaic devices is rarely mentioned. Moreover, the vertical component distribution in SD‐processed devices is still under debate. This study demonstrates that SD can achieve the entire bulk heterojunction morphology by precisely controlling the morphology of the active layer. To further promote photovoltaic performance, two post treatments, thermal annealing (TA) and solvent vapor annealing (SVA), are conducted to compare their effects on SD‐processed inverted photovoltaic devices. The results verify that SD can significantly enhance the thermal stability of devices. This work provides a valuable insight for systematically understanding SD processing and the preparation of stable inverted OSCs with superior performance.