Concave Surface Research Articles

A novel approach to achieve semi-sustained drug delivery to the eye through asymmetric loading of soft contact lenses

Soft contact lenses are increasingly being explored as a vehicle for controlled delivery of ophthalmic drugs. However, traditional methods of drug-loading by soaking have limitations such as burst delivery and the release of drugs at the front side of the lens, leading to poor drug efficacy and systemic side effects. This study introduces a new methodology, termed asymmetric drug loading, whereby the ophthalmic drug ‘Rebamipide’ is attached to and released from the post-lens (=cornea-contacting) surface exclusively. The methodology involves using polymeric microparticles that carry a lipophilic crystalline ophthalmic drug at their surface. These drug-loaded microparticles first transfer the drug to the concave surface of the contact lens, and when worn, the drug is transferred again, now from the lens to the cornea. This is achieved through the diffusion of the drug from one hydrophobic microenvironment (the silicone moieties of the contact lens polymer network) to another hydrophobic microenvironment (the corneal epithelium) over a short pathway. The second drug transfer was observed and studied in experiments using an ex vivo porcine eye model. The results show that the drug amount that was absorbed by the cornea after applying the rebamipide-loaded contact lenses is approximately 3× (10.7 ± 3.1 μg) as much as the amount of rebamipide that gets transferred after the instillation of one eye drop (1% solution (p < 0.001). The new drug-loading method offers a practical and reproducible means of delivering ophthalmic drugs to the cornea through soft contact lenses. The drug payloads achieved are comparable to dosages used during eye drop therapy.

Automatic 3D joint erosion detection for the diagnosis and monitoring of rheumatoid arthritis using hand HR-pQCT images.

Rheumatoid arthritis (RA) is a chronic inflammatory disease. It leads to bone erosion in joints and other complications, which severely affect patients' quality of life. To accurately diagnose and monitor the progression of RA, quantitative imaging and analysis tools are desirable. High-resolution peripheral quantitative computed tomography (HR-pQCT) is such a promising tool for monitoring disease progression in RA. However, automatic erosion detection tools using HR-pQCT images are not yet available. Inspired by the consensus among radiologists on the erosions in HR-pQCT images, in this paper we define erosion as the significant concave regions on the cortical layer, and develop a model-based 3D automatic erosion detection method. It mainly consists of two steps: constructing closed cortical surface, and detecting erosion regions on the surface. In the first step, we propose an initialization-robust region competition methods for joint segmentation, and then fill the surface gaps by using joint bone separation and curvature-based surface alignment. In the second step, we analyze the curvature information of each voxel, and then aggregate the candidate voxels into concave surface regions and use the shape information of the regions to detect the erosions. We perform qualitative assessments of the new method using 59 well-annotated joint volumes. Our method has shown satisfactory and consistent performance compared with the annotations provided by medical experts.

Mineralogy and geochemistry of ferromanganese nodules in semiarid calcareous soils from Northeastern Brazil

Fe/Mn nodules are important records of pedogenesis, weathering processes, and pedoenvironmental conditions. However, data regarding the morphology and mineralogy of Fe/Mn nodules are limited due to difficulties concerning the identification of their low crystallinity Fe/Mn oxides. The hypothesis is that nodules in calcareous soils in Northeastern Brazil present crystalline forms of Mn oxides, whose mineralogy and chemical composition are linked to slight variations in relief. This study investigated the mineralogy and geochemistry of Fe/Mn nodules of soils on different relief surfaces (convex, flat, and concave). The nodules were analyzed using sequential selective dissolution procedure (SSDP), X-ray diffraction, elemental analyses, micromorphology scanning electron microscopy, and energy dispersive spectroscopy. Improvements of the SSDP were needed to identify Mn oxide minerals (birnessite and lithiophorite) in nodules. The relief features are determinants for the distribution and formation of minerals in nodules. The occurrence of calcite silt-sized on the convex and straight surfaces indicates pedogenetic genesis. An increase in kaolinite, highly crystalline lithiophorite, and the absence of calcite in the nodules close to the concave surface also indicates synchronism with pedogenesis. Pseudo-hexagonal lithiophorite and birnessite with plate-like habits are important scavengers of Ce, Co, V, and Ba. This research represents the first record of the detailed morphology and identification of Mn minerals in Fe/Mn nodules using SSDP in semiarid calcareous soils from Northeastern Brazil.

Cartilage Lacuna-Inspired Microcarriers Drive Hyaline Neocartilage Regeneration.

Cartilage equivalents from hydrogels containing chondrocytes exhibit excellent potential in hyaline cartilage regeneration, yet current approaches have limited success at reconstituting the architecture to culture nondifferentiated chondrocytes in vitro. In this study, specially designed lacunar hyaluronic acid microcarriers (LHAMCs) with mechanotransductive conditions that rapidly form stable hyaluronic acid (HA) N-hydroxy succinimide ester (NHS-ester) are reported. Specifically, carboxyl-functionalized HA is linked to collagen type I via amide-crosslinking, and gas foaming produced by ammonium bicarbonate forms concave surface of the microcarriers. The temporal 3D culture of chondrocytes on LHAMCs uniquely remodels the extracellular matrix to induce hyaline cartilaginous microtissue regeneration and prevents an anaerobic-to-aerobic metabolism transition in response to the geometric constraints. Furthermore, by inhibiting the canonical Wnt pathway, LHAMCs prevent β-catenin translocation to the nucleus, repressing chondrocyte dedifferentiation. Additionally, the subcutaneous implantation model indicates that LHAMCs display favorable cytocompatibility and drive robust hyaline chondrocyte-derived neocartilage formation. These findings reveal a novel strategy for regulating chondrocyte dedifferentiation. The current study paves the way for a better understanding of geometrical insight clues into mechanotransduction interaction in regulating cell fate, opening new avenues for advancing tissue engineering.

Visualizing experimental investigation on gas–liquid replacements in a microcleat model using the reconstruction method

AbstractCleats are the main channels for fluid transport in coal reservoirs. However, the microscale flow characteristics of both gas and water phases in primary cleats have not been fully studied as yet. Accordingly, the local morphological features of the cleat were determined using image processing technology and a transparent cleat structure model was constructed by microfluidic lithography using the multiphase fluid visualization test system. Besides, the effect of microchannel tortuosity characteristics on two‐phase flow was analyzed in this study. The results are as follows: (1) The local width of the original cleat structure of coal was strongly nonhomogeneous. The cleats showed contraction and expansion in the horizontal direction and undulating characteristics in the vertical direction. (2) The transient flow velocity fluctuated due to the structural characteristics of the primary cleat. The water‐driven gas interface showed concave and convex instability during flow, whereas the gas‐driven water interface presented a relatively stable concave surface. (3) The meniscus advanced in a symmetrical pattern in the flat channel, and the flow stagnated due to the influence of undulation points in a partially curved channel. The flow would continue only when the meniscus surface bypassed the stagnation point and reached a new equilibrium position. (4) Enhanced shearing at the gas–liquid interface increased the gas‐injection pressure, which in turn increased residual liquids in wall grooves and liquid films on the wall surface.

A study on microchip cooling performance increment by using air jet impingement with one and double rows

The impinging jet technique is a high-performance cooling technology for microchips which are basic elements of computer systems and have high heat generation rates in small volumes. In this study, the improvement of heat transfer of the desktop microchips used in all technological products today by air-impinging jet flow was examined. For this purpose, numerical research was carried out on the cooling of copper plate surfaces with two different patterns, concave and roof shaped having 1000 W/m2 constant heat flux in rectangular cross-sectional ducts by one and double air jets with distances of Dh and 2 Dh between them. Numerical analysis was performed steady and in three dimensions with the k– ε turbulence model by the Ansys–Fluent program. The obtained results were compared with the numerical and experimental results of the study in the literature and it was seen that they are determined to be compatible. The results were presented as the mean Nu number for each of both patterned surfaces and the mean outlet temperature of the jet flow ( Tmoj) and the mean Nu number ( Num) of all patterned surfaces in single and double jet channels with different distances. Besides, pressure drop (Δ P), friction factor ( f), thermal resistance ( Rt) and thermo-hydraulic performance (THP) of concave and roof-patterned surfaces in the channels with different jet setup configurations were analyzed. Streamline and temperature contour distributions of the jet flow along the channel for different H/ Dh ratios and jet numbers were evaluated for both patterned surfaces. In H/ Dh = 4 and at Re = 7000, the average Nu number for roof-patterned surfaces was found to be 30.52% higher than concave patterned surfaces in the case of double jets with a distance of Dh. Rt reduction values of the roof and concave pattern surfaces with a double jet arrangement having 2 Dh distance at Re = 5000 and H/ Dh = 8 are 163.7% and 36.23% when compared to single jet, respectively.

High-accuracy three-dimensional surface detection in smoothed particle hydrodynamics for free-surface flows

In this study, we investigate high-accuracy three-dimensional surface detection in smoothed particle hydrodynamics for free-surface flows. A new geometrical method is first developed to enhance the accuracy of free-surface particle detection in complex flows. This method detects free-surface particles via continuous global scanning inside the sphere of a particle through a cone region whose vertex corresponds to the particle position. The particle is identified as a free-surface particle if there exists a cone region with no neighboring particles. Next, an efficient semi-geometrical method is proposed based on the geometrical method to reduce the computational cost. It consists of finding particles near the free surface via position divergence and then accurately detecting these particles using the geometrical method to identify free-surface particles. The accuracy and robustness of the proposed method are demonstrated by performing tests on several model problems. In particular, the test demonstrating the surface detection of the free surface with periodic perturbations shows that the detection accuracy of the proposed method is improved compared with the traditional methods because the detection capability for concave surfaces is enhanced and the detection accuracy is independent of the estimation of the normal vector of particles.

Curvature Matters: Modeling Calcium Binding to Neutral and Anionic Phospholipid Bilayers.

In this work, the influence of membrane curvature on the Ca2+ binding to phospholipid bilayers is investigated by means of molecular dynamics simulations. In particular, we compared Ca2+ binding to flat, elastically buckled, or uniformly bent zwitterionic and anionic phospholipid bilayers. We demonstrate that Ca2+ ions bind preferably to the concave membrane surfaces in both types of bilayers. We also show that the membrane curvature leads to pronounced changes in Ca2+ binding including differences in free ion concentrations, lipid coordination distributions, and the patterns of ion binding to different chemical groups of lipids. Moreover, these effects differ substantially for the concave and convex membrane monolayers. Comparison between force fields with either full or scaled charges indicates that charge scaling results in reduction of the Ca2+ binding to curved phosphatidylserine bilayers, while for phosphatidylcholine membranes, calcium binds only weakly for both force fields.

Thermal-Hydraulic and Entropy Generation Optimization of Capsule-Type Plate Heat Exchangers With Spherical Dimples

The capsule-type plate heat exchanger (PHE) is a new type of equipment with great potential, which is characterized by the concave and convex capsule-like surface. In this article, new structures consisting of capsules and spherical dimples of PHE were proposed. Flow through a periodic unit cell with four different geometries is simulated numerically to characterize the pressure drop, heat transfer coefficients, and entropy generation rate. The numerical results show good consistency with the existing experimental data. Results show that the flow in capsule-type plate can be divided into recirculation zone and high-velocity zone. The staggered capsule structure and the spherical dimple shape generate more secondary and impinging flows, which provide higher Nusselt number and friction factor. The maximum Nusselt number area changed from the upwind region of capsule to the vicinity of dimple region because of the downwash effect and the fluid impact effect. The Nusselt number is enhanced by 19%–46%, and the friction factor is 1.21–2.9 times to that of the primary capsule-type plate. In addition, Entropy analysis illustrates that the maximum reduction in the dimensionless entropy generation rate is 43.6%.

Flow measurements of jet impingement upon a semicylinder with crossflow

In this work, time-resolved particle image velocimetry (TR-PIV) measurements have been carried out to investigate the structural features of a submerged transverse round liquid turbulent jet discharged into a confined laminar crossflow. The duct Reynolds number based on crossflow velocity is fixed at Re=3000, and the impinging jet is directed to a semicylindrical concave surface located in one of the walls of a vertical square duct. The spatial development and flow dynamics are analyzed along several orthogonal planes parallel/perpendicular to the jet axis for jet Reynolds numbers based on the jet exit diameter of Rej=3000, 6000 and 9000 (jet-to-crossflow velocity ratios of r=3.27, 6.53 and 9.80), respectively. For this purpose, mean and ensemble-averaged velocity and vorticity distributions, turbulent statistics, and Reynolds shear stresses are obtained for various injection rates. Spectral analysis reveals the shedding frequencies of the wake vortices, and the pairing and breakup processes of the evolving large-scale coherent structures have been related to the measured wake Strouhal numbers. Our results indicate that due to the curvature of the target surface and the upwash of the jet impact, the size of coherent structures decreases with increase in the value of Rej. Proper orthogonal decomposition (POD) of the flow using the snapshot method is applied to extract the dominant features of the turbulent flow. It is observed that at the symmetry plane and for Rej=3000, 6000 and 9000, the energy collected by the first two dominant eddies contribute to 14.98%, 18.68%, and 17.89% of the turbulence kinetic energy, respectively. Our results show that the evolution of the time-resolved temporal coefficients of degenerate pairs of modes (1, 2) represent the flapping motion of the jet. Moreover, the amplitude of the oscillations of the flapping jet and the complexity of the flow structure increase for increasing values of Rej.

Aerodynamic performance improvements for a Savonius turbine above a forward-facing step via inclined solar panel: A computational study

The transformation of urban energy structure is an urgent problem to be solved in sustainable construction. To fully exploit and utilise renewable energy, this study proposes a novel wind–solar energy hybrid harvesting system that combines an inclined solar panel and a Savonius wind turbine installed on a building roof. The effects of the tilt angle of the solar panels and tip speed ratios (TSRs) on the aerodynamic performance of the turbine were investigated using high-fidelity large-eddy simulations (LES) at a Reynolds number of Re = 4.45 × 105. Five tilt angles in the range of 30°–60° were tested, and the range of TSR was 0.2–1.6. For comparison, two other installation cases were also studied, including the case of a Savonius turbine alone and the case of a single Savonius turbine placed at a fixed height position on a forward-facing step. The results showed that the power coefficient of the Savonius turbine increased and then decreased with tilt angle or TSR. When TSR = 1, the power coefficient in the system reached a maximum value of Cpmax = 0.638 at a tilt angle of 45°, 254.4% and 11.7% higher than those of the other two installation cases, respectively. The flow-field comparison results reveal why the proposed system can improve the energy harvesting efficiency. The presence of a solar panel with a suitable tilt angle increases the velocity and volume of the airflow hitting the advancing blade, creating a greater pressure difference around the blades that is caused mainly by the decrease in the low pressure on the concave surface of the advancing blade. Thus, the net torque applied to the turbine blades increases, which is conducive to driving turbine rotation. The proposed system is beneficial for improving the aerodynamic performance of Savonius turbines and the utilisation of renewable energy in urban areas.

Effect of single and multiple protrusions on thermal performance of slot jet impingement with curved surface

The current study uses numerical methods to evaluate the thermal and flow characteristics of air jet impinging on concave surfaces with single and multiple protrusions on a surface. The impact of different operating parameters is also studied, including Reynolds number, jet inclination angle and nozzle-to-plate distance (H/B). No significant improvement in the overall thermal performance is noted with a single protrusion on the surface, although a higher heat transfer is observed in the stagnation zone. On the other side, the multiple protrusions on the surface have shown an increase or decrease in the overall thermal performance of jet impingement depending on protrusion diameter and height. The maximum improvement in the overall Nu is noted up to 19 % for the multi-protruded surface at H/B = 6 with orthogonal jet impingement. An oblique jet decreased the overall thermal performance compared to the orthogonal jet, regardless of the jet inclination angle.

Bound Phospholipids Assist Cholesteryl Ester Transfer in the Cholesteryl Ester Transfer Protein.

Cholesteryl ester transfer protein (CETP) is a plasma glycoprotein that assists the transfer of cholesteryl esters (CEs) from antiatherogenic high-density lipoproteins (HDLs) to proatherogenic low-density lipoproteins (LDLs), initiating cholesterol plaques in the arteries. Consequently, inhibiting the activity of CETP is therefore being pursued as a novel strategy to reduce the risk of cardiovascular diseases (CVDs). The crystal structure of CETP has revealed the presence of two CEs running in the hydrophobic tunnel and two plugged-in phospholipids (PLs) near the concave surface. Other than previous animal models that rule out the PL transfer by CETP and PLs in providing the structural stability, the functional importance of bound phospholipids in CETP is not fully explored. Here, we employ a series of molecular dynamics (MD) simulations, steered molecular dynamics (SMD) simulations, and free energy calculations to unravel the effect of PLs on the functionality of the protein. Our results suggest that PLs play an important role in the transfer of neutral lipids by transforming the unfavorable bent conformation of CEs into a favorable linear conformation to facilitate the smooth transfer. The results also suggest that the making and breaking interactions of the hydrophobic tunnel residues with CEs with a combined effort from PLs are responsible for the transfer of CEs. Further, the findings demonstrate that the N-PL has a more pronounced effort on CE transfer than C-PL but efforts from both PLs are essential in the transfer. Thus, we propose that the functionally important PLs can be considered with potential research interest in targeting cardiovascular diseases.

Local heat transfer characteristics of circular multiple air jet impinging on a semicircular concave surface

ABSTRACT The local heat transfer characteristics of circular multiple air jet impingement on semicircular concave surface were studied experimentally. For constant Reynolds number (Re = 9,000), the effect of jet to concave surface spacing (z/d = 1, 4.2, 6), ratio of curvature (D/d = 4.28, 6, 8.6), jet-to-jet spacing (s/d = 2.4, 4, 5.6), and number of jets were considered. The local heat transfer characteristics were determined by using infrared thermal camera and thin foil method. Lower curvature value ratio (D/d = 4.28) resulted higher average heat transfer coefficient due to broader spread of heat transfer distribution, whereas higher curvature ratio (D/d = 8.6) resulted in lower average heat transfer coefficient due to steeper heat transfer distribution in the stagnation area. At lower D/d, z/d, and s/d with seven jet configuration, the heat transfer coefficients were found effective as compared to other configurations due to broad heat transfer distribution and less interaction between the jets. At given D/d and s/d configuration, the stagnation Nu at θ = 0° do not coincide with jet hole center axis and this shift is more pronounced at higher z/d value. This could be due to additional push before jet impinging on concave surface. The secondary peaks were observed between two neighboring stagnation regions in Nu distribution along the center longitudinal line for lower z/d and higher s/d values. This resulted due to upwash that was obtained from jet interactions related to collisions with the wall jets. The correlations of stagnation line average Nu and overall average Nu were obtained. The coefficient of variance of local heat transfer coefficient for each configuration was determined, and correlation was proposed to analyze the degree of non-uniformity.

Micro-Scale Surface Recognition via Microscope System Based on Hu Moments Pattern and Micro Laser Line Projection

The surface engineering of metals develops high technology to detect microscale convex, concave and flat surface patterns. It is because the manufacturing industry requires technologies to recognize microscale surface features. Thus, it is necessary to develop microscopic vision technology to recognize microscale concave, convex and flat surfaces. This study addresses microscale concave, convex and flat surface recognition via Hu moments’ patterns based on micro-laser line contouring. In this recognition, a Hu moments’ pattern is generated from a Bezier model to characterize the surface recovered through microscopic scanning. The Bezier model is accomplished by employing a genetic algorithm and surface coordinates. Thus, the flat, convex and concave surfaces are recognized based on the Hu moments’ pattern of each one. The microscope system projects a 40 μm laser line on the object and a camera acquires the object’s contour reflection to retrieve topographic coordinates. The proposed technique enhances the microscale convex, concave, flat, and surface recognition, which is performed via optical microscope systems. The contribution of microscopic shape recognition based on the Hu moments’ pattern and microscopic laser line is elucidated by a discussion based on the microscopic shape recognition performed through the optical microscopic image processing.

Understanding Charge-Transfer and Mass-Transfer Effects on Dendrite Growth and Fast Charging of Li Metal Battery

Lithium (Li) metal is facing the challenge of poor cyclic performance and potential safety hazards caused by Li dendrites growth. Herein, the role of charge-transfer and mass-transfer process on dendrite growth and fast charging is illustrated. The effects of charge-transfer coefficient, applied current density, concave-convex structure, and properties of artificial solid electrolyte interphase (SEI) on guiding the Li dendrite growth are investigated via an electrochemical multiphysics model. The charge-transfer coefficient is meaningful for regulating the redox rate of electrode surface. Large applied current density and high ion conductivity of artificial SEI influence the distribution of local deposition rate significantly. Different deposition behaviors are found on concave and convex Li metal surfaces. The convex surface is sensitive than concave surface and is easy to generate Li dendrites under the conditions of high applied current density and high ion conductivity. Moreover, the experimental results can well reflect the influence of dendrite growth and dead Li on the capacity. This study not only provides an essential perspective on designing the artificial SEI for resolving the harmful dendrite issues but also boosts the practical applicability of Li metal battery.

Bespoke Implants for Cranial Reconstructions: Preoperative to Postoperative Surgery Management System.

Traumatic brain injury is a leading cause of death and disability worldwide, with nearly 90% of the deaths coming from low- and middle-income countries. Severe cases of brain injury often require a craniectomy, succeeded by cranioplasty surgery to restore the integrity of the skull for both cerebral protection and cosmetic purposes. The current paper proposes a study on developing and implementing an integrative surgery management system for cranial reconstructions using bespoke implants as an accessible and cost-effective solution. Bespoke cranial implants were designed for three patients and subsequent cranioplasties were performed. Overall dimensional accuracy was evaluated on all three axes and surface roughness was measured with a minimum value of 2.209 μm for Ra on the convex and concave surfaces of the 3D-printed prototype implants. Improvements in patient compliance and quality of life were reported in postoperative evaluations of all patients involved in the study. No complications were registered from both short-term and long-term monitoring. Material and processing costs were lower compared to a metal 3D-printed implants through the usage of readily available tools and materials, such as standardized and regulated bone cement materials, for the manufacturing of the final bespoke cranial implants. Intraoperative times were reduced through the pre-planning management stages, leading to a better implant fit and overall patient satisfaction.

Sodium-Based Concave Metasurfaces for High Performing Plasmonic Optical Filters by Templated Spin-on-Sodiophobic-Glass.

Optical filters have aroused tremendous excitement in advanced photonic instruments and modern digital displays due to their flexible capability of spectrum manipulation. Plasmonic metasurfaces of narrow bandwidth, high spectral contrast, and robust structure tolerance are highly desired for optical filtration (especially in the visible regime) but rather challenging as large spectral broadening from intrinsic ohmic loss and design/fabrication deviations. Here the high-performing sodium-based metasurfaces are demonstrated for optical filtration across 450 to 750nm by unique structure design of spatially decoupled concave surfaces and precise fabrication through templated solidification of liquid metals. Thanks to the distinct suppression of metallic loss as well as fabrication tolerance of interfacial structures, the as-prepared concave metasurfaces enable a minimum linewidth of ≈15nm, a maximal optical contrast of ≈93%, and a high measure-to-design spectral match ratio ≈1500. These results have for the first time pushed the operation wavelengths of sodium-based plasmonic devices from infrared to visible which in turn demonstrates the capability of filling the blank of commercial dielectric optical filters thus far.

Thermal eye injuries from dermatologic laser treatments—an experimental study

In recent years, severe ocular complications after dermatological laser therapies have been reported. One hypothesis is thermal damage due to heating of the metal eye shields. The aim of the present study is to evaluate the safety of ocular metal eye shields during laser therapy of the periocular region. For the experimental study, porcine eyelids were exposed to continuously increasing laser energy and multiple pulses using a number of dermatologic laser systems. Temperature differences of the convex and concave surface of metal eye shields were constantly measured using a thermocouple. Maximum increase of the convex surface of shields was + 8.9 °C (± 0.1 °C) provided by the long-pulsed alexandrite laser (20–25-J/cm2 energy, 15-mm spot size, 20-ms pulse duration, 1 Hz). Present data indicate that metal eye shields provide sufficient thermal protection when clinically used laser parameters are applied. Other safety precautions continue to be essential to protect both the patient and the laser operator. These include the use of nonreflective metal eye shields, precise knowledge of laser physics, and a clear understanding of how they interact with ocular and periocular anatomy.

Superconformal Film Growth: From Smoothing Surfaces to Interconnect Technology.

ConspectusElectronics manufacturing involves Cu electrodeposition to form 3D circuitry of arbitrary complexity. This ranges from nanometer-wide interconnects between individual transistors to increasingly large multilevel intermediate and global scale on-chip wiring. At larger scale, similar technology is used to form micrometer-sized high aspect ratio through-silicon vias (TSV) that facilitate chip stacking and multilevel printed circuit board (PCB) metallization. Common to all of these applications is void-free Cu filling of lithographically defined trenches and vias. While line-of-sight physical vapor deposition processes cannot accomplish this feat, the combination of surfactants and electrochemical or chemical vapor deposition enables preferential metal deposition within recessed surface features known as superfilling. The same superconformal film growth processes account for the long-reported but poorly understood smoothing and brightening action provided by certain electroplating additives. Prototypical surfactant additives for superconformal Cu deposition from acid-based CuSO4 electrolytes include a combination of halide, polyether suppressor, sulfonate-terminated disulfide, and/or thiol accelerator and possibly a N-bearing cationic leveler. Many competitive and coadsorption dynamics underlie functional operation of the additives. Upon immersion, Cu surfaces are rapidly covered by a saturated halide layer that makes the interface more hydrophobic, thereby supporting the formation of a polyether suppressor layer. Also, halide serves as a cosurfactant supporting the adsorption of amphiphilic molecular disulfide species on the surface while inhibiting copper sulfide formation and incorporation into the growing deposit. Furthermore, the dangling hydrophilic sulfonate end group of the accelerator enables activated metal deposition by hindering polyether suppressor assembly. A common thread in superconformal feature filling is additive-derived positive feedback of the metal deposition reaction within recessed or re-entrant regions. For submicrometer features or optically rough surfaces, area reduction that accompanies the motion of concave surface segments results in the most strongly bound adsorbates' enrichment, which for the suppressor-accelerator systems is the sulfonate-terminated disulfide accelerator species. The superfilling and smoothing process is quantitatively captured by the curvature-enhanced adsorbate coverage mechanism. For larger features, such as TSV, whose depths approach the thickness of the hydrodynamic boundary layer, significant compositional and electrical gradients couple with the metal deposition process to give a negative differential resistance and related nonlinear effects on morphological evolution. For certain suppressor-only electrolytes, remarkable bottom-up feature filling occurs where metal deposition disrupts inhibiting adsorbates at the bottom of the TSV or overruns the ability of the suppressor to form due to kinetic or transport limitations. Because the electrical response to changes in interface chemistry is more rapid than mass transport processes, deposition on planar substrates proceeds by bifurcation into passive and active zones, generating Turing patterns. On patterned substrates, active zone development is biased toward the most recessed regions. The distinction between packaging and on-chip metallization will be blurred as the dimensions of the former merge with those of early day on-chip 3D metallization.