3d printing and testing of rose thorns or limpet teeth inspired anchor device for tendon tissue repair

Purposes. Advancements in medical technology have enabled medical specialists to resolve significant problems concerning tendon injuries. However, despite the latest improvements, surgical tendon repair remains challenging. This study aims to explore the capabilities of the current state-of-the-art technologies for implantable devices. Methods. After performing extensive patent landscaping and literature review, an anchored tissue fixation device was deemed the most suitable candidate. This design was firstly investigated numerically, realizing a Finite Element Model of the device anchored to two swine tendons stumps, to simulate its application on a severed tendon. Two different hook designs, both bio-inspired, were tested while retaining the same device geometry and anchoring strategy. Then, the applicability of a 3D-printed prototype was tested on swine tendons. Finally, the device-tendon stumps ensemble was subjected to uniaxial tensile tests. Results. The results show that the investigated device enables a better load distribution during the immobilized limb period in comparison to standard suture-based approaches, yet it still presents several design flaws. Conclusions. The current implantable solutions do not ensure an optimal result in terms of strength recovery. This and other weak points of the currently available proposals will serve as a starting point for future works on bio-inspired implantable devices for tendon repair

Methylphenidate Exposure Induces Dopamine Neuron Loss and Activation of Microglia in the Basal Ganglia of Mice

Background: Methylphenidate (MPH) is a psychostimulant that exerts its pharmacological effects via preferential blockade of the dopamine transporter (DAT) and the norepinephrine transporter (NET), resulting in increased monoamine levels in the synapse. Clinically, methylphenidate is prescribed for the symptomatic treatment of ADHD and narcolepsy; although lately, there has been an increased incidence of its use in individuals not meeting the criteria for these disorders. MPH has also been misused as a ‘‘cognitive enhancer’ ’ and as an alternative to other psychostimulants. Here, we investigate whether chronic or acute administration of MPH in mice at either 1 mg/kg or 10 mg/kg, affects cell number and gene expression in the basal ganglia. Methodology/Principal Findings: Through the use of stereological counting methods, we observed a significant reduction (,20%) in dopamine neuron numbers in the substantia nigra pars compacta (SNpc) following chronic administration of 10 mg/kg MPH. This dosage of MPH also induced a significant increase in the number of activated microglia in the SNpc. Additionally, exposure to either 1 mg/kg or 10 mg/kg MPH increased the sensitivity of SNpc dopaminergic neurons to the parkinsonian agent 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Unbiased gene screening employing Affymetrix GeneChipH HT MG-430 PM revealed changes in 115 and 54 genes in the substantia nigra (SN) of mice exposed to 1 mg/kg and 10 mg/kg MPH doses, respectively. Decreases in the mRNA levels of gdnf, dat1, vmat2, and th in the substantia nigr

Delivery of a Chlamydial Adhesin N-PmpC Subunit Vaccine to the Ocular Mucosa Using Particulate Carriers

Trachoma, caused by the intracellular bacterium Chlamydia trachomatis (Ct), remains the world's leading preventable infectious cause of blindness. Recent attempts to develop effective vaccines rely on modified chlamydial antigen delivery platforms. As the mechanisms engaged in the pathology of the disease are not fully understood, designing a subunit vaccine specific to chlamydial antigens could improve safety for human use. We propose the delivery of chlamydia-specific antigens to the ocular mucosa using particulate carriers, bacterial ghosts (BGs). We therefore characterized humoral and cellular immune responses after conjunctival and subcutaneous immunization with a N-terminal portion (amino acid 1-893) of the chlamydial polymorphic membrane protein C (PmpC) of Ct serovar B, expressed in probiotic Escherichia coli Nissle 1917 bacterial ghosts (EcN BGs) in BALB/cmice. Three immunizations were performed at two-week intervals, and the immune responses were evaluated two weeks after the final immunization in mice. In a guinea pig model of ocular infection animals were immunized in the same manner as the mice, and protection against challenge was assessed two weeks after the last immunization. N-PmpC was successfully expressed within BGs and delivery to the ocularmucosa was well tolerated without signs of inflammation. N-PmpC- specific mucosal IgA levels in tears yielded significantly increased levels in the group immunized via the conjunctiva compared with the subcutaneously immunized mice. Immunization with N-PmpC EcN BGs via both immunization routes prompted the establishment of an N-PmpC-specific IFN gamma immune response. Immunization via the conjunctiva resulted in a decrease in intensity of the transitional inflammatory reaction in conjunctiva of challenged guinea pigs compared with subcutaneously and non-immunized animals. The delivery of the chlamydial subunit vaccine to the ocular mucosa using a particulate carrier, such as BGs, induced both humoral and cellular immune responses. Further investigations are needed to improve the immunization scheme and dosage

Ion exchange resins catalysed esterification for the production of value added petrochemicals and oleochemicals

This book chapter is formulated with the aim to review the literature relevant to the esterification reactions catalysed by strong acidic ion exchange resins. Priority has been given to the works that have been published during the last 15 years. Industrially important esterification reactions in the petrochemical and oleochemical industries have been delineated. Various types of strongly acidic ion exchange resins produced by different manufacturers have been used to accelerate the rate of esterification reactions. In the esterification reactions in both petrochemical and oleochemical industries, gel-type resins showed comparable activity with the macro-reticular type resins after swollen by the polar solvents during the reactions, otherwise the macroporous-type resins always performed better. Gel-type resins were also preferred, in particular, for the esterification reactions involved bulky reactant molecules due to the mass transfer restriction of the macro-reticular type resins. In contrast to the comprehensive studies on the activity of ion exchange resin in the esterification reactions, the works that are related to the reusability, recovery and regeneration of these resin catalysts are rather scarce. In order to scale up the esterification processes catalysed by strongly acidic ion exchange resins to the industrial level, future works should be focusing on the solutions to overcome of the aforementioned constraints and limitations