Mechanics of Mineralized Collagen Fibrils upon Transient Loads

Collagen is a key structural protein in the human body, which undergoes mineralization during the formation of hard tissues. Earlier studies have described the mechanical behavior of bone at different scales, highlighting material features across hierarchical structures. Here we present a study that aims to understand the mechanical properties of mineralized collagen fibrils upon tensile/compressive transient loads, investigating how the kinetic energy propagates and it is dissipated at the molecular scale, thus filling a gap of knowledge in this area. These specific features are the mechanisms that nature has developed to passively dissipate stress and prevent structural failures. In addition to the mechanical properties of the mineralized fibrils, we observe distinct nanomechanical behaviors for the two regions (i.e., overlap and gap) of the D-period to highlight the effect of the mineralization. We notice decreasing trends for both wave speeds and Young's moduli over input velocity with a marked strengthening effect in the gap region due to the accumulation of the hydroxyapatite. In contrast, the dissipative behavior is not affected by either loading conditions or the mineral percentage, showing a stronger damping effect upon faster inputs compatible to the bone behavior at the macroscale. Our results offer insights into the dissipative behavior of mineralized collagen composites to design and characterize bioinspired composites for replacement devices (e.g., prostheses for sound transmission or conduction) or optimized structures able to bear transient loads, for example, impact, fatigue, in structural applications

Kajian Inventarisasi dan Estimasi Upaya Penurunan Emisi Karbon Dioksida di Pltu Suralaya Unit 1–7, Banten

PLTU Suralaya merupakan pembangkit listrik batubara terbesar di Indonesia terdiri dari 7 unit dengan total kapasitas 3.400MW (Unit 1–4 masing-masing 400MW, Unit 5–7 masing-masing 600MW). Masalahnya PLTU batubara mengemisikan sejumlah besar GRK khususnya CO sehingga perlu diupayakanpenurunan emisinya. Penelitian bertujuan untuk mengetahui beban emisi GRK (CO ) Unit 1–7 tahun 2010–2014; estimasi emisi CO tahun 2015–2024; dan upaya penurunan emisi CO yang dapat dilakukan. Metode penelitian mengacu pada IPCC-GL-2006 untuk perhitungan beban emisi dan UN-FCCC metode AM0061 ver.02.1untuk perhitungan penurunan emisi. Hasil penelitian menunjukkan emisi CO total Unit 1–7 tahun 2010–2014 sebesar 112.165.480 ton. Intensitas emisi CO tertinggi pada Unit 3 sebesar 1.152 ton/MWh. Faktor-faktor yang mempengaruhi emisi CO adalah kualitas batubara yang digunakan, efisiensi peralatan pembangkit, dan umur ekonomis pengoperasian peralatan. Estimasi emisi CO pada kondisi BaU tahun 2015–2024 mencapai 250.708.682 ton. Upaya rehabilitasi unit dengan menaikkan efisiensi proses pembakaran 1% diestimasi mampu menurunkan emisi CO2 sebesar 18% yaitu rata-rata 183.826 tonCO /tahun (total 735.304 tonCO /tahun Unit 1– 4)dan 263.887 tonCO /tahun (total 791.664 tonCO /tahun Unit 5–7). Upaya ini tergolong proyek CDM dalam Kyoto Protokol. Teknologi CCS pasca-pembakaran dapat menurunkan emisi CO hingga 80% dengan rata-rata 2.443.493 tonCO /tahun (Unit 1–4)dan 3.745.727 tonCO /tahun (Unit 5–7)

Inhibitory Activity Of Allium Sativum L. Extract Against Streptococcus Pyogenes And Pseudomonas Aeruginosa

Background: One of the most common health problems is infectious diseases. Infectious disease can be caused by bacteria. There were two groups of bacteria based on the staining, Gram-positive and Gram-negative bacteria. Purpose: Antibiotics are the main therapy used in the incidence of bacterial infections. But over time, some antibiotics became resistance. Several studies have shown that garlic has an antibacterial effect. The content of allicin, ajoene, saponins, and flavonoids is found in garlic which has antibacterial properties. The antibiotic activity test of garlic was carried out on the bacteria Streptococcus pyogenes and Pseudomonas aeruginosa. The goal of this study is to investigate the antibacterial effect of Allium sativum L. extract against Streptococcus pyogenes and Pseudomonas aeruginosa. Methods: Garlic extract was made using the maceration method using 96% alcohol as the solvent. Tube dilution method elected to observe garlic antibiotic activity. This test aims to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). There were eight different concentration used, i.e. 2 grams/ml, 1 gram/ml, 0.5 gram/ml, 0.25 gram/ml, 0.125 gram/ml, 0.0625 gram/ml, 0.03125 gram/ml, and 0.015625 gram/ml. Replication is done three times. Results: In this experiment, the extract produced was turbid that MIC could not be determined and there was no momentous differentiation between before and after treatment. There was no growth of Streptococcus pyogenes in 1 gram/ml and Pseudomonas aeruginosa in 0.5 gram/ml. This number indicates the MBC for each bacteria. Conclusion: Garlic (Allium sativum L.) has an effect of bactericidal activity, it can perform as an antibacterial for Streptococcus pyogenes and Pseudomonas aeruginosa. Garlic extract was more effective for Pseudomonas aeruginosa than Streptococcus pyogenes

Analisa Peluang Perusahaan Kontraktor Kualifikasi Menengah di Kota Pontianak Untuk Mendapatkan Proyek Konstruksi Tahun 2016-2018

Tingkat kebutuhan akan tempat tinggal, sarana prasarana, serta fasilitas umum sangat tinggi seiring dengan pertumbuhan penduduk Indonesia. Peran kontraktor merupakan salah satu kontribusi penting dalam pembangunan dan perekonomian negara. Banyaknya perusahaan kontraktor yang ada di kota Pontianak, ini menyebabkan berkurangnya dan makin sedikitnya peluang perusahaan untuk mendapatkan proyek yang tersedia dan juga persaingan antar perusahaan kontraktor pun semakin besar untuk mendapatkan proyek. Maka perlu untuk kita mengetahui seberapa besar peluang tiap perusahaan mendapatkan proyek yang ada khususnya proyek di Kalimantan Barat. Pada penulisan ini, perlu untuk di ketahui perbandingan antara proyek yang ada di Kalimantan Barat pada tahun 2016-2018 dan perusahaan kontraktor kualifikasi menengah di kota Pontianak. Perbandingan tersebut untuk mengetahui seberapa besar peluang yang didapatkan perusahaan terhadap proyek yang tersedia. Pada penulisan ini dapat disimpulkan bahwa proyek Kalimantan Barat sangat berbanding lurus dengan jumlah perusahaan kontraktor yang ada di kota Pontianak, namun tidak semua perusahaan dapat mengikuti pelelangan proyek yang ada, karena tidak semua perusahaan kontraktor memiliki kemampuan untuk mengikuti persyaratan yang disedikan pada proyek yang dilelangkan

Pullulan for advanced sustainable body- And skin-contact applications

The present review had the aim of describing the methodologies of synthesis and properties of biobased pullulan, a microbial polysaccharide investigated in the last decade because of its interesting potentialities in several applications. After describing the implications of pullulan in nano-technology, biodegradation, compatibility with body and skin, and sustainability, the current applications of pullulan are described, with the aim of assessing the potentialities of this biopolymer in the biomedical, personal care, and cosmetic sector, especially in applications in contact with skin

Biodegradable polymeric micro/Nano-structures with intrinsic antifouling/antimicrobial properties: Relevance in damaged skin and other biomedical applications

Bacterial colonization ofimplanted biomedical devicesis themain cause of healthcare-associated infections, estimated to be 8.8 million per year in Europe. Many infections originate from damaged skin, which lets microorganisms exploit injuries and surgical accesses as passageways to reach the implant site and inner organs. Therefore, an effective treatment of skin damage is highly desirable for the success of many biomaterial-related surgical procedures. Due to gained resistance to antibiotics, new antibacterial treatments are becoming vital to control nosocomial infections arising as surgical and post-surgical complications. Surface coatings can avoid biofouling and bacterial colonization thanks to biomaterial inherent properties (e.g., super hydrophobicity), specifically without using drugs, which may cause bacterial resistance. The focus of this review is to highlight the emerging role of degradable polymeric micro- and nano-structures that show intrinsic antifouling and antimicrobial properties, with a special outlook towards biomedical applications dealing with skin and skin damage. The intrinsic properties owned by the biomaterials encompass three main categories: (1) physical-mechanical, (2) chemical, and (3) electrostatic. Clinical relevance in ear prostheses and breast implants is reported. Collecting and discussing the updated outcomes in this field would help the development of better performing biomaterial-based antimicrobial strategies, which are useful to prevent infections

Neuron Compatibility and Antioxidant Activity of Barium Titanate and Lithium Niobate Nanoparticles

The biocompatibility and the antioxidant activity of barium titanate (BaTiO3) and lithium niobate (LiNbO3) were investigated on a neuronal cell line, the PC12, to explore the possibility of using piezoelectric nanoparticles in the treatment of inner ear diseases, avoiding damage to neurons, the most delicate and sensitive human cells. The cytocompatibility of the compounds was verified by analysing cell viability, cell morphology, apoptotic markers, oxidative stress and neurite outgrowth. The results showed that BaTiO3 and LiNbO3 nanoparticles do not affect the viability, morphological features, cytochrome c distribution and production of reactive oxygen species (ROS) by PC12 cells, and stimulate neurite branching. These data suggest the biocompatibility of BaTiO3 and LiNbO3 nanoparticles, and that they could be suitable candidates to improve the efficiency of new implantable hearing devices without damaging the neuronal cells

Relevance of terpenoids on flammability of Mediterranean species: an experimental approach at a low radiant heat flux

One of the major factors influencing forest fuel combustion are terpenoids, a fraction of flammable Biogenic Volatile Organic Compounds (BVOCs) produced and stored by most Mediterranean species. The qualitative and quantitative effect of terpenoids on flammability has been only partially explained. In this study several major terpenoid-storing Mediterranean species (common cypress and three pines) were considered and compared to Holm oak as a reference non-storing species. The terpenoids were quantified via gas chromatography (GC-MS) analysis from both live fine fuel (LFF) and litter samples, and the relations between flammability and the terpenoids content were investigated by categories (Monoterpenoids, oxygenated Monoterpenoids, Sesquiterpenoids). The effect of fuel moisture content and species on ignition probability of LFF was also explored. A very different ignition probability was observed at the same fuel moisture content for the different species (Pinus spp. > C. sempervirens > Q. ilex). The stored terpenoids explained 19% to 50% of the whole flammability of both LFF and litter. Fuel moisture content (FMC) did not substantially change the relative effect of terpenoids on flammability, except in C. sempervirens. Monoterpenoids do not seem to significantly affect flammability, while sesquiterpenoids greatly influenced most flammability components, though their relative effect varied among species. A relation between storing structure of terpenoids and flammability was suggested. The results of this study indicate that isoprenoids should be included in physical models of the prediction and propagation of wildfire in Mediterranean vegetation as significant factors in driving flammability. © SISEF

Mimicking the Human Tympanic Membrane: The Significance of Scaffold Geometry

The human tympanic membrane (TM) captures sound waves from the environment and transforms them into mechanical motion. The successful transmission of these acoustic vibrations is attributed to the unique architecture of the TM. However, a limited knowledge is available on the contribution of its discrete anatomical features, which is important for fabricating functional TM replacements. This work synergizes theoretical and experimental approaches toward understanding the significance of geometry in tissue-engineered TM scaffolds. Three test designs along with a plain control are chosen to decouple some of the dominant structural elements, such as the radial and circumferential alignment of the collagen fibrils. In silico models suggest a geometrical dependency of their mechanical and acoustical responses, where the presence of radially aligned fibers is observed to have a more prominent effect compared to their circumferential counterparts. Following which, a hybrid fabrication strategy combining electrospinning and additive manufacturing has been optimized to manufacture biomimetic scaffolds within the dimensions of the native TM. The experimental characterizations conducted using macroindentation and laser Doppler vibrometry corroborate the computational findings. Finally, biological studies with human dermal fibroblasts and human mesenchymal stromal cells reveal a favorable influence of scaffold hierarchy on cellular alignment and subsequent collagen deposition