Incorporation of Protecting Groups in Organic Chemistry: A Mini-Review.

The approach of utilizing protecting groups (PGs) in organic chemistry has led to the successful syntheses of an array of useful organic compounds. This strategy has also addressed some of the complexities associated with many organic reactions. These PGs find useful applications in simple and complex reactions that involve the synthesis of large organic compounds such as peptides, and oligosaccharides. The fundamental role of PGs is to prevent undesired reactions that could hinder the progress or completion of such reactions. Ideal PGs must be utilized in this regard to achieve the desired objectives. This review describes the diverse protecting groups found in the literatures, the functional moieties for the protection, deprotection strategies, and their relevant applications in organic synthesis.

Novel Benzimidazole-Based Compounds as Antimicrobials: Synthesis, Molecular Docking, Molecular Dynamics and in silico ADME Profile Studies.

Some novel benzimidazole derivatives were synthesized and their antimicrobial activities were evaluated. Compounds 3a and 3b exhibited excellent antibacterial activity with MIC values <4 µg/mL against Staphylococcus aureus ATCC 29213 (MSSA) and Staphylococcus aureus ATCC 43300 (MRSA). Molecular docking analyzes of compounds with MIC values of 16 µg/mL and below against gram-positive bacteria and fungi were performed using FabH (ß-ketoacyl-acyl carrier protein synthase III) as bacterial protein and CYP51 (sterol 14α-demethylase) as the fungal target protein. According to the molecular docking analysis, it was calculated that sufficient protein-ligand interaction energy was liberated between the compounds 2f, 3a, 3b, 3e and 3h and the antibacterial target protein FabH and strong interactions were formed between 2f and 3h and the antifungal target protein. According to RMSD, RMSF and MMPBSA measurements obtained from molecular dynamics, it is understood that compounds 3a and 3b maintain protein-ligand stability in silico physiological conditions.

Successful cryopreservation of honey bee drone spermatozoa with royal jelly supplemented extenders.

The aim of the present study was to evaluate different concentrations of royal jelly (RJ) supplemented extenders for post-thawing quality of drone sperm. Semen samples were collected from sexually mature drones. Pooled semen was diluted with extender without RJ (control) or supplemented with different concentrations of RJ (1, 2, 4 or 8%). Sperm motility, plasma membrane functional integrity, and acrosomal integrity were evaluated. At post thaw, the highest sperm motility and acrosomal integrity rates were obtained in the RJ1 group. Functional integrity of sperm membrane was better preserved in the RJ1 and RJ2 groups compare to the other groups. The study shows that RJ supplemented extenders have beneficial effects on drone semen parameters. The results of the present study demonstrated advantage of using 1% RJ supplemented extender.

System Integration and In Vivo Testing of a Robot for Ultrasound Guidance and Monitoring During Radiotherapy.

We are developing a cooperatively controlled robot system for image-guided radiation therapy (IGRT) in which a clinician and robot share control of a 3-D ultrasound (US) probe. IGRT involves two main steps: 1) planning/simulation and 2) treatment delivery. The goals of the system are to provide guidance for patient setup and real-time target monitoring during fractionated radiotherapy of soft tissue targets, especially in the upper abdomen. To compensate for soft tissue deformations created by the probe, we present a novel workflow where the robot holds the US probe on the patient during acquisition of the planning computerized tomography image, thereby ensuring that planning is performed on the deformed tissue. The robot system introduces constraints (virtual fixtures) to help to produce consistent soft tissue deformation between simulation and treatment days, based on the robot position, contact force, and reference US image recorded during simulation. This paper presents the system integration and the proposed clinical workflow, validated by an in vivo canine study. The results show that the virtual fixtures enable the clinician to deviate from the recorded position to better reproduce the reference US image, which correlates with more consistent soft tissue deformation and the possibility for more accurate patient setup and radiation delivery.

An Inertial and Optical Sensor Fusion Approach for Six Degree-of-Freedom Pose Estimation.

Optical tracking provides relatively high accuracy over a large workspace but requires line-of-sight between the camera and the markers, which may be difficult to maintain in actual applications. In contrast, inertial sensing does not require line-of-sight but is subject to drift, which may cause large cumulative errors, especially during the measurement of position. To handle cases where some or all of the markers are occluded, this paper proposes an inertial and optical sensor fusion approach in which the bias of the inertial sensors is estimated when the optical tracker provides full six degree-of-freedom (6-DOF) pose information. As long as the position of at least one marker can be tracked by the optical system, the 3-DOF position can be combined with the orientation estimated from the inertial measurements to recover the full 6-DOF pose information. When all the markers are occluded, the position tracking relies on the inertial sensors that are bias-corrected by the optical tracking system. Experiments are performed with an augmented reality head-mounted display (ARHMD) that integrates an optical tracking system (OTS) and inertial measurement unit (IMU). Experimental results show that under partial occlusion conditions, the root mean square errors (RMSE) of orientation and position are 0.04° and 0.134 mm, and under total occlusion conditions for 1 s, the orientation and position RMSE are 0.022° and 0.22 mm, respectively. Thus, the proposed sensor fusion approach can provide reliable 6-DOF pose under long-term partial occlusion and short-term total occlusion conditions.