Mechanism Of Penetration Research Articles

Short-circuit mechanism induced by crack propagation spurred by inhomogeneous electric field in garnet-based solid electrolyte

Li7La3Zr2O12 (LLZO) is well received as a solid electrolyte for batteries. Its excellent properties render the implementation of lithium (Li) metal batteries, leading to the improvement of the performances of the batteries. However, a short-circuit failure by Li propagation through the LLZO is a crucial issue and major obstacle for Li-based batteries to overcome. Here, we investigate various growth mechanism of Li penetration through the LLZO. Because of cracks on the surface, the electric field inside the batteries becomes inhomogeneous. Li ions gather near cracks to form lithium dendrites or they also get together along the grain boundaries of LLZO to form the dendrites. Thus, some dendrites grow through grain boundaries once the cracks propagate. If electric field becomes uniform at the interfaces by surface etching or laser treatment, Li dendrite propagation on cracks and/or grain boundaries can be avoided.

A Comprehensive Analysis of Metabolomics and Transcriptomics Reveals Novel Biomarkers and Mechanistic Insights on Lorlatinib Crosses the Blood-Brain Barrier

Of late, lorlatinib has played an increasingly pivotal role in the treatment of brain metastasis from non-small cell lung cancer. However, its pharmacokinetics in the brain and the mechanism of entry are still controversial. The purpose of this study was to explore the mechanisms of brain penetration by lorlatinib and identify potential biomarkers for the prediction of lorlatinib concentration in the brain. Detection of lorlatinib in lorlatinib-administered mice and control mice was performed using liquid chromatography and mass spectrometry. Metabolomics and transcriptomics were combined to investigate the pathway and relationships between metabolites and genes. Multilayer perceptron was applied to construct an artificial neural network model for prediction of the distribution of lorlatinib in the brain. Nine biomarkers related to lorlatinib concentration in the brain were identified. A metabolite-reaction-enzyme-gene interaction network was built to reveal the mechanism of lorlatinib. A multilayer perceptron model based on the identified biomarkers provides a prediction accuracy rate of greater than 85%. The identified biomarkers and the neural network constructed with these metabolites will be valuable for predicting the concentration of drugs in the brain. The model provides a lorlatinib to treat tumor brain metastases in the clinic.

High grade renal trauma: Does the mechanism of penetrating injury influence renal salvage rate?

BackgroundMost of the data on high grade Traumatic renal injuries (TRI) has come from centres which predominantly encounter blunt trauma. Blunt and penetrating mechanisms are not analogous, and it is imprudent to blindly extrapolate management strategies between the two groups. In addition, within the broad group of penetrating mechanisms of injury there are also major differences between gunshot wounds (GSW) and stab wounds (SW). The aim of this comparative study of GSW and SW to the kidney is to quantify the impact of the mechanism of injury on nephrectomy rate in high grade TRI. MethodsA prospective trauma registry was interrogated retrospectively. All patients sustaining a high grade (Grade III to V) penetrating TRI were included. The diagnosis was made either with cross-sectional imaging or intra-operative findings. The nephrectomy rate of the different mechanisms of penetrating (GSW vs SW) TRI was compared in each grade. ResultsA total of 28 GSW and 27 SW causing high grade TRIs (Grade III-V) were included over the 85 months of the study. GSW lead to a higher nephrectomy rate than SWs 50.0 vs 19%, (p = 0.023). When comparing grade for grade, Grade III: 20.0 (GSW) vs 21% (SW), (p = 1). Grade IV: 71 (GSW) vs 17%, (SW) (p = 0.058) and Grade V: 100 (GSW) vs 0%, (SW) (p = 0.28). When comparing Grade IV – V together, the difference is 85 (GSW) vs 15%, (SW) (p = 0.001). ConclusionOn a grade to grade comparison GSWs have a much higher risk for nephrectomy than SW's in grade IV and V TRI. TRI secondary to GSWs appears to be an independent risk factor for nephrectomy in high grade injuries. The mechanism of penetrating TRI should be considered in future management algorithms and clinical approaches.

Experimental and Numerical Investigation of the Effect of Projectile Nose Shape on the Deformation and Energy Dissipation Mechanisms of the Ultra-High Molecular Weight Polyethylene (UHMWPE) Composite.

The effect of projectile nose shape on the ballistic performance of the ultra-high molecular weight polyethylene (UHMWPE) composite was studied through experiments and simulations. Eight projectiles such as conical, flat, hemispherical, and ogival nose projectiles were used in this study. The deformation process, failure mechanisms, and the specific energy absorption (SEA) ability were systematically investigated for analyzing the ballistic responses on the projectile and the UHMWPE composite. The results showed that the projectile nose shape could invoke different penetration mechanisms on the composite. The sharper nose projectile tended to shear through the laminate, causing localized damage zone on the composite. For the blunt nose projectile penetration, the primary deformation features were the combination of shear plugging, tensile deformation, and large area delamination. The maximum value of specific energy absorption (SEA) was 290 J/(kg/m2) for the flat nose projectile penetration, about 3.8 times higher than that for the 30° conical nose projectile. Furthermore, a ballistic resistance analytical model was built based on the cavity expansion theory to predict the energy absorption ability of the UHMWPE composite. The model exhibited a good match between the ballistic resistance curves in simulations with the SEA ability of the UHMWPE composite in experiments.

Rational design and synthesis of multimorphology mesoporous carbon@silica nanoparticles with tailored structure

The remarkable architecture of nanoparticles with anisotropy or hierarchically multicavity mesoporous structure is critical for multifunctional application. However, it is still a great challenge to simultaneously tailor their composition, external morphology and interior structure. Herein, an emulsion-induced interfacial self-assembly strategy has been developed for the first time to fabricate mesoporous carbon@mesoporous silica nanoparticles (MC@MSs) with manipulatable morphology from hollow rambutan-like nanospheres to hollow bowl-like MC@MSs (HBMC@MSs) with different concave degree and surface roughness. Impressively, the cavity number and location of MC@MSs can be modulated, i.e., the evolution of internal structure can be transformed from hollow to multicavity and flower-like by varying the solution polarity of primary emulsion, which is a great breakthrough. A novel swelling-double penetration mechanism is proposed to shed light on the growth kinetics of multimorphology nanoparticles. Moreover, the multifunctional platforms ingeniously overcome three disadvantages: (1) the agglomeration during high-temperature annealing process; (2) low biocompatibility caused by high hydrophobicity; (3) poor affinity with hydrophobic drug molecules. Noticeably, the cellular uptake property of HBMC@MSs with red blood cell biomimetic morphology is more favorable than that of spherical nanoparticles. This strategy endows new understanding of fabricating well-defined MC@MSs and rationally designing the nanomedicine carrier for efficient delivery.

Exploring the affluent potential of glyceryl mono oleate – myristol liquid crystal nanoparticles mediated localized topical delivery of Tofacitinib: Study of systematic QbD, skin deposition and dermal pharmacokinetics assessment

This study aimed to design and characterize Tofacitinib (TF)-loaded lyotropic liquid crystalline nanoparticles (TF-LCNP) gel using quality by design-driven approach to enhance the skin delivery of TF. The present work investigated the impact of two different liquid lipids on different critical quality attributes of LCNP. The optimized lyotropic liquid crystals system was constructed with the glyceryl monooleate,myristol, Lutrol® and water system. The optimized TF - LCNP showed particle size of 74.82 ± 4.26 nm, polydispersity index of 0.124 ± 0.024, and entrapment efficiency of 68.29 ± 5.24 %. The TF-LCNP showed sustained release for 24 h and followed quasi-Fickian diffusion from non-swellable matrix diffusion with n value of 0.197. The ex vivo permeation studies exhibited that amount of TF permeated through LCNP gel and cream after 24 h were found to be 61.11 ± 1.5 µg/cm2 and 37.7 ± 3.5 µg/cm2, respectively. The penetration mechanism of TF-LCNP gel through skin layers followed the Korsmeyer- Peppas model (n-value of 1.687), indicated Case-II relaxational release of TF. The tape stripping studies showed that TF loaded LCNPs retained 3 fold and 2.81 fold greater TF in stratum corneum and viable skin layers than conventional cream. The coumarin – 6 loaded LCNP study using Fluorescence microscopy confirmed the penetration of TF-LCNP into the deeper layers of skin. The dermal pharmacokinetic studies revealed that the LCNP showed a steady equilibrium state in 5–8 h in epidermis and dermis layers. The total amount of TF permeated with developed LCNP formulation was 3.42 times and 2.19 times higher in epidermis and dermis compared to the TF-cream. The developed formulation exhibited good spreadability and rheology and has not shown any significant changes in stability and scale-up studies. In a nutshell, the developed TF-LCNP strategy poses excellent potential in targeting the viable skin layer.

ENT2 facilitates brain endothelial cell penetration and blood-brain barrier transport by a tumor-targeting anti-DNA autoantibody.

The blood-brain barrier (BBB) prevents antibodies from penetrating the CNS and limits conventional antibody-based approaches to brain tumors. We now show that ENT2, a transporter that regulates nucleoside flux at the BBB, may offer an unexpected path to circumventing this barrier to allow targeting of brain tumors with an anti-DNA autoantibody. Deoxymab-1 (DX1) is a DNA-damaging autoantibody that localizes to tumors and is synthetically lethal to cancer cells with defects in the DNA damage response. We found that DX1 penetrated brain endothelial cells and crossed the BBB, and mechanistic studies identify ENT2 as the key transporter. In efficacy studies, DX1 crosses the BBB to suppress orthotopic glioblastoma and breast cancer brain metastases. ENT2-linked transport of autoantibodies across the BBB has potential to be exploited in brain tumor immunotherapy, and its discovery raises hypotheses on actionable mechanisms of CNS penetration by neurotoxic autoantibodies in CNS lupus.

Generation and characterization of three human induced pluripotent stem cell lines (EURACi007-A, EURACi008-A, EURACi009-A) from three different individuals of the same family with arrhythmogenic cardiomyopathy (ACM) carrying the plakophillin2 p.N346Lfs*12 mutation

Arrhythmogenic Cardiomyopathy (ACM) is a genetically based cardiomyopathy associated with ventricular arrhythmias and fibro-fatty substitution of cardiac tissue. It is characterized by incomplete penetrance. We generated human iPSCs by episomal reprogramming of blood cells from three members of the same family: the proband, affected by ACM and carrying the heterozygous plakophillin2 p.N346Lfs*12 mutation, one asymptomatic carrier of the same mutation and one apparently healthy control. hiPSCs were characterized according to standard protocols including karyotyping, pluripotency marker expression and differentiation towards the three germ layers. These hiPSC lines can be used to study the mechanisms of ACM incomplete penetrance in vitro.

Size-Dependent Absorption through Stratum Corneum by Drug-Loaded Liposomes

Topical treatment of various skin disorders requires drug absorption and penetration through the stratum corneum (SC) into the epidermis and dermis tissues. The use of nano-drug delivery systems including liposomes and lipid nanoparticles (SLNs) have been shown to facilitate SC penetration. The goal of this work was to study the impact of liposome sizes and the resulted drug distribution inside various skin tissue. All trans retinoic acid (ATRA) was used as the model drug and loaded into gel phase HSPC/CHOL/DSPE-PEG liposomes (lipo-ATRA) with sizes ranging from 80nm to more than 300nm. The percutaneous drug absorption process was monitored and analyzed. There were significant differences in percutaneous absorption and tissue distribution resulted from liposomes smaller than 100nm and those bigger than 200nm. Lipo-ATRA with a mean diameter of 83nm can deliver the content to epidermis and dermis. But for 200nm - 300nm liposomes, the resulted epidermis and dermis ATRA levels were less than about one third, suggesting bigger liposomes had poor penetration through the brick and mortar structure of SC. Gel phase liposomes with sizes under 100nm improved encapsulated drug absorption and distribution into the epidermis and dermis tissues. A size dependent mechanism for liposome penetration of the stratum corneum was proposed.

Mechanical properties of a female reproductive tract of a beetle and implications for penile penetration.

Coevolution of male and female genitalia is widespread in animals. Nevertheless, few studies have examined the mechanics of genital interactions during mating. We characterized the mechanical properties of the elongated female genitalia, the spermathecal duct, of the small cassidine beetle, Cassida rubiginosa. The data were compared with the mechanical properties of the elongated male genitalia, the flagellum. We analysed the material distributions of the spermathecal duct using a microscopy technique, established a tensile test setup under a light microscope and conducted tensile tests. Diameter and tensile stiffness gradients were present along the spermathecal duct, but its Young's modulus and material distribution were more or less homogeneous. The results confirmed the hypothesis based on numerical simulations that the spermathecal duct is more rigid than the flagellum. In the study species, the penile penetration force is simply applied to the base of the hyper-elongated flagellum and conveyed along the flagellum to its tip. Considering this simple penetration mechanism, the relatively low flexibility of the spermathecal duct, compared to the flagellum, is likely to be essential for effective penetration of the flagellum.

Brain Disposition of Antibody-Based Therapeutics: Dogma, Approaches and Perspectives.

Due to their high specificity, monoclonal antibodies have been widely investigated for their application in drug delivery to the central nervous system (CNS) for the treatment of neurological diseases such as stroke, Alzheimer’s, and Parkinson’s disease. Research in the past few decades has revealed that one of the biggest challenges in the development of antibodies for drug delivery to the CNS is the presence of blood–brain barrier (BBB), which acts to restrict drug delivery and contributes to the limited uptake (0.1–0.2% of injected dose) of circulating antibodies into the brain. This article reviews the various methods currently used for antibody delivery to the CNS at the preclinical stage of development and the underlying mechanisms of BBB penetration. It also describes efforts to improve or modulate the physicochemical and biochemical properties of antibodies (e.g., charge, Fc receptor binding affinity, and target affinity), to adapt their pharmacokinetics (PK), and to influence their distribution and disposition into the brain. Finally, a distinction is made between approaches that seek to modify BBB permeability and those that use a physiological approach or antibody engineering to increase uptake in the CNS. Although there are currently inherent difficulties in developing safe and efficacious antibodies that will cross the BBB, the future prospects of brain-targeted delivery of antibody-based agents are believed to be excellent.

Venous Chimney Procedure: A Novel Technical Solution to Prevent Iatrogenic Budd– Chiari Syndrome Following Retrohepatic Vena Cava Injury

Traumatic inferior vena cava (IVC) lesions account for approximately 25% of abdominal vascular injuries and are among the most challenging and lethal lesions sustained by trauma patients. Whether caused by blunt or penetrating mechanisms of injury, the overall mortality rate is up to 92%; as many as 50% of the patients with those injuries die before reaching medical care, and the mortality rate among patients who arrive to a trauma center, with signs of life and/or receive operative treatment, ranges between 20% and 57% (1).
 Retrohepatic Vena Cava (RHVC) injuries (RHVCI) are extremely rare and as such both the treating trauma surgeon, as well as the vascular surgeon, lacks the necessary experience to deal with such complicated injuries. The mortality rates secondary to these injuries are extremely high, even with damage control management concepts application. Improving the outcome of these injuries remains a significant challenge of modern trauma care (2, 3).
 The treatment of RHVCI confronts the treating surgeon, with major obstacles, which raises from the anatomic location of the RHVC at the posterior aspect of the liver and the abundancy of bridging veins between the RHVC and the liver. These anatomic obstacles creates a major technical challenge of gaining proximal and distal control, in proximity to the injured RHVC. This many times necessitates abdominal as well as thoracic exposure in order to gain proper control.
 The average trauma, as well as the vascular, surgeons are not familiar with handling such complex injuries. This is even truer as referred to the new generation of vascular surgeons, whose experience with open vascular surgery, mainly in such extreme situations, decreases with the increasing usage of endovascular techniques (4). 
 The advancements in endovascular techniques have introduced new alternatives to traditional open repair strategies. In many cases, RHVCI treatment requires exploration of a retro-hepatic hematoma, which might be the single thing that prevents free venous rupture and as such, it should be avoided. Venous balloon occlusion is a novel endovascular strategy that may be particularly advantageous in those circumstances as a bridging maneuver, for proximal and distal control, during hybrid repair. Our case in unique since it highlights the option of total endovascular treatment, using arterial treatment concepts, to treat this extremely challenging injury. 

Venous Chimney Procedure: A Novel Technical Solution to Prevent Iatrogenic Budd– Chiari Syndrome Following Retrohepatic Vena Cava Injury

Traumatic inferior vena cava (IVC) lesions account for approximately 25% of abdominal vascular injuries and are among the most challenging and lethal lesions sustained by trauma patients. Whether caused by blunt or penetrating mechanisms of injury, the overall mortality rate is up to 92%; as many as 50% of the patients with those injuries die before reaching medical care, and the mortality rate among patients who arrive to a trauma center, with signs of life and/or receive operative treatment, ranges between 20% and 57% (1).
 Retrohepatic Vena Cava (RHVC) injuries (RHVCI) are extremely rare and as such both the treating trauma surgeon, as well as the vascular surgeon, lacks the necessary experience to deal with such complicated injuries. The mortality rates secondary to these injuries are extremely high, even with damage control management concepts application. Improving the outcome of these injuries remains a significant challenge of modern trauma care (2, 3).
 The treatment of RHVCI confronts the treating surgeon, with major obstacles, which raises from the anatomic location of the RHVC at the posterior aspect of the liver and the abundancy of bridging veins between the RHVC and the liver. These anatomic obstacles creates a major technical challenge of gaining proximal and distal control, in proximity to the injured RHVC. This many times necessitates abdominal as well as thoracic exposure in order to gain proper control.
 The average trauma, as well as the vascular, surgeons are not familiar with handling such complex injuries. This is even truer as referred to the new generation of vascular surgeons, whose experience with open vascular surgery, mainly in such extreme situations, decreases with the increasing usage of endovascular techniques (4). 
 The advancements in endovascular techniques have introduced new alternatives to traditional open repair strategies. In many cases, RHVCI treatment requires exploration of a retro-hepatic hematoma, which might be the single thing that prevents free venous rupture and as such, it should be avoided. Venous balloon occlusion is a novel endovascular strategy that may be particularly advantageous in those circumstances as a bridging maneuver, for proximal and distal control, during hybrid repair. Our case in unique since it highlights the option of total endovascular treatment, using arterial treatment concepts, to treat this extremely challenging injury. 

Vesicular Systems Used for Wound Healing

Abstract When the skin is injured through physical, chemical, mechanical, and/or thermal damage, a spontaneous series of events start to happen, often called the “cascade of healing,” so as to restore the injured tissues, replace the damaged structures and prevent the invasion of pathogens into the damaged tissues. A number of traditional products are available for wound healing such as gels, creams, ointments, dressings and solutions, which depend mainly on moisture intake so as to help tissue repair, yet they do not provide optimal conditions to permit recovery of the wounds. Nanocarriers play a significant role in wound healing, since they are reported to improve drug delivery into the skin through alternation of pharmacokinetics and biodistribution of drugs, hence they increase bioavailability of drugs. Vesicular systems such as liposomes, niosomes, transfersomes, penetration enhancer containing vesicles (PEVs) and ethosomes are among the carriers proven to enhance the therapeutic action of drugs applied for wound healing. In this review, we summarize and discuss different vesicular systems used for wound healing, their composition, their advantages and disadvantages, their methods of preparation and their mechanisms of skin penetration.

Abstract OR-6: Baseplate Structure of Bacteriophage Phi812 and Mechanism of Cell Wall Binding and Penetration

Background: Antibiotic-resistant strains of Staphylococcus aureus cause human infections that are difficult to treat and can lead to death. Bacteriophage (phage) phi812K1/420 from the family Myoviridae infects 95% of clinical isolates of S. aureus and therefore is a promising candidate for a phage therapy agent. As the native phage particle approaches its host cell, phage receptor-binding proteins make a contact with the host cell wall. This interaction triggers a cascade of structural changes in the baseplate resulting in phage tail contraction and genome ejection. Mechanistic description of the baseplate re-organization, however, remains unknown. Methods: Using cryo-electron microscopy (cryo-EM), we studied the baseplate of the phage phi812K1/420. Also, selected proteins involved in the host cell wall binding and penetration were produced in recombinant form and their structures were solved using X-ray crystallography and cryo-EM single-particle reconstruction. Results: We reconstructed the phage baseplate in native and contracted states. The reconstruction of the native baseplate reaches a resolution of 4 Å, which enables us to discern individual protein structures. Solved protein structures will be fitted into the reconstruction of the contracted baseplate. Conclusion: Our results provide the first structural characterization of contractile phage infecting a Gram-positive bacterium. Comparison of the two distinct baseplate states will allow us to describe the molecular mechanism of the initial stage of phage infection in detail.

Roles of Ionic Transport in Dendrite Growth through Solid State Electrolytes at the Critical Current Density

Lithium metal anodes hold the promise to significantly increase the energy density of current Li-ion batteries by replacing the bulkier graphite anode. However, these batteries have low cycling efficiency and internal short circuiting due to metal dendrites. A strategy to prevent dendritic growth is using a stiff solid electrolyte that can mechanically block their growth, while in reality, penetration through the tough solid electrolytes by soft Li metal filaments still occurs at a relatively low critical current density.Inspired by the dendrite initiation at the system-specific limiting current in liquid electrolytes, we explore the possibility in this study that dendrite growth in solid state electrolytes at the critical current density (CCD) is a transport limited phenomenon determined by ionic conduction. Previous studies have used galvanostatic cycling [1] as the basis for measuring the CCD, however cycling presents problems of interfacial stripping and delamination leading to a reduction in contact surface area and high localized current densities. Here we use linear sweep voltammetry (LSV) with the implementation of stack pressure to mitigate these effects to initially determine the CCD and develop a model connected to the ionic conduction. With the experimentally determined CCD, we then investigate the penetration time at various higher-than-CCD constant current densities to uncover a Sand’s time-like behavior, which offers insights on the transport dynamics consistent with our previous work [2]. Operando and postmortem analyses were also performed to complement the electrochemical characterization toward a self-consistent comprehensive understanding. In conclusion, our new method allows us to understand the growth mechanism of dendrites in solid electrolytes, while still connecting microstructural and interfacial aspects from previous published works[3][4], to present a unified approach to understanding the metal dendrite initiation at the CCD.References E. Kazyak, R. Garcia-Mendez, W.S. LePage, A. Sharafi, A.L. Davis, A.J. Sanchez, K.-H. Chen, C. Haslam, J. Sakamoto and N.P. Dasgupta. Li Penetration in Ceramic Solid Electrolytes: Operando Microscopy Analysis of Morphology, Propagation, and Reversibility. Matter 2, 1025-1048, (2020).P. Bai, J. Li, F.R. Brushett and M.Z. Bazant. Transition of lithium growth mechanisms in liquid electrolytes. Energ Environ Sci 9, 3221-3229, (2016).L. Porz, T. Swamy, B.W. Sheldon, D. Rettenwander, T. Frömling, H.L. Thaman, S. Berendts, R. Uecker, W.C. Carter and Y.-M. Chiang. Mechanism of Lithium Metal Penetration through Inorganic Solid Electrolytes. Advanced Energy Materials 7, 1701003-n/a, (2017).T. Krauskopf, H. Hartmann, W.G. Zeier and J. Janek. Toward a Fundamental Understanding of the Lithium Metal Anode in Solid-State Batteries—An Electrochemo-Mechanical Study on the Garnet-Type Solid Electrolyte Li6.25Al0.25La3Zr2O12. ACS Applied Materials & Interfaces 11, 14463-14477, (2019). Figure 1

Experimental study of the mechanism of grouting colloidal nano-silica in over-broken coal mass

Grouting is an important process for stability control of unfavourable geology. A multi-parameter grouting monitoring device was designed to monitor pump pressure, inlet density, outlet density, outlet electrical resistance and osmotic pressure. On the basis of multi-source information, this paper presents an experimental study of the process of grouting colloidal nano-silica into an over-broken coal mass, which was verified by percolation mechanics theory and numerical simulation simultaneously. The porosity and permeability of the injected sample were 15.34% and 5.45 mD. The results showed that the variation of pump pressure generally showed an obvious three-stage regularity. The time-dependent curves of outlet density and outlet resistance were consistent with that of pump pressure, whereas the curve of inlet density was opposite to that of pump pressure. The law of the dominant penetration mechanism was as follows: miscible displacement mechanism in the first stage (0–46 min), Darcy flow in the second stage (46–200 min) and filtration flow in the third stage. This research can guide grouting theory study and design in an over-broken rock mass.

Percutaneous penetration and dermal exposure risk assessment of chlorinated paraffins

The widespread occurrence of chlorinated paraffins (CPs) in environmental matrices has resulted in a high frequency exposure to CPs via dermal contact. To quantitatively estimate percutaneous penetration of CPs, Episkin® human skin equivalents (HSE) was applied as an in vitro model to evaluate the mechanism of percutaneous penetration of CPs. The co-exposure of CPs mixtures to HSE showed that about 11.7% and 10.2% of short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) could penetrate the HSE and enter the receptor fluid, while no long-chain CPs (LCCPs) (C>17) were able to penetrate the HSE during the 36-h assay period. The experimentally obtained permeability coefficient (Kp) values for CPs were significantly (p < 0.01) negatively correlated with their log octanol–water partition coefficient (log Kow). Furthermore, 24 participants were recruited to assess direct human dermal exposure to CPs in China with the total CPs collected onto hand wipes and forehead wipes being 96,600 and 30,400 ng/person, respectively. The proportion of total SCCPs and MCCPs intake via dermal penetration (skin area investigated in this study) accounting for 2.0% of the total intake of CPs. Considering the total skin surface of human body is around 20 times of the area studied, the total intake of CPs through dermal penetration could be a significant exposure pathway.

Formationmechanism of high‐pressure water penetration induced fiber orientation in overflow water‐assisted injection molded short glass fiber‐reinforced polypropylene

AbstractRecently, there has been growing interest in water‐assisted injection molding (WAIM) not only for its advantages over gas‐assisted molding (GAIM) and conventional injection molding (CIM), but also for its great potential advantages in industrial applications. To understand the formation mechanism of water penetration induced fiber orientation in overflow water‐assisted injection molding (OWAIM) parts of short glass fiber‐reinforced polypropylene (SGF/PP), in this work, the external fields and water penetration process within the mold cavity were investigated by experiments and numerical simulations. The results showed that the difference of fiber orientation distribution in thickness direction between WAIM moldings and CIM moldings was mainly ascribed to the great external fields generated by water penetration. Besides, fiber orientation depended on the position both across the part thickness and along the flow direction. Especially in the radial direction, fiber orientation varied considerably. The results also showed that the melt temperature is the principal parameter affecting the fiber orientation along the flow direction, and a higher melt temperature significantly facilitated more fibers to be oriented along the flow direction, which is quite different from the results as previously reported in short‐shot water‐assisted injection molding (SSWAIM). A higher water pressure, shorter water injection delay time, and higher melt temperature significantly induced more fibers to be orderly oriented in OWAIM moldings, which may improve their mechanical performances and broaden their application scope.

Design, Preparation, and Characterization of Effective Dermal and Transdermal Lipid Nanoparticles: A Review

Limited permeability through the stratum corneum (SC) is a major obstacle for numerous skin care products. One promising approach is to use lipid nanoparticles as they not only facilitate penetration across skin but also avoid the drawbacks of conventional skin formulations. This review focuses on solid lipid nanoparticles (SLNs), nanostructured lipid nanocarriers (NLCs), and nanoemulsions (NEs) developed for topical and transdermal delivery of active compounds. A special emphasis in this review is placed on composition, preparation, modifications, structure and characterization, mechanism of penetration, and recent application of these nanoparticles. The presented data demonstrate the potential of these nanoparticles for dermal and transdermal delivery.