Coexistence of two quadruplex–duplex hybrids in the PIM1 gene

The triple-negative breast cancer (TNBC), a subtype of breast cancer which lacks of targeted therapies, exhibits a poor prognosis. It was shown recently that the PIM1 oncogene is highly related to the proliferation of TNBC cells. A quadruplex–duplex hybrid (QDH) forming sequence was recently found to exist near the transcription start site of PIM1. This structure could be an attractive target for regulation of the PIM1 gene expression and thus the treatment of TNBC. Here, we present the solution structures of two QDHs that could coexist in the human PIM1 gene. Form 1 is a three-G-tetrad-layered (3+1) G-quadruplex containing a propeller loop, a lateral loop and a stem-loop made up of three G•C Watson–Crick base pairs. On the other hand, Form 2 is an anti-parallel G-quadruplex comprising two G-tetrads and a G•C•G•C tetrad; the structure has three lateral loops with the middle stem-loop made up of two Watson-Crick G•C base pairs. These structures provide valuable information for the design of G-quadruplex-specific ligands for PIM1 transcription regulation.

Chicken Microchromosomes in the Lampbrush Phase: A Cytogenetic Description

Lampbrush chromosomes are giant, transcriptionally active, meiotic chromosomes found in oocytes of all vertebrates with the exception of mammals. Lampbrush chromosomes offer a convenient tool for cytogenetic mapping and, in particular, have been instrumental in mapping genes and linkage groups on chicken (GGA) chromosomes. Whereas cytogenetic maps of macrochromosome GGA1-10 and microchromosome GGA11-16 lampbrush bivalents have been established, identification and description of smaller microchromosome bivalents are still missing. In this work, we used specific FISH probes for the identification of 12 chicken lampbrush chromosomes formed by GGA17-28. Our observations on chromomere and lateral loop arrangement and chiasma position allowed us to construct the respective cytogenetic maps for these microchromosomes. For the 10 smallest chicken microchromosomes, GGA29-38, no individual molecular tags are available, yet they can be collectively marked using the PO41 repeat. The reported results contribute to building of working cytogenetic maps of the chicken karyotype.

Receding Horizon Control on Automatic Landing Lateral Loop of Carrier-Based Aircraft

Since the angled deck is only tens miles width, the task of landing an aircraft on an aircraft carrier requires precise control, especially lateral loop. For this problem, this paper focuses on researching the aircraft automatic landing lateral control. In lateral control, the most crucial parts are controlling the off center distance and keeping the desired landing attitude. So firstly a nonlinear kinetic model of aircraft landing in lateral directional axis is established, and then transformed into error states. The controller is designed for an angle of attack of 11.7 deg and an airspeed of 40m/s, the equilibrium point. Receding horizon control methodology is employed to solve the aircraft lateral control problem. This controller is solved in MATLAB, and sent to the 3D simulation environment by network communication, to control the aircraft landing lateral loop. The simulation environment is programmed based on VC++ software. The simulation results show that receding horizon control method can achieve trajectory tracking and attitude tracking of nonlinear aircraft landing system.

Midsubtemporal Ridge as a Predictor of the Lateral Loop Formed by the Maxillary Nerve and Mandibular Nerve: A Cadaveric Morphological Study

BACKGROUND: The lateral loop formed by the maxillary nerve (V2) and the mandibular nerve (V3) consists of a part of the far lateral triangle of the cavernous sinus. Because this triangle becomes a surgical corridor of the preauricular infratemporal fossa approach and a landmark of the extradural approach for the ganglion-type trigeminal schwannomas, identification of the lateral loop has important implications at the early stage of middle cranial base surgery. We realized that a bony ridge usually existed just lateral to the lateral loop. OBJECTIVE: To nominate midsubtemporal ridge (MSR) as the name for this anatomically unnamed bony ridge and to clarify its features. METHODS: Using 35 cadaver heads, we measured the shape of the MSR on both sides and the distance between the MSR and the adjacent structures. RESULTS: The MSR was recognized in 60 of 70 specimens (85.7%). The bony protrusion was 2.9 ± 1.1 mm in height, 6.0 ± 2.1 mm in width, and 9.1 ± 3.2 mm in length. A single peak with anteroposterior length was common in 47 of 60 specimens (78.3%). The MSR was located at the midpoint of the V2 and V3 in 28 specimens (46.7%) and existed 10.7 ± 3.6 mm lateral from the line that bound the foramen rotundum and the foramen ovale. CONCLUSION: We demonstrate morphological characteristics of the MSR. These data on the MSR will assist the surgeon in identifying the lateral loop as a surgical landmark during middle cranial base surgery.

Anatomical characteristics of two enigmatic and two poorly known Pisidium species (Bivalvia: Sphaeriidae) from Southern South America

The shell morphology and anatomy of two enigmatic Pisidium species, Pisidium dorbignyi Clessin, 1879, never re-examined after the original description, and Pisidium lebruni Mabille, 1884, a species not reported again until 1995, are described. The type of P. dorbignyi (new name for Cyclas pulchella d´Orbigny, 1835) is lost, for which, and in order to define the taxonomic status of the species, a neotype is herein selected. Both species share as common features: the presence of only the anal siphonal aperture, only one pair of demibranchs, the inner and the type of nephridium, closed with lateral loop visible from dorsal view, consistently differing in shell morphology. Previously unknown details on the anatomy of Pisidium sterkianum Pilsbry, 1897 and Pisidium vile Pilsbry, 1897, particularly those concerning the type of nephridium and inner radial mantle musculature, are described and illustrated for the first time.

The Anteroinferior Cerebellar Artery Embedded in the Subarcuate Fossa: A Rare Anomaly and Its Clinical Significance

ABSTRACT OBJECTIVE: The purpose of this study is to call attention to an anomaly in which a segment of the anteroinferior cerebellar artery (AICA) is embedded in the dura or bone surrounding the subarcuate fossa, a small depression in the bone posterior to the internal acoustic meatus (IAM), through which the subarcuate artery enters the bone. This anomaly places the artery at risk in removing the posterior wall of the IAM. METHODS: An anomalous AICA having a segment that was embedded in the dura covering on the bone surrounding the subarcuate fossa was found during a microsurgical dissection course. The senior author (ALR) has observed this anomaly in four patients during surgery for acoustic neuromas and in three specimens in microsurgery dissection courses. To define the microsurgical anatomy of the anomalous artery further, the latex-injected specimen was dissected in a stepwise manner using ×3 to ×40 magnification. RESULTS: The anomalous AICA described in this report bifurcated into a rostral trunk and a caudal trunk near the facial-vestibulocochlear nerve complex. The caudal trunk formed a sharp lateral loop that was embedded in the dura covering the subarcuate fossa. The involved trunk continued to supply the suboccipital area normally supplied by the posteroinferior cerebellar artery, which was hypoplastic. The dura surrounding the anomalous loop was opened, and the adjacent bone was removed to free the anomalous loop from the subarcuate fossa so that the artery could be displaced medially to remove the posterior wall of the IAM. Although it has been reported that the AICA may occasionally be adherent to the dura over the subarcuate fossa, this study is the first to demonstrate an AICA that is embedded in the dura and bone of the subarcuate fossa. CONCLUSION: Mobilizing the AICA loop that is embedded in the subarcuate fossa posterior to the IAM places the involved AICA at significant risk in exposing the contents of the IAM.