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Ke Chen, Zhihao Yu, Zhenfeng Gong, Qingxu Yu
An all-optical photoacoustic spectroscopy based on lock-in white-light interferometry is proposed for trace gas detection. The cavity length of the fiber-optic Fabry-Perot cantilever microphone is demodulated by a high-speed white-light interferometer, whose spectral sampling is synchronously triggered by a phased locked signal. To improve the signal-to-noise ratio, the demodulated digital photoacoustic signal is further processed by a specially designed virtual lock-in amplifier. The designed photoacoustic spectrometer has been tested for trace acetylene (C2 H2 ) detection in the near-infrared region...
October 15, 2018: Optics Letters
B Gülenç, E Kuyucu, S Yalçin, A Çakir, A M Bülbül
PURPOSE OF THE STUDY Non-osseous giant cell tumors are locally aggressive tumors arising around joints. They are commonly located around synovial joints such as wrist and knee and occasionally cause mechanical symptoms. MATERIAL AND METHODS This retrospective case series includes 7 patients operated due to intraarticular lesion. The mean age of the patients was 28.7 (range 22-37) years. Mean follow-up period was 12 months. RESULTS All patients underwent arthroscopic debridement. They were followed monthly with clinical examination and magnetic resonance imaging (MRI) was obtained at third month for all patients...
2018: Acta Chirurgiae Orthopaedicae et Traumatologiae Cechoslovaca
Sandro Heuke, Barbara Sarri, Alberto Lombardini, Xavier Audier, Hervé Rigneault
High-speed imaging is of the utmost importance for video-rate live cell investigations or to study extended sample areas at sufficient spatial resolution within reasonable time scales. Improving the speed of single-focus stimulated Raman scattering (SRS) microscopy is ultimately restricted by the sample's damage threshold and the shot noise of the demodulated laser source. To overcome this limitation, we present a dual-focus SRS approach modulating the pump laser for each focus at a distinct frequency. The corresponding probe beams are detected each by a photodiode and demodulated individually by two separate lock-in units to avoid inter-focal cross-talk...
October 1, 2018: Optics Letters
Yingying Meng, Huan Liu, Hui Wang, Ye Liu, Butuo Zhu, Zuoyi Wang, Yaling Hou, Pengcheng Zhang, Jiangqi Wen, Hongshan Yang, Kirankumar S Mysore, Jianghua Chen, Million Tadege, Lifang Niu, Hao Lin
The formation and maintenance of the shoot apical meristem (SAM) is critical for plant development. However, the underlying molecular mechanism of regulating meristematic cell activity is poorly understood in the model legume Medicago truncatula. Using forward genetic approaches, we identified HEADLESS (HDL), a homologue of Arabidopsis WUSCHEL, required for M. truncatula SAM maintenance and leaf development. Disruption of HDL led to disorganized specification and arrest of the SAM and axillary meristems resulting in the hdl mutant being locked in the vegetative phase without apparent stem elongation...
September 29, 2018: Journal of Experimental Botany
Simon P Pearce, Matthias Heil, Oliver E Jensen, Gareth Wyn Jones, Andreas Prokop
Microtubules are filamentous tubular protein polymers which are essential for a range of cellular behaviour, and are generally straight over micron length scales. However, in some gliding assays, where microtubules move over a carpet of molecular motors, individual microtubules can also form tight arcs or rings, even in the absence of crosslinking proteins. Understanding this phenomenon may provide important explanations for similar highly curved microtubules which can be found in nerve cells undergoing neurodegeneration...
November 2018: Bulletin of Mathematical Biology
Fanxing Meng, Yuanyuan Zhang, Jianbo Zhou, Ming Li, Ge Shi, Rixin Wang
Unlike the normal anadromous lifestyle, Chinese native Dolly Varden char (Salvelinus malma) is locked in land and lives in fresh water lifetime. To explore the effect of freshwater adaption on its immune system, we constructed a pooled cDNA library of hepatopancreas and spleen of Chinese freshwater Dolly Varden char (S. malma). A total of 27,829 unigenes were generated from 31,233 high-quality transcripts and 17,670 complete open reading frames (ORF) were identified. Totally 25,809 unigenes were successfully annotated and it classified more native than adaptive immunity-associated genes, and more genes involved in toll-like receptor signal pathway than those in complement and coagulation cascades (51 vs 3), implying the relative more important role of toll-like receptors than the complement system under bacterial injection for the freshwater Dolly Varden char...
September 25, 2018: Fish & Shellfish Immunology
Yasuo Itami, Teruhisa Mihata, Michelle H McGarry, Charles C Lin, Nilay A Patel, Adam Kantor, Masashi Neo, Thay Q Lee
BACKGROUND: Scapular dyskinesis among throwers is thought to affect kinetic chain function and increase the load demands on the shoulder and/or elbow. However, the biomechanical relationship between scapular orientation and elbow valgus load, which is associated with ulnar collateral ligament (UCL) injury, has not been determined. PURPOSE: To evaluate the effect of increased scapular internal rotation (IR) and glenohumeral external rotation (GHER) on elbow valgus load in a static simulation of the late cocking phase of throwing...
September 28, 2018: American Journal of Sports Medicine
Tanvir Rizvi, Prem Batchala, Sugoto Mukherjee
Brain death (BD) is an irreversible cessation of functions of the entire brain, including the brainstem. The diagnosis of BD is made on clinical grounds and neurologic examination. In the United States, clinical criteria set by the American Academy of Neurology (AAN) emphasize 3 specific clinical findings to confirm BD, which include coma, absence of brainstem reflexes and apnea. Ancillary tests are needed when neurologic examination or apnea test cannot be performed. AAN recommended ancillary tests include electroencephalogram, which confirms electrical activity loss; catheter cerebral angiogram, which confirms loss of cerebral blood flow; as well as transcranial Doppler and nuclear scintigraphy...
October 2018: Seminars in Ultrasound, CT, and MR
Audrey Vanhaudenhuyse, Vanessa Charland-Verville, Aurore Thibaut, Camille Chatelle, Jean-Flory L Tshibanda, Audrey Maudoux, Marie-Elisabeth Faymonville, Steven Laureys, Olivia Gosseries
Despite recent advances in our understanding of consciousness disorders, accurate diagnosis of severely brain-damaged patients is still a major clinical challenge. We here present the case of a patient who was considered in an unresponsive wakefulness syndrome/vegetative state for 20 years. Repeated standardized behavioral examinations combined to neuroimaging assessments allowed us to show that this patient was in fact fully conscious and was able to functionally communicate. We thus revised the diagnosis into an incomplete locked-in syndrome, notably because the main brain lesion was located in the brainstem...
2018: Frontiers in Neurology
Marc Recasens, Joachim Gross, Peter J Uhlhaas
Emerging evidence supports the role of neural oscillations as a mechanism for predictive information processing across large-scale networks. However, the oscillatory signatures underlying auditory mismatch detection and information flow between brain regions remain unclear. To address this issue, we examined the contribution of oscillatory activity at theta/alpha-bands (4-8/8-13 Hz) and assessed directed connectivity in magnetoencephalographic data while 17 human participants were presented with sound sequences containing predictable repetitions and order manipulations that elicited prediction-error responses...
September 18, 2018: Scientific Reports
Cheryl J Briggs, Thomas C Adam, Sally J Holbrook, Russell J Schmitt
Coral reef systems can undergo rapid transitions from coral-dominated to macroalgae-dominated states following disturbances, and models indicate that these may sometimes represent shifts between alternative stable states. While several mechanisms may lead to alternate stable states on coral reefs, only a few have been investigated theoretically. We explore a model that illustrates that reduced vulnerability of macroalgae to herbivory as macroalgae grow and mature could be an important mechanism: when macroalgae are palatable to herbivores as juveniles, but resistant as adults, coral-dominated and algae-dominated states are bistable across a wide range of parameter space...
2018: PloS One
Pablo S Corona, Matías Vicente, Kevin Tetsworth, Vaida Glatt
BACKGROUND: Preoperative planning for circular external fixators is considered vital towards achieving the best results for complex post-traumatic tibial deformities, and patient-specific 3D printed (3DP) models were used here as a planning aid. The main goal was to investigate the fidelity of the preoperative planning process, by assessing the potential to reduce operative time and determining the need to adjust pre-constructed frames intra-operatively. PATIENTS AND METHODS: Nine patients (10 limbs) underwent treatment for post-traumatic tibial complications using circular external fixation...
September 2018: Injury
Uwe Walter, José Luis Fernández-Torre, Timo Kirschstein, Steven Laureys
The widely accepted concept of brain death (BD) comprises the demonstration of irreversible coma in combination with the loss of brainstem reflexes and irreversible apnea. In some countries the combined clinical finding of coma, apnea, and loss of all tested brainstem reflexes ("brainstem death") is sufficient for diagnosing BD irrespective of the primary location of brain lesion. The present article aims to substantiate the need for ancillary testing in patients with primary infratentorial brain lesions...
September 1, 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Eran Klein, Betts Peters, Matt Higger
Brain-computer interface (BCI) is a promising technology for restoring communication in individuals with locked-in syndrome (LIS). BCI technology offers a potential tool for individuals with impaired or absent means of effective communication to use brain activity to control an output device such as a computer keyboard. Exploratory studies of BCI devices for communication in people with LIS are underway. Research with individuals with LIS presents not only technological challenges, but ethical challenges as well...
October 2018: Cambridge Quarterly of Healthcare Ethics: CQ: the International Journal of Healthcare Ethics Committees
Hossein Derakhshandeh, Sara Saheb Kashaf, Fariba Aghabaglou, Ian O Ghanavati, Ali Tamayol
Chronic non-healing wounds are major healthcare challenges that affect a noticeable number of people; they exert a severe financial burden and are the leading cause of limb amputation. Although chronic wounds are locked in a persisting inflamed state, they are dynamic and proper therapy requires identifying abnormalities, administering proper drugs and growth factors, and modulating the conditions of the environment. In this review article, we discuss technologies that have been developed to actively monitor the wound environment...
September 6, 2018: Trends in Biotechnology
Manuel Gruber, Alexander Weismann, Richard Berndt
In the scanning tunnelling microscope, the many-body Kondo effect leads to a zero-bias feature of the differential conductance spectra of magnetic adsorbates on surfaces. The intrinsic line shape of this Kondo resonance and its temperature dependence in principle contain valuable information. We use measurements on a molecular Kondo system, all- trans retinoic acid on Au(1 1 1), and model calculations to discuss the role of instrumental broadening. The modulation voltage used for the lock-in detection, noise on the sample voltage, and the temperature of the microscope tip are considered...
October 24, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
T H Jones, J Javor, E K Sequin, J D West, S Prakash, V V Subramaniam
We present a method for designing and optimizing an in-house designed electromagnetic probe for distinguishing morphological differences in biological tissues. The probe comprises concentric multi-wound coils, the inner being the primary coil and the outer being the detector coil. A time-varying voltage is imposed on the primary coil, resulting in an induced current in the detector coil. For highly conductive samples, eddy currents are induced in the sample and inductively couple with the electromagnetic probe...
August 2018: Review of Scientific Instruments
Chunlei Jiang, Yunfei Liu, Bo Yu, Shuxin Yin, Peng Chen
A novel method for the detection of the second-harmonic component of tunable laser diode absorption spectroscopy-wavelength-modulated absorption spectroscopy is proposed in this study. The proposed method is based on spectral analysis, and the second-harmonic component is obtained in the frequency domain through a rectangular window. The validity, correctness, and noise immunity of the proposed method are verified through simulations and experiments. Experimental results demonstrate that the relative detection error level of the proposed method is <3%...
August 2018: Review of Scientific Instruments
R Tesař, M Šindler, J Koláček, L Skrbek
We report the design, construction, and testing of a broadband-tunable terahertz circular polarizer, which we developed for our magneto-optical measurements using the far-infrared/THz laser source in the range of 0.25-7.5 THz. We present a thorough analysis of the lock-in amplifier signal generated by using a rotating analyzer with regard to setting the desired state of polarization. The phase-sensitive detection method is applied to a combination of a wire-grid polarizer and a parallel translation mirror providing a tunable retardance...
August 2018: Review of Scientific Instruments
Zhi-Cong Zeng, Zachary D Schultz
We report a compact, fast, and low-noise large area photodiode preamplifier designed for photothermal heterodyne imaging (PHI). The preamplifier exhibits a noise level of 7 nV/Hz1/2 and a bandwidth from DC to 12 MHz sufficient for PHI experiments. Simulations of the preamplifier bandwidth and noise agree with the observed experimental characterization and performance in our home-built PHI system. The observed noise is close to the inherent limitations of the SR844 lock-in amplifier used. The results indicate that the preamplifier is also useful for any other single frequency pump-probe detection technique, such as stimulated Raman scattering...
August 2018: Review of Scientific Instruments
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