C1 C2 C3 Research Articles

Rod Migration into the Posterior Cranial Fossa after C1–C2–C3–C4 Screw Fixation: Case Report and Review of the Literature

AbstractScrew loosening, avulsion, fracture, and rod migration are mechanical complications associated with dorsal fixation of the cervical spine. These usually occur in the late postoperative period and range from 2 to 5%. In this article, we describe a rare case of rod migration into the posterior cranial fossa 4 years after C1–C2–C3–C4 screw fixation in a patient with traumatic fracture of the C2 and C3 vertebrae.

Poly(1-trimethylsilyl-1-propyne) of a <i>cis</i>-Rich Configuration — a Membrane Material for the Separation of Butane/Methane Mixtures as Natural Gas Components

In this work, for the first time, we studied the permeability of individual lower hydrocarbons and in a C1/C4 mixture for films based on PTMSP of a new cis-enriched configurational composition (the content of cis-units in the samples was 80 and 90%). The methane permeability of freshly prepared cis-regular PTMSP films (90% of cis-units) exposed to air for a month is higher than the corresponding values of PTMSP films with 80% cis-units. The X-ray diffraction data indicate a looser packing of the cis-regular PTMSP. The introduction of the antioxidant Irganox 1076 into PTMSP films leads to a decrease in the initial level of the methane flux. At the same time, the permeability of films with the addition of Irganox 1076 over time (within 1 month) decreases much more slowly compared to films without the addition of an antioxidant. The permeability of individual lower hydrocarbons through PTMSP films without and with the addition of Irganox 1076 increases in the order С1 C2 C3 C4. The value of the separation factor in the n-butane/methane mixture reaches 33, which is almost 7 times higher than the selectivity for individual components. The high level of n‑butane permeability of cis-enriched PTMSP is maintained for at least a month of films storage in air.

Clinical and Surgical Characteristics of Patients with Atlantoaxial Dislocation in the Setting of Sandwich Fusion: A Case-Control Analysis of Over 500 Patients with Mid-Term to Long-Term Follow-up.

Patients with "sandwich" fusion (concomitant C1 occipitalization and C2-C3 nonsegmentation), a subtype of Klippel-Feil syndrome, are at particular risk for developing atlantoaxial dislocation (AAD). However, the clinical and surgical characteristics of AAD in patients with sandwich fusion have not been clearly defined. A retrospective case-control study with a large sample size and a minimum 2-year follow-up was performed. From 2000 to 2018, 253 patients with sandwich AAD underwent a surgical procedure; these patients constituted the case group, and a matching number of patients with non-sandwich AAD were randomly selected to form the control group. Clinical data from electronic medical records and various imaging studies were analyzed and compared. The Japanese Orthopaedic Association (JOA) scale was used to evaluate neurological function. Patients with sandwich AAD, compared with patients with non-sandwich AAD, had symptom onset at a younger age (34.8 compared with 42.8 years; p < 0.001) and had a higher likelihood for myelopathy (87.4% compared with 74.7%; p < 0.001). Patients with sandwich AAD had a higher incidence of lower cranial nerve palsy (7.9% compared with 0.0%; p < 0.001), a lower preoperative JOA score (13.4 compared with 14.2; p < 0.001), and higher incidences of accompanying Type-I Chiari malformation (20.9% compared with 1.2%; p < 0.001) and syringomyelia (21.3% compared with 1.6%; p < 0.001). Finally, patients with sandwich AAD had higher likelihoods of undergoing transoral release (28.5% compared with 5.1%; p < 0.001) and use of salvage fixation techniques (34.4% compared with 6.3%; p < 0.001), and had lower postoperative results for the JOA score (14.9 compared with 15.9; p < 0.001) and improvement rate (43.8% compared with 58.2%; p < 0.001). Patients with sandwich AAD demonstrated distinct clinical manifestations. Versatility involving the use of various internal fixation techniques and transoral release procedures was frequently required in the surgical management of these patients, and meticulous and personalized preoperative planning would be of paramount importance. Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

In silico study of CYP450 inhibitor activity of (E)-1-(3-((4-chlorophenyl) diazenyl)-4-hydroxyphenyl)ethanone

Molecular docking and single crystal study of azo dye (E)-1-(3-((4-chlorophenyl)diazenyl)-4-hydroxyphenyl)ethanone (3) is reported here. It has been synthesized by diazotization of 4-chloroaniline followed by coupling with 4-hydroxyacetophenone. Molecule is almost planar with acetyl as well as azo groups only slightly deviating from the plane of C3–C8 phenyl ring as evident by C1–C2–C3–C8 and N2–N1–C7–C6 torsion angles of –3.6(3)° and –3.9(3)°, respectively. Torsion angle N1–N2–C9–C14 between azo group and chlorophenyl ring is somewhat larger being –13.1(3)° leading to torsion angle between phenyl C3–C8 and chlorophenyl C9–C14 ring of 17.26(11)°. Intramolecular O2–H2···N2 hydrogen-bonding is observed here. Pillars along b-axis are formed due to π∙∙∙π stacking interactions of parallel molecules in head-to-head fashion with centroid-to-centroid distance of 3.8829(14) Å and ring slippage of 1.416 Å. Title compound shows good binding affinity towards six enzymes of CYP450 family. Both nitrogens of the azo bond show significant involvement in bonding interactions with proteins in case of all the six enzymes.

S-Shaped Fused Azacorannulene Dimer: Structural and Redox Properties

S-Shaped Fused Azacorannulene Dimer: Structural and Redox Properties

Co-crystals of ethenzamide with 2-nitrobenzoic acid - Conformational analysis, MD simulations and DFT investigations

In crystal engineering and pharmaceutical chemistry, co-crystals have a wide range of applications. Ethenzamide (EA) is found to form co-crystal with 2-nitrobenzoic acid (NBA). Geometry properties like stability energy, charge distribution, bond length, electronic properties and thermodynamic characteristics have been analyzed. The C–H⋯O hydrogen bond involves C–H of EA and oxygen of NBA. Configuration with the angle, N3–C4–C5–C6 gives the lowest energy conformation. Partition coefficient value suggests that EA-NBA has pharmaceutics behavior. RMSD values show the simulation's relative stability and the complexes, remained stable throughout.

Perception evaluation kit: a case study with materials and learning styles.

Materials are elements that configure our built environment and are key components in design and engineering education. This research aims to understand learners’ sensorial perception of materials as stimuli and what constitutes the most appropriate communication channel for learning about their characteristics without losing information in accordance with their VAK learning styles–visual, auditory and kinaesthetic–. Seventy-five people participated in this workshop. Using evaluation tools in a test format, they evaluated all the sensory properties of the following materials: Alusion™, PolarMoss, and Silkworms. These three materials were presented in various interaction formats, called channels: a text plus image–C1–, video–C2–, and a physical sample plus audio–C3–. Two types of experiments were carried out: mixed per person—interaction with the three materials in a different channel each time in random order—and blocked per person—interaction with the same material in the three channels, in an order of C1–C3. The data obtained was analysed using mixed models with the channel as a fixed factor and the individuals and material as the random factors. The most relevant results indicate significant differences between channels in accordance with the sensory property, normally C2 and C3. The level of responses between the two experiments is similar, therefore showing that the order C1–C2–C3 does not affect perception. Although the three learning styles–visual, auditory, and kinaesthetic–coexist in the participants, the vast majority agree that they prefer C3 as easier to evaluate, more entertaining and the best way to learn.

Experimental Measurement of Multiple Hydrate Structure Formation in Binary and Ternary Natural Gas Analogue Systems by Isochoric Equilibrium Methods

Traditionally, it is commonly assumed that a single gas hydrate (or clathrate hydrate) structure/phase is formed in natural gas systems—e.g., “s-II natural gas (NG) hydrates” or “s-I methane hydrates”—based on that which is understood to be the most thermodynamically stable at incipient phase boundary conditions. This applies with respect to both studies of hydrates in natural sediments, and in the case of hydrocarbon production operations, including the testing of low-dosage hydrate inhibitors (LDHIs). Here, we present the results of experimental studies of simple propane (C₃), binary methane–propane (C₁–C₃), and ternary methane–ethane–propane (C₁–C₂–C₃) hydrate systems, aimed at investigating phase behavior at higher subcoolings where significant water conversions to clathrates—and associated gas fractionation—might be expected to result in the formation of more than one hydrate structure. Measurements were made by means of established, reliable, isochoric equilibrium step-heating/cooling approaches. In the single guest propane system, pressure–temperature (PT) conditions follow the gas hydrate phase boundary, in agreement with the univariant hydrate + gas + water (H + G + W) equilibrium. By contrast, binary and ternary mixes clearly show PT behavior consistent with the growth of at least two and four hydrate phases, respectively, with these forming sequentially on cooling, and dissociating in the corresponding reverse order upon heating. In-house hydrate model (HydraFLASH) predictions support experimental observations, pointing to processes being gas fractionation driven; the mixed C₃–C₁ or C₃–C₂–C₁ s-II type hydrates formed first close to the phase boundary preferentially incorporating the most strongly clathrate cage (5¹²6⁴) stabilizing propane, making the remaining gas leaner. Once C₃ is largely consumed, trends agree with less stable C₂–C₁ structures (s-II followed by s-I) then growing (where ethane is present), with this, like C₃ uptake, making remaining free gas increasingly of almost pure C₁. This ultimately drives systems toward the final simple, single guest C₁ s-I clathrate formation as the well-established univariant phase boundary for this structure is reached. As observed phase behavior arises because of gas fractionation, it can be expected to occur during hydrate formation in all mixed gas systems of relatively fixed composition (at constant volume or pressure). The findings highlight that care should be taken in the application of isochoric methods to multicomponent gas systems, given the potential for numerous (rather than just one) clear changes in heating curve slopes as different hydrate structures form/dissociate. In addition, results show that extending equilibrium steps well into the hydrate region can reveal important information on clathrate phase behavior with potentially significant implications for issues such as gas production from hydrates in sediments, hydrate technologies for gas capture/separation/storage in the energy industry, and flow assurance in hydrocarbon production operations.

Two-bond 13C-13C spin-coupling constants in saccharides: dependencies on exocyclic hydroxyl group conformation.

Seven doubly 13C-labeled isotopomers of methyl β-D-glucopyranoside, methyl β-D-xylopyranoside, methyl β-D-galactopyranoside, methyl β-D-galactopyranosyl-(1→4)-β-D-glucopyranoside and methyl β-D-galactopyranosyl-(1→4)-β-D-xylopyranoside were prepared, crystallized, and studied by single-crystal X-ray crystallography and solid-state 13C NMR spectroscopy to determine experimentally the dependence of 2JC1,C3 values in aldopyranosyl rings on the C1-C2-O2-H torsion angle, θ2, involving the C2 carbon of the C1-C2-C3 coupling pathway. Using X-ray crystal structures to determine θ2 in crystalline samples and by selecting compounds that exhibit a relatively wide range of θ2 values in the crystalline state, 2JC1,C3 values measured in crystalline samples were plotted against θ2 and the resulting plot compared to that obtained from density functional theory (DFT) calculations. For θ2 values ranging from ∼90° to ∼240°, very good agreement was observed between the experimental and theoretical plots, providing strong validation of DFT-calculated spin-coupling dependencies on exocyclic C-O bond conformation involving the central carbon of geminal C-C-C coupling pathways. These findings provide new experimental evidence supporting the use of 2JCCC values as non-conventional spin-coupling constraints in MA'AT conformational modeling of saccharides in solution, and the use of NMR spin-couplings not involving coupled hydroxyl hydrogens as indirect probes of C-O bond conformation. Solvomorphism was observed in crystalline βGal-(1→4)-βGlcOCH3 wherein the previously-reported methanol solvate form was found to spontaneously convert to a monohydrate upon air-drying, leading to small but discernible conformational changes in, and a new crystalline form of, this disaccharide.

Alternations in Enzyme Activities of Clarias gariepinus Infected with Aeromonas hydrophila and Pseudomonas aeruginosa

Clarias gariepinus were infected with Aeromonas hydrophila and Pseudomonas aeruginosa, and blood samples were collected weekly for biochemical analysis to analyse their enzyme activities and pathogenesis for four weeks. The enzymes includes: aspartate aminotransferase (AST), alkaline phosphastase (ALP), acid phosphastase (ACP) and lactate – dehydrogenase (LDH). The fish were distributed in three different groups in triplicates as: control (C1 C2 C3), A. hydrophila (A1, A2, A3) and P. aeruginosa (P1, P2, P3). After two weeks of acclimatization, A1 – A3 were injected with 1.5 ml of 106 cfu/ml of A. hydrophila, P1-P3 were injected with 1.5 ml of 106 cfu/ml of P. aeruginosa, while C1-C3 were pathogen free. At the end of the experiment, it was observed that there was a constant increase, in the enzyme activities of the infected fish, indicating increase in virulence with respect to weeks of exposure but P. aeruginosa had higher pathogenicity compared to A. hydrophila.

Safety and Efficacy of Posterior Atlanto-Axial Stabilization Using Intraoperative Navigation System with Preoperative Computed Tomographic Scan

Surgical approaches for posterior C1-C2 arthrodesis, such as C1-C2 transarticular and C1-C2 screw stabilization, are known to be demanding because of the anatomic close proximity of cervical vertebrae to neurovascular structures. Currently, navigation by fluoroscopy or intraoperative computed tomography (ICT) is the standard practice. However, fluoroscopy has various limitations, and ICT is time consuming and not available in many centers; furthermore, both diagnostic tools lead to exposure of the operating room staff to radiation exposure. We evaluate the safety, efficacy, and facility of a navigation system using only preoperative cervical computed tomography and computed tomographic angiography (CT/CTA), to prevent the risk of neurovascular damage in atlantoaxial stabilization. The authors report a series of 21 patients who underwent posterior upper cervical spine fixation using a navigation system with intraoperative single-level vertebral registration on preoperative cervical CT/CTA (software BrainLab IPlan Spine 3.0). Intraoperative and postoperative comparative analysis was performed to verify the correspondence between the virtual anatomic position of the surgical instruments and screws represented on the neuronavigator, and the actual positions verified intraoperatively and on postoperative CT. Thirteen patients underwent C1-C2 arthrodesis with a Harms construct, 1 patient with transarticular screw fixation and 4 patients with occipitocervical stabilization. Three patients underwent C1-C2-C3 stabilization with C1 hooks, C2-C3 screws, and rod construct. On postoperative CT, the position of all screws appeared satisfactory. No neurovascular damage occurred in any patients. The use of a neuronavigation system, based on preoperative acquired cervical CT and intraoperative single-vertebra registration, may provide a valuable support for the improvement of the surgical accuracy of posterior C1-C2 screw fixation.

Formation mechanism of hydroxyacetone in glucose pyrolysis: A combined experimental and theoretical study

During fast pyrolysis of biomass, hydroxyacetone (HA, also known as 1-hydroxy-2-propanone) is a vital linear ketone product from fragmentation (ring scission) of cellulose. In this study, density functional theory (DFT) calculations are employed to reveal the HA formation mechanisms and pathways from fast pyrolysis of glucose that is the cellulose-based monosaccharide. Moreover, isotopic labeling fast pyrolysis experiments were conducted to confirm the theoretical calculation results from glucose. The results indicate that during glucose pyrolysis, HA is mainly derived from C1–C2–C3 and C4–C5–C6 segments, with C1 or C6 in the methyl group of HA. The HA from C1–C2–C3 is mainly generated via the 3-ketohexose intermediate, while the formation of the HA from C4–C5–C6 mainly involves the d-fructose intermediate. In addition, the formation of HA is parallel and competitive with the formation of levoglucosan (LG, the most important pyrolytic product of glucose), and the secondary decomposition of LG will result in trace of the HA from C4–C5–C6.

Quantitative Theoretical Predictions and Qualitative Bonding Analysis of the Divinylborinium System and Its Al, Ga, In, and Tl Congeners.

A substituted divinylborinium cation was synthesized recently and characterized crystallographically as a gauche structure with a 153° C1-C2-C3-C4 dihedral angle. A full theoretical geometrical optimization of the bis(2-mesityl-1,2-diphenylvinyl)-borane cation shows excellent agreement with the crystal structure. However, for the parent unsubstituted divinylborinium cation, we predict a nearly 90° C1-C2-C3-C4 dihedral angle using the CCSD(T)/cc-pVTZ coupled cluster method. The cis and trans planar geometries (0° and 180° for the C1-C2-C3-C4 dihedral angle) proved to be transition states with energy barriers of 2.8 and 2.3 kcal/mol, respectively, with respect to unimolecular conversion to the gauche equilibrium. The structures of the heavier boron group cations (Al, Ga, In, and Tl) have also been investigated here, finding even lower energy barriers (0.3-0.7 kcal/mol). After the ZPVE corrections, the barriers are further decreased. The torsional angles for the unknown Al, Ga, In, and Tl dimesityl substituted compounds should be somewhat less than 153°. Many of these findings may be understood in terms of qualitative electronic structure theory. The torsional folding of borane complex, including cationic divinylborinium and elementary vinylborane (C2H3BH2) or chlorovinylborane (C2H3BHCl) precursors, are investigated with natural bond orbital (NBO) analysis to unveil the electronic origins of the torsional properties. The NBO-based descriptors are employed to systematically deconstruct complex torsional dependence into a balanced portrayal of hyperconjugative and steric effects.

Chemical kinetics evaluation and its application of natural gas generation derived from the Yacheng Formation in the deep-water area of the Qiongdongnan Basin, China

The natural gas generation process is simulated by heating source rocks of the Yacheng Formation, including the onshore-offshore mudstone and coal with kerogens of Type II2-III in the Qiongdongnan Basin. The aim is to quantify the natural gas generation from the Yacheng Formation and to evaluate the geological prediction and kinetic parameters using an optimization procedure based on the basin modeling of the shallow-water area. For this, the hydrocarbons produced have been grouped into four classes (C1 C2 C3 and C4-6). The results show that the onset temperature of methane generation is predicted to occur at 110°C during the thermal history of sediments since 5.3 Ma by using data extrapolation. The hydrocarbon potential for ethane, propane and heavy gaseous hydrocarbons (C4-6) is found to be almost exhausted at geological temperature of 200°C when the transformation ratio (TR) is over 0.8, but for which methane is determined to be about 0.5 in the shallow-water area. In contrast, the end temperature of the methane generation in the deep-water area was over 300°C with a TR over 0.8. It plays an important role in the natural gas exploration of the deep-water basin and other basins in the broad ocean areas of China. Therefore, the natural gas exploration for the deep-water area in the Qiongdongnan Basin shall first aim at the structural traps in the Ledong, Lingshui and Beijiao sags, and in the forward direction of the structure around the sags, and then gradually develop toward the non-structural trap in the deep-water area basin of the broad ocean areas of China.

Surgical treatment of C2 hangman’s fracture

Purpose. To evaluate the treatment efficacy in patients with C2 hangman’s fracture. Materials and methods. During the period from 2012 to2015 in the Regional Neurosurgical Department 5 patients with hangman’s fracture of C2 vertebra underwent surgery (3 males and 2 females). Fracture type II was diagnosed in 2 patients, IIа type — in 2 persons, type III — in 1 patient. All patients had such clinical symptoms as cervicalgia, deteriorating on the movement. Four patients underwent transpedicular stabilization of C1—C2–C3 with skeletezation of lateral mass, one patient had a combination of posterior instrumentation with anterior plating C2–C3 by Medtronic Atlantis. Posterior stabilization was achieved by Medronic Vertex system. Results. During the operation, all patients achieved fusion of an injured segement. The patients were activated the same or next day after surgery. The volume of rotational motion in craniovertebral junction was limited to 180є—200є, but this did not worse the quality of life of the (VAS 8.9 and 2.3, NDI 80.6—19.6 % before and within the investigation, respectively). CT control was performed in 6 months. Fracture healing and the complete stability of the damaged segment were achieved in 6 months. Conclusions. Surgical treatment of C2 hangman’s fractures by posterior transpedicular/transarticular or anterior-posterior stabilization is a high-effective method for rapid restoration of ordinary physically active social life.

Contourite vs gravity-flow deposits of the Pleistocene Faro Drift (Gulf of Cadiz): Sedimentological and mineralogical approaches

Pleistocene succession at Sites U1386 and U1387 (IODP 339) from palaeo-moat and drift domains of the Faro Drift has been examined to characterize the lithofacies and to identify the most useful criteria for distinguishing between contourite and gravity-flow deposits. Three lithofacies, A, B, and C, are defined based on a combination of sedimentological and mineralogical analyses. The dominant lithofacies A corresponds to contourite deposits; lithofacies B and C comprise turbidites and debrites respectively. Three main criteria have been utilized to distinguish between these deposits: (i) the vertical trend of the grain-size and the sedimentary structures. The contourites show complete sequences (C1 to C5 divisions) and truncate sequences (basecut-out divisions, e.g., C3–C2–C1, and C3). The turbidites display mainly Td–Te divisions, although Tc division is also present to a lesser extent. The debrites display deformational and shearing structures; (ii) the modal frequency distribution. The contourite sequences show similar mode grain-size values in different textures suggesting that the steady conditions of supply are maintained over time. In contrast, turbidite and debrite sequences display different modes, primarily conditioned by mixing of components from allochthonous sources and their downslope gravitational transport; (iii) the sediment composition (clay mineral, bulk mineral and sand fraction) and provenance that reflect long- and short-distance transport modes. Most of the terrigenous components of the contourites come from the Guadalquivir drainage basin, whereas for the turbidites and debrites these are sourced from the neighbouring fluvial drainage basins (Guadiana, Tinto-Odiel). The biogenic components in the latter indicate shallow depositional environments prior to seafloor failure. The spatial and temporal distributions of the lithofacies reflect the different (palaeo) environments of the Faro Drift. Debrite and incomplete turbidite sequences characterize the palaeo-moat domain during the Early Pleistocene. Complete contourite sequences (C1 to C5) and basecut-out sequences (C3–C4–C5, and C3) characterize the proximal palaeo-drift domain during the Early and Middle Pleistocene and the complete contourite sequences represent the distal drift domain during the Late Pleistocene.

Nonadiabatic ab initio molecular dynamics of photoisomerization reaction between 1,3-cyclohexadiene and 1,3,5-cis-hexatriene

The photoisomerization process between 1,3-cyclohexadiene (CHD) and 1,3,5-cis-hexatriene (HT) has been studied by nonadiabatic ab initio molecular dynamics based on trajectory surface-hopping approach with a full-dimensional reaction model. The quantum chemical calculations were treated at MS-MR-CASPT2 level for 8 electrons in 8 orbitals with the cc-pVDZ basis set. The Zhu–Nakamura formula was employed to evaluate nonadiabatic transition probabilities. S1 and S2 states were included in the photoisomerization dynamics. Lifetimes and CHD:HT branching ratios were computationally estimated on the basis of statistical analysis of multiple executed trajectories. The analysis of trajectories suggested that the nonadiabatic transitions at the S0/S1 and S1/S2 conical intersections (CoIn) are correlated to the Kekulé-type vibration and the C3–C4–C5 bending motion, respectively. The one-sided branching ratio was obtained by excitations to the S2 state; 70:30. The critical branching process was found to be dominated by the location of CoIn in potential energy hypersurface of the excited state.

Near-silence of isothiocyanate carbon in (13)C NMR spectra: a case study of allyl isothiocyanate.

(1)H and (13)C NMR spectra of allyl isothiocyanate (AITC) were measured, and the exchange dynamics were studied to explain the near-silence of the ITC carbon in (13)C NMR spectra. The dihedral angles α = ∠(C1-C2-C3-N4) and β = ∠(C2-C3-N4-C5) describe the conformational dynamics (conformation change), and the bond angles γ = ∠(C3-N4-C5) and ε = ∠(N4-C5-S6) dominate the molecular dynamics (conformer flexibility). The conformation space of AITC contains three minima, Cs-M1 and enantiomers M2 and M2'; the exchange between conformers is very fast, and conformational effects on (13)C chemical shifts are small (νM1 - νM2 < 3 ppm). Isotropic chemical shifts, ICS(γ), were determined for sp, sp(x), and sp(2) N-hybridization, and the γ dependencies of δ(N4) and δ(C5) are very large (10-33 ppm). Atom-centered density matrix propagation trajectories show that every conformer can access a large region of the potential energy surface AITC(γ,ε,...) with 120° < γ < 180° and 155° < ε < 180°. Because the extreme broadening of the (13)C NMR signal of the ITC carbon is caused by the structural flexibility of every conformer of AITC, the analysis provides a general explanation for the near-silence of the ITC carbon in (13)C NMR spectra of organic isothiocyanates.

SHADOW DETECTION USING COLOR AND EDGE INFORMATION

Shadows appear in many scenes. Human can easily distinguish shadows from objects, but it is one of the challenges for shadow detection intelligent automated systems. Accurate shadow detection can be difficult due to the illumination variations of the background and similarity between appearance of the objects and the background. Color and edge information are two popular features that have been used to distinguish cast shadows from objects. However, this become a problem when the difference of color information between object, shadow and background is poor, the edge of the shadow area is not clear and the shadow detection method is supposed to use only color or edge information method. In this article a shadow detection method using both color and edge information is presented. In order to improve the accuracy of shadow detection using color information, a new formula is used in the denominator of original c1 c2 c3. In addition using the hue difference of foreground and background is proposed. Furthermore, edge information is applied separately and the results are combined using a Boolean operator.

Batch fermentative hydrogen production by enriched mixed culture: Combination strategy and their microbial composition

The effect of individual and combined mixed culture on dark fermentative hydrogen production performance was investigated. Mixed cultures from cow dung (C1), sewage sludge (C2), and pig slurry (C3) were enriched under strict anaerobic conditions at 37°C with glucose as the sole carbon source. Biochemical hydrogen production test in peptone-yeast-glucose (PYG) and basal medium was performed for individual mixed cultures (C1, C2 and C3) and their combinations (C1-C2, C2-C3, C1-C3 and C1-C2-C3) at a glucose concentration of 10 g/L, 37°C and initial pH 7. Maximum hydrogen yields (HY) of 2.0 and 1.86 [Formula: see text] by C2, and 1.98 and 1.95 mol(H2)/mol(glucose) by C2-C3 were obtained in PYG and basal medium, respectively. Butyrate and acetate were the major soluble metabolites produced by all the cultures, and the ratio of butyrate to acetate was ∼2 fold higher in basal medium than PYG medium, indicating strong influence of media formulation on glucose catabolism. The major hydrogen-producing bacterial strains, observed in all mixed cultures, belonged to Clostridium butyricum, C. saccharobutylicum, C. tertium and C. perfringens. The hydrogen production performance of the combined mixed culture (C2-C3) was further evaluated on beverage wastewater (10 g/L) at pH 7 and 37°C. The results showed an HY of 1.92 mol(H2)/mol(glucose-equivalent). Experimental evidence suggests that hydrogen fermentation by mixed culture combination could be a novel strategy to improve the HY from industrial wastewater.