Spatiotemporal patterns corresponding to phase synchronization and generalized synchronization states of thermoacoustic instability.

Thermoacoustic instability in turbulent combustion systems emerges from the complex interplay among the flame, flow, and acoustic subsystems. While the onset of thermoacoustic instability exhibits a global order, the characteristics of local interactions between subsystems responsible for this order are not well understood. Here, we utilize the framework of synchronization to elucidate the spatiotemporal interactions among heat release rate fluctuations in the flame, velocity fluctuations in the flow, and acoustic pressure fluctuations in a turbulent combustor, across the bluff-body stabilized flame.

Comparative assessment of groundwater quality indices of Kannur District, Kerala, India using multivariate statistical approaches and GIS.

The aim of the study was to determine the groundwater characteristics of rural and industrial zones in the Kannur region. In 2011, 25 groundwater data were collected from the centre for water resource development management (CWRDM), and in 2019, 25 groundwater samples from rural and near-industrial areas were collected and analysed for major anions (HCO-, CO, Cl, NO- and SO), and cations (TH, Ca, Mg, Na, K and Fe) using APHA standards. To better understand the link between water quality parameters, multivariate statistical analysis approaches such as principal component analysis (PCA), hierarchical cluster analysis (HCA), correlation matrix analysis (CMA), and Pearson correlation bivariate one-tailed analysis (PCBOTA) were used to analyse the inter-relationship of data.

Rijke tube: A nonlinear oscillator.

Dynamical systems theory has emerged as an interdisciplinary area of research to characterize the complex dynamical transitions in real-world systems. Various nonlinear dynamical phenomena and bifurcations have been discovered over the decades using different reduced-order models of oscillators. Different measures and methodologies have been developed theoretically to detect, control, or suppress the nonlinear oscillations.

Dynamical states and bifurcations in coupled thermoacoustic oscillators.

The emergence of rich dynamical phenomena in coupled self-sustained oscillators, primarily synchronization and amplitude death, has attracted considerable interest in several fields of science and engineering. Here, we present a comprehensive theoretical study on the manifestation of these exquisite phenomena in a reduced-order model of two coupled Rijke tube oscillators, which are prototypical thermoacoustic oscillators. We characterize the dynamical behaviors of two such identical and non-identical oscillators by varying both system parameters (such as the uncoupled amplitudes and the natural frequencies of the oscillators) and coupling parameters (such as the coupling strength and the coupling delay).

Identification of potent HDAC 2 inhibitors using E-pharmacophore modelling, structure-based virtual screening and molecular dynamic simulation.

Histone deacetylase 2 (HDAC 2) of class I HDACs plays a major role in embryonic and neural developments. However, HDAC 2 overexpression triggers cell proliferation by diverse mechanisms in cancer. Over the decades, many pan and class-specific inhibitors of HDAC were discovered.

Experimental investigation on the susceptibility of minimal networks to a change in topology and number of oscillators.

Understanding the global dynamical behavior of a network of coupled oscillators has been a topic of immense research in many fields of science and engineering. Various factors govern the resulting dynamical behavior of such networks, including the number of oscillators and their coupling schemes. Although these factors are seldom significant in large populations, a small change in them can drastically affect the global behavior in small populations.

Synchronization route to weak chimera in four candle-flame oscillators.

Synchronization and chimera are examples of collective behavior observed in an ensemble of coupled nonlinear oscillators. Recent studies have focused on their discovery in systems with least possible number of oscillators. Here we present an experimental study revealing the synchronization route to weak chimera via quenching, clustering, and chimera states in a single system of four coupled candle-flame oscillators.

Oscillation quenching and phase-flip bifurcation in coupled thermoacoustic systems.

Oscillatory instabilities, although ubiquitous in nature, are undesirable in many situations such as biological systems, swaying of bridges and skyscrapers, aero-acoustic flutter, prey-predator and disease spread models, and thermoacoustic systems, where they exhibit large amplitude periodic oscillations. In the present study, we aim to study the suppression mechanism of such undesired oscillations in a pair of thermoacoustic oscillators, also known as horizontal Rijke tubes. These oscillators are coupled through a connecting tube whose length and diameter are varied as coupling parameters.

Experimental Evidence of Amplitude Death and Phase-Flip Bifurcation between In-Phase and Anti-Phase Synchronization.

Nonlinear phenomena emerging from the coupled behaviour of a pair of oscillators have attracted considerable research attention over the years, of which, amplitude death (AD) and phase-flip bifurcation (PFB) are two noteworthy examples. Although theoretical research has postulated the coexistence of AD and PFB upon variation of different control parameters, such an occurrence has not been reported in practical systems. Here, we provide the first experimental evidence of the coexistence of AD and PFB in a physical system, comprising of a coupled pair of candle-flame oscillators.

Conservative management of psoas haematoma following complex lumbar surgery.

We report psoas hematoma communicating with extradural hematoma and compressing on lumbar nerve roots during the postoperative period in a patient who underwent L3/4 level dynamic stabilization and L4/5 and L5/S1 posterior lumbar interbody fusion. Persistent radicular symptoms occurring soon after posterior lumbar surgery are not an unknown entity. However, psoas hematoma communicating with the extradural hematoma and compressing on L4 and L5 nerve roots soon after surgery, leading to radicular symptoms has not been reported.

Prevalence of insomnia in patients with chronic back pain.

Purpose: To estimate the prevalence of insomnia in patients with chronic back pain, and to correlate insomnia with severity of back pain and disability.

Methods: 63 women and 57 men aged 24 to 83 (mean, 55) years who presented with chronic back pain for >6 months were asked to complete a self-administered questionnaire to evaluate the Insomnia Severity Index (ISI), Oswestry Disability Index (ODI), and Numerical Rating Scale (NRS) for back pain.

Results: Of the 120 patients, 25 had no insomnia, 39 had sub-threshold insomnia, and 56 had clinically significant insomnia.

Effect of psychological status on outcome of posterior lumbar interbody fusion surgery.

Study Design: Prospective longitudinal study.

Purpose: To determine if preoperative psychological status affects outcome in spinal surgery.

Overview Of Literature: Low back pain is known to have a psychosomatic component.

Less invasive posterior lumbar interbody fusion and obesity: clinical outcomes and return to work.

Study Design: Single-center retrospective study.

Objective: The purpose of this study was to examine the relationship between obesity (body mass index [BMI] >30) and the incidence of perioperative complications, outcome of surgery, and return to work in a cohort of patients undergoing elective less invasive posterior lumbar interbody fusion (LI-PLIF) of the lumbar spine for low back pain and leg pain.

Summary Of Background Data: Spine surgery in the obese is challenging and an increasing problem.

Are high-intensity zones and Modic changes mutually exclusive in symptomatic lumbar degenerative discs?

Object: Modic changes (MCs) and high-intensity zones (HIZs) potentially serve as variably sensitive markers for discogenic chronic low-back pain (CLBP). No study has hitherto assessed the phenomenon of MC-HIZ coexistence at a single level, and the goal in this study was to assess the nature and frequency of this phenomenon.

Methods: One hundred twenty consecutive patients with discogenic CLBP in whom lumbar MR imaging studies had demonstrated an HIZ, an MC, or both were included.

Does symptom duration correlate negatively with outcome after posterior lumbar interbody fusion for chronic low back pain?

Study Design: Original report.

Objective: To investigate the putative negative correlation between the duration of symptoms (DOS) and outcome after surgery for chronic low back pain (CLBP).

Summary Of Background Data: Posterior lumbar interbody fusion (PLIF) is a well established treatment for CLBP.

Do design variations in the artificial disc influence cervical spine biomechanics? A finite element investigation.

Various ball and socket-type designs of cervical artificial discs are in use or under investigation. Many artificial disc designs claim to restore the normal kinematics of the cervical spine. What differentiates one type of design from another design is currently not well understood.

Significantly improved outcomes with a less invasive posterior lumbar interbody fusion incorporating total facetectomy.

Study Design: Original study.

Objective: Prospective comparison of clinical outcomes after a standard posterior lumbar interbody fusion (ST-PLIF) and after a limited exposure PLIF incorporating total facetectomy (LI-PLIF).

Summary Of Background Data: Most groups have reported significantly improved clinical outcomes after ST-PLIF.

Primary erector spinae pyomyositis causing an epidural abscess: case report and literature review.

Background Context: Primary pyomyositis (PM) is a rare bacterial infection of skeletal muscle usually restricted to tropical zones. Typically caused by Staphylococcus aureus, primary staphylococcal PM associated with an epidural abscess has not been reported before.

Purpose: We present the first case of staphylococcal PM associated with an epidural abscess.

Donor site morbidity following iliac crest bone harvesting for cervical fusion: a comparison between minimally invasive and open techniques.

We have studied the occurrence of donor site morbidity, cosmesis and overall satisfaction with graft procedure in 76 patients who had undergone iliac crest bone harvesting for anterior cervical discectomy and fusion (ACDF). Totally 24 patients underwent an open procedure and 52 a minimally invasive trephine harvesting method. Although our study demonstrated substantial donor site pain and its effect on ambulation in both groups, this was of limited duration.

Lumbar total disc arthroplasty: coronal midline definition and optimal TDA placement.

It is a general principle with arthroplasty insertion that precise implant centering is critical for long term function and outcome. Whilst some authors have proclaimed that lumbar total disc arthroplasty (TDA) may be different, and that off -centre placement may be functionally well tolerated, these claims are premature: significantly worse clinical results have already been reported with poorly placed TDA at 2 years. Accurate TDA placement requires a precise and consistent definition of the desired coronal midline target (which is currently lacking), as well as a procedural mechanism to optimize placement at that target.

The accuracy and validity of "routine" X-rays in estimating lumbar disc arthroplasty placement.

Study Design: Original study.

Objective: To compare the accuracy of radiograph (XR) estimates of lumbar total disc arthroplasty placement with high-resolution computed tomography (CT).

Summary Of Background Data: Most lumbar disc arthroplasties are inserted and subsequently analyzed using anteroposterior and lateral XR: XR estimates are often correlated with clinical outcomes.

Significantly improved lumbar arthroplasty placement using image guidance: technical note.

Study Design: Technical report.

Objective: To compare the accuracy of lumbar total disc arthroplasty placement using an image-guidance system (IGS) with conventional fluoroscopy.

Summary Of Background Data: Most disc arthroplasties are inserted and analyzed using fluoroscopy.

Subsidence and malplacement with the Oblique Maverick Lumbar Disc Arthroplasty: technical note.

Background: The A-Mav (Medtronic, Sofamor Danek, Memphis, TN) is a well-established lumbar total disc arthroplasty device. The O-Mav (Medtronic) is a more recent innovation designed to minimize the potential vascular complications associated with A-Mav insertion at L4/5. No study has hitherto studied the relative accuracy or safety of the two techniques.

Incidence, etiology, classification, and management of neuralgia after posterior lumbar interbody fusion surgery in 226 patients.

Background Context: Neurological symptoms are a well-recognized complication after posterior lumbar interbody fusion (PLIF) surgery. Concerns about this potential problem may deter surgeons from performing the procedure.

Purpose: To determine the incidence, etiology, prevention, and management of neuralgia after PLIF surgery.

Reverse transformation of Modic type 2 changes to Modic type 1 changes during sustained chronic low-back pain severity. Report of two cases and review of the literature.

Modic Type 2 (MT2) neuroimaging changes are considered stable or invariant over time and relatively quiescent, whereas Modic Type 1 (MT1) changes are considered unstable and more symptomatic. The authors report two cases in which MT2 changes were symptomatic and evidently unstable, and in which chronic low-back pain severity remained unaltered despite a MT2-MT1 reverse transformation. Two women (41 and 48 years old) both presented with chronic low-back pain.