Abattoirs dispose of sheepskins as solid waste due to low price and poor demand for sheepskin leather. In principle, as an alternative to being disposed of in landfill, sheepskins can serve as a source of the protein collagen or the hydrolysis product, gelatin. In this research, sheepskins collected from abattoirs were used as a source of collagen. Three extraction methods were compared: acid extraction, acid with enzymes, and alkali extraction. The extracted material was characterized using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), small angle X-ray scattering (SAXS), and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The collagen and gelatin extraction yield ranged from 3.1% to 4.8% with the product purity determined by hydroxyproline, ranging from 7.8% for the alkali process to 59% and 68% for the acid and acid-enzyme processes. SDS PAGE showed that the acid process produced fragments with molecular weights in the range 100 to >250 kDa, while acid–enzyme resulted in smaller fragments, below 30 kDa. The FTIR region of the amide I band at 1800–1550 cm−1, which was used as an indicator of the collagen and gelatin content, showed that the gelatin dominated in the acid extracts, and the alkaline extract contained a large portion of keratin. SAXS was found to be a sensitive method for showing the presence of intact collagen fibrils in materials from all of the extraction methods, albeit at low concentrations. Herein, sheepskin is shown to be a useful source for collagen–gelatin material of varying molecular weights.

It is well established that solutions of both polymeric and oligomeric κ-carrageenan exhibit a clear change in optical rotation (OR), in concert with gel-formation for polymeric samples, as the solution is cooled in the presence of certain ions. The canonical interpretation – that this OR change reflects a ‘coil-to-helix transition’ in single chains – has seemed unambiguous; the solution- or ‘disordered’-state structure has ubiquitously been assumed to be a ‘random coil’, and the helical nature of carrageenan in the solid-state was settled in the 1970s. However, recent work has found that κ-carrageenan contains substantial helical secondary structure elements in the disordered-state, raising doubts over the validity of this interpretation. To investigate the origins of the OR, density-functional theory calculations were conducted using atomic models of κ-carrageenan oligomers. Changes were found to occur in the predicted OR owing purely to dimerization of chains, and - together with the additional effects of slight changes in conformation that occur when separated helical chains form double-helices - the predicted OR changes are qualitatively consistent with experimental results. These findings contribute to a growing body of evidence that the carrageenan ‘disorder-to-order’ transition is a cooperative process, and have further implications for the interpretation of OR changes demonstrated by macromolecules in general.

Osteoarthritis is a leading cause of lameness and joint disease in horses. A simple, economical, and accurate diagnostic test is required for routine screening for OA. This study aimed to evaluate infrared (IR)-based synovial fluid biomarker profiling to detect early changes associated with a traumatically induced model of equine carpal osteoarthritis (OA). Unilateral carpal OA was induced arthroscopically in 9 of 17 healthy thoroughbred fillies; the remainder served as Sham-operated controls. The median age of both groups was 2 years. Synovial fluid (SF) was obtained before surgical induction of OA (Day 0) and weekly until Day 63. IR absorbance spectra were acquired from dried SF films. Following spectral pre-processing, predictive models using random forests were used to differentiate OA, Sham, and Control samples. The accuracy for distinguishing between OA and any other joint group was 80%. The classification accuracy by sampling day was 87%. For paired classification tasks, the accuracies by joint were 75% for OA vs. OA Control and 70% for OA vs. Sham. The accuracy for separating horses by group (OA vs. Sham) was 68%. In conclusion, SF IR spectroscopy accurately discriminates traumatically induced OA joints from controls.

Biomarkers for osteoarthritis (OA) in horses have been extensively investigated, but translation into clinical use has been limited due to cost, limited sensitivity, and practicality. Identifying novel biomarkers that overcome these limitations could facilitate early diagnosis and therapy. This study aimed to compare the concentrations of synovial fluid (SF) and plasma cell-free DNA (cfDNA) over time in control horses with those with induced carpal OA. Following an established model, unilateral carpal OA was induced in 9 of 17 healthy Thoroughbred fillies, while the remainder were sham-operated controls. Synovial fluid and plasma samples were obtained before induction of OA (Day 0) and weekly thereafter until Day 63, and cfDNA concentrations were determined using fluorometry. The SF cfDNA concentrations were significantly higher for OA joints than for sham-operated joints on Days 28 (median 1430 μg/L and 631 μg/L, respectively, p = 0.017) and 63 (median 1537 μg/L and 606 μg/L, respectively, p = 0.021). There were no significant differences in plasma cfDNA between the OA and the sham groups after induction of carpal OA. Plasma cfDNA measurement is not sufficiently sensitive for diagnostic purposes in this induced model of OA. Synovial fluid cfDNA measurement may be used as a biomarker to monitor early disease progression in horses with OA.

The influence of bound anthocyanins on pectin-protein complexation was studied by comparing two types of pectin-protein mixtures: (i) the anthocyanin-rich blackcurrant pectin-whey protein (BCP-WP) mixture and (ii) the anthocyanin-free citrus pectin-WP (CP-WP) mixture. The mixtures were prepared at pH 4.5 with (Pectin:Protein Ratio—1:1, 1:5, 1:10) and without (Pectin:Protein Ratio—1:1) heat treatment at 85 °C. Increasing protein ratio upon heating led to the formation of complexes which eventually destabilized the BCP-WP and CP-WP mixtures. However, no direct relationship was observed between the presence of anthocyanins and the destabilization of mixtures. FTIR analyses demonstrated that there were slight perturbations to the bond strengths of BCP, CP and WP functional groups when they were mixed, with or without heating, confirming the occurrence of pectin-protein complexation. Additionally, the spectrum of BCP-WP sedimented fractions showed the emergence of a peak at 800-1200 cm−1, signifying the presence of anthocyanin-protein interactions. This peak, however, was not seen in the spectrum of anthocyanin-free CP-WP sedimented fractions, indicating that the bound anthocyanins of BCP provided WP with additional binding sites. Moreover, the heated BCP-WP mixture at 1:10 ratio had similar net charge as the BCP control (both ca. −20 mV), yet its CP-WP counterpart had a net charge (ca. −19 mV) that was significantly (p < 0.05) lower than the CP control (ca. −33 mV). Considering the findings from FTIR analyses, it was likely that with heat treatment the BCP and WP had interacted mainly via non-electrostatic forces—through hydrophobic interactions and later reinforced by hydrogen bonds upon cooling.

The influence of bound anthocyanins on pectin-protein complexation was studied by comparing two types of pectin-protein mixtures: (i) the anthocyanin-rich blackcurrant pectin-whey protein (BCP-WP) mixture and (ii) the anthocyanin-free citrus pectin-WP (CP-WP) mixture. The mixtures were prepared at pH 4.5 with (Pectin: Protein Ratio-1:1, 1:5, 1:10) and without (Pectin:Protein Ratio-1:1) heat treatment at 85 degrees C. Increasing protein ratio upon heating led to the formation of complexes which eventually destabilized the BCP-WP and CPWP mixtures. However, no direct relationship was observed between the presence of anthocyanins and the destabilization of mixtures. FTIR analyses demonstrated that there were slight perturbations to the bond strengths of BCP, CP and WP functional groups when they were mixed, with or without heating, confirming the occurrence of pectin-protein complexation. Additionally, the spectrum of BCP-WP sedimented fractions showed the emergence of a peak at 800-1200 cm-1, signifying the presence of anthocyanin-protein interactions. This peak, however, was not seen in the spectrum of anthocyanin-free CP-WP sedimented fractions, indicating that the bound anthocyanins of BCP provided WP with additional binding sites. Moreover, the heated BCP-WP mixture at 1:10 ratio had similar net charge as the BCP control (both ca. -20 mV), yet its CP-WP counterpart had a net charge (ca. -19 mV) that was significantly (p < 0.05) lower than the CP control (ca. -33 mV). Considering the findings from FTIR analyses, it was likely that with heat treatment the BCP and WP had interacted mainly via non-electrostatic forces-through hydrophobic interactions and later reinforced by hydrogen bonds upon cooling.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

This study sought to explore the combined use of confocal Raman microscopy and microfluidic channels to probe the location and mobility of hydrophobic antioxidant (β-carotene) incorporated at the interface of food-grade droplet-stabilized emulsions (DSEs).Microfluidic channels were used to isolate emulsion droplets for efficient investigation of antioxidant mobility. This approach proved more conclusive than fixing the sample in agarose, because a single layer of droplets could be obtained. Results also indicated that the migration of β-carotene incorporated in shell droplets of olive oil and trimyristin DSEs to core droplets was minimal and beta-carotene remained mostly localised at the interface even after 3 days of production.This work demonstrates that microfluidic isolation of emulsion droplets combined with confocal Raman microscopy can give new insights into the spatial variation of chemical composition within emulsions.This study revealed that the migration of β-carotene between shell and core was minimal and hence it may be possible to concurrently deliver two incompatible compounds by spatially segregating them between shell and core compartments of DSEs.

The occurrence of spontaneous humeral fractures in primiparous dairy cows from New Zealand prompted the study of bone material from affected cows to further characterize this condition and to outline a likely pathogenesis. Previous studies indicate that these cows developed osteoporosis due to periods of suboptimal bone formation followed by increased bone resorption during the period of lactation complicated by copper deficiency. We hypothesized that there are significant differences in the chemical composition/bone quality in bones from cows with spontaneous humeral fracture compared to cows without humeral fractures. In this study, Raman and Fourier transform infrared spectroscopy band ratios were, for the first time, measured, calculated, and compared in bone samples from 67 primiparous dairy cows that suffered a spontaneous fracture of the humerus and 14 age-matched post-calving cows without humeral fractures. Affected bone showed a significantly reduced mineral/matrix ratio, increased bone remodeling, newer bone tissue with lower mineralization and, lower carbonate substitution, and reduced crystallinity. As such, is likely that these have detrimentally impacted bone quality and strength in affected cows.

A series of salts with a diaminohalocyclopropenium cation and halide anion [C-3((NPr2)-Pr-i)(2)X]X (X =Cl ([1]Cl) or Br ([2]Br) were isolated with a variety of solvates and, in one case, as a co-crystal with hydronium chloride. In particular, the initial synthesis of MCI formed a co-crystal with hydronium and with CH2Cl2 solvate ([1](2)[OH3Cl3]center dot CH2Cl2) upon isolation from acetone/CH2Cl2. Recrystallization of this from chloroform gave a dichloroform adduct [1 ]Cl center dot 2CHCl(3), whereas treatment with ICI formed an octahalide cluster [1](2)I4Cl4. The bromine salt [2]Br center dot C2H4Br2 was prepared by treatment of MCI with dibromoethane and was isolated as a solvate. The hydronium cation was found as part of a hydronium trichloride cluster [OH3Cl3](2-) and this, along with a partially-deuterated analogue of [OHD2Cl3](2-) and [OD3Cl3](2-), was studied computationally and by mid-and far-infrared spectroscopy. Significant halogen bonds were found between 1 + or 2+ and chloride or bromide, respectively. On the other hand, the distance to the octahalide [I4Cl4](2-) is too long for a halogen bond. Hydrogen bonding from the halides to the halomethane solvates is also significantly stronger than to the cation isopropyl groups. The geometries formed at the halide ions with respect to the halogen bond and strong hydrogen bonds are pyramidal with approximately orthogonal angles.

A complexation study between blackcurrant pectin (BCP) and whey protein (WP) was carried out to investigate the impact of bound anthocyanins on pectin–protein interactions. The effects of pH (3.5 and 4.5), heating (85 °C, 15 min), and heating sequence (mixed-heated or heated-mixed) were studied. The pH influenced the color, turbidity, particle size, and zeta-potential of the mixtures, but its impact was mainly significant when heating was introduced. Heating increased the amount of BCP in the complexes—especially at pH 3.5, where 88% w/w of the initial pectin was found in the sedimented (insoluble) fraction. Based on phase-separation measurements, the mixed-heated system at pH 4.5 displayed greater stability than at pH 3.5. Heating sequence was essential in preventing destabilization of the systems; mixing of components before heating produced a more stable system with small complexes (<300 nm) and relatively low polydispersity. However, heating WP before mixing with BCP prompted protein aggregation—producing large complexes (>400 nm) and worsening the destabilization. Peak shifts and emergence (800–1200 cm−1) in infrared spectra confirmed that BCP and WP functional groups were altered after mixing and heating via electrostatic, hydrophobic, and hydrogen bonding interactions. This study demonstrated that appropriate processing conditions can positively impact anthocyanin-bound pectin–protein interactions.

Traditionally, industrial scale production of the TiO2 pigment is achieved by hydrolysis from H2SO4 solution or by hydrolysis of TiCl4. However, the H2SO4 route produces FeSO4 waste, which is problematic, and the TiCl4 route requires a high grade rutile feedstock or chemically upgraded ilmenite (FeTiO3). Here, we investigate a direct route from ilmenite to TiO2 using aqueous HCI. New Zealand ilmenite digested in 35 wt % HCl to achieve a solution containing typically 1.18 mol kg(-1) Fe-(aq)(2+) and 1.14 mol kg(-1) Ti (4+)((aq)) was hydrolyzed under reflux, after seed preparation in water, or with phosphoric or citric acid. The structure of the seed was determined by Raman spectroscopy and X-ray powder diffraction using pair distribution function analysis, the latter enabling the identification of short-range order in poorly crystalline materials. TiO2 hydrate was precipitated from HCl in either the anatase or the rutile structure. Unlike from H2SO4, the natural structure formed without the use of structure determining agents is rutile. However, seed preparation using 0.4 mol H3PO4 per mole of Ti (resulting in 0.35 wt% H3PO4 in the hydrate) results in anatase hydrate formation. Sodium citrate or citric acid addition also seed anatase hydrate. The mechanism for polymorph control may be kinetic rather than a structural template or surface adsorption. This process has the potential to be used for the commercial scale production of the TiO2 pigment. Anatase hydrate has the advantage that traces of iron may be more readily removed by washing than from rutile precipitate, making the HCl process from ilmenite feasible for pigment grade material.

Surface-enhanced Raman spectroscopy using functionalised nanoparticles or nano-engineered surfaces provides a highly selective and sensitive technique for detecting and quantifying analyte binding. However, practical diagnostic and sensing applications are hindered by technical variability due to hot-spotting and analyte drift, as well as variability in sample preparation and substrate uniformity. In this work, we introduce a novel joint experimental design and computational analysis procedure to minimize and/or control for these sources of error. Sample variability is minimized by preparing functionalised nanoparticles with and without analyte under the same conditions, and then recording and analysing difference spectra. To account for technical variability, multiple spectra are recorded from each sample. The key novelty of our analysis procedure is that all information about sample and technical variability is retained through to the final comparative analysis step, and we apply principal component analysis twice - once to extract "variance-minimized" spectra as principal loading vectors and again to distinguish between samples with and without the target analyte. Proof of principle experiments using thiolated aptamers to detect CoV-SARS-2 spike protein reveal that analyte binding show that analyte binding primarily shows up as a depletion of free covalent stretching bands, coupled to appearance of corresponding hydrogen-bonded stretching bands. This is quite different from previous work which largely focusses on changes in the "fingerprint" region where we find that the signal may be obscured by greater technical variability. Our computational analysis code can be freely downloaded from https://github.com/dlc62/DeltaPCA.

Objective: to determine the accuracy of infrared (IR)-based serum biomarker profiling to differentiate horses with early inflammatory changes associated with a traumatically induced model of equine carpal osteoarthritis (OA) from controls. Method: unilateral carpal OA was induced in 9 of 17 healthy Thoroughbred fillies, while the remainder served as sham operated controls. Serum samples were obtained before induction of OA (Day 0) and weekly thereafter until Day 63 from both groups. Films of dried serum were created, and IR absorbance spectra acquired. Following pre-processing, partial least squares discriminant analysis (PLSDA) and principal component analysis (PCA) were used to assess group and time differences and generate predictive models for wavenumber ranges 1300-1800 cm-1 and 2600-3700 cm-1. Results: the overall correct classification rate when classifying samples by group (OA or Sham) was 52.7% (s.d. = 12.8%), while it was 94.0% (s.d. = 1.4%) by sampling Day. The correct classification results by group-sampling Day combinations with pre-intervention serum (Day 0) was 50.5% (s.d. = 21.7%). Conclusion: with the current approach IR spectroscopic analysis could not differentiate serum of horses with induced carpal OA from that of controls. The high classification rate obtained by Day of sampling may reflect the effect of exercise on the biomarker profile. A longer study period (advanced disease) or naturally occurring disease may provide further information on the suitability of this technique in horses.

We report a set of resonantly enhanced defect modes in the Raman spectrum of molybdenum disulfide (MoS2) which are fully analogous to the D mode of graphene, allowing sensitive defect quantification and differentiation of zigzag and armchair edge structures. These modes become active at edges under indirect resonance conditions at 785 nm excitation due to strict backscatter constraints in real and reciprocal space, which exclusively select phonon wavevectors perpendicular to the edge direction. We assign features to single LA(K), TA(K), and TA(Q) phonons along the direction of the Brillouin zone and identify a separate preresonant enhancement of the whole spectrum along the direction, which is lost in thinner material as the band gap increases. In addition, we identify a clear incident polarization dependence of the K and M phonons, which suggests the presence of an inhomogeneous optical absorption analogous to that of graphene. We anticipate this indirect double resonance Raman technique will provide a powerful tool for materials characterization, allowing quantification of active sites in catalytic MoS2 and characterization of the structure-dependent properties of MoS2 nanomaterials. In addition, the intervalley scattering pathways provide a sensitive probe of the low energy landscape of the conduction band and may reveal a wealth of electronic information and scattering dynamics important for spin-valley coupled systems. We anticipate similar modes can be found in other transition metal dichalcogenide systems, given the appropriate excitation energy.

The emergence of a new strain of coronavirus in late 2019, SARS-CoV-2, led to a global pandemic in 2020. This may have been preventable if large scale, rapid diagnosis of active cases had been possible, and this has highlighted the need for more effective and efficient ways of detecting and managing viral infections. In this work, we investigate three different optical techniques for quantifying the binding of recombinant SARS-CoV-2 spike protein to surface-immobilized oligonucleotide aptamers. Biolayer interferometry is a relatively cheap, robust, and rapid method that only requires very small sample volumes. However, its detection limit of 250 nM means that it is not sensitive enough to detect antigen proteins at physiologically relevant levels (sub-pM). Surface plasmon resonance is a more sensitive technique but requires larger sample volumes, takes longer, requires more expensive instrumentation, and only reduces the detection limit to 5 nM. Surface-enhanced Raman spectroscopy is far more sensitive, enabling detection of spike protein to sub-picomolar concentrations. Control experiments performed using scrambled aptamers and using bovine serum albumin as an analyte show that this apta-sensing approach is both sensitive and selective, with no appreciable response observed for any controls. Overall, these proof-of-principle results demonstrate that SERS-based aptasensors hold great promise for development into rapid, point-of-use antigen detection systems, enabling mass testing without any need for reagents or laboratory expertise and equipment.

Vacuum drying of sorbitol or xylitol‐coated Lactobacillus reuteri LR6 cells and fluidised bed drying with different excipients were compared for the cell viability post‐drying. L. reuteri cells coated with xylitol and desiccated in unsupported form or together with skim milk powder as an excipient were found to be better protected at high drying temperatures. Examination of the protein and polypeptide components of the cell envelopes via Fourier transform infrared spectroscopy revealed different degrees of structural deformation in individual samples, indicating milk solids as supporting excipient and fluidised bed drying helps in retaining high cell viability.

Chemical and physical changes take place when hides and skins are processed to leather that affect the quality and strength of the material. Understanding the structure at each leather-making stage is the basis of this study but also intend to improve the process through a biochemical approach, employing a proteolytic enzyme for processing leather more cleanly with reduced environmental impact. Raman and ATR-FTIR spectroscopy in conjunction with chemometrics was used to investigate each leather-making stage from fresh green cattle hide to dry crust leather. The changes in proteins, lipids, nucleic acids and other biomolecules with leather processing was measured and reported using three novel Raman ratiometric markers, 920/1476, 1345/1259 and 1605/1476 cm-1, to discriminate the structural changes in collagen of hide using standard chemical and enzymatic method. Amide I band was deconvoluted to investigate thecollagen secondary structures using curve fitting by Gaussians function. The results of Principal Component Analysis are well-corroborated with the ratiometric markers of structural changes.

In this work, we introduce a novel joint experimental design and computational analysis procedure to reliably and reproducibly quantify protein analyte binding to DNA aptamer-functionalised silver nanoparticles using slippery surface-enhanced Raman spectroscopy. We employ an indirect detection approach, based upon monitoring spectral changes in the covalent bond-stretching region as intermolecular bonds are formed between the surface-immobilized probe biomolecule and its target analyte. Sample variability is minimized by preparing aptamer-only and aptamer-plus-analyte samples under the same conditions, and then analysing difference spectra. To account for technical variability, multiple spectra are recorded from the same sample. Our new DeltaPCA analysis procedure takes into account technical variability within each spectral data set while also extracting statistically robust difference spectra between data sets. Proof of principle experiments using thiolated aptamers to detect CoV-SARS-2 spike protein reveal that analyte binding is mediated through the formation of N-H...X and C-H...X hydrogen bonds between the aptamer (H-bond donor) and protein (H-bond acceptor). Our computational analysis code can be freely downloaded from https://github.com/dlc62/DeltaPCA.

Carotenoids are powerful antioxidants capable of helping to protect the skin from the damaging effects of exposure to sun by reducing the free radicals in skin produced by exposure to ultraviolet radiation, and they may also have a physical protective effect in human skin. Since carotenoids are lipophilic molecules which can be ingested with the diet, they can accumulate in significant quantities in the skin. Several studies on humans have been conducted to evaluate the protective function of carotenoids against various diseases, but there is very limited published information available to understand the mechanism of carotenoid bioavailability in animals. The current study was conducted to investigate the skin carotenoid level (SCL) in two cattle skin sets - weaners with an unknown feeding regime and New Generation Beef (NGB) cattle with monitored feed at three different ages. Rapid analytical and sensitive Raman spectroscopy has been shown to be of interest as a powerful technique for the detection of carotenoids in cattle skin due to the strong resonance enhancement with 532 nm laser excitation. The spectral difference of both types of skin were measured and quantified using univariate and linear discriminant analysis. SCL was higher in NGB cattle than weaners and there is a perfect classification accuracy between weaners and NGB cattle skin using carotenoid markers as a basis. Further work carried out on carotenoid rich NGB cattle skin of 8, 12 and 24 months of age identified an increasing trend in SCL with age. The present work validated the ability of Raman spectroscopy to determine the skin carotenoid level in cattle by comparing it with established HPLC methods. There is an excellent correlation of R-2 = 0.96 between the two methods that could serve as a model for future application for larger population studies.