Hydrothermal upgrading of wood biomass: Influence of the addition of K2CO3 and cellulose/lignin ratio

The hydrothermal treatment of two different wood biomass samples such as cherry (hard wood) and cypress (soft wood), whose composition is different i.e. lignin, cellulose and hemicellulose were performed at 280 °C for 15 min with aq. K₂CO₃ with different concentrations (0–1 M). The soft wood biomass contains higher lignin content than hard wood biomass. The cellulose rich cherry wood biomass produced higher proportion of acetic acid than cypress. The lignin rich cypress produced the hydrocarbons with major portion of phenolic hydrocarbons and derivatives than cherry. The total oil yields from both cherry and cypress wood biomass produced 50 wt% of liquid hydrocarbons at 280 °C for 15 min with 0.5 M K₂CO₃ solution. The volatility distribution of liquid hydrocarbons showed the characteristic features of soft and hard wood biomasses.     

Transiliac catheterization of the inferior vena cava for long-term venous access in children

In infants and children requiring prolonged, multiple central venous (CV) catheterizations, the superior (SVC) and inferior vena cava may become thrombosed or stenotic, making CV access a difficult problem. Use of the iliac vein may be an acceptable alternative. We report a patient with thrombosis of the SVC in whom the external iliac vein was accessed through a retroperitoneal approach for placement of an implantable port. This technique is easy to perform, and there are no special materials or patient positioning required.     

Composition of organic and conventionally produced sunflower seed oil

The aim of the present study was to highlight the main differences between seed oils produced from conventionally cultivated crops and organically cultivated ones and processed using mild extraction procedures. The composition and the nutritional and health aspects of both types of sunflower seed oils were compared and were analytically tested to determine the macroscopic differences in proximate composition, the main differences in the minor components, the main quality parameters, the in vitro antioxidant activity, and the presence of trans-ethylene steroisomers in FA. No significant trends were found in the oil samples for TAG and FA composition, but remarkable differences were found in the composition of minor components and in the main chemical and analytical quality properties. The organically grown samples had a higher total antioxidant activity compared with the conventional samples. Trans FA were found only in the conventional oils.     

Chain Vacancies in 2D Crystals

Defects in bulk crystals can be classified into vacancies, interstitials, grain boundaries, stacking faults, dislocations, and so forth. In particular, the vacancy in semiconductors is a primary defect that governs electrical transport. Concentration of vacancies depends mainly on the growth conditions. Individual vacancies instead of aggregated vacancies are usually energetically more favorable at room temperature because of the entropy contribution. This phenomenon is not guaranteed in van der Waals 2D materials due to the reduced dimensionality (reduced entropy). Here, it is reported that the 1D connected/aggregated vacancies are energetically stable at room temperature. Transmission electron microscopy observations demonstrate the preferential alignment direction of the vacancy chains varies in different 2D crystals: MoS₂ and WS₂ prefer direction, while MoTe₂ prefers direction. This difference is mainly caused by the different strain effect near the chalcogen vacancies. Black phosphorous also exhibits directional double‐chain vacancies along 〈01〉 direction. Density functional theory calculations predict that the chain vacancies act as extended gap (conductive) states. The observation of the chain vacancies in 2D crystals directly explains the origin of n‐type behavior in MoTe₂ devices in recent experiments and offers new opportunities for electronic structure engineering with various 2D materials.     

A Droplet‐Based High‐Throughput SERS Platform on a Droplet‐Guiding‐Track‐Engraved Superhydrophobic Substrate

A novel droplet‐based surface‐enhanced Raman scattering (SERS) sensor for high‐throughput real‐time SERS monitoring is presented. The developed sensors are based on a droplet‐guiding‐track‐engraved superhydrophobic substrate covered with hierarchical SERS‐active Ag dendrites. The droplet‐guiding track with a droplet stopper is designed to manipulate the movement of a droplet on the superhydrophobic substrate. The superhydrophobic Ag dendritic substrates are fabricated through a galvanic displacement reaction and subsequent self‐assembled monolayer coating. The optimal galvanic reaction time to fabricate a SERS‐active Ag dendritic substrate for effective SERS detection is determined, with the optimized substrate exhibiting an enhancement factor of 6.3 × 10⁵. The height of the droplet stopper is optimized to control droplet motion, including moving and stopping. Based on the manipulation of individual droplets, the optimized droplet‐based real‐time SERS sensor shows high resistance to surface contaminants, and droplets containing rhodamine 6G, Nile blue A, and malachite green are successively controlled and detected without spectral interference. This noble droplet‐based SERS sensor reduces sample preparation time to a few seconds and increased detection rate to 0.5 µ L s^?1 through the simple operation mechanism of the sensor. Accordingly, our sensor enables high‐throughput real‐time molecular detection of various target analytes for real‐time chemical and biological monitoring.     

Cu-NMR study on high-T c cuprate La1.89Ca1.11Cu2O6+δ (La2126)

Cu-NMR spectra and the nuclear spin-lattice relaxation rate T ₁ ^-1 have been studied intensively on the bilayer type high-T_c cuprate La_1.89Ca_1.11Cu₂O₆₊ (La2126). The resonance line shift showed a monotonic decrease with lowering temperature in the normal state, indicating that this compound belongs to the lightly-doped region. The Curie-Weiss temperature dependence of (T₁T)^–1 in the normal state shows that the pseudo spin-gap does not always exist in the light-doped bilayer systems.     

Enzymatic Analysis of Positional Distribution of Fatty Acids in Solid Fat by 1,3-Selective Transesterification with Candida antarctica Lipase B

A protocol for the analysis of the positional distribution of fatty acids (FA) in solid triacylglycerols (TAG) was developed using sn-1(3) selective alcoholysis catalyzed by immobilized Candida antarctica lipase B (CALB). One part by weight of solid fat and ten parts by weight of ethanol (99.5 %) were warmed to liquefy the fat. After adding 0.44 parts by weight of CALB, the mixture was shaken at 50 °C for 10 min then at 30 °C for 2.8 h. The recovery of 2-MAG after the 3-h transesterification reaction was ca. 85 % of the maximum theoretical yield (33 mol%), with the loss of 15 % attributable to the acyl migration from sn-2 to sn-1(3). The recovery was similar to that of the solvent-free alcoholysis of structured lipids, 1,3-dipalmitoyl, 2-oleoyl glycerol and 1,3-dioleoyl, 2-palmitoyl glycerol, conducted at 30 °C for 3 h. In contrast, the acyl migration from sn-1(3) to sn-2 was hardly observed. Because the detected acyl migration was only in the direction of sn-2 to sn-1(3), and not vice versa, it is proposed to determine the FA composition of the sn-2 position of TAG by the gas chromatographic analysis of 2-MAG fraction recovered from the enzymatic reaction mixture, and the FA composition of sn-1(3) position by a mass balance using the FA composition of TAG and of the sn-2 position as inputs. The procedure was successfully applied to palm oil and shea butter, and docosahexaenoic acid (DHA)-rich single cell oil from Aurantiochytrium sp. KH105 for the first time.     

Antiferromagnetic Transition in Sr14−x Ca x Cu24O41 Investigated by Specific Heat Measurements

Results for low temperature specific heat for single crystals of ladder/chain materials Sr _14–x Ca _x Cu ₂₄ O ₄₁ (x= 0, 8, 10, 11.5) in magnetic field up to 15 T are reported. A sharp peak of the specific heat of a single crystal Sr _2.5 Ca _11.5 Cu ₂₄ O ₄₁, was found at 2.3 K, clearly indicating the onset of a long range order. In measurements of the specific heat in magnetic fields the transition temperature, T _N , was found to shift to lower temperatures with increasing magnetic field, indicating that the ordering is antiferromagnetic, which has been confirmed by neutron scattering measurements. With decreasing x T _N rapidly shifts to lower temperatures. For x=10 T _N decreases to 1 K and for x= 0 no anomaly indicating the transition was found down to 0.6K     

Dynamic finite element simulation of the gunshot injury to the human forehead protected by polyvinyl alcohol sponge

Although there are some traditional models of the gunshot wounds, there is still a need for more modeling analyses due to the difficulties related to the gunshot wounds to the forehead region of the human skull. In this study, the degree of damage as a consequence of penetrating head injuries due to gunshot wounds was determined using a preliminary finite element (FE) model of the human skull. In addition, the role of polyvinyl alcohol (PVA) sponge, which can be used as an alternative to reinforce the kinetic energy absorption capacity of bulletproof vest and helmet materials, to minimize the amount of skull injury due to penetrating processes was investigated through the FE model. Digital computed tomography along with magnetic resonance imaging data of the human head were employed to launch a three-dimensional (3D) FE model of the skull. Two geometrical shapes of projectiles (steel ball and bullet) were simulated for penetrating with an initial impact velocity of 734 m/s using nonlinear dynamic modeling code, namely LS-DYNA. The role of the damaged/distorted elements were removed during computation when the stress or strain reached their thresholds. The stress distributions in various parts of the forehead and sponge after injury were also computed. The results revealed the same amount of stress for both the steel ball and bullet after hitting the skull. The modeling results also indicated the time that steel ball takes to penetrate into the skull is lower than that of the bullet. In addition, more than 21 % of the steel ball’s kinetic energy was absorbed by the PVA sponge and, subsequently, injury sternness of the forehead was considerably minimized. The findings advise the application of the PVA sponge as a substitute strengthening material to be able to diminish the energy of impact as well as the load transmitted to the object.