直径小于1 cm孤立性肺结节的18F-FDG PET/CT诊断研究进展

孤立性肺结节的鉴别诊断一直是胸部影像学的研究热点。早期且准确地鉴别肺内小结节的良恶性,对于患者治疗方案的确定以及随访情况的评估均具有重要的临床意义。~(18)F-FDG PET/CT在鉴别诊断恶性肿瘤方面具有明显优于其他传统检查的高特异性和高敏感性,其公认的恶性肿瘤的诊断阈值是最大化标准摄取值(maximum standard uptake value, SUVmax)为2.5,然而部分临床数据显示一些直径小于1 cm的恶性肺结节的SUVmax数值小于2.5。因此在早期研究中,~(18)F-FDG PET/CT在诊断直径较小的肺结节的其临床价值仍存在争议。为了尽量降低SUVmax的测量误差,提高~(18)F-FDG PET/CT诊断的准确率,衍生出了许多SUVmax辅助诊断方法以及优化的重建算法、放射性显像剂的联合应用等手段。本文将对~(18)F-FDG PET/CT鉴别诊断直径小于1 cm孤立性肺结节的研究进展进行综述。     

Dispersal and Infectivity of the Entomogenous Nematode,Neoaplectana carpocapsae Weiser (Rhabditida: Steinernematidae), in Sand

Laboratory tests determined the lateral and vertical dispersal patterns of Neoaplectana carpocapsae in sand. In the vertical tests, placement of infective juveniles 15 cm below the sand''s surface resulted in the majority (77%) being recovered above the point of placement after 48 h. Placement of the nematodes on the sand''s surface resulted in the majority (90.4%) remaining within 1 cm of the sand''s surface. Placement of nematodes at depths of 2.5 cm and 5.0 cm below the sand''s surface also resulted in little nematode dispersal. However, vertical hioassay tests showed that juvenile nematodes placed on the sand''s surface dispersed 12 cm down to infect 67% of the Galleria mellonella pupae placed at the depth. Conversely, when nematodes were placed 11 cm below the insect pupae no infection was observed, but 53% infection occurred when nematodes were 7 cm below the site of the insect pupae. In lateral dispersal, 87% of the nematodes rentained within 2 cm of the placement site, although 0.5% were recovered at 12-14 cm away from the point of placement. Lateral bioassay tests indicated that the nematodes were capable of infecting 90, 35, and 5% of the G. mellonella pupae at 7 cm, 10 cm, and 14 cm from the point of placement, respectively.     

Attraction characteristics of insect pests and natural enemies according to the vertical position of yellow sticky traps in a strawberry farm with high-raised bed cultivation

The objectives of study was to evaluate the vertical space of flying insects using YST (yellow sticky traps) trapping in a strawberry farm with a high-raised bed system; with assuming the presence of species-specific flying zone. The experimental farm used styrofoam beds (width 30 cm, depth 20 cm) placed on a supporting frame 70 cm high. Small YSTs (12.5 × 7.5 cm, single sticky side) were installed vertically around the high-raised bed system in a 3 × 7 configuration (column × row) vertically at 30-cm intervals, reaching 270 cm high, and spaced 50 cm apart horizontally. The trap positions within the second-ranking (here referred to as ‘zone’) to attract thrips were 60 cm traps above the top of the bed center (TBC), 30 cm traps above the side of the bed (SOB), and 70 cm traps from the ground on the SOB. The attraction zone of whiteflies was the same as that of the thrips except of the 60 cm traps above the SOB. The zones for leafhoppers were formed in all 60 cm traps above the top of the bed (TOB), the 90 cm side traps above the TOB, and 30 cm traps above the TBC. Aphids were frequently attracted at all 90 cm traps above the TBC and 60 cm above the TBC. Sciarid pests were mostly attracted to the traps placed just below the bed center. The zones of natural enemies (total) were formed in 30 cm above the TBC and 70 cm from the ground at the SOB. Thus, the zone 60 cm above the TBC was common position where various pests were frequently attracted with reducing a harmful effect on natural enemies. Consequently, our results could be used as a guideline for the use of YSTs in strawberry farms with high-raised bed systems until new directions are developed.     

A novel stereotactic frame for real PET-guided biopsies: A preclinical proof-of-concept

Purpose: To design, build and test a stereotactic device that allows PET image-guided biopsies to be performed. Methods: An initial prototype consisting of four main pieces, one of which contains radioactive markers to make it visible in the PET images, was built using a 3D printer. Once the device is mounted, a spherical coordinate system is built with the entrance needle point in the skin as the origin of coordinates. Two in-house software programs, namely getCoord.ijm, which obtains the spherical coordinates of the tumour tissue to be biopsied, and getNeedle.ijm, which virtualizes the inner needle tip once the puncture has taken place, were written. This prototype was tested on an FDG-doped phantom to characterize both the accuracy of the system and the procedure time. Results: Up to 11 complete biopsy procedures were conducted. The mean total procedure time was less than 20 min, which is less than the procedure time of conventional standard CT-guided biopsies. The overall accuracy of the system was found to be 5.0 ± 1.3 mm, which outperforms the criterion used in routine clinical practice when targeting tumours with a diameter of 10 mm. Conclusions: A stereotactic frame to conduct real PET image-guided biopsies has been designed and built. A proof-of-concept was performed to characterize the system. The procedure time and accuracy of the system were found to meet the current needs of physicians performing biopsies.     

Concurrent validity and reliability of a mobile tracking technology to measure angular and linear movements of the neck

The neck can be moved in six degrees of freedom. Current 3D-optoelectronic motion-capture systems capable of measuring these movements are inappropriate for use in clinical practice because they are stationary, expensive and time-consuming. We therefore developed a less complex 3D-tracking technology based on Steam®VR to measure six degrees of freedom in a clinical setting. The aim of this study was to assess the validity and reliability of this system.The developed prototype consists of two infrared-emitting lighthouses and sensors, mounted on the participant’s helmet and trunk belt, to detect the orientation of the head and trunk. The system was evaluated by means of an infrared light-reflecting marker tracking system. Twenty healthy participants, equipped with these sensors and markers, performed thirteen neck movement tasks. Linear and angular movements were measured. These tasks were repeated after six to eight days to assess test-retest reliability. Concurrent validity was assessed by the root mean square error, and reliability with generalizability theory.With an average root mean square error between 1.2 and 2.0° in angular and 0.4–0.5 cm in linear movements, the prototype was shown to precisely track these movements. Reliability of the prototype and the reference system was comparable for all tasks. A high contribution of participant’s variability to the observed variance was generally detected, with the exception of joint repositioning error and upper cervical flexion.The reliability was task-specific and did not differ between the systems. The prototype system was shown to be valid, although the reliability of the repositioning and upper cervical flexion tests needs to be reconsidered.     

基于心率检测的便携式儿童情绪感知系统研制

目的:检测儿童的情绪能力,从而检验儿童情绪能力发展是否正常以及协助训练孤独症儿童的情绪能力。方法:设计了一套便携式的儿童情绪感知系统,检测儿童的情绪能力。本系统由心率信号采集模块,PC机端的软件以及情绪能力数据分析组成。结果:研制的儿童情绪能力感知系统具有便携、可穿戴等优点,能够准确地检测儿童情绪能力。结论:儿童情绪能力感知系统能够检测使用者的情绪能力,也能够在儿童情绪能力干预训练中记录孤独症儿童的情绪变化,为干预训练提供帮助。     

Low frequency magnetic emissions and resulting induced voltages in a pacemaker by iPod portable music players

Background

Recently, malfunctioning of a cardiac pacemaker electromagnetic, caused by electromagnetic interference (EMI) by fields emitted by personal portable music players was highly publicized around the world. A clinical study of one patient was performed and two types of interference were observed when the clinicians placed a pacemaker programming head and an iPod were placed adjacent to the patient's implanted pacemaker. The authors concluded that "Warning labels may be needed to avoid close contact between pacemakers and iPods". We performed an in-vitro study to evaluate these claims of EMI and present our findings of no-effects" in this paper.

Methods

We performed in-vitro evaluations of the low frequency magnetic field emissions from various models of the Apple Inc. iPod music player. We measured magnetic field emissions with a 3-coil sensor (diameter of 3.5 cm) placed within 1 cm of the surface of the player. Highly localized fields were observed (only existing in a one square cm area). We also measured the voltages induced inside an 'instrumented-can' pacemaker with two standard unipolar leads. Each iPod was placed in the air, 2.7 cm above the pacemaker case. The pacemaker case and leads were placed in a saline filled torso simulator per pacemaker electromagnetic compatibility standard ANSI/AAMI PC69:2000. Voltages inside the can were measured.

Results

Emissions were strongest (≈ 0.2 μT pp) near a few localized points on the cases of the two iPods with hard drives. Emissions consisted of 100 kHz sinusoidal signal with lower frequency (20 msec wide) pulsed amplitude modulation. Voltages induced in the iPods were below the noise level of our instruments (0.5 mV pp in the 0 - 1 kHz band or 2 mV pp in the 0 - 5 MHz bandwidth.

Conclusion

Our measurements of the magnitude and the spatial distribution of low frequency magnetic flux density emissions by 4 different models of iPod portable music players. Levels of less than 0.2 μT exist very close (1 cm) from the case. The measured voltages induced inside an 'instrumented-can' pacemaker were below the noise level of our instruments. Based on the observations of our in-vitro study we conclude that no interference effects can occur in pacemakers exposed to the iPod devices we tested.     

A Dual Tracer PET-MRI Protocol for the Quantitative Measure of Regional Brain Energy Substrates Uptake in the Rat

We present a method for comparing the uptake of the brain''s two key energy substrates: glucose and ketones (acetoacetate [AcAc] in this case) in the rat. The developed method is a small-animal positron emission tomography (PET) protocol, in which ¹¹C-AcAc and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) are injected sequentially in each animal. This dual tracer PET acquisition is possible because of the short half-life of ¹¹C (20.4 min). The rats also undergo a magnetic resonance imaging (MRI) acquisition seven days before the PET protocol. Prior to image analysis, PET and MRI images are coregistered to allow the measurement of regional cerebral uptake (cortex, hippocampus, striatum, and cerebellum). A quantitative measure of ¹¹C-AcAc and ¹⁸F-FDG brain uptake (cerebral metabolic rate; μmol/100 g/min) is determined by kinetic modeling using the image-derived input function (IDIF) method. Our new dual tracer PET protocol is robust and flexible; the two tracers used can be replaced by different radiotracers to evaluate other processes in the brain. Moreover, our protocol is applicable to the study of brain fuel supply in multiple conditions such as normal aging and neurodegenerative pathologies such as Alzheimer''s and Parkinson''s diseases.     

Variable place-cell coupling to a continuously viewed stimulus: evidence that the hippocampus acts as a perceptual system.

A key feature of perception is that the interpretation of a single, continuously available stimulus can change from time to time. This aspect of perception is well illustrated by the use of ambiguous figures that can be seen in two different ways. When people view such a stimulus they almost universally describe what they are seeing as jumping between two states. If it is agreed that this perceptual phenomenon is causally linked to the activity of nerve cells, the state jumps would have to occur in conjunction with changes in neural activity somewhere in the nervous system. Our experiments suggest that hippocampal place cells are part of a perceptual system. We conducted variations of a ''cue-card rotation'' experiment on rats in which the angular position of a prominent visual stimulus on the wall of cylinder is changed in the rat''s presence. The three main results are that (i) place-cell firing fields remain stationary if the cue is rotated by 180 degrees, so the relation between the cue and the field is altered; (ii) firing fields rotate by 45 degrees when the cue is rotated by 45 degrees, so the relation between the field and the card is maintained; and (iii) if the cue is first rotated by 180 degrees and then rotated in a series of 45 degrees steps, the field winds up at a different angular position relative to the card when the card is back in its original position. Thus, place cells can fire in two different ways in response to a continuously viewed stimulus. We conclude that place cells reveal that the hippocampal mapping system also has properties expected of a perceptual system.     

The Complete Mitochondrial DNA Sequence of the Bichir (Polypterus Ornatipinnis), a Basal Ray-Finned Fish: Ancient Establishment of the Consensus Vertebrate Gene Order

The evolutionary position of bichirs is disputed, and they have been variously aligned with ray-finned fish (Actinopterygii) or lobe-finned fish (Sarcopterygii), which also include tetrapods. Alternatively, they have been placed into their own group, the Brachiopterygii. The phylogenetic position of bichirs as possibly the most primitive living bony fish (Osteichthyes) made knowledge about their mitochondrial genome of considerable evolutionary interest. We determined the complete nucleotide sequence (16,624 bp) of the mitochondrial genome of a bichir, Polypterus ornatipinnis. Its genome contains 13 protein-coding genes, 22 tRNAs, two rRNAs and one major noncoding region. The genome''s structure and organization show that this is the most basal vertebrate that conforms to the consensus vertebrate mtDNA gene order. Bichir mitochondrial protein-coding and ribosomal RNA genes have greater sequence similarity to ray-finned fish than to either lamprey or lungfish. Phylogenetic analyses suggest the bichir''s placement as the most basal living member of the ray-finned fish and rule out its classification as a lobe-finned fish. Hence, its lobe-fins are probably not a shared-derived trait with those of lobe-finned fish (Sarcopterygii).     

The influence of foot position on standing balance

To test the hypothesis that variations in foot position would significantly affect standing balance, we studied ten normal subjects on a Kistler force platform which measured the travel and center of pressure displacement. With the feet together there was substantially more mediolateral (ML) travel than with the axes of the feet 15, 30 or 45 cm apart and the mean ML position of the center of pressure was displaced toward the right; there was no consistent effect on anteroposterior (AP) travel or position. As the right foot was placed 10 and 30 cm forward or back, the least amount of ML and AP travel occurred with the feet even or at 10 cm either direction; the mean AP and ML position moved toward the foot which was placed more posteriorly. Of the five foot angles ranging from toes-out 45 degrees to toes-in 45 degrees, the extent of ML and AP travel was lowest in the toes-out 25 degrees position and greatest in the toes-in 45 degrees position; the mean AP and ML position was farthest forward and to the right with toes-in 45 degrees. These findings have implications for the prosthetic replacement of the lower limbs, sports, ergonomics and postural sway studies.     

Synthesis and Evaluation of Two Coumarin‐Type Derivatization Reagents for Fluorescence Detection of Chiral Amines and Chiral Carboxylic Acids

The synthesis of two fluorescent coumarin‐type chiral derivatization agents ( 4 and 11 ) is reported. A chiral side chain was introduced at position 7 of the coumarin via Mitsunobu reaction. The two coumarins bear in this side chain either a free amino group or a carboxyl group, making them useful for further transformations. Conjugates of chiral prototype drugs with 4 or 11 were prepared by amide coupling of the analyte's carboxyl group to the reagent's amine group, or vice versa. The separation of seven diastereomeric conjugates through achiral high‐performance liquid chromatography (HPLC) on a common C18 column is demonstrated. Chirality 25:957–964, 2013. © 2013 Wiley Periodicals, Inc.     

Fair Innings and Time‐Relative Claims

Greg Bognar has recently offered a prioritarian justification for ‘fair innings’ distributive principles that would ration access to healthcare on the basis of patients' age. In this article, I agree that Bognar's principle is among the strongest arguments for age‐based rationing. However, I argue that this position is incomplete because of the possibility of ‘time‐relative' egalitarian principles that could complement the kind of lifetime egalitarianism that Bognar adopts. After outlining Bognar's position, and explaining the attraction of time‐relative egalitarianism, I suggest various ways in which these two kinds of principle could interact. Since various options have very different implications for age‐based rationing, proponents of such a rationing scheme must take a position on time‐relative egalitarianism to complement a lifetime prioritarian view like Bognar's.     

The enigmatic cytochrome b-559 of oxygenic photosynthesis

The ubiquitous and obligatory association of cytochrome b -559 with the photosystem II reaction center of oxygenic photosynthesis is a conundrum since it seems not to have a function in the primary electron transport pathway of oxygen evolution. A model for the cytochrome structure that satisfies the cis -positive rule for membrane protein assembly consists of two short, non-identical hydrophobic membrane-spanning polypeptides (α and β), each containing a single histidine residue, as ligands for the bridging heme prosthetic group that is on the side of the membrane opposite to the water splitting apparatus. The ability of the heterodimer, but not the single α-subunit, to satisfy the cis -positive rule implies that the cytochrome inserts into the membrane as a heterodimer, with some evidence implicating it as the first membrane inserted unit of the assembling reaction center. The very positive redox potential of the cytochrome can be explained by a position for the heme in a hydrophobic niche near the stromal aqueous interface where it is also influenced by the large positive dipole potential of the parallel α-helices of the cytochrome. The requirement for the cytochrome in oxygenic photosynthesis may be a consequence of the presence of the strongly oxidizing reaction center needed for H₂O-splitting. This may lead to the need, under conditions of stress or plastid development, for an alternate source of electrons when the H₂O-splitting system is not operative as a source of reductant for the reaction center.     

Navigation in Familiar Environments by the Weakly Electric Elephantnose Fish,Gnathonemus petersii L. (Mormyriformes,Teleostei)

Gnathonemus petersii use electrolocation to navigate in unfamiliar environments. The goal of these experiments was to determine whether fish could learn the location of a fixed aperture after interference with selected sensory input. By manipulating environmental cues (aperture height and water depth) and comparing the fish's performance, the contributions of the electrosensory system, vision, and hydrostatic pressure were examined. The fish's task was to find a circular aperture in a wall dividing a 200-litre aquarium into two equal compartments. In experiment 1, the position of the aperture was raised by 10.1 cm after the fish had become familiar with its original location. In experiment 2, the water level was raised by 10 cm (leaving the aperture unchanged). When the aperture was raised, intact fish found the new aperture with no difficulty, whereas blind, electrically 'silent', and sham-operated fish were slow finding the new position. When the water level was raised, all fish increased the height at which they contacted the wall, increased their electric-organ discharge (EOD) rate, and located the aperture. This increase, in response to the rapid change in water depth, suggests that all fish used hydrostatic pressure cues to maintain depth orientation, and that those fish that learned the aperture height had used hydrostatic cues to locate its position. The data suggest that G. petersii develop an internal representation based on an electrosensory central expectation and hydrostatic cues. The fish develop a sensory 'image' of their immediate environment and associate a specific image with a specific depth. As the environment becomes more familiar, the fish apparently attend less to electrosensory information and navigate according to the internal representation, relying primarily on hydrostatic pressure cues.     

Mechanosensory‐based orientation to elevated prey by a benthic fish

Lake Michigan mottled sculpin, Cottus bairdi, respond to both live and artificial (e.g., vibrating sphere) prey with an unconditioned movement towards the source of vibration, followed by a step‐by‐step approach and final strike at the source. In addition to these well‐studied, whole‐body movements along the horizontal plane of the substrate, sculpin exhibit a little‐studied behavior in which the vertical position of the fish's head can vary from being flush with the substrate to several cm's above the substrate. To test the hypothesis that sculpin can determine source elevation via mechanosensory cues, we measured head elevation of blinded fish as a function of source elevation and distance as fish approached a small (3 mm radius), 50 Hz vibrating sphere. At distances associated with pre‐strike positions (< 2 cm), head elevations were positively correlated with source elevation before but not after pharmacological blocking of the lateral line with CoCl₂. These results demonstrate that sculpin are able to determine source elevation using mechanosensory cues alone and that in the absence of visual and olfactory cues, vertical orientation of the head towards the source requires the lateral line system.     

Mind the gap: the minimal detectable separation distance between two objects during active electrolocation

In a food‐rewarded two‐alternative forced‐choice procedure, it was determined how well the weakly electric elephantnose fish Gnathonemus petersii can sense gaps between two objects, some of which were placed in front of complex backgrounds. The results show that at close distances, G. petersii is able to detect gaps between two small metal cubes (2 cm × 2 cm × 2 cm) down to a width of c. 1·5 mm. When larger objects (3 cm × 3 cm × 3 cm) were used, gaps with a width of 2–3 mm could still be detected. Discrimination performance was better (c. 1 mm gap size) when the objects were placed in front of a moving background consisting of plastic stripes or plant leaves, indicating that movement in the environment plays an important role for object identification. In addition, the smallest gap size that could be detected at increasing distances was determined. A linear relationship between object distance and gap size existed. Minimal detectable gap sizes increased from c. 1·5 mm at a distance of 1 cm, to 20 mm at a distance of 7 cm. Measurements and simulations of the electric stimuli occurring during gap detection revealed that the electric images of two close objects influence each other and superimpose. A large gap of 20 mm between two objects induced two clearly separated peaks in the electric image, while a 2 mm gap caused just a slight indentation in the image. Therefore, the fusion of electric images limits spatial resolution during active electrolocation. Relative movements either between the fish and the objects or between object and background might improve spatial resolution by accentuating the fine details of the electric images.     

Anti-Amyloid-β-Mediated Positron Emission Tomography Imaging in Alzheimer's Disease Mouse Brains

Antibody-mediated imaging of amyloid β (Aβ) in Alzheimer''s disease (AD) offers a promising strategy to detect and monitor specific Aβ species, such as oligomers, that have important pathological and therapeutic relevance. The major current limitation of antibodies as a diagnostic and imaging device is poor blood-brain-barrier permeability. A classical anti-Aβ antibody, 6E10, is modified with 10 kDa polyethylene glycol (PEG) and a positron emitting isotope, Copper-64 (t_½ = 12.7 h), and intravenously delivered to the TgCRND8 mouse model of Alzheimer''s disease. Modification of 6E10 with PEG (6E10-PEG) increases accumulation of 6E10 in brain tissue in both TgCRND8 and wild type control animals. 6E10-PEG differentiates TgCRND8 animals from wild type controls using positron emission tomography (PET) and provides a framework for using antibodies to detect pathology using non-invasive medical imaging techniques.     

Compact optical microfluidic uric acid analysis system

We designed, fabricated and tested a novel compact fluorescence analysis system for quantification of uric acid (UA) in clinical samples at the point-of-care. To perform an analysis, diluted saliva, urine or blood samples are simply placed in a disposable thin-film sample holder using a dropper. A new enzyme immobilization technique was developed to retain within the sample holder two enzymes and a molecule, which transforms into a fluorescer in amounts depending on the UA concentration. The small instrument (7.5 cm × 5 cm × 5 cm) into which the sample holder is placed for analysis contains an LED, a narrow-band filter and an amplified photodiode. The analysis time is 30s, and the dynamic range of the system is 4-400 μM of UA. The calibration curve for transparent saliva and urine was made using solutions of UA. The calibration curve for opaque blood was obtained with spiked samples of blood. The three different types of clinical samples were collected from three subjects and simply diluted before their measurements. Analysis with our instrument yielded UA concentrations within the expected concentration ranges. Development of instruments based on the current laboratory prototype is expected to result in products for clinical trials and point-of-care.     

Improved Infrared-Sensing Running Wheel Systems with an Effective Exercise Activity Indicator

This paper describes an infrared-sensing running wheel (ISRW) system for the quantitative measurement of effective exercise activity in rats. The ISRW system provides superior exercise training compared with commercially available traditional animal running platforms. Four infrared (IR) light-emitting diode/detector pairs embedded around the rim of the wheel detect the rat’s real-time position; the acrylic wheel has a diameter of 55 cm and a thickness of 15 cm, that is, it is larger and thicker than traditional exercise wheels, and it is equipped with a rubber track. The acrylic wheel hangs virtually frictionless, and a DC motor with an axially mounted rubber wheel, which has a diameter of 10 cm, drives the acrylic wheel from the outer edge. The system can automatically train rats to run persistently. The proposed system can determine effective exercise activity (EEA), with the IR sensors (which are connected to a conventional PC) recording the rat exercise behavior. A prototype of the system was verified by a hospital research group performing ischemic stroke experiments on rats by considering middle cerebral artery occlusion. The experimental data demonstrated that the proposed system provides greater neuroprotection in an animal stroke model compared with a conventional treadmill and a motorized running wheel for a given exercise intensity. The quantitative exercise effectiveness indicator showed a 92% correlation between an increase in the EEA and a decrease in the infarct volume. This indicator can be used as a noninvasive and objective reference in clinical animal exercise experiments.