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With the advancement of genetic engineering, monoclonal antibodies (mAbs) have made far-reaching progress in the treatment of various human diseases. However, due to the high cost of production, the increasing demands for antibody-based therapies have not been fully met. Currently, mAb-derived alternatives, such as antigen-binding fragments (Fab), single-chain variable fragments, bispecifics, nanobodies, and conjugated mAbs have emerged as promising new therapeutic modalities. They can be readily prepared in bacterial systems with well-established fermentation technology and ease of manipulation, leading to the reduction of overall cost. This review aims to shed light on the strategies to improve the expression, purification, and yield of Fab fragments in Escherichia coli expression systems, as well as current advances in the applications of Fab fragments.

In addition to the vibration loads caused by offshore structure construction, the offshore foundation pit can also be affected by additional hydraulic loads such as waves, tides, and typhoons, hindering our understanding of the mechanical performance of the foundation pit supporting structure. In order to illuminate this mechanical performance under waves, tides, hammering, and unbalanced loads, this paper analyzed the supporting structure with theoretical and numerical simulations. The results were verified with field monitoring data. Moreover, the influences of loads, including construction vibration loads and unbalanced loads, on structure and soil were discussed. By applying these results to the engineering design, this research could provide a reference for studying mechanical properties of relevant supporting structures and the construction of offshore foundation pits.

Three new diterpenes, xishacorenes A–C, featuring an undescribed bicyclo[3.3.1]nonane nucleus bearing 1-vinyl and 13-[(E)-4-methylpenta-1,3-dien-1-yl] alkyl chains, and a related monocyclic known compound, were isolated from the Xisha soft coral Sinularia polydactyla. The structures of xishacorenes A–C, including their absolute configurations, were elucidated by extensive spectroscopic analysis and TDDFT ECD calculations. The new compounds exhibit an interesting dose-dependent promotion effect on the ConA-induced T lymphocyte proliferation. A plausible biosynthetic pathway of xishacorenes A–C is proposed.

Detailed numerical analysis was conducted to explore the in∞uences of segments cracks on dynamic response of shield tunnel in operation. Three-dimensional solid elements are adopted to stimulate lining structures; Goodman elements and connecting springs were respectively applied to stimulate cracks and joints. Dynamic responses of shield tunnel with cracks under train moving loads were discussed. Research shows that the in∞uences on displacement response of segment are very tiny, while stress responses are signiflcantly impacted by the cracks. Stress responses of segments greatly change in the cracking. So cracks should be fully considered. Distribution of deformation and stress of cracking side are obviously difierent from non-cracking side, and therefore using single-plane stress elements to simulate segments is not adequate. The re∞ection of vibration wave enhances and dynamic response is more intense in the cracking. The intense response area of ground is mainly in a certain range that around the tunnel. The closer to the bottom of lining segment, the more intense the response is.

In order to explore the immersed tunnel foundation treated by sand-flow method, modeling principles for the full-scale model test of sand flow were put forward. In addition, a sand-flow test model was built, which consisted of model system, equipment system and measurement system. The situation of sand-deposit expanding and the water pressure in the foundation trench were evaluated through the model test. The results show that a semi-closed space was formed between the model board and the expanding sand deposit, which made the water pressure in it rising with little range of volatility. The sand deposit gradually became non-circular truncated cone which shaped with its expanding radius, and the difference of the water pressure increased at each direction. The water pressure in crater had a linear increase with the sand-deposit radius, with a maximal value of 0.015 2 MPa. The volatility of the water pressure under the tunnel board and the water pressure value in the crater could be used as bases of construction control.

A three-dimensional refined model of composite lining is built with the example of shield tunnel of Xijiang water diversion project in Guangzhou by using finite element software. Segment opening and steel pile deformation characteristics are analyzed. Necessity of light material and steel pile is detailed explained. The results show that the maximal segment opening of composite lining is 0.361 millimeter. The bolts are in elastic state and not appear plastic deformation, so segment without leakage. Steel pipe strain curve is approximate circular symmetry in whole circle. It is necessary to add light material and steel pile, because they can effectively reduce the stress of concrete and prevent cracking.

The profile layout rationality and internal stress structure of a large-section cable tunnel and a cable-laying scheme at splicing locations were studied through full-scale model test. The full scale shield tunnel which the diameter was 6m was built on the ground. The model tests test the displacement of cable bearers, the coupling area between horizontal beam and steel ring, the coupling area between horizontal beam and steel pillar, edge beam and center beam under design loads, and the safety and reliability of an arc steel framing system that supports the cable load inside the cable tunnel during the operation stage were demonstrated. The cable-laying schemes for the cross section and straight-through-type and T-type couplings of a large-section cable tunnel were optimized through experiment on actually laid-out cables. For the section layout of a large-section cable tunnel, it is believed that the double-deck scheme prevails over the single-deck scheme, and such a cable-splicing scheme can meet the cable-laying requirement.

The finite element software ADINA was employed in this paper to study the ventilation effect of a large cross-section cable tunnel by using a computational fluid dynamics method. The temperature and ventilation zoning inside a cable tunnel were determined according to the characteristics of the large cross-section cable tunnel. With the ambient tunnel characteristics and tunnel cross-section layout being taken into consideration, a three-dimensional model for large cross-section cable tunnels was established; the computations indicate that the main influential factors of ventilation effect of large cross-section cable tunnels are intake airflow rate, intake air temperature, exhaust airflow rate, ventilation duration, tunnel length, fire door layout, and so on. The average air velocity in the tunnel was about 60 % of the intake airflow rate. The intake air temperature has much impact on tunnel temperature distribution within a range of 30 m away from the tunnel origin, as shown by a significant cooling effect when intake air temperature falls; whereas the intake air temperature has less impact on tunnel temperature distribution beyond 30 m from the tunnel origin.

In this study, the authors present a novel proof on the maximal rates of space-time block codes from complex orthogonal design (COD). The method of the proof is derived from an observation about the CODs, which reveals some inherent laws of their structure. The proof is applicable to any CODs, rather than to some specific designs, and does not need any auxiliary matrix or matrix transformation. The conclusion in this study also indicates that the upper bound of the CODs’ rate conjectured by the authors is tight and achievable.

Ramoplanins are lipopeptides effective against a wide range of Gram-positive pathogens. Ramoplanin A2 is in Phase III clinical trials. The structure-activity relationship of the unique 2Z,4E-fatty acid side-chain of ramoplanins indicates a significant contribution to the antimicrobial activities but ramoplanin derivatives with longer 2Z,4E-fatty acid side-chains are not easy to obtain by semi-synthetic approaches. To construct a strain that produces such analogues, an acyl-CoA ligase gene in a ramoplanin-producing Actinoplanes was inactivated and a heterologous gene from an enduracidin producer (Streptomyces fungicidicus) was introduced into the mutant. The resulting strain produced three ramoplanin analogues with longer alkyl chains, in which X1 was purified. The MIC value of X1 was ~0.12 μg/ml against Entrococcus sp. and was also active against vancomycin-resistant Staphylococcus aureus (MIC = 2 μg/ml).

Ramoplanins produced by Actinoplanes are new structural class of lipopeptide and are currently in phase III clinical trials for the prevention of vancomycin-resistant enterococcal infections. The depsipeptide structures of ramoplanins are synthesized by non-ribosomal peptide synthetases (NRPS). Romo-orf17, a stand-alone NRPS, is responsible for the recruitment of Thr into the linear NRPS pathways for which the corresponding adenylation domain is absent. Here, systematical gene inactivation and complementation have been carried out in a Actinoplanes sp. using homologous recombination and site-specific integration methods. A hybrid gene coding for the N-terminal region of the stand-alone NRPS and the A-PCP domains of a heterologous NRPS restored production of ramoplanins. The results elucidate the unusual N-terminal region which is essential for the biosynthesis of ramoplanins.

A compound method which includes overall site stability analysis, stratum stability analysis on deep excavation boundary and 3D FEM is proposed to evaluate the effect of building settlement due to adjacent deep excavation. A typical deep excavation project was used to evaluate the feasibility of the compound method. The analysis results indicate the ground stability analysis is useful to understand the stratum situation of deep excavation and adjacent area. In 3D FEM, undulate stratum can simulate the supporting system of more accurately. The compound method brings a new analysis method for foundation pit project in complex environment and complex geological conditions.

The studies carried out to appropriate slope ratio for underwater trench of immersed tunnel of Hongkong-Zhuhai-Macau Bridge. A test trench of 100-meter-long and 21-meter-width was excavated under Lingding Ocean along designed axis of immersed tunnel. The trench includes four slope ratio, such as 1:5, 1:6, 1:8 and 1:10. Two actual measurement which includes multibeam measurement and single beam double frequency measurement were used to measure water depth and section form in different time. It is recommended that slope ratio 1:6 can be adopted for underwater trench of immersed tunnel of HZM Bridge.

In this paper, the influence of different sintering temperatures on the microstructure, density, shrinkage and final phase content of hydroxyapatite-zirconia (HA-ZrO2) composites was studied. Composites of hydroxyapatite with 3 mol% Y2O3stabilized zirconia with MgO were sintered between 1100 °C and 1400 °C. The reaction and the transformation of phases were investigated by X-ray diffraction and FTIR spectroscopic measurements. Those results indicated that the processes of HA dehydroxylation were found, the mean grain size of the sample sintered was varied from 1.2 µm to 5.3 µm. Dimension shrinkage increased to 0.24% as the sintered temperature increased from 1100 °C to 1400 °C, the bulk density increased monotonically to 95.6% with increasing temperature up to 1400 °C.

Guangzhou Xita Project uses a special exterior frame which consists of huge inclining concrete-filled columns. To ensure the engineering quality and select the suitable concrete-filled steel tube column structure, two concrete-filled steel tube column structure experiments have been carried out. To ensure the quality of the concrete-filled steel tube column structure experiment, the C100, C90 and C70 high performance concrete experimental research have been done specially, and the result of the experimental researches has been used in concrete-filled steel tube column structure sample successfully. The raw materials, mixture proportions and performance of the high performance concrete were discussed in this paper.

The chloride-resistant high performance concrete to be used is a basic technology to increase its durability in high chloride-ion environment. On the base of “Application technology guide for anti-seawater concrete of Guangdong province” (consultant version), the raw materials, mix proportion, placement of concrete, and the quality tests etc were discussed in detail.

With the wide application of pumping concrete， and the increasing of pumping height and distance， more and more attention of researchers focus on the workability of pumping concrete. Traditionally， the research method of workability of pumping concrete is mainly experiment. With the increasing of pumping height and distance，experimental method for workability of pumping concrete becomes more difficult. Combining simulation computation and experimental method to solve pumping construction problems of concrete under complicated conditions is a feasible method. Research progress about experimental method and simulation computation of workability of pumping concrete are presented， which would provide research thinking and research method for combining simulation computation and experimental method.

In this paper, a 3D finite element (FE) program ADINA was applied to analyzing a tunnel with 9 segment rings. The loads acting on these segment rings included the squeezing action of tail brush of shield machine under attitude deflection, the jacking forces, the grouting pressure and the soil pressure. The analyses focused on the rebar stress in two statuses: (1) normal construction status without shield machine squeezing; (2) squeezing action induced by shield machine under attitude deflection. The analyses indicated that the rebar stress was evidently affected by the construction loads. In different construction status, the rebar stress ranges from −80 MPa to 50 MPa, and the rebar is in elastic status. Even some cracks appear on segments, the stress of segment rebar is still at a low level. It is helpful to incorporate a certain quantity of steel fiber to improve the anti-crack and shock resistance performance.

The bioactivity of potassium titanate whiskers (PTW) was evaluated by soaking in simulated body fluids (SBF, Kokubo solution). At first, PTW was chemically treated by 1 M HCl and 1 M NaOH solutions at 60 oC for 48 h, respectively. Then PTW before and after treated were soaked in SBF solution and cultured at 37 oC for different times. The apatite deposit on PTW was examined by FTIR and SEM/EDX. The results showed that there was not apatite deposit on the raw PTW even after soaked for 14 days while apatite appeared on the treated PTW after soaked for only 7 days. This implies that treatment by HCl/NaOH solutions can improve the in vitro bioactivity of PTW. The possible mechanism is that more Ti–OH groups occur after treatment and induce Ca2+ and PO4 3- aggregate and accelerate to deposit of apatite. The bioactive PTW with good biocompatibility is a potential candidate as reinforcing agent to improve the mechanical properties of calcium phosphate ceramics or cements.

Attitude deflection of shield machine is inevitable in process of driving forward, therefore, the tail brush, circular shape retainer and even shell of shield machine will extrude the exterior surfaces of segments. The squeezing action acting on segments causes dislocation, stress concentration and even crack in segments. Finite element code, ADINA, was used to analyze numerical tunnel model of 9 segment rings. The loads acting on different segment rings included squeezing action of tail brush under four attitude deflection, jacking forces, grouting pressure and earth pressure. The aspects of analysis included displacement feature and stress distribution. The analysis results indicate attitude deflection of shield machine causes biggish dislocation between segments, and the key segment is the most affected and weakest part in same ring which causes irregular displacement and dislocation in whole tunnel structure. In general, under squeezing action induced by shield machine, circumferential seam is much more affected than longitudinal seam. The squeezing action causes the segment dislocation exceed the limiting dislocation value which means curved bolt has extruded bolt hole and crack or breakage frequently concentrates in key segment and adjacent segment. Deflection of shield machine attitude is inevitable, but two deflection attitudes, including shield machine attitude deviates right direction and the head of shield machine goes down, should be avoided.

Ramoplanin and enduracidin are lipopeptide antibiotics effective against Gram-positive pathogens, which share close similarity in structure and biosynthetic pathway. Both compounds have chlorine atoms attached to 4-hydroxyphenylglycine (Hpg) but with different chlorinating sites and levels. Here, to probe the factor affecting the site and level of halogenation, gene inactivation and heterologous expression were carried out in Actinoplanes sp. ATCC33076 by homologous recombination. Metabolite analysis confirmed that ram20 encodes the only halogenase in ramoplanin biosynthetic pathway, and enduracidin halogenase End30 could heterologously complement the ram20-deficient mutant. Additionally, the mannosyltransferase-deficient mutant produces a dichlorinated ramoplanin aglycone with the halogenation site at Hpg(13). This study has refined our understanding of how halogenation occurs in ramoplanin biosynthetic pathway, and lays the foundation for further exploitation of ramoplanin and enduracidin halogenase in combinatorial biosynthesis.

Deformation and dislocations of segments of shield tunnel in construction stage have apparent effect on tunnel structure stress and even cause local cracks and breakage in tunnel. 3D finite element method was used to analyze two segment ring models under uniform injected pressure: (1) segment ring without wedge-shaped segment, which has 16 types of preinstall erection tolerance; (2) segment ring with wedge-shaped segment, which has no preinstall erection tolerance. The analysis results indicate that different erection tolerances can cause irregular deformation in segment ring under uniform injected pressure, and that the tolerance values are enlarged further. Wedge-shaped segment apparently affects the overall deformation of segment ring without erection tolerances. The uniform injected pressure can cause deformation of ring with wedge-shaped segment irregular, and dislocations also appear in this situation. The stress of segment with erection tolerances is much larger than that of segment without erection tolerances. Enlarging the central angle of wedge-shaped segment can make the irregular deformation and dis- locations of segments smaller. The analysis results also provide basis for erection tolerance control and improvement of segment constitution.

Rough set theory was used to analyze the stability level and risk grade of 30 site tests of cement-soil pile in Chaozhou Water Supply Control Project. And the confidence level and risk of cement-soil pile composite foundation was evaluated to determine the stability of whole Chaozhou Water Supply Control Project. With the refined deduce of rough set analysis theory, the results according to five steps are shown in this paper. The results indicate that the contrast test between rough set analysis results and the site test results are consistent. The contrast results prove that the risk assessment method of rough set theory is effective for analysis cement-soil pile composite foundation.

Gentamicin is an aminoglycoside antibiotic obtained from cultures of Micromonospora as the important anti-infective agents. Gentamicin which lacks 3'-hydroxyl group can avoid the attack from the modification enzymes of antibiotic-resistant bacteria in clinic. Consequently, C-3' dehydroxylation is the key step in gentamicins biosynthesis. We suppose that there are some enzymes responsible for converting intermediate JI-20A to 3',4'-bisdehydroxylated final product gentamicin C(1a), while phosphorylation of 3'-OH is possibly the first step for C-3' dehydroxylation. The gentamicin biosynthetic gene gntI, encoding an aminoglycoside phosphotransferase, was cloned from Micromonospora echinospora ATCC15835 and overexpressed in Escherichia coli. The resulting phosphotransferase was purified, and the kinetic parameters for Kanamycin A, Kanamycin B, Neomycin B and Amikacin were determined. Elucidation of NMR data of phosphorylated kanamycin B has unambiguously demonstrated a regiospecific phosphorylation of 3'-hydroxyl of the 6-aminohexose ring. The results described here partly confirm that the 3'-dehydroxylation step is preceded by a 3' phosphorylation step. It is predicted that GntI belongs to a new aminoglycoside phosphotransferase group involved with aminoglycoside antibiotics biosynthesis pathway.

The studies used a test foundation trench to carry site measurement of siltation of Hongkong-Zhuhai-Macau Bridge. A test foundation trench which was 100-meter-long and 21-meter-wide was excavated near the west artificial island. The medial axis of trench was consistent with the designed axis of immersed tunnel. The data of 12-month site measurements indicates siltation happened on trench bottom and surface of trench slopes. North slope is more obvious than south slope. There was no obvious siltation on east and west slope. It has little chance that serious siltation happens on foundation trench of immersed tunnel after storm surge.

To reconstruct a finite element model of human middle ear and measure characteristic dimensions of this model and calculate the mass properties of the ossicles.The proposed method starts with the histologic section preparation of human temporal bone. Through tracing outlines of the middle ear components on the sections in AutoCAD2005, a set of exterior contours of the components is obtained. The three-dimensional solid model of middle ear, including tympanic membrane, ossicular bones, middle ear suspensory ligaments/muscles, are reconstructed using these contours in Unigraphics (UG). To prepare for finite element analysis (FEA) of the middle ear, all surfaces of the solid model are translated into ADINA, a commercial FE model package. Based on these surfaces, FE meshes of the middle ear are created, and material properties and boundaries are set up. The characteristic dimensions of this model are measured and the mass properties of the ossicles are calculated to confirm the accuracy of the geometric model constructed following the proposed method.The three-dimensional finite element model of the human middle ear that included tympanic membrane, ossicular bones and middle ear suspensory ligaments/muscles was reconstructed. The accuracy of this geometric model was confirmed with the outcome of the characteristic dimensions of this model and the mass properties of the ossicles.The proposed method not only provides an effective, convenient, economic, accurate way to reconstruct the three dimensional finite element model of human middle, but also provides a detailed knowledge of middle ear geometry that is required for finite element analysis.

Correction for ‘Spin mixed charge transfer states of iridium complex Ir(ppy)3: transient absorption and time-resolved photoluminescence’ by Mohan Singh Mehata et al., RSC Adv., 2015, 5, 34094–34099.