In-situ crosslinked wet spun collagen triple helices with nanoscale-regulated ciprofloxacin release capability

The design of antibacterial-releasing coatings or wrapping materials with controlled drug release capability is a promising strategy to minimise risks of infection and medical device failure in vivo. Collagen fibres have been employed as medical device building block, although they still fail to display controlled release capability, competitive wet-state mechanical properties, and retained triple helix organisation. We investigated this challenge by pursuing a multiscale design approach integrating drug encapsulation, in-situ covalent crosslinking and fibre spinning. By selecting ciprofloxacin (Cip) as a typical antibacterial drug, wet spinning was selected as a triple helix-friendly route towards Cip-encapsulated collagen fibres; whilst in–situ crosslinking of fibre-forming triple helices with 1,3–phenylenediacetic acid (Ph) was hypothesised to yield Ph-Cip π-π stacking aromatic interactions and enable controlled drug release. Higher tensile modulus and strength were measured in Ph–crosslinked fibres compared to state-of-the-art carbodiimide–crosslinked controls. Cip-encapsulated Ph-crosslinked fibres revealed decreased elongation at break and significantly-enhanced drug retention in vitro with respect to Cip-free variants and carbodiimide-crosslinked controls, respectively. This multiscale manufacturing strategy provides new insight aiming at wet spun collagen triple helices with nanoscale-regulated tensile properties and drug release capability

Biomimetic wet-stable fibres via wet spinning and diacid-based crosslinking of collagen triple helices

One of the limitations of electrospun collagen as bone-like fibrous structure is the potential collagen triple helix denaturation in the fibre state and the corresponding inadequate wet stability even after crosslinking. Here, we have demonstrated the feasibility of accomplishing wet-stable fibres by wet spinning and diacid-based crosslinking of collagen triple helices, whereby fibre ability to act as bone-mimicking mineralisation system has also been explored. Circular dichroism (CD) demonstrated nearly complete triple helix retention in resulting wetspun fibres, and the corresponding chemically crosslinked fibres successfully preserved their fibrous morphology following 1-week incubation in phosphate buffer solution (PBS). The presented novel diacid-based crosslinking route imparted superior tensile modulus and strength to the resulting fibres indicating that covalent functionalization of distant collagen molecules is unlikely to be accomplished by current state-of-the-art carbodiimide-based crosslinking. To mimic the constituents of natural bone extra cellular matrix (ECM), the crosslinked fibres were coated with carbonated hydroxyapatite (CHA) through biomimetic precipitation, resulting in an attractive biomaterial for guided bone regeneration (GBR), e.g. in bony defects of the maxillofacial region

Pengaruh Quenching Terhadap Beban Impak Pada Besi Cor Kelabu

This study aims to determine the effect of Quenching on gray cast iron to impact loads. This study uses sand molds with cylindrical wood pattern. The methodology of this research is done with cast iron melting in induction furnace and then is poured in sand molds for making gray cast iron specimen. Tests in liquid form gray cast iron using test equipment CE Meter and the specimen gray cast iron Before the test process is carried out heat treatments Qhuenching reached 7500C in an interval of 4 hours, then tested the composition and in the impact test as well as in hardness and micro photograph to to know the difference atara in heat treatments and without heat treatment Quenching Quenching. Results of the research is a chart obtained from CE Meter shows the temperature 1278.0 ° C during tapping early in the cast in the mold at the start on the chart that reads CE Meter decrease the temperature, the liquid temperature of 1154.2 ° C shape is still liquid to a temperature solid 1112.6 ° C so that the obtained value CEL = 4.10%; C = 3.43%; and SI = 2.28% where the metal solid starts but is still red up to a temperature of 1060 ° C, while the test results of the chemical composition in the form of solid or solid among others: Fe 93.57%; C 3.43%; 1.86% Si and other elements under 1%. The impact test results show through heat treatment qhuenching get results Impact Value 0.03 J / mm and without heat tratment qhuenching impact value of 0.02 J / mm. The test results of micro structures are shaped graphite eutectic. Based on these data we can conclude that through a process of heat treatment may affect the results kekerasandan qhunching also testing impack greater

Pengaruh Putaran Spindle Terhadap Hasil Pemesinan Retrofit Cnc Bubut Bv 20l Dengan Variasi 600rpm, 700rpm, 800rpm

This study aims to determine the effect of rotation variations spindle on the manufacture of pin stand paddock machine retrofit CNC BV 20L lathe on aluminum material, against surface roughness produced in units (Ra) which results are good, and the effect of rotation variations spindle on the machining process time. This study uses aluminum and uses a retrofit CNC BV20L lathe with mach3 control machining process performed with spindle rotation variations, and surface roughness testing using a roughness test equipment (TR200 type Roughnes tester with ISO standard). The results showed that spindle rotation variations produced different roughness levels on the machining of BV20L CNC retrofit lathe, the level of surface roughness with aluminum material will produce an average N7 roughness level. From the test results it can be seen that the best average roughness (Ra) of the spindle rotation, obtained in specimen B by using a 700 rpm spindle rotational speed with an average roughness value of 1.242 µm. Based on the results of the measurement of noise pollution (dB) when the retrofit machining process, the lowest noise BV20L lathe was obtained in specimen B with a 700 rpm spindle with a noise level of 70 dB. Keywords: Aluminum, CNC BV20L lathe, Roughness

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

State of the art and future direction of additive manufactured scaffolds-based bone tissue engineering

Purpose - This paper aims to review the advances in additive manufactured (AM) scaffolds for bone tissue engineering (TE). A discussion on the state of the art and future trends of bone TE scaffolds have been done in terms of design, material and different AM technologies. Design/methodology/approach - Different structural features and materials used for bone TE scaffolds are evaluated along with the discussion on the potential and limitations of different AM scaffolds. The latest research to improve the biocompatibility of the AM scaffolds is also discussed. Findings - The discussion gives a clear understanding on the recent research trend in bone TE AM scaffolds. Originality/value - The information available here would be useful for the researchers working on AM scaffolds to get a quick overview on the recent research trends and/or future direction to work on AM bone TE scaffolds