Dynamic Fixation Techniques for the Prevention of Adjacent Segment Disease: A Retrospective Controlled Study

Fuster Salvador,Martínez-Anda Jaime Jesús,Castillo-Rivera Sergio Antonio,Vargas-Reverón Caribay,Tornero Eduard 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.3

Study Design: Retrospective, controlled study.Purpose: Dynamic fixation (topping-off technique) adjacent to a transforaminal lumbar interbody fusion (TLIF) level was developed to reduce the risk of adjacent segment disease (ASDi). This study was designed to compare the clinical and radiological outcomes between patients who underwent circumferential lumbar fusion (CLF) without the topping-off technique, CLF with dynamic rod constructs (DRC), and CLF with interspinous device (ISD).Overview of Literature: Lumbar fusion can result in the re-distribution of stress, increased mobility, and increased intradiscal pressure at adjacent levels, ultimately leading to adjacent segment degeneration (ASDe) and ASDi. Dynamic fixation techniques (topping-off techniques) adjacent to vertebral fusion have been developed to reduce the risk of ASDe and ASDi because they provide a transitional zone between a caudal rigid fused segment and cephalad-mobile unfused levels.Methods: A single-center, retrospective, controlled study was designed, including all patients who underwent CLF due to degenerative lumbar spinal disease in Hospital Clinic of Barcelona between 2012 and 2018. Three groups of patients were evaluated as per the type of topping-off technique used: CLF alone group, DRC group, and ISD group. Clinical and radiological outcomes were evaluated.Results: A total of 117 patients were enrolled in the study. Sixty patients (51.3%) underwent CLF without dynamic stabilization, 24 (20.5%) were treated with DRC as topping-off technique, and 33 (28.5%) were treated with an ISD. A total of 12 patients (20.0%) in the CLF alone group showed ASDi at the final follow-up, compared to 1 (4.2%) in the DRC group (p=0.097) and 2 (6.1%) in the ISD group (p=0.127). The Cox regression model identified a significantly decreased risk of ASDi when a topping-off technique (DRC or ISD) was used (hazard ratio, 0.154; 95% confidence interval, 0.31–0.77).Conclusions: Dynamic fixation adjacent to CLF was a safe and efficient procedure associated with improved clinical outcomes in patients with lumbar spine degenerative disease.

Prediction of the transfer length of prestressing strands with neural networks

José R. Martí-Vargas,Víctor Yepes,Francesc J. Ferri 사단법인 한국계산역학회 2013 Computers and Concrete, An International Journal Vol.12 No.2

This paper presents a study on the prediction of transfer length of 13 mm seven-wire prestressing steel strand in pretensioned prestressed concrete members with rectangular cross-section including several material properties and design and manufacture parameters. To this end, a carefully selected database consisting of 207 different cases coming from 18 different sources spanning a variety of practical transfer length prediction situations was compiled. 16 single input features and 5 combined input features are analyzed. A widely used feedforward neural regression model was considered as a representative of several machine learning methods that have already been used in the engineering field. Classical multiple linear regression was also considered in order to comparatively assess performance and robustness in this context. The results show that the implemented model has good prediction and generalization capacity when it is used on large input data sets of practical interest from the engineering point of view. In particular, a neural model is proposed -using only 4 hidden units and 10 input variables- which significantly reduces in 30% and 60% the errors in transfer length prediction when using standard linear regression or fixed formulas, respectively.

Locking Stand-Alone Cage Constructs for the Treatment of Cervical Spine Degenerative Disease

Roberto Alfonso De Leo–Vargas,Ildefonso Muñoz–Romero,Michel Gustavo Mondragón–Soto,Jaime Jesús Martínez–Anda 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.4

Study Design: Prospective case series study. Purpose: Description of the outcome of stand-alone cervical cages for single and multilevel cervical degenerative spine disease. Overview of Literature: The aim of anterior cervical discectomy and fusion (ACDF) for cervical spine disease is to improve patient symptoms and spine stability and restore lordosis. Locking stand-alone cages were developed with the goal of minimizing soft tissue disruption anterior to the vertebrae and reducing the profile of the construct by avoiding an anterior plate, thereby maximizing ACDF benefits. Methods: This study comprises a case series of patients surgically treated between July 2015 and February 2018 who received single or multilevel ACDF with a zero-profile stand-alone cervical cage. Surgical and clinical preoperative evaluation and surgical outcomes were evaluated using pre- and postoperative Nurick, Visual Analog Scale (VAS), Neck Disability Index (NDI), Japanese Orthopedic Association (JOA) score for myelopathy scales, cervical Cobb angles, postoperative surgical complications, and fusion and subsidence rates. Results: Fifty-three patients underwent ACDF; the mean age of these patients was 58.8 years, and their preoperative VAS, NDI, and JOA scores were 8.1, 31.6, and 15.3, respectively. The preoperative Cobb angle was 30.7°. Forty-five percent of patients had one-level, 54.7% had two-level, and 13.2% had three-level procedures. On preoperative magnetic resonance imaging, foraminal stenosis was present in 94.3% of patients, whereas medullar stenosis was present in 41.5%. The rate of complications was 5.7%: two patients had postoperative dysphagia (3.7%), and one patient had a surgical site hematoma. Mean postoperative follow-up time was 6.7 months; postoperative VAS, NDI, and JOA scores were 2.4, 15.9, and 15.8, respectively. Postoperative Cobb angle was 35.9°, fusion rate was 84.9%, and subsidence rate was 11.3%. Conclusions: ACDF with zero-profile stand-alone cervical devices is an excellent option for cervical degenerative disc disease of one, two, and three levels, with similar results reported when using ACDF with either cage or plate.

The gut bacteria symbionts from the monophagous insect Acrobasis nuxvorellaproduce tannase for the digestion of Carya illinoinensis tannins

Consuelo G. Corrales-Maldonado,Vargas-Arispuro Irasema,Luis Martínez-Carrillo José,Pérez-Morales Rosalva,Ángel Martínez-Téllez Miguel,Aispuro-Hernández Emmanuel,Arellano-Gil Maritza,Castro-Espinoza Lu 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.4

Acrobasis nuxvorella Neuzing (Lepidoptera: Pyralidae), or the Pecan Nut Casebearer (PNC), is a monophagous pecan nut [Carya illinoinensis (Wang) K. Koch] herbivore. This insect has caused major crop losses, despite pecan nut trees producing a high concentration of tannins, which are deterrent compounds for insects. The PNC consumes and processes tannin-rich tissues without any negative effects on its nutrition. Certain bacterial species of the herbivore gut microbiota have been proven to produce tannase, therefore, we hypothesize that the PNC has symbiotic bacteria that produce tannase for the digestion of tannin contained in their food. In this work, live PNC larvae were extracted from pecan nutlets. The larval guts were dissected and their contents were cultured to obtain the cultivable bacteria. A total of 224 bacterial isolates were recovered, 19 of which tested positive for tannase activity. Isolates LB66, LB24, TT29, and TP8 displayed comparable activity to the control strain Pseudomonas aeruginosa. Further enzyme semi-purification steps showed specific tannase ac tivity values in the range of 39.5–3.7 U/mg of protein. The isolates were identified as Bacillus pumilus strain TT29, Bacillus pumilus strain LB66, Bacillus pumilus strain LB24 and Sthaphylococcus warneri (TP8) by 16S ribo somal RNA gene sequencing. Our findings indicate that PNC larvae contain gut bacteria able to produce tannase that hydrolyze the galloyl ester bonds in tannins.

Brain-lung interaction: a vicious cycle in traumatic brain injury

Ariana Alejandra Chacón-Aponte,Érika Andrea Durán-Vargas,Jaime Adolfo Arévalo-Carrillo,Iván David Lozada-Martínez,Maria Paz Bolaño-Romero,Moscote-Salazar Luis Rafael,Pedro Grille,Janjua Tariq 대한중환자의학회 2022 Acute and Critical Care Vol.37 No.1

The brain-lung interaction can seriously affect patients with traumatic brain injury, triggering a vicious cycle that worsens patient prognosis. Although the mechanisms of the interaction are not fully elucidated, several hypotheses, notably the “blast injury” theory or “double hit” model, have been proposed and constitute the basis of its development and progression. The brain and lungs strongly interact via complex pathways from the brain to the lungs but also from the lungs to the brain. The main pulmonary disorders that occur after brain injuries are neurogenic pulmonary edema, acute respiratory distress syndrome, and ventilator-associated pneumonia, and the principal brain disorders after lung injuries include brain hypoxia and intracranial hypertension. All of these conditions are key considerations for management therapies after traumatic brain injury and need exceptional case-by-case monitoring to avoid neurological or pulmonary complications. This review aims to describe the history, pathophysiology, risk factors, characteristics, and complications of brain-lung and lung-brain interactions and the impact of different old and recent modalities of treatment in the context of traumatic brain injury.

Potential Control of Foodborne Pathogenic Bacteria by Pediococcus pentosaceus and Lactobacillus graminis Isolated from Fresh Vegetables

C.J. González-Pérez1,I. Vargas-Arispuro,E. Aispuro-Hernández,C.L. Aguilar-Gil,Y.E. Aguirre-Guzmán,A. Castillo,A. Hernández-Mendoza,J.F. Ayala-Zavala,M.A. Martínez-Téllez1 한국미생물·생명공학회 2019 한국미생물·생명공학회지 Vol.47 No.2

The consumption of fresh vegetables has been related to recurrent outbreaks of foodborne diseases (FBD) worldwide. Therefore, the development of effective alternative technologies is necessary to improve the safety of these products. This study aimed to isolate and identify epiphytic lactic acid bacteria (LAB) from fresh fruits and leafy vegetables and characterize their antagonistic capacity due to their ability to produce bacteriocins or antibacterial compounds. For this, 92 LAB isolates from fruits and leafy vegetables were screened for antagonistic activity. Two strains with the highest and broadest antagonistic activities were selected for further characterization; one from cantaloupe melon (strain CM175) and one from cilantro leaves (strain C15). The cell-free supernatants (CFS) of CM175 and C15 were found to exhibit antagonistic activity against FBD-causing pathogens. The CM175 and C15 strains were identified as Pediococcus pentosaceus and Lactobacillus graminis, respectively. Notably, the P. pentosaceus CM175 CFS stopped the growth of Salmonella Typhimurium, Salmonella Saintpaul, Staphylococcus aureus, and Listeria monocytogenes, and delayed Escherichia coli O157:H7 growth. Moreover, L. graminis C15 CFS delayed the growth of all indicator pathogens, but did not completely stop it. Organic acids and bacteriocin-like molecules were determined to be possibly exerting the observed antagonistic activity of the identified LAB strains. Thus, application of the antagonistic compounds produced by Pediococcus pentosaceus and Lactobacillus graminis could be a novel and ecological strategy in developing antimicrobial biopreservatives for the food industry and mitigating FBD by reducing the biological contamination in fruit and vegetable orchards, mainly via their potential in controlling both gram-negative and gram-positive pathogenic bacteria.

Development of Collagen/Poly(vinyl alcohol)/Chondroitin Sulfate and Collagen/Poly(vinyl alcohol)/HA Electrospun Scaffolds for Tissue Engineering

Luis Humberto Delgado-Rangel,Julia Hernández-Vargas,Marymar Becerra-González,Ataúlfo Martínez-Torres,Evgen Prokhorov,J. Betzabe González Campos 한국섬유공학회 2019 Fibers and polymers Vol.20 No.12

The combination of collagen (CG), chondroitin sulfate (CS), and hyaluronic acid (HA) with poly(vinyl alcohol)(PVA) was explored to produce 3D tri-component scaffolds with enhanced mechanical properties and potential use in tissueengineering. The CG/PVA/CS and CG/PVA/HA electrospun scaffolds were crosslinked with citric acid, a cytocompatiblecrosslinker, which induced improved mechanical properties in both dry and wet state, especially with large elongation atbreak in the wet state. Ultimate tensile stress under the dry and wet state are significantly higher than those previouslyreported about collagen based nanofibers. IR, DSC and dielectric analysis demonstrated homogenous blending without phaseseparation and strong interactions between components. All scaffolds had swelling pH-sensitive behavior, making thempromising materials for drug delivery systems. The nanofiber mats permitted adhesion and proliferation of human embryonickidney cells; this cell line formed clusters that adapted well to the mats’ surface, through which the cells extended theirprocesses.

Bond mechanism of 18-mm prestressing strands: New insights and design applications

Canh N. Dang,José R. Martí-Vargas,W. Micah Hale 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.1

Pretensioned concrete (PC) is widely used in contemporary construction. Bond of prestressing strand is significant for composite-action between the strand and concrete in the transfer and flexural-bond zones of PC members. This study develops a new methodology for quantifying the bond of 18-mm prestressing strand in PC members based on results of a pullout test, the Standard Test for Strand Bond (STSB). The experimental program includes: (a) twenty-four pretensioned concrete beams, using a wide range of concrete compressive strength; and (b) twelve untensioned pullout specimens. By testing beams, the transfer length, flexural-bond length, and development length were all measured. In the STSB, the pullout forces for the strands were measured. Experimental results indicate a significant relationship between the bond of prestressing strand to the code-established design parameters, such as transfer length and development length. However, the code-predictions can be unconservative for the prestressing strands having a low STSB pullout force. Three simplified bond equations are proposed for the design applications of PC members.

Magnetic field emergence in mesogranular-sized exploding granules observed with sunrise/IMaX data

Palacios, J.,Blanco Rodrí,guez, J.,Vargas Domí,nguez, S.,Domingo, V.,Martí,nez Pillet, V.,Bonet, J. A.,Bellot Rubio, L. R.,Iniesta, J. C. del Toro,Solanki, S. K.,Barthol, P.,Gandorfe EDP Sciences 2012 Astronomy and astrophysics Vol.537 No.-

<P>We report on magnetic field emergences covering significant areas of exploding granules. The balloon-borne mission SUNRISE provided high spatial and temporal resolution images of the solar photosphere. Continuum images, longitudinal and transverse magnetic field maps and Dopplergrams obtained by IMaX onboard SUNRISE are analyzed by local correlation traking (LCT), divergence calculation and time slices, Stokes inversions and numerical simulations are also employed. We characterize two mesogranular-scale exploding granules where~10<SUP>18</SUP> Mx of magnetic flux emerges. The emergence of weak unipolar longitudinal fields (~100 G) start with a single visible magnetic polarity, occupying their respective granules’ top and following the granular splitting. After a while, mixed polarities start appearing, concentrated in downflow lanes. The events last around 20 min. LCT analyses confirm mesogranular scale expansion, displaying a similar pattern for all the physical properties, and divergence centers match between all of them. We found a similar behaviour with the emergence events in a numerical MHD simulation. Granule expansion velocities are around 1 kms<SUP>−1</SUP> while magnetic patches expand at 0.65 kms<SUP>−1</SUP>. One of the analyzed events evidences the emergence of a loop-like structure. Advection of the emerging magnetic flux features is dominated by convective motion resulting from the exploding granule due to the magnetic field frozen in the granular plasma. Intensification of the magnetic field occurs in the intergranular lanes, probably because of being directed by the downflowing plasma.</P>