Exclusive Production Research Articles

Optimization of Ru/ZSM-5 catalyst for selective d-glucose hydrogenation to sorbitol: A box-behnken design approach

The hydrogenation of D-glucose to sorbitol holds significant importance in biomass biorefineries. With a focus on enhancing the efficiency and selectivity of this reaction, this research investigated various optimization parameters (catalyst dosage, reaction time, and temperature) over 0.5 %Ru/ZSM-5 prepared via impregnation method. The optimization process was carried out using Box-Behnken design (BBD). The results showed accurate predictive equations for all reaction responses, with R2 values exceeding 97 % and no significant errors observed. Additionally, the 2D contour plot revealed the relationship between time and temperature, highlighting that a long reaction time and high temperature could lead to reduced sorbitol yield due to the formation of by-products. Under the optimal catalyst dosage of 0.6 g, reaction time of 100 min, and temperature of 120°C, the D-glucose conversion and sorbitol yield were 99.6 ± 0.35 % and 99.43 ± 0.45 %, respectively. NMR results confirmed the exclusive production of sorbitol under these optimal conditions. Furthermore, the study demonstrated that the catalyst could be reused at least seven times without a significant decrease in D-glucose conversion or sorbitol yield, while ICP-OES analysis confirmed no Ru leaching during the reaction. Therefore, this research provides a biomass valorization strategy by optimizing the production process of sorbitol via D-glucose hydrogenation.

Comparing self-rated health among exclusive e-cigarette users and traditional cigarette smokers: an analysis of the Health Survey for England 2019.

The health implications of e-cigarette use compared to traditional cigarette smoking continue to attract significant public health interest. This study examines self-rated health (SRH) outcomes among exclusive e-cigarette users versus exclusive traditional cigarette smokers, using data from the Health Survey for England 2019. From an initial sample of 10,299 participants, the study focused on 8204 adults, excluding those aged 0-15. Further refinement to exclusive nicotine product users led to 274 e-cigarette users and 1017 cigarette smokers, after excluding dual users, never users, ex-users, non-responders, and users of other tobacco products such as pipes and cigars. SRH was derived from participants' responses to a question asking how they rated their general health, with five possible options: "very good", "good", "fair", "bad", and "very bad". For the purposes of this study, these responses were collapsed into two categories: "Good Health" (combining "very good" and "good") and "Poor Health" (combining "fair", "bad", and "very bad"). Consequently, 834 participants were classified as reporting good health, while 457 reported poor health. Binary logistic regression, adjusted for factors such as age, sex, ethnicity, residence, education, body mass index, alcohol use, age started smoking, physical or mental health conditions, and frequency of GP visits, revealed that exclusive e-cigarette users were significantly more likely to report good health compared to exclusive cigarette smokers, with an odds ratio(OR) of 1.59 (95% CI: 1.10 - 2.32, p = 0.014). As a sensitivity analysis, a generalized ordered logistic regression model was performed using the original five SRH categories. The adjusted model confirmed consistent results, with exclusive e-cigarette users showing higher odds of reporting better health across the full range of SRH outcomes (OR = 1.40, 95% CI: 1.08-1.82, p = 0.011). These findings suggest that exclusive e-cigarette users perceive their health more positively than traditional cigarette smokers, contributing useful insights to the discussions around harm reduction strategies.

Reactions of Diphenylamine with OH Radicals in the Environment: Theoretical Insights into the Mechanism, Kinetics, Temperature, and pH Effects.

Diphenylamine (DPL) has been widely utilized in industrial chemicals, but its degradation by HO• radicals in the environment has not been fully studied yet. The present study uses quantum chemical calculations to evaluate the reaction of DPL with HO• radicals in atmospheric and aqueous environments. The results showed that, in the atmosphere, the diphenylamine reacted with the HO• radical rapidly, with an overall rate constant of 9.24 × 1011 to 1.34 × 1011 M-1 s-1 and a lifetime of 0.17 to 1.55 h at 253-323 K. The calculated overall rate constant in water (koverall = 1.95 × 1010 M-1 s-1, pH = 3-14) is in excellent agreement with the experimental value (koverall = 1.00 × 1010-1.36 × 1010 M-1 s-1). The HO• + DPL reaction in water could occur following the hydrogen transfer (15.4%), single electron transfer (41.6%), and radical adduct formation (41.7%) mechanisms, clarifying that addition products were not exclusive products. Nevertheless, variations in temperature and pH within aqueous environments had an impact on the mechanisms, kinetics, and degradation products of the reaction of DPL with HO• radicals.

A 3D Macroporous Carbon NiCu Single‐Atom Catalyst for High Current Density CO2 Electroreduction

AbstractTransition metal and nitrogen co‐decorated carbon materials are promising platforms for CO2 electroreduction. A hard‐template 2‐step pyrolysis method is proposed for the fabrication of highly dispersed Ni and Cu atomic active sites on a 3D macroporous carbon matrix. The pyrrolic N‐type Ni−Nx sites serve as dominant active sites toward selective CO2 electroreduction to CO. The incorporation of Cu alters the distribution of N species and simultaneously optimizes the electronic state and geometric structure of the Ni−Nx moiety, thereby improving its adsorption and activation capacity for CO2. Moreover, the isolated Cu atomic sites enhance the resistance of corresponding gas‐diffusion electrodes against electrolyte flooding. The optimal catalyst 3D NiCu‐69 achieves nearly exclusive production of CO with a Faraday efficiency (FECO) of 98% at a current density of −700 mA cm−2 in a CO2‐gas‐fed flow‐through electrolyzer and delivers a CO production rate of 1363 mol(m2s)−1, which is exceeding most reported electrocatalysts. The FECO remained as high as 94% after electrolyzing at a current density of −100 mA cm−2 for 22 h. 3D NiCu‐69 exhibits a favorable performance in both acidic and neutral conditions, with a high FECO of ≈90.2% within the current density range of −100 to −500 mA cm−2.

DEMPgen: Physics event generator for deep exclusive meson production at Jefferson lab and the EIC

DEMPgen: Physics event generator for deep exclusive meson production at Jefferson lab and the EIC

Nonresonant central exclusive production from CMS+TOTEM

The central exclusive production of charged hadron pairs in pp collisions at a center-of-mass energy of 13[Formula: see text]TeV is examined, based on data collected in a special high-[Formula: see text] run of the LHC. Events are selected by requiring both scattered protons detected in the TOTEM Roman pots, exactly two oppositely charged identified particles in the CMS silicon tracker, and the energy–momentum balance of these four particles. The nonresonant continuum processes are studied with the invariant mass of the centrally produced two-pion system in the resonance-free region, [Formula: see text][Formula: see text]GeV or [Formula: see text][Formula: see text]GeV. Differential cross sections as functions of the azimuthal angle between the surviving protons, squared four-momenta, and two-hadron invariant mass are measured in a wide region of scattered protons with transverse momentum between 0.2 and 0.8[Formula: see text]GeV and for pion rapidities [Formula: see text]. A rich structure of interactions related to double pomeron exchange emerges. The parabolic minimum in the distribution of the two-proton azimuthal angle is observed for the first time. It can be understood as an effect of additional pomeron exchanges between the protons, and of the interference between the bare and the rescattered amplitudes. After model tuning, various physical quantities related to the pomeron cross section, proton–pomeron and hadron–pomeron form factors, trajectory slopes and intercepts, as well as coefficients of diffractive eigenstates of the proton are determined.

Global Biodiversity: Extinct Arctic Mammoth Tusks as Substitute Resource to Save Live Elephants

Objective: The aim of this article is to justify an approach to natural resource substitution using fossilised mammoth bones from the Arctic to conserve live elephants. Theoretical Framework - The theoretical idea and basis of the article is the replacement of ivory with the tusks of extinct mammoths against the background of melting permafrost in the Arctic. This approach is considered within the framework of a kind of 'mammoth pipeline' - the journey of extinct fossil mammoth tusks and their transformation into eternal values in the form of exclusive products, as well as their ultimate contribution to the conservation of living elephant populations. The theoretical basis of the study is the concept of sustainable development, the theory of natural resource substitution, biodiversity conservation, the concept of benefit sharing paradigm in Arctic mining. Method - The study is based on an interdisciplinary approach using methods from economics and management, ethnology and palaeontology, social research and monitoring. The evaluation of the effectiveness of the ivory to mammoth tusk substitution scheme is considered in terms of the benefits to global biodiversity conservation, including the maintenance of wild elephant populations and the development of traditional fisheries by indigenous peoples of the North. Results and Discussion - This article assesses the world resource of mammoth bone remains, concentrated in the Russian Arctic, and shows the possibilities of their use as a substitute natural resource for elephant conservation and socio-economic development of areas inhabited by indigenous peoples of the North. The influence of ongoing climate change on the increase in the extraction of fossil mammoth tusks is shown. The stages and links of the 'mammoth pipeline' under consideration, including the extraction of mammoth bones, the export and trade of tusks, and the substitution of mammoth tusks for ivory, are substantiated. The factors influencing the formation of the world demand for mammoth tusks are identified and the directions of their use for elephant conservation and socio-economic development of the local population in the Arctic territories in the areas of their extraction are shown. Research Implications - The results of the study can be used to conserve global biodiversity, develop a green economy, substitute mammoth tusks for ivory and conserve elephant populations. The authors estimate that supplying the world market with an average of 10 kilograms of mammoth ivory can save one elephant; exporting even half of the mammoth tusks extracted in Yakutia can save 60,000 elephants. At the same time, issues of social and economic support for the traditional trades and livelihoods of the indigenous peoples of the North are being addressed. Originality/ Value - The originality of the research and its value lie in the new scientific formulation of the solution to the scientific problem of global biodiversity conservation through the substitution of natural resources, the use of own empirical data obtained in the Arctic territories, as well as the possibility of practical application of the results obtained in the field of green economy.

Retailer-manufacturer partnerships in E-commerce: Dual product strategy and market share dynamics

A new practice among online retail platforms, e.g., Amazon and Wayfair, is to offer their own private label product and a substitutable exclusive manufacturer product. We employ a game theoretic approach to examine conditions under which a retailer and a manufacturer find it optimal to enter into such a partnership. Our analysis reveals that a retailer finds it profitable to partner with a manufacturer with one of two profiles. The first is a manufacturer with low unit production and holding costs and large capacity, and the retailer gives the manufacturer most of the market share. In this case, the retailer uses a low private product price and marketing effort to pressure the manufacturer to set a low exclusive product price, which increases the manufacturer's revenue and the retailer's fees. The second is a manufacturer with a large consumer base, high unit production and holding costs, and small capacity. For this profile, the retailer takes most of the market share by offering a low private product price, and the manufacturer is unable to counteract the retailer's low private product price and marketing effort. The partnership results in a lower price when the marketing effort is costly and the retailer relies on private product price, intensifying price competition. Under some conditions, the retailer's profit may decrease in his share of the manufacturer's revenue. Also, the retailer may increase the marketing effort and decrease the private product price, not to take market share, but to pressure the manufacturer to decrease price.

Commercialization of Hip-Hop Culture and the Evolution of Youth Consumption Patterns from Symbols of Rebellion to Fashion Trends

This paper explores the commercialization of hip-hop culture and its profound influence on fashion and youth consumption patterns. Originally a symbol of rebellion and a voice for marginalized communities, hip-hop has evolved into a mainstream cultural force, reshaping global fashion trends. The transition from underground streetwear to luxury fashion is analyzed through key moments in hip-hop’s history, including collaborations with major brands like Adidas, Nike, and Gucci. The rise of streetwear brands such as Supreme, Off-White, and Yeezy exemplifies how hip-hop’s commercial success has transformed it into a powerful influence on youth identity and social status. However, this commercialization presents a double-edged sword, raising concerns about the loss of authenticity and cultural roots. The paper examines how social media and digital platforms have amplified hip-hop’s reach and discusses the ongoing tension between its original rebellious spirit and its role as a commercial enterprise. The study also highlights the global impact of hip-hop on consumption behaviors, focusing on the rise of exclusive product drops and the commodification of streetwear.

Neurosurrealism in the Service of Revolution: Aesthetic Features and Critical Potential of Neural Network Art

The rapid development of neural network technologies in recent years has given rise to the formation of many interdisciplinary research areas, including neural network aesthetics. The aesthetics of generative creativity today is studied not only in the context of the history of digital art, but also in comparison with the practices of other artistic trends and schools. Thus, the expression “neural surrealism”, which has become entrenched in popular discourse, undoubtedly refers to the aesthetics of classical surrealism, framed and fixed in Andre Breton’s program texts: neural network algorithms allow you to create images that seem both realistic and absurd due to unexpected combinations of objects, distorted proportions and presence of uncanny images. Although “neural surrealism” can be seen as a depoliticized and unbiased game of generated images in contrast to the surrealism of the 1920s and 30s, which was not merely an artistic movement but a radical social project, it appears that the very ability of neural networks to generate extraordinary and unpredictable images holds a certain critical potential. Using the methods of formal-stylistic and ideological-content analysis, the author of the article concludes that “neurosurrealism” in a sense continues the line of classical surrealism to undermine the automatism of perception and patterns of thinking. Generative algorithms become a kind of “exclusion production machines” that allow you to see reality from an unexpected angle. In addition, the very fact of using neural networks in art raises important questions about the nature of creativity, the limits of artificial intelligence and the future of man in the world of smart machines. Neurosurrealism problematizes well-established ideas about the originality and intentionality of artistic expression, which indicates the close connection of generative artistic practices with the aesthetics of classical surrealist creativity. The conducted research will be useful to specialists of a wide profile: media theorists, art historians, philosophers, cultural scientists, as well as developers and representatives of the creative industries.

Application of Biotechnology and Chiral Technology Methods in the Production of Ectoine Enantiomers

Natural ectoine, (+)-(4S)-2-methyl-1,4,5,6-tetrahydropyrimidine-4-carboxylic acid, is an extremely important small biomolecule belonging to the class of osmolytic/osmoprotective compounds. It stabilizes biomacromolecules such as DNA and proteins and protects them from denaturation by heat, dehydration, and UV radiation. The rapidly growing interest in this compound resulted in currently exclusive biotechnological production, while a chemical process along with enantioseparation as an alternative has not yet been established. An improved chemical synthesis of racemic ectoine starting from γ-butyrolactone in very good yield is described. Regioselective monoacetylation is achieved by the complexation of a copper(II)-ion with two molecules of 2,4-diamonobutyric acid in the key synthetic step. The racemic ectoine was synthesized with the aim of being successfully enantioseparated for the first time by high-performance liquid chromatography (HPLC) using a teicoplanin-based Chiral-T column in different solvent systems. The presence of (+)-ectoine was determined and quantified using an HPLC protocol on the Synergy Polar-RP column in fermentation broths inoculated with different strains of Streptomyces sp. bacteria isolated from the Adriatic Sea and grown on different NaCl concentrations.

Exclusive catalytic hydrogenation of nitrobenzene toward p-aminophenol over atomically precise Au36(SR)24 clusters.

Despite the advances in devising green methodologies for selective hydrogenation of nitrobenzene toward p-aminophenol, it is still difficult to realize p-aminophenol as the exclusive product in heterogeneous metal catalysis, as the excessive hydrogenation of nitrobenzene usually results in the aniline byproduct. Herein we report that a metal cluster containing 36 gold atoms capped by 24 thiolate ligands provides a unique pathway for nitrobenzene hydrogenation to achieve a p-aminophenol selectivity of ∼100%. The gold cluster can efficiently suppress the over-hydrogenation of amino groups via hydroxyl rearrangement with the aid of water and sequentially the proton transfer promoted by acid toward p-aminophenol. More notably, remarkable catalytic performances can be extended to clusters with similar structures such as Au28(SR)20 and Au44(SR)28, where only an atomic layer change of 2.1 Å thickness in the Au36(SR)24 cluster can tailor the proton affinity for the amino group of the key intermediate phenylhydroxylamine, thereby altering the activity while the p-aminophenol selectivity remained.

Effects of adding metals to Beta zeolite on ethanol conversion to hydrocarbons

This study investigated the effects of Beta zeolite ion exchange with Fe, Zn, and Co on ethanol conversion to hydrocarbons. Various characterization techniques such as X-ray fluorescence (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray diffraction (XRD), magic angle rotation nuclear magnetic resonance spectrometry (MAS NMR) of 29Si and 27Al, scanning electron microscopy (SEM), nitrogen physisorption, ammonia temperature-programmed desorption (NH3-TPD) and Fourier transform infrared spectroscopy (FTIR) were employed. Catalytic tests were performed at temperatures from 475 to 550 °C under ambient pressure. The metal addition to Beta zeolite reduced micropore area and volume, decreased the concentration of the extra-framework aluminum, and increased total acid site density and Lewis acid sites, except for Fe. For all catalysts, ethylene was identified as the primary product. However, catalysts containing Zn and Co displayed the formation of propylene and C1 to C3 paraffins. The catalyst with Fe exhibited the highest deactivation and a significant decrease in acidity, attributed to the formation of extra-framework aluminum, resulting in exclusive ethylene production.

Effect of the competitive exclusion culture on the growth, blood parameters, leg health, and innate immunity of broiler chickens

Abstract The primary aim of poultry production is to obtain a high yield and quality end product. To reduce the risk of disease, many direct-fed microbial products have been developed. That appears to be an excellent tool for disease prevention. We evaluated the influence of the commercial, competitive exclusion (CE) product, Broilact®, on the growth rate, hematology, serum biochemistry, and innate immunity in male ROSS-308 chickens, randomly divided into two groups (Broilact® treatment and control) raised for 42 days. The birds’ body weight was determined at 1, 7, 14, 28, 35, and 42 days, and the blood samples were collected at days 22 and 42 of life. We observed lower mortality, better gait score, and higher final body weight in the Broilact® group. At day 22, birds from the treated group presented higher white blood cells counts (WBC) and T cytotoxic lymphocyte (CD8+) counts, higher total protein (TP) (fraction globulin and albumin), and lower triglyceride (TAG) and Ca2+ plasma concentrations. No differences were found in acute phase proteins (APPs). At day 42, only the K+ and Na+ concentrations were higher, while the IL-10 was lower in treated birds’ blood serum. Our results indicate that treatment with one dose of the Broilact® product at day one of life has a beneficial influence, which improves the chickens’ performance, leg health and some serum enzymes activity, maintains electrolyte homeostasis, and influences leukocyte count with the rise of T CD8+ subpopulations.

Revealing the Role of Solvent in anti-Oxypalladation-Triggered Regiocontrolled Domino Reactions for the Synthesis of Benzazepine- and Tetrahydroquinoline-Containing Scaffolds: A Combined Computational and Experimental Study.

Palladium-catalyzed regiocontrolled intramolecular oxypalladation-initiated cascades of multifunctional internal alkyne bearing an N-tosyl tether deliver functionalized benzazepine as an exclusive product via 6-endo-dig pathway in 1,4-dioxane solvent and tetrahydroquinoline scaffold as a major product via the 5-exo-dig pathway in the DMSO solvent. The role of the solvent in controlling the regioselectivity is still unknown which can be a major hurdle for further reaction development. Moreover, the reaction in DMSO suffered from having a mixture of products, and no exclusive formation of tetrahydroquinoline was achieved. Herein, we report a concerted computational and experimental study, revealing the role of the solvent in controlling the reaction outcome. DFT study revealed that the formation of the σ-vinylpalladium intermediate is reversible for the 5-exo-dig pathway while it is irreversible for the 6-endo-dig mechanism in 1,4-dioxane and consequently, the 5-exo-dig pathway is difficult to proceed. In contrast, both the 5-exo-dig and 6-endo-dig pathways are irreversible in DMSO. We predicted an exclusive formation of isobenzofuranone-fused chromane via the 5-exo-dig pathway when the N-tosyl tether is replaced by the O-tether in the internal alkyne in DMSO. The experimental study confirms the theoretical hypothesis and provides a highly chemo-divergent approach for the synthesis of biologically significant chromane with a large substrate scope and up to 95% yield at room temperature.

Where is the Middle School Movement Today? Interrogating Consequential Organizations

In an effort to advance the middle school movement, this paper examines the research trends from three organizations that support middle grades educational innovation, assessment, and research: The Carnegie Corporation of New York, the Educational Testing Service, and the Institute of Education Sciences. Using an instrumental, multiple case study design, trends within and across these organizations regarding research on middle grades education were identified. We found trends across these organizations that reveal the following: They privilege quantitative methodologies; the research topics examined are limited in focus; and the end-result for much of their work results in exclusive products for sale. Further, each of these organizations has deep pockets that provide significant funds for their research projects and products.

Drug supply and assurance: a cross-sectional study of drug shortage monitoring varieties in China

BackgroundDrug shortage is a worldwide problem that seriously threatens public health. China released the most comprehensive list of key drug shortage monitoring varieties ever in 2022. We aim to analyze the attributes and characteristics of the medicines within the list to provide a reference for improving China’s supply security of shortage drugs.MethodsWe used public data to extract information on drug types, dosage forms, indications, classification of clinical uses, whether they were included in medical catalogs such as the National Essential Drugs, and the number of drug and active pharmaceutical ingredient (API) manufacturers. A descriptive statistical analysis was used.ResultsOf the 980 drugs on the list, 99.59% were chemicals and 92.65% were injectables. Drugs for blood and hematopoietic organs, the cardiovascular system, and the digestive tract and metabolism ranked among the top three shortages. Verification of the medical catalogs showed that 90.41% of the drugs belonged to the national essential drugs, 95.10% were medicare drugs, 2.55% were volume-based procurement drugs, and 14.70% were for rare diseases, and 42.04% were for children. In terms of drug supply capacity, 21.33% of drug approvals are less than 10, and there were even 26 drugs for exclusive production, close to 90% of manufacturers need to purchase APIs from outside. Among the 256 APIs included in the list, 152 APIs had less than 10 manufacturers, and there were even 5 APIs produced by only one enterprise nationwide.ConclusionsThe situation of drug shortages in China was severe and complex, with serious shortages of medicines adapted to basic medical and healthcare needs and clinically necessary medicines, and a need to improve the production capacity of drugs and the ability to supply APIs. We recommend strengthening drug monitoring and stockpiling and accelerating the approval of shortage drugs to improve drug supply security.

Competitive exclusion products as an antimicrobial alternative to control Salmonella Heidelberg in broilers.

Intestinal infections caused by non-typhoidal Salmonella spp., along with antimicrobial resistance spread are a major food safety concern worldwide. Here, we evaluate the potential of competitive exclusion products developed by anaerobic or aerobic conditions to control systemic infection, cecal colonization, fecal excretion, and improve the intestinal health in broilers challenged by Salmonella Heidelberg (SH). A total of 105 day-old chickens were randomly distributed into three experimental groups: A (untreated control), B (treated with anaerobic culture), and C (treated with aerobic culture). During 21 days, morphometric parameters of the small intestine were analyzed using microscopy, fecal excretions by cloacal swabs, systemic infection, and cecal colonization by colony-forming unit counts (CFU/g). The results indicated the lowest number of positive swabs (45.33%) recovered from Group C, followed by Group B (71.8%) and Group A (85.33%). The bacterial enumeration revealed the lowest amounts in Group C at the necropsy realized in 5-, 7-, and 14-days post-infection (DPI) (P=0.0010, P=0.0048, and P=0.0094, respectively). Statistical differences between intestinal morphometrics were observed in the Group C at 21 DPI. Our results suggest that the product developed under aerobic conditions can improve intestinal health, protecting birds against SH.

Revisiting azimuthal angular asymmetries in diffractive di-jet production

We explore the impact of initial state soft gluon radiations on the azimuthal angle asymmetries in photo-production of hard di-jet via coherent diffraction in ultraperipheral heavy ion collisions, as well as in electron-proton (ep) and electron-nucleus (eA) collisions. The primary production mechanism is identified as the diffractive production of two hard jets, accompanied by a collinear gluon emission along the beam direction. In contrast, the diffractive exclusive di-jet production, where the initial state radiation is absent, is suppressed due to color transparency. Our analysis shows that azimuthal asymmetries, traditionally attributed to final state gluon emissions, are reduced by the presence of initial state radiations. The sensitivity of azimuthal asymmetries to both initial and final state radiations suggests that they could provide novel insights into the mechanisms of di-jet production in diffractive processes.

Structural Characterization of Disulfide-Linked p53-Derived Peptide Dimers.

Disulfide bonds provide a convenient method for chemoselective alteration of peptide and protein structure and function. We previously reported that mild oxidation of a p53-derived bisthiol peptide (CTFANLWRLLAQNC) under dilute non-denaturing conditions led to unexpected disulfide-linked dimers as the exclusive product. The dimers were antiparallel, significantly α-helical, resistant to protease degradation, and easily reduced back to the original bisthiol peptide. Here we examine the intrinsic factors influencing peptide dimerization using a combination of amino acid substitution, circular dichroism (CD) spectroscopy, and X-ray crystallography. CD analysis of peptide variants suggests critical roles for Leu6 and Leu10 in the formation of stable disulfide-linked dimers. The 1.0 Å resolution crystal structure of the peptide dimer supports these data, revealing a leucine-rich LxxLL dimer interface with canonical knobs-into-holes packing. Two levels of higher-order oligomerization are also observed in the crystal: an antiparallel "dimer of dimers" mediated by Phe3 and Trp7 residues in the asymmetric unit and a tetramer of dimers mediated by Trp7 and Leu10. In CD spectra of Trp-containing peptide variants, minima at 227 nm provide evidence for the dimer of dimers in dilute aqueous solution. Importantly, and in contrast to the original dimer model, the canonical leucine-rich core and robust dimerization of most peptide variants suggests a tunable molecular architecture to target various proteins and evaluate how folding and oligomerization impact various properties, such as cell permeability.