Skin simulants for wound ballistic investigation - an experimental study

Gunshot wound analysis is an important part of medicolegal practice, in both autopsies and examinations of living persons. Well-established and studied simulants exist that exhibit both physical and biomechanical properties of soft-tissues and bones. Current research literature on ballistic wounds focuses on the biomechanical properties of skin simulants. In our extensive experimental study, we tested numerous synthetic and natural materials, regarding their macromorphological bullet impact characteristics, and compared these data with those from real bullet injuries gathered from medicolegal practice. Over thirty varieties of potential skin simulants were shot perpendicularly, and at 45°, at a distance of 10 m and 0.3 m, using full metal jacket (FMJ) projectiles (9 × 19 mm Luger). Simulants included ballistic gelatine at various concentrations, dental silicones with several degrees of hardness, alginates, latex, chamois leather, suture trainers for medical training purposes and various material compound models. In addition to complying to the general requirements for a synthetic simulant, results obtained from dental silicones shore hardness 70 (backed with 20 % by mass gelatine), were especially highly comparable to gunshot entry wounds in skin from real cases. Based on these results, particularly focusing on the macroscopically detectable criteria, we can strongly recommend dental silicone shore hardness 70 as a skin simulant for wound ballistics examinations.

Observing the fragmentation of two expanding bullet types and a full metal-jacketed bullet with computed tomography-a forensic ballistics case study

Computed tomography (CT) may have a crucial role in the forensic documentation and analysis of firearm injuries. The aim of this forensic ballistics case study was to explore whether two types of expanding bullets and a full metal-jacketed bullet could be differentiated by inspecting bullet fragments and fragmentation pattern in CT. Three types of .30 caliber bullets (full metal-jacketed Norma Jaktmatch, expanding full-copper Norma Ecostrike, and expanding soft-point Norma Oryx) were test fired from a distance of 5 m to blocks of 10% ballistic gelatine. CT scans of the blocks were obtained with clinical equipment and metal artifact reduction. Radiopaque fragments were identified and fragmentation parameters were obtained from the scans (total number of fragments, maximum diameter of the largest fragment, distance between entrance and the closest fragment, length of the fragment cloud, and maximum diameters of the fragment cloud). The fragmentation patterns were additionally visualized by means of 3D reconstruction. In CT, the bullet types differed in several fragmentation parameters. While the expanding full-copper bullet Ecostrike left behind only a single fragment near the end of the bullet channel, the soft-point Oryx had hundreds of fragments deposited throughout the channel. For both expanding bullets Ecostrike and Oryx, the fragments were clearly smaller than those left behind by the full metal-jacketed Jaktmatch. This was surprising as the full metal-jacketed bullet was expected to remain intact. The fragment cloud of Jaktmatch had similar mediolateral and superoinferior diameters to that of Oryx; however, fragments were deposited in the second half of the gelatine block, and not throughout the block. This case study provides a basis and potential methodology for further experiments. The findings are expected to benefit forensic practitioners with limited background information on gunshot injury cases, for example, those that involve several potential firearms or atypical gunshot wounds. The findings may prove beneficial for both human and wildlife forensics.

Purification and separation of glucomannan from porang tuber flour (Amorphophallus muelleri) using microwave assisted extraction as an innovative gelatine substituent

Gelatine is frequently used as a food ingredient. However, Indonesia imports almost all of its gelatine, totaling 3990152 tons annually. Gelatine could be replaced with glucomannan compound which was found in porang tubers. However, it also contains calcium oxalate, which is harmful for the human body. In this study, calcium oxalate was first eliminated by the purification process using 10 % NaCl (w/w). Moreover, the microwave-assisted extraction method was used to extract the glucomannan compound by applying 300 W of microwave power with different extraction times (5, 10, 15, and 20 min) and different ethanol concentrations (60, 70, 80, and 96 %). Statistical analysis was used to optimize and identify significant parameters influencing the glucomannan concentration. The best conditions for glucomannan extraction were an extraction time of 10 min and an ethanol concentration of 80 % (v/v), resulting in a glucomannan yield of ≥96 %. Machine learning was successfully applied for data modelling using a Long Short-Term Memory block with an average R-square of 0.9772 (97.72 % accuracy) and an average MSE of 4.7719. Furthermore, physical and chemical characteristics of the extracted porang flour were accorded with SNI gelatine standards 06-3735 in 1995, which consisted of glucomannan (96.359 ± 1.164 %), calcium oxalate (0.009 ± 0.001 %), water (2.290 ± 0.986 %), ash (0.018 ± 0.002 %), fat (0.0235 ± 0.120 %), heavy metals (not identified), and pH (6.455 ± 0.191). Finally, the extracted glucomannan can be used as a potential regional substitute for gelatine production.

Clarification of pomegranate and strawberry juices: Effects of various clarification agents on turbidity, anthocyanins, colour, phenolics and antioxidant activity

Effects of clarification on turbidity, anthocyanins (ACNs), colour, phenolics, ascorbic acid and antioxidant activity (AA) of pomegranate (PJ) and strawberry juices (SJ) were investigated. Cold-clarification was applied to PJ using only gelatine. For hot-clarification of both juices, bentonite, gelatine and kieselsol were used. Moreover, pectolytic enzyme was added to SJ that contains pectin. Depectinization caused an increase in colour density of SJ and bentonite treatment resulted in low turbidity (9.5 NTU). However, gelatine and kieselsol significantly reduced ACN content (15%) and increased turbidity (70.1 NTU). In PJ, no step during hot-clarification provided low turbidity (93.2-162.0 NTU), while relatively low turbidity (28.7 NTU) and anthocyanin loss (9.8%) was achieved during cold-clarification. Hot-clarification of SJ showed no effect on AA and phenolics, while cold-clarification of PJ reduced both to a limited extent. Therefore, depectinization and bentonite treatment are recommended for hot-clarification of SJ and gelatine for cold-clarification of PJ.

A combined cowhide/gelatine soft tissue simulant for ballistic studies

The ballistic resistance of a combined soft tissue simulant was studied, consisting of gelatine as a simulant for human muscle tissue and tanned cowhide (leather) as a simulant for human skin. The simulant was manufactured by applying cowhide to liquid ballistic gelatine, as the gelatine solidified in its mould. Combining a skin and muscle tissue simulant in this adhered way opens the possibility to produce purpose-built proxies for human body parts in ballistic studies or for forensic shooting incident reconstructions. Ballistic resistance of adhered cowhide - (bonded) to solidifying ballistic gelatine - was compared to that of the same material applied on gelatine blocks in loose condition. Ballistic resistance of tanned cowhide was found to be more consistent in adhered condition. This enhanced consistency is a benefit, increasing reproducibility of results in ballistic studies. Additionally, two ways to assess ballistic resistance of a skin simulant were described and compared. Logistic regression, from a number of measured velocities and associated (non)perforations is recommended for testing ballistic resistance.

A review: Gelatine as a bioadhesive material for medical and pharmaceutical applications

Bioadhesive polymers offer versatility to medical and pharmaceutical inventions. The incorporation of such materials to conventional dosage forms or medical devices may confer or improve the adhesivity of the bioadhesive systems, subsequently prolonging their residence time at the site of absorption or action and providing sustained release of actives with improved bioavailability and therapeutic outcomes. For decades, much focus has been put on scientific works to replace synthetic polymers with biopolymers with desirable functional properties. Gelatine has been considered one of the most promising biopolymers. Despite its biodegradability, biocompatibility and unique biological properties, gelatine exhibits poor mechanical and adhesive properties, limiting its end-use applications. The chemical modification and blending of gelatine with other biomaterials are strategies proposed to improve its bioadhesivity. Here we discuss the classical approaches involving a variety of polymer blends and composite systems containing gelatine, and gelatine modifications via thiolation, methacrylation, catechol conjugation, amination and other newly devised strategies. We highlight several of the latest studies on these strategies and their relevant findings.

Numerical study of the dynamic expansion behaviour of 9 mm expansion bullets in gelatine

Due to their limited penetration power, expansion bullets are known for their good effectiveness and less endangerment to bystanders, thereby playing an important role in the fight against terrorism and violence. This study considered 20 bullet configurations with different shape parameters influencing the motion and deformation of 9 mm expansion bullets in gelatine. Owing to the constraints of high-speed photography, experimental observations have limitations. However, through numerical simulation, this study found that the penetration process of the 9 mm expansion bullets through biological tissues, as represented by the gelatine block in this study, can be subdivided into four stages. Further, the expansion bullet is highly sensitive to the impact velocity, and did not completely expand when travelling at speeds below the critical velocity and over-expanded when travelling at speeds above the threshold velocity. The results of this study revealed the interaction mechanism between expansion bullets and gelatine, which are significant to ballistic wounding assessment and treatment of expansion bullets.

Correlation between physical and sensorial properties of gummy confections with different formulations during storage

Gummy confections are popular products formulated with sucrose, glucose syrups, gelling agents, acids, flavourings and colouring agents. They have various commercial types in terms of formulation, texture, taste and colour, however, there is inadequate investigation on storage behavior of these products. The aim of this study is to investigate the effects of glucose syrup:sucrose ratio (1.1 and 1.5), starch (0% and 1.5%) and gelatine concentration (3% and 6%) on texture profile, colour and sensory properties of gummy confections during storage. It was also aimed to correlate sensorial changes with physical properties measured by instrumental techniques during storage at 10 °C, 20 °C and 30 °C. The highest increase in hardness was observed for formulation with 1.1 glucose syrup:sucrose ratio, no starch and 6% gelatine. Storage temperature had no significant effect on cohesiveness. It was seen that rate of colour change increased with storage time and temperature. Formulation with glucose syrup:sucrose ratio of 1.5, no starch and 6% gelatine had the highest sensory scores. This formulation was found to be the most stable formulation in terms of hardness and gumminess, meaning that it would need a stable mastication during storage. Sensorial changes of gummy confections were found to be correlated with instrumental results of texture and colour.

Efficacy and safety of early target-controlled plasma volume replacement with a balanced gelatine solution versus a balanced electrolyte solution in patients with severe sepsis/septic shock: study protocol, design, and rationale of a prospective, randomized, controlled, double-blind, multicentric, international clinical trial : GENIUS-Gelatine use in ICU and sepsis

BACKGROUND

Sepsis is associated with capillary leakage and vasodilatation and leads to hypotension and tissue hypoperfusion. Early plasma volume replacement is required to achieve haemodynamic stability (HDS) and maintain adequate tissue oxygenation. The right choice of fluids to be used for plasma volume replacement (colloid or crystalloid solutions) is still a matter of debate, and large trials investigating the use of colloid solutions containing gelatine are missing. This study aims to investigate the efficacy and safety of plasma volume replacement using either a combined gelatine-crystalloid regime (1:1 ratio) or a pure crystalloid regime.

METHODS

This is a prospective, controlled, randomized, double-blind, international, multicentric phase IV study with two parallel groups that is planned to be conducted at European intensive care units (ICUs) in a population of patients with hypovolaemia in severe sepsis/septic shock. A total of 608 eligible patients will be randomly assigned to receive either a gelatine-crystalloid regime (Gelaspan® 4% and Sterofundin® ISO, B. Braun Melsungen AG, in a 1:1 ratio) or a pure crystalloid regime (Sterofundin® ISO) for plasma volume replacement. The primary outcome is defined as the time needed to achieve HDS. Plasma volume replacement will be target-controlled, i.e. fluids will only be administered to volume-responsive patients. Volume responsiveness will be assessed through passive leg raising or fluid challenges. The safety and efficacy of both regimens will be assessed daily for 28 days or until ICU discharge (whichever occurs first) as the secondary outcomes of this study. Follow-up visits/calls will be scheduled on day 28 and day 90.

DISCUSSION

This study aims to generate evidence regarding which regimen-a gelatine-crystalloid regimen or a pure crystalloid regimen-is more effective in achieving HDS in critically ill patients with hypovolaemia. Study participants in both groups will benefit from the increased safety of target-controlled plasma volume replacement, which prevents fluid administration to already haemodynamically stable patients and reduces the risk of harmful fluid overload.

TRIAL REGISTRATION

The European clinical trial database EudraCT 2015-000057-20 and the ClinicalTrials.gov Protocol Registration and Results System ClinicalTrials.gov NCT02715466 . Registered on 17 March 2016.

The use of gelling agents to preserve burnt teeth within the dental alveoli for dental human identification - a study utilising sheep mandibles

Dental comparison is one of the primary methods of scientific identification of severely incinerated human remains. However, due to the fragile nature of the remains dental structures may be lost or damaged during recovery and transportation, limiting the amount of evidence available for examination. In addition to protecting the head, stabilization of the oral structures with an adhesive substance that will not interfere with the dental examination is ideal. A number of materials have been described in previous studies, however, no optimal method has yet to be indicated. Many of these materials contain petrochemicals, which have been shown to be a contamination risk. Wheatpaste solution has been demonstrated to be a viable alternative but has demonstrated handling issues and is not optimal in some environments. This study explores the stabilization of burnt teeth utilizing gelatin and agar solutions as alternatives to wheatpaste. Like wheatpaste solution, these materials are inexpensive, simple to use and are free from petrochemicals. Anterior sections of sheep mandibles were incinerated and subsequently solutions of agar, gelatin or wheatpaste were applied. The jaw fragments were then subjected to vibration and the number of teeth retained within the bone was recorded and compared to untreated incinerated jaw fragments. Although agar solution demonstrated serious handling issues, gelatin solution provided stabilization equivalent to that of wheatpaste. Gelatin also performed well at lower temperature conditions under which wheatpaste has been shown to perform poorly.

Development and physicochemical analysis of genipin-crosslinked gelatine sponge as a potential resorbable nasal pack

Nasal injury following nasal surgery is an adverse consequence, and prompt treatment should be initiated. Nasal packing, either non-absorbable or absorbable, are commonly used after nasal surgery to prevent bleeding and promote wound healing. In the current study, a novel gelatine sponge crosslinked with genipin was evaluated for suitability to be used as nasal packing and compared to one of the frequently used commercial nasal packing made up of polyurethane. Gelatine at 7% and 10% (w/v) concentration were crosslinked with varying concentrations of genipin, 0.5%, 0.25%, and 0.2% (v/v). The gelatine sponges were further characterised by its water uptake ability, biodegradation, water vapour transmission rate, porosity, contact angle, chemical composition, crosslinking degree, and mechanical properties. The gelatine sponges absorbed five times more water than their dry weight and were degraded within five days. The water vapour transmission rate of the gelatine sponges was 1187.7 ± 430.2 g/(m^-2 day) for 7% gelatine and 779.4 ± 375.5 g/(m^-2 day) for 10% gelatine. Crosslinking of gelatine with genipin resulted in lower porosity and did not affect the wettability of gelatine sponge (contact angle: 95.3 ± 12.1° for 7% gelatine and 88.4 ± 7.2° for 10% gelatine). In terms of biodegradability, the gelatine sponges took 24-48 h to degrade completely. Genipin crosslinking improved the degradation resistance and mechanical strength of gelatine sponge. The physical and chemical properties of the gelatine sponge, i.e. biodegradability and mechanical durability, support its potential as nasal packing.

Tissue-engineered PLLA/gelatine nanofibrous scaffold promoting the phenotypic expression of epithelial and smooth muscle cells for urethral reconstruction

The repair and regeneration of tissues using tissue-engineered scaffolds represent the ultimate goal of regenerative medicine. Despite rapid developments in the field, urethral tissue engineering methods are still insufficient to replicate natural urethral tissue because the bioactivity of existing scaffolds is inefficient, especially for large tissue defects, which require large tissue-engineered scaffolds. Here, we describe the efficiency of gelatine-functionalized, tubular nanofibrous scaffolds of poly(l-lactic acid) (PLLA) in regulating the phenotypic expression of epithelial cells (ECs) and smooth muscle cells (SMCs) for urethral reconstruction. Flexible PLLA/gelatine tubular nanofibrous scaffolds with hierarchical architecture were fabricated by electrospinning. The PLLA/gelatine nanofibrous scaffold exhibited enhanced hydrophilicity and significantly promoted the adhesion, oriented elongation, and proliferation of New Zealand rabbit autologous ECs and SMCs simultaneously. Compared with pure PLLA nanofibrous scaffold, PLLA/gelatine nanofibrous scaffolds upregulated the expression of keratin (AE1/AE3) in ECs and actin (α-SMA) in SMCs as well as the synthesis of elastin. Three months of in vivo scaffold replacement of New Zealand rabbit urethras indicated that a tubular cellularized PLLA/gelatine nanofibrous scaffold maintained urethral patency and facilitated oriented SMC remodeling, lumen epithelialization, and angiogenesis. Our observations showed the synergistic effects of nano-morphology and biochemical clues in the design of biomimetic scaffolds, which can effectively promote urethral regeneration.

The Effects of Sodium Hypochlorite on Organic Matters: Influences of Concentration, Renewal Frequency and Contact Area

Introduction

Sodium hypochlorite (NaOCl) reacts mainly with proteins and its effectiveness depends on the substances chemical reactivity. It has been reported that volume, concentration, renewal, time, temperature and contact area affect the diffusion of NaOCl in the root canal. However, the relationship between some of these factors is not clear. The purpose of this study was to test the effect of volume, contact area, concentration and renewal frequency of 2.5% and 9.8% NaOCl solutions on their organic matter dissolving-capacity.

Methods and Materials

Pieces of gelatine (18% w/v) with standardized weight, form and structure were either fully or partially exposed to a 2.5% or 9.8% NaOCl solution. In three successive studies, biological dissolution-capacity of NaOCl was tested under different conditions. In experiment 1 the effect of volume/time, in experiment 2 the time/concentration/renewal frequency and in experiment 3 the contact area/renewal frequency/concentration/time of 2.5% or 9.8% NaOCl solutions on dissolving-capacity of organic matter were studied. The weight loss of gelatine pieces over time was registered. The non-parametric tests of Mann-Whitney and Kruskal-Wallis at the 5% threshold were used for statistical analysis.

Results

The differences between the two concentrations of NaOCl solution (2.5% and 9.8%) are statistically significant in the effects of different volumes on total dissolution time (P<0.05). Differences in weight loss according to the concentration of the NaOCl solution used (2.5% or 9.8%) were significant after 2 min of contact time (P<0.05). Differences in weight loss between the model and the tube are significant (P<0.05) when the solution is repeated every 30 sec and every 1 min after 2 min of contact.

Conclusion

This in vitro study showed that using a more concentrated NaOCl solution would certainly improve the endodontic disinfection, but the biological risk in case of apical extrusion should be considered.

Intracellular trafficking and cytotoxicity of a gelatine-doxorubicin conjugate in two breast cancer cell lines

Details of intracellular pathways of cytotoxicity remain unclear for doxorubicin conjugates being studied to treat breast cancer tumours. A high molecular weight gelatine-doxorubicin conjugate was investigated with an emphasis on lysosome participation. The conjugate was synthesised and characterised. Cell uptake and cellular localisation in MCF-7 and triple negative breast cancer (TNBC) MDA-MB-231 cells were determined with fluorescence microscopy. Nuclear content of released DOX was determined by UHPLC. Cytotoxicity was determined by the MTT assay. Lysosome membrane permeabilization (LMP) was followed by lysosomal release of fluorescently labelled dextran. After incubation at an equivalent 10 µM DOX, conjugate lysosome accumulation was substantial in both cell lines by 24 h, at which time the conjugate cytotoxic effect was first observed. By 48 h, the conjugate was nearly fourfold more toxic in TNBC than in MCF-7 cells. The MCF-7 nucleus drug content from conjugate released DOX was small but confirmed intra-lysosomal drug release. The conjugate induced LMP in 100% of TNBC cells but LMP was virtually absent in MCF-7 cells. These results suggest that the conjugate induces cytotoxicity by a lysosomal pathway in MDA-MB-231 cells and has potential for treatment of TNBC tumours. Support: NIH/NCI R15CA135421, the Agnes Varis Trust for Women's Health.

Optical properties and colorimetry of gelatine gels prepared in different saline solutions

Gelatine has been widely used in many multidisciplinary research fields due to its biocompatibility. Using saline solutions in the gelation of gelatine allows for new properties to be incorporated into the prepared gels. This study examined the optical and colour properties of gelatine gels prepared in saline solutions, containing three different metal chlorides (NiCl₂·6H₂O, CoCl₂·6H₂O, and CrCl₃·6H₂O) with concentrations of up to 50%, to prepare three groups of gels. FTIR spectroscopy indicated a loss in the helical structure of the metal-containing gelatine gels, and a shift in the amide bands towards lower wavenumbers. From the thermogravimetric analysis (TGA), the starting degradation temperatures (SDTs) of the prepared gelatine gels were found to be correlated to the concentration of the gelling solutions. All SDTs were above 250 °C, making these gels suitable for standing temperatures beyond the daily range. UV-vis spectroscopy showed that d-d transitions were responsible for the colour properties of the metal-containing gelatine gels. It is concluded that the studied properties and the measured parameters were found to depend on both salt type and concentration. With the current findings, the prepared gels can be used as optical thermometers, colour-selective corner cube retroreflectors, laser components, and coatings for OLEDs.

The effect of military clothing on gunshot wounding patterns in gelatine

With no two gunshot wounds (GSW) being the same, novel research into wound ballistics is challenging. It is evident that the majority of previous wound ballistic research has been conducted without the presence of clothing. Whilst the effect of clothing on wound contamination has been explored, there is a paucity of literature examining the effect of clothing on GSW patterns. The aim of this study was to test the effect of Multi-Terrain Pattern (MTP) UK military clothing on GSW patterns within calibrated blocks of 10% by mass gelatine, using two types of ammunition commonly used in recent conflicts—7.62 × 39 mm and 5.45 × 39 mm. In total, 36 blocks were shot, 18 by each projectile type, further divided into 6 with no clothing layers (C_nil), 6 with a single clothing layer (C_min) and 6 with maximum clothing layers (C_max) worn on active duty. Blocks were analysed with high-speed video and dissection to capture measurements of damage, and results compared using analysis of variance (ANOVA). Results showed significantly different damage measurements within blocks with C_max for both ammunition types compared to the other clothing states. This may result in GSWs that require more extensive surgical management, inviting further study.

Impact of capsule type on aerodynamic performance of inhalation products: A case study using a formoterol-lactose binary or ternary blend

The aerodynamic performance of a dry powder for inhalation depends on the formulation and the dry powder inhaler (DPI). In the case of capsule-based DPIs, the capsule also plays a role in the powder aerosolisation and the dispersion of the micronized drug during the inhalation. This study evaluated the impact of gelatine capsules (Quali-G™ and Hard Gelatine Capsules for DPIs), cold-gelled hypromellose (HPMC) capsules (Quali-V^®-I and Vcaps^®) and thermal-gelled HPMC capsules (Vcaps^®Plus) from Qualicaps^® and Capsugel^® respectively, on the delivered dose (DD), fine particle dose (FPD), and capsule retention for formoterol-lactose binary and ternary blends. This study used a low resistance Axahaler^® DPI based on the RS01 design (Plastiape, Italy). Similar trends were observed with the different capsule types that packaged both dry powder formulations. The highest DD and FPD and the lowest formoterol capsule retention were observed with cold-gelled HPMC capsules such as Quali-V-I^® and Vcaps^®, without significant differences between these capsules (p > 0.05, one-way ANOVA with Newman-Keuls post-hoc test) for both dry powders. Therefore, the capsule composition and manufacturing process have an influence on aerodynamic performance. In addition, the ternary blend showed higher DDs and FPDs but also higher capsule retention in comparison to the binary blend.

The use of gelatine in wound ballistics research

Blocks of gelatine are used in both lethality and survivability studies for broadly the same reason, i.e. comparison of ammunition effects using a material that it is assumed represents (some part of) the human body. The gelatine is used to visualise the temporary and permanent wound profiles; elements of which are recognised as providing a reasonable approximation to wounding in humans. One set of researchers aim to improve the lethality of the projectile, and the other to understand the effects of the projectile on the body to improve survivability. Research areas that use gelatine blocks are diverse and include ammunition designers, the medical and forensics communities and designers of ballistic protective equipment (including body armour). This paper aims to provide an overarching review of the use of gelatine for wound ballistics studies; it is not intended to provide an extensive review of wound ballistics as that already exists, e.g. Legal Med 23:21-29, 2016. Key messages are that test variables, projectile type (bullet, fragmentation), impact site on the body and intermediate layers (e.g. clothing, personal protective equipment (PPE)) can affect the resulting wound profiles.

Fabrication and characterisation of a novel biomimetic anisotropic ceramic/polymer-infiltrated composite material

OBJECTIVE

To fabricate and characterise a novel biomimetic composite material consisting of aligned porous ceramic preforms infiltrated with polymer.

METHOD

Freeze-casting was used to fabricate and control the microstructure and porosity of ceramic preforms, which were subsequently infiltrated with 40-50% by volume UDMA-TEGDMA polymer. The composite materials were then subjected to characterisation, namely density, compression, three-point bend, hardness and fracture toughness testing. Samples were also subjected to scanning electron microscopy and computerised tomography (Micro-CT).

RESULTS

Three-dimensional aligned honeycomb-like ceramic structures were produced and full interpenetration of the polymer phase was observed using micro-CT. Depending on the volume fraction of the ceramic preform, the density of the final composite ranged from 2.92 to 3.36g/cm³, compressive strength ranged from 206.26 to 253.97MPa, flexural strength from 97.73 to 145.65MPa, hardness ranged from 1.46 to 1.62GPa, and fracture toughness from 3.91 to 4.86MPam^1/2.

SIGNIFICANCE

Freeze-casting provides a novel method to engineer composite materials with a unique aligned honeycomb-like interpenetrating structure, consisting of two continuous phases, inorganic and organic. There was a correlation between the ceramic fraction and the subsequent, density, strength, hardness and fracture toughness of the composite material.

The effect of helmet materials and simulated bone and tissue layers on bullet behaviour in a gelatine model of overmatch penetrating head injury

The aim of this work was to simulate an overmatch ballistic event against a head wearing a helmet. The experiments were designed to understand how layers of bone (or synthetic bone), synthetic skin and currently used helmet materials influence the behaviour of full metal jacket mild steel core (FMJ MSC) 7.62 × 39 mm bullets, impacting on targets with a mean velocity of 650 m/s. Bullet behaviour within 10% (by mass) gelatine blocks was assessed by measurements made of the temporary cavity within the blocks using high-speed video and of the permanent cavity by dissecting blocks post firing. While ANOVA did not find significant difference at the 0.05 level in the mean values of most of the measurements, there was a significant difference in neck length within the gelatine blocks. The addition of material layers did produce greater variability in the temporary cavity measurements under some of the conditions. One of the synthetic bone polymers with a synthetic skin layer produced similar results within the gelatine blocks to the horse scapulae (with residual tissue) and may be suitable for future ballistic experiments.

Mineralization potential of cellulose-nanofibrils reinforced gelatine scaffolds for promoted calcium deposition by mesenchymal stem cells

Cellulose-nanofibrils (CNFs) enriched gelatine (GEL) scaffolds were fabricated in-situ by the combined freeze-thawing process and carbodiimide crosslinking chemistry. The original- and variously surface anionised CNFs (carboxylated/CNF-COOH/, and phosphonated with 3-AminoPropylphosphoric Acid/CNF-COOH-ApA/) were used in order to tune the scaffolds' biomimetic structure towards a more intensive mineralization process. The pore size reduction (from 208±35μm to 91±35μm) after 50% v/v of CNFs addition to GEL was identified, while separated pore-walls' alignment vs. shorter, dense and elongated pores are observed when using 80% v/v of original-CNFs vs. anionised-CNFs, all of them possessed osteoid-like compressive strength (0.025-0.40MPa) and elasticity (0.04-0.15MPa). While randomly distributed Ca²⁺-deficient hydroxyapatite/HAp/(Ca/P≈1.4) aggregates were identified in the case of original-CNF prevalent scaffolds after four weeks of incubation in SBF, the more uniform and intensified deposition with HAp-like (Ca/P≈1.69) structures were established using CNF-COOH-Apa. The growth of Mesenchymal Stem Cells (MSCs) was observed on all CNF-containing scaffolds, resulting in more extensive Ca²⁺ deposition compared to the positive control or pure GEL scaffold. Among them, the scaffold prepared with the 50% v/v CNF-COOH-ApA showed significantly increased mineralization kinetic as well as the capacity for bone-like patterning in bone tissue regeneration.

Gelatine modified monetite as a bone substitute material: An in vitro assessment of bone biocompatibility

Calcium phosphate phases are increasingly used for bone tissue substitution, and the load bearing properties of these inherently brittle biomaterials are increased by inclusion of organic components. Monetite prepared using mineralization of gelatine pre-structured through phosphate leads to a significantly increased biaxial strength and indirect tensile strength compared to gelatine-free monetite. Besides the mechanical properties, degradation in physiological solutions and osteoblast and osteoclast cell response were investigated. Human bone marrow stromal cells (hBMSCs) showed considerably higher proliferation rates on the gelatine modified monetite than on polystyrene reference material in calcium-free as well as standard cell culture medium (α-MEM). Osteogenic differentiation on the material was comparable to polystyrene in both medium types. Osteoclast-like cells derived from monocytes were able to actively resorb the biomaterial. Osteoblastic differentiation and perhaps even more important the cellular resorption of the biomaterial indicate that it can be actively involved in the bone remodeling process. Thus the behavior of osteoblasts and osteoclasts as well as the adequate degradation and mechanical properties are strong indicators for bone biocompatibility, although in vivo studies are still required to prove this.

STATEMENT OF SIGNIFICANCE

New and unique? A low temperature precipitationprocessforcalcium anhydrous hydrogen phosphateallows for the first time to produce monolithic compact composites of monetite and gelatine. The composite is degradable and resorbable. To prove that, the question arises: what is bone biocompatibility? The reaction of both mayor cell types of bone represents this biocompatibility. Therefore, human bone marrow stromal cells were seeded revealing the materials pro-osteogenic properties. Monocyte cultivation, becoming recently focus of interest, revealed the capability of the biomaterial to be actively resorbed by derived osteoclast-like cells. Not new but necessary ismechanical characterization, which is often only investigated as uniaxial property. Here, a biaxial method is applied, to characterize the materials properties closer to its application loads.

Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films

Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91-1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate - rice starch based films offering the most enhanced stability. The film's shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively.

[Improvement of sonographic visualization of cannula needle tips by alignment of the needle lumen : In vitro investigation of established needle tip forms]

BACKGROUND

In the context of ultrasound-guided peripheral nerve blocks (regional anesthesia), clear visualization of the needle tip and the target structure are mandatory for the performance of a safe puncture and injection. The purpose of this in vitro study was to analyze the visualization of different forms of needle tips and calibers of cannulas in a phantom simulating human tissue, with the help of a standardized image analysis system. Different depths and angles of the puncture needle in relation to the ultrasound probe were tested.

MATERIAL AND METHODS

Cannula needles established for use in regional anesthesia with different surfaces, diameters and needle tip form in 23 different combinations were analyzed. A gelatine-based phantom was used to simulate human tissue. The standardized visualization of the needle tip with the ultrasound probe was performed in plane at different angles (30°, 45° and 60°), depths of penetration (1 cm, 2 cm and 3 cm) and two different alignments of the cannula needle lumen to the ultrasound probe (0° and 180°). The screenshots of the ultrasound pictures were analyzed by quantifying the pixel brightness around the needle tip (region of interest) with a standardized software (score 0-255).

RESULTS

In this study 1104 ultrasound images of cannula needles were analyzed. Diminished scores (reduced pixel brightness) of the needle tips were documented with increasing distance from the ultrasound probe. Comparison of punctures at angles of 30° and 45° showed no differences in needle tip visibility (same scores) but punctures at an angle of 60° were poorly visualized compared with 30° and 45° (mean scores 87.90 ± 11.60 vs. 78.40 ± 12.07, p < 0.001 and 81.85 ± 11.79 vs. 78.40 ± 12.07, p < 0.001, respectively). The direct alignment of the cannula lumen towards the ultrasound probe (0°) was significantly more easily visualized when compared with the reverse alignment of 180° (mean scores 86.90 ± 12.74 vs. 84.80 ± 11.66, p = 0.003, respectively). No differences in visibility were detected between the different cannula needle diameters examined. The Sprotte cannula showed the best visibility score with respect to the cut of the needle tip (mean score 89.40 ± 11.72).

CONCLUSION

The visibility of cannulas in ultrasound scans depends on the ultrasound frequency, angle of the puncture in relation to the ultrasound probe and the depth of penetration. The results of this study showed that direct alignment of the cannula needle lumen towards the ultrasound probe (0°) independently improved needle tip visualization. This simple measure allows a significant improvement in the safe performance of ultrasound-guided peripheral nerve blocks.

Method to Reduce Target Motion Through Needle-Tissue Interactions

During minimally invasive surgical procedures, it is often important to deliver needles to particular tissue volumes. Needles, when interacting with a substrate, cause deformation and target motion. To reduce reliance on compensatory intra-operative imaging, a needle design and novel delivery mechanism is proposed. Three-dimensional finite element simulations of a multi-segment needle inserted into a pre-existing crack are presented. The motion profiles of the needle segments are varied to identify methods that reduce target motion. Experiments are then performed by inserting a needle into a gelatine tissue phantom and measuring the internal target motion using digital image correlation. Simulations indicate that target motion is reduced when needle segments are stroked cyclically and utilise a small amount of retraction instead of being held stationary. Results are confirmed experimentally by statistically significant target motion reductions of more than 8% during cyclic strokes and 29% when also incorporating retraction, with the same net insertion speed. By using a multi-segment needle and taking advantage of frictional interactions on the needle surface, it is demonstrated that target motion ahead of an advancing needle can be substantially reduced.

In vivo performance of novel soybean/gelatin-based bioactive and injectable hydroxyapatite foams

Major limitations of calcium phosphate cements (CPCs) are their relatively slow degradation rate and the lack of macropores allowing the ingrowth of bone tissue. The development of self-setting cement foams has been proposed as a suitable strategy to overcome these limitations. In previous work we developed a gelatine-based hydroxyapatite foam (G-foam), which exhibited good injectability and cohesion, interconnected porosity and good biocompatibility in vitro. In the present study we evaluated the in vivo performance of the G-foam. Furthermore, we investigated whether enrichment of the foam with soybean extract (SG-foam) increased its bioactivity. G-foam, SG-foam and non-foamed CPC were implanted in a critical-size bone defect in the distal femoral condyle of New Zealand white rabbits. Bone formation and degradation of the materials were investigated after 4, 12 and 20weeks using histological and biomechanical methods. The foams maintained their macroporosity after injection and setting in vivo. Compared to non-foamed CPC, cellular degradation of the foams was considerably increased and accompanied by new bone formation. The additional functionalization with soybean extract in the SG-foam slightly reduced the degradation rate and positively influenced bone formation in the defect. Furthermore, both foams exhibited excellent biocompatibility, implying that these novel materials may be promising for clinical application in non-loaded bone defects.

Recovery, viscoelastic and functional properties of Barbel skin gelatine: investigation of anti-DPP-IV and anti-prolyl endopeptidase activities of generated gelatine polypeptides

The characteristics and functional properties of gelatine from freshwater fish skin (Barbus callensis) were investigated. The gelatine extraction efficiency was improved by an acid-swelling process in the presence of barbel crude acid protease extract. Barbel skin gelatine (BSG) contained 92.15% protein, 0.31% lipid and 0.72% ash. The amino acid profile of BSG showed a high percentage of imino acids. The electrophoretic profile showed that BSG is mainly composed of α- and β-components. BSG showed an excellent solubility and possessed interfacial properties, which were governed by the protein concentration. Biological activities of the hydrolysates obtained after digestion of BSG with several commercial proteases were evaluated. The results suggested that these hydrolysates are a good source of natural inhibitors of dipeptidyl peptidase-IV and prolyl endopeptidase and could potentially be used as dietary ingredients in the management of type 2-diabetes and/or neuropathological disorders.

Effect of incorporation of mahua extract, fining agent and ageing on the quality characteristics of red wine

Mahua (Madhuca longfolia) extract and black grapes (Vitis vinifera) must samples 100:0 (grape:mahua), 95:5 (grape:mahua) and 90:10 (grape:mahua) were analyzed for quality characteristics. Samples were kept for fermentation and monitored for quality analysis for 15 days. 90:10 (grape:mahua) sample was found to be best on the basis of ranking test and subjected to clarification using bentonite and gelatine. Sample treated with a combination of 0.02 g/100 g bentonite and 0.04 g/100 g gelatin showed better results for anthocyanin (52.2 mg/100 g) and tannin (0.038%w/v). After ageing of 3 months TSS was found highest (2.7ºBx) in the non-clarified sample and lowest (2.1ºBx) in sample treated with 0.06 g/100 g bentonite and 0.03 g/100 g gelatine. pH was highest (3.29) in sample treated with 0.06 g/100 g bentonite and 0.03 g/100 g gelatine and lowest (3.16) in sample with 0.04 g/100 g bentonite and 0.03 g/100 g gelatine. Anthocyanin content was highest (56.1 mg/100 g) in control sample and lowest (29.22 mg/100 g) in sample treated with 0.04 g/100 g bentonite and 0.02 g/100 g gelatin. Tannin content was found to be highest (0.079%w/v) in control sample and lowest (0.03%w/v) in sample treated with 0.02 g/100 g bentonite and 0.04 g/100 g gelatine.