bluuebunny/crossref_metadata_2025 huggingface dataset:
1166. Development of a Bedside Tool to Predict the Probability of Drug-Resistant Pathogens Among an Adult Population With Gram-Negative Infections
Authors: Lodise Jr. Thomas P , Bonine Nicole G , Ye J Michael , Folse Henry J , Gillard Patrick
Published: November 2018

Background

Identification of infections caused by antimicrobial-resistant microorganisms is critical to administration of early appropriate antibiotic therapy. We developed a clinical bedside tool to estimate the probability of carbapenem-resistant Enterobacteriaceae (CRE), extended spectrum β-lactamase-producing Enterobacteriaceae (ESBL), and multidrug-resistant Pseudomonas aeruginosa (MDRP) among hospitalized adult patients with Gram-negative infections.

Methods

A retrospective observational study of the Premier Hospital Database (PHD) was conducted. The study included adult hospitalized patients with complicated urinary tract infection (cUTI), complicated intraabdominal infection (cIAI), bloodstream infections (BSI), or hospital-acquired/ventilator-associated pneumonia (HAP/VAP) with a culture-confirmed Gram-negative infection in PHD from 2011 to 2015. Model development steps are shown in Figure 1. The study population was split into training and test cohorts. Prediction models were developed using logistic regression in the training cohort (Figure 1). For each resistant phenotype (CRE, ESBL, and MDRP), a separate model was developed for community-acquired (index culture ≤3 days of admission) and hospital-acquired (index culture >3 days of admission) infections (six models in total). The predictive performance of the models was assessed in the training and test cohorts. Models were converted to a singular user-friendly interface for use at the bedside.

Results

The most important predictors of antibiotic-resistant Gram-negative bacterial infection were prior number of antibiotics, infection site, prior infection in the last 3 months, hospital prevalence of each resistant pathogen (CRE, ESBL, and MDRP), and age (Figure 2). The predictive performance was highly acceptable for all six models (Figure 3).

Conclusion

We developed a clinical prediction tool to estimate the probability of CRE, ESBL, and MDRP among hospitalized adult patients with community- and hospital-acquired Gram-negative infections. Our predictive model has been implemented as a user-friendly bedside tool for use by clinicians to predict the probability of resistant infections in individual patients, to guide early appropriate therapy.

Disclosures

T. P. Lodise Jr., Motif BioSciences: Board Member, Consulting fee. N. G. Bonine, Allergan: Employee, Salary. J. M. Ye, Allergan: Employee, Salary. H. J. Folse, Evidera: Employee, Salary. P. Gillard, Allergan: Employee, Salary.
LB3. Daptomycin Plus Fosfomycin vs. Daptomycin Monotherapy for Methicillin-Resistant Staphylococcus aureus Bacteremia: A Multicenter, Randomized, Clinical Trial
Authors: Pujol Miquel , Miro Jose-Maria , Shaw Evelyn , Aguado Jose Maria , Garrido Rafael San-Juan , Puig Mireia , Pigrau Carle , Calbo Esther , Montejo Jose Miguel , Rodriguez Regino , Garcia-Pais Maria Jose , Pintado Vicente , Escudero Rosa , Lopez-Contreras Joaquin , Morata Laura , Montero Milagro , Andres Marta , Pasquau Juan , Padilla Belen , Murillas Javier , Jover Alfredo , Lopez-Cortes Luis Eduardo , Garcia-Pardo Graciano , Gasch Oriol , Videla Sebastian , Tebe Cristian , Pallares Natalia , Hereu Pilar , Sanllorente Mireia , Dominguez Maria Angeles , Camara Jordi , Padulles Ariadna , Carratala Jordi
Published: November 2018

Background

Daptomycin plus fosfomycin combination has demonstrated synergistic and bactericidal effect in animal models of methicillin-resistant Staphylococcus aureus bacteremia (MRSAB), but there is lack of data in humans.

Method

A randomized (1:1), open-label, clinical trial involving adults with MRSAB was conducted at 18 medical centers in Spain. Patients were assigned to receive daptomycin, 10 mg/kg IV daily plus fosfomycin, 2 g IV/6 hour (combination therapy) or to receive daptomycin 10 mg/kg/24 h IV (monotherapy) during 10 up to 14 days for uncomplicated bacteremia and 28 up to 42 days for complicated bacteremia. The primary efficacy endpoints were: (a) treatment success at Test-of-Cure visit (ToC: 6 weeks after end of therapy) and (b) treatment success at 7 days (defined as alive at day 7 and clearance of bacteremia without relapse from 8 to 90 days after randomization), according with the proposed primary endpoints for use in clinical trials in bloodstream infections in adults.

Result

Between December 2013 and November 2017, 674 patients with MRSAB were evaluated and 155 patients were randomized: 74 received combination therapy and 81 monotherapy. In intention-to-treat analysis, (a) at ToC visit successful outcome was achieved in 40 of 74 patients (54,1%) who received combination therapy as compared with 34 of 81 patients (42%) who were given monotherapy (54.1% vs. 42.0%; absolute difference, 12.1%; 95% confidence interval, 0%-27.0%); (b) at 7 days after starting the therapy: a successful outcome was achieved in 69 of 74 patients who received combination therapy as compared with 62 out of 81 patients who received monotherapy (93.2% vs. 76.5%; absolute difference, 16.7%; 95% confidence interval, 5.4%–27.7%). Combination therapy was associated with lower rates of microbiologic failure than monotherapy at ToC visit (0 vs. 9 patients, P = 0.009). Combination therapy, as compared with daptomycin monotherapy, was associated with a nonsignificantly higher rate of adverse events due to study medication leading to treatment failure and discontinuation of therapy: 6/74 (8.1%) vs. 3/81 (3.7%) (P = 0.31).

Conclusion

The combination of daptomycin plus fosfomycin was more effective than daptomycin alone for treating MRSAB (NCT01898338).

Disclosures

All authors: No reported disclosures.
LB7. Contract Tracing Investigation Following First Case of Andes Virus in the United States
Authors: Kofman Aaron , Eggers Paula , Kjemtrup Anne , Hall Rebecca , Brown Shelley , Choi Mary , Yaglom Hayley , Duwell Monique , Knust Barbara , Klena John , Alvarado-Ramy Francisco , Shoemaker Trevor , Towner Jonathan , Nichol Stuart ,   The Andes Virus Investigation Working Group
Published: November 2018

Background

In January 2018, a patient admitted to a Delaware hospital tested positive for New World hantavirus by IgM and IgG ELISA. Subsequent testing by CDC’s Viral Special Pathogens Branch (VSPB) confirmed Andes virus (ANDV) by reverse transcription polymerase chain reaction (RT-PCR) and sequencing. ANDV is transmitted to humans through contact with long-tailed rice rats endemic to Argentina and Chile. Unlike other hantavirus species, ANDV can be transmitted person to person, but transmission is typically limited to close contacts of ill persons. Because of this risk, a contact tracing investigation was initiated by CDC, state and county health departments.

Method

A suspect case was defined as a person with close contact with the traveler who became ill within the maximum incubation period (42 days) following last contact. A high-risk contact was defined as a person with exposure to the traveler’s body fluids. A low-risk contact was defined as a person who had provided care or in-flight service to, or was seated near the traveler for at least 1 hour, in the absence of exposure to body fluids. All contacts were advised to self-monitor their temperature daily for 42 days from last contact, and to seek medical care for any of the specified symptoms. Contacts that developed symptoms were tested for ANDV by RT-PCR and serology by VSPB.

Result

Fifty-three contacts were identified in six states; 51 were successfully reached. Of these, 28 were healthcare workers, 15 were airline contacts, seven were acquaintances of the traveler, and one was a hospital roommate. Two high-risk contacts were identified, both of whom remained asymptomatic. Six low-risk contacts reported influenza-like illness, diarrhea, or mild rhinitis during the incubation period. All six symptomatic low-risk contacts tested negative for ANDV by PCR, IgM, and IgG. The remaining low-risk contacts remained asymptomatic.

Conclusion

Hospitalized patients with ANDV should be managed with standard, contact, and droplet precautions. While the risk of human-to-human transmission is low, contact tracing should be considered to identify potential cases and limit additional exposures. Health providers should consider ANDV in returning travelers with a nonspecific febrile or acute respiratory illness who have traveled to the Andes region of Argentina or Chile in the preceding 6 weeks.

Disclosures

All authors: No reported disclosures.
SWAT Unit Proactive Search Warrant Deployments: A Mixed Effects Model Exploration
Authors: Dobrin Adam , Fallik Seth W , Mello Brian P
Published: November 2018

This research examines American police operations by Special Weapons and Tactics (SWAT) units. In this study, SWAT unit proactive search warrant deployments in Maryland over a 4-year period (2010–13) were analysed to see if they were influenced by violent crime rates, property crimes rates, vice crime rates, and the number of sworn law enforcement officers across four models (two random effects and fixed effects models). The results reveal an inverse relationship between proactive vice type arrests and SWAT unit proactive search warrant deployments. The results are discussed as they inform SWAT unit policies in a democracy.
Clinical Reasoning in Physical Therapy: A Concept Analysis
Authors: Huhn Karen , Gilliland Sarah J , Black Lisa L , Wainwright Susan F , Christensen Nicole
Published: November 2018

Background

Physical therapy, along with most health professions, struggles to describe clinical reasoning, despite it being a vital skill in effective patient care. This lack of a unified conceptualization of clinical reasoning leads to variable and inconsistent teaching, assessment, and research.

Objective

The objective was to conceptualize a broad description of physical therapists’ clinical reasoning grounded in the published literature and to unify understanding for future work related to teaching, assessment, and research.

Design/Methods

The design included a systematic concept analysis using Rodgers’ evolutionary methodology. A concept analysis is a research methodology in which a concept's characteristics and the relation between features of the concept are clarified.

Results

Based on findings in the literature, clinical reasoning in physical therapy was conceptualized as integrating cognitive, psychomotor, and affective skills. It is contextual in nature and involves both therapist and client perspectives. It is adaptive, iterative, and collaborative with the intended outcome being a biopsychosocial approach to patient/client management.

Limitations

Although a comprehensive approach was intended, it is possible that the search methods or reduction of the literature were incomplete or key sources were mistakenly excluded.

Conclusions

A description of clinical reasoning in physical therapy was conceptualized, as it currently exists in representative literature. The intent is for it to contribute to the unification of an understanding of how clinical reasoning has been conceptualized to date by practitioners, academicians, and clinical educators. Substantial work remains to further develop the concept of clinical reasoning for physical therapy, including the role of movement in our reasoning in practice.
RADIATION EXPOSURE FROM NATURAL RADIONUCLIDES IN BUILDING MATERIALS
Authors: Madruga M J , Miró C , Reis M , Silva L
Published: November 2018

Building materials from Iberian Peninsula (Portugal and Spain) were collected and analysed for 226Ra, 232Th and 40K using HPGe gamma-ray spectrometers. The results show that the highest mean value of 226Ra and 232Th activities are 2168 and 390 Bq kg−1, respectively, measured in zircon. For 40K, this value is 1290 Bq kg−1, measured in granite. The mean concentrations of the three radionuclides in the different building materials, excluding the zircon and the industrial by-products (ashes, gypsum and phosphogypsum), are 62, 31 and 519 Bq kg−1 for 226Ra, 232Th and 40K, respectively. The radiological health hazard parameters: radium equivalent activity (Raeq), activity concentration index (I) absorbed and effective dose rates, associated with these radionuclides, were evaluated. These values are within the EU recommended limits in building materials, except for same samples of aggregates, granites, ceramics, phosphogypsum and zircon. This study will contribute for the worldwide data pooling on the radioactivity of the building materials.
Developmental Dynamics of Meloidogyne hapla in Washington Wine Grapes
Authors: East Katherine E. , Zasada Inga A. , Schreiner R. Paul , Moyer Michelle M.
Published: November 2018

Meloidogyne hapla is the most prevalent plant-parasitic nematode in Washington state wine grape vineyards. Understanding the developmental dynamics of M. hapla can improve the timing of diagnostic sampling and nematicide application. Three Vitis vinifera vineyards in Washington were sampled March 2015 to March 2017 to determine the developmental dynamics of M. hapla by measuring second-stage juveniles (J2) in soil, eggs and adult females in roots, and fine root tips. A model of M. hapla J2 development based on soil growing degree days using a base temperature (Tb) of 0°C (GDDsoil) and a start date of 1 March was developed. This model was validated at two additional vineyards in Washington and was robust with R2 values > 0.74. M. hapla has one generation per year and overwinters primarily as the J2 infective stage. Juvenile populations declined after 1 March, reaching their lowest density in early July and reaching a maximum density over the winter. M. hapla egg and root tip densities reached a maximum in early August. The number of females per root tip did not vary throughout the year. A single generation with defined peaks in J2 population densities will allow for specific timing of nematicide interventions.
Perioperative Invasive Vascular Catheterization Associated With Increased Risk of Postoperative Infection in Lumbar Spine Surgery
Authors: Compton Edward , Heindel Patrick , Formanek Blake , Schoell Kyle , Buser Zorica , Wang Jeffrey C.
Published: November 2018

Study Design:

This is a retrospective cohort study.

Objective:

This study’s objective was to determine whether perioperative invasive vascular catheter placement, independent of comorbid conditions, modified the risk of postoperative infection in lumbar spine surgery.

Summary of Background Data:

Infection is a risk inherent to lumbar spine surgery, with overall postoperative infection rates of 0.86%–8.5%. Patients experiencing postoperative infection have higher rates of mortality, revision surgeries, pseudarthrosis, and worsening pain and disability.

Methods:

Data were collected for patients undergoing lumbar spine surgery between January 2007 and October 2015 with records in the nationwide Humana private insurance database. Patients receiving fusion, laminectomy, and discectomy were followed for 3 months from the date of surgery for surgical site infection (SSI), 6 months for subsequent incision and drainage (I&D), and 1 year for vertebral osteomyelitis (VO). Risk factors investigated included central venous catheter and arterial-line placement.

Results:

Analysis of 114,259 patient records showed an overall SSI rate of 3.2% within 1 month and 4.5% within 3 months, overall vertebral osteomyelitis rate of 0.82%–0.83% within 1 year, and overall I&D rate of 2.8% within 6 months. Patients receiving a first-time invasive vascular catheter on the day of surgery were more likely to experience SSI within 1 month [risk ratios (RR), 2.5, 95% confidence interval (CI): 2.3–2.7], SSI within 3 months (RR, 2.4; 95% CI: 2.3–2.7), osteomyelitis within 1 year (RR, 4.2–4.3; 95% CI: 3.7–4.5), and undergo an I&D within 6 months (RR, 1.9; 95% CI: 1.8–2.0). These trends were consistent by procedure type and independent of the patient’s weighted comorbidity index score (Charlson Comorbidity Index).

Conclusions:

Perioperative invasive vascular catheterization was significantly associated with an increased the risk of postoperative infections in lumbar spine surgery, independent of a patient’s concomitant comorbidities. Therefore, in patients with an indication for invasive catheterization, surgeons should consider risks and benefits of surgery carefully.

Level of Evidence:

Level III.
The risk for childhood malignancies in the offspring of mothers with previous gestational diabetes mellitus: a population-based cohort study
Authors: Kessous Roy , Wainstock Tamar , Walfisch Asnat , Sheiner Eyal
Published: November 2018

The hyperglycemic intrauterine environment has been shown to have long-term effects on offspring. We aimed to evaluate its effect on the long-term risk of childhood malignancies. This was a population-based cohort analysis comparing the risk for long-term childhood malignancies (≤18 years) in children born to mothers with and without gestational diabetes mellitus (GDM). Childhood malignancies were diagnosed by physicians and recorded in hospital medical files according to predefined codes based on ICD-9. Deliveries occurred between the years 1991 and 2014 in a tertiary medical center. Children to mothers with pre-GDM, with fetal congenital malformations, and with benign tumors were excluded from the analysis. Kaplan–Meier survival curve was constructed to compare cumulative oncological morbidity in both groups over time. Cox proportional hazards model was used to control for confounders. During the study period, 236 893 infants met the inclusion criteria; 10 294 (4.3%) of whom were born to mothers with GDM. Hospitalizations involving malignancy diagnoses were comparable between the groups (0.11 vs. 0.12%; P=0.424), as were the cumulative incidences of total oncological morbidity using a Kaplan–Meier survival curve (log-rank P=0.820). In the Cox regression model, maternal GDM was not associated with increased childhood oncological hospitalizations while controlling for maternal age, gestational age, and hypertensive disorders (adjusted hazard ratio: 1.02, 95% confidence interval: 0.58–1.82, P=0.932). Exposure to intrauterine hyperglycemic environment due to maternal GDM does not increase the risk for childhood malignancies.
Infantile Acute Conjunctivitis Induced by β-Lactamase–Positive Amoxicillin–Clavulanate–Resistant Strain of Haemophilus influenzae: A Report of Three Cases
Authors: Inada Noriko , Shoji Jun , Yamagami Satoru
Published: November 2018

This study is a retrospectively recruited case series. We report three infants with acute conjunctivitis induced by β-lactamase–positive, ampicillin/clavulanic acid-resistant strains of Haemophilus influenzae (BLPACR). Patients with BLPACR-positive cultures were recruited from among 5,107 patients with inflammatory diseases of the ocular surface who underwent examinations, including bacterial culturing of conjunctival sac or corneal scrapings, between 2000 and 2015. Three BLPACR-positive patients were recruited, including a 10-month-old boy, a 4-month-old girl, and a 7-month-old girl. All three demonstrated BLPACR conjunctivitis. The clinical findings in these patients included fever, mucopurulent discharge, lid swelling, and conjunctival hyperemia. Samples of conjunctival swabs were obtained from all three infants, and BLPACR was isolated from all these conjunctival swabs. Antimicrobial susceptibility testing showed sensitivity to levofloxacin and resistance to ampicillin, cefaclor, and clarithromycin. We conclude that in infantile BLPACR conjunctivitis, simultaneous investigation for the determination of causative organism and antibiotic susceptibility testing are crucial aspects of the medical treatment.
Factors Associated With Hospices’ Nonparticipation in Medicare’s Hospice Compare Public Reporting Program
Authors: Hsu Sylvia H. , Hung Peiyin , Wang Shi-Yi
Published: November 2018

Background:

To enhance the quality of hospice care and to facilitate consumers’ choices, the Centers for Medicare and Medicaid Services (CMS) began the Hospice Quality Reporting Program, in which CMS posted the quality measures of participating hospices on its reporting website, Hospice Compare. Little is known about the participation rate and the types of nonparticipating hospices.

Objective:

To examine the factors associated with hospices’ nonparticipation in Hospice Compare.

Research Design:

We analyzed data from the CMS 2016 Hospice Compare. “Nonparticipants” were those who did not submit any quality measure. With the data of the Provider of Service file, the Healthcare Cost Report Information System, and the Area Health Resources File, multivariate logistic regressions estimated the association between nonparticipants and hospice and market characteristics, including ownership, size, nurse staffing ratio, and market competition intensity.

Results:

Among the 4123 certified hospices subject to penalty from nonparticipation, 259 did not participate in Hospice Compare. California, New Mexico, Texas, and Wyoming had participation rates lower than 80%. Hospices that were for-profit, had no accreditation, had few nurses per patient day, provided no inpatient care, and were located in competitive markets were less likely to participate than other hospices.

Conclusions:

Hospice Compare successfully motivated hospice in participating in the quality report program in most of states. For-profit hospices, hospices with less quality, and hospices located in competitive markets were less likely to participate. Further research is warranted to examine the quality of these nonparticipants, especially in the 4 states with a lower participation rate.
Timing of Antibiotic Administration in Pediatric Sepsis
Authors: Creedon Jessica K. , Vargas Sigella , Asaro Lisa A. , Wypij David , Paul Raina , Melendez Elliot
Published: November 2018

Objectives

Antibiotic administration within 1 hour of hypotension has been shown to reduce mortality. It is unknown whether antibiotics before hypotension in children who eventually meet criteria for septic shock improves outcomes. This study assesses whether antibiotic timing from the time of meeting criteria for sepsis in children with septic shock impacts morbidity and mortality.

Methods

This is a retrospective study of children 18 years or younger presenting to a tertiary free-standing children's hospital emergency department with sepsis that subsequently progressed to septic shock and were admitted to an intensive care unit from 2008 to 2012. The time when the patient met criteria for sepsis to the time of first antibiotic administration was assessed and correlated with patient morbidity and mortality.

Results

Among 135 children (median age, 13.1 years), 34 (25%) were previously healthy, whereas 49 (36%) had 2 or more medical comorbidities. Twenty-seven children (20%) had positive blood cultures, 17 (13%) had positive urine cultures, and 34 (25%) had chest x-ray findings that were interpreted as pneumonia. Among the 42 (31%) with antibiotics within 1 hour from criteria for sepsis, there was higher mortality (4/42 vs 0/93, P = 0.009), more organ dysfunction, longer time on a vasoactive infusion, and increased intensive care unit and hospital lengths of stay (all P < 0.05).

Conclusions

Children with criteria for sepsis who subsequently progressed to septic shock who received antibiotics within 1 hour of meeting sepsis criteria had increased mortality, length of stay, and organ dysfunction.
Psychosocial Support in Adolescents and Young Adults With Cancer
Authors: Penn Anthony , Kuperberg Aura
Published: November 2018

Various forms of psychosocial support have been suggested in working with adolescents and young adults (AYAs) as they attempt to cope with cancer, including peer-based interventions, individual psychoeducational counseling, and skill-based interventions. More recently, modern electronic applications created technology-based ways to deliver information and support and have grown in popularity to satisfy AYA needs for information and support. Such support should be offered routinely rather than in a response to a crisis. This article focuses on psychosocial interventions for AYAs aged 15 to 39 years with cancer at diagnosis, during treatment, and shortly after.
Adolescent and Young Adult Cancer Biology
Authors: Tricoli James V. , Bleyer Archie
Published: November 2018

Adolescent and young adult (AYA) patients with cancer have not attained the same improvements in overall survival as either younger children or older adults. One possible reason for this disparity may be that the AYA cancers exhibit unique biologic characteristics, resulting in differences in clinical and treatment resistance behaviors. Our current understanding of the unique biological/genomic characteristics of AYA cancers is limited. However, there has been some progress that has provided clues about the biology of AYA cancers. We here review the latest findings in the area of AYA cancer biology and discuss what is required to advance the field for the more effective treatment of this patient population.
Lymphoma in Adolescents and Young Adults
Authors: Hochberg Jessica , Cairo Mitchell S.
Published: November 2018

Lymphomas in adolescents and young adults represent approximately one quarter of all cancers in this age group. Historically, adolescent and young adult cancer patients represent a unique population with diverging issues surrounding psychosocial hardships/barriers, economics, and lack of standardization of therapeutic approaches.

Furthermore, the biologic differences within the adolescent and young adult population seen in various lymphoma subtypes likely play a role in overall outcomes for this group. Without an organized approach to clinical and translational research for adolescent and young adult patients within specialized treatment centers, this population may continue to experience inferior results. Here we look at the current perspectives of adolescent and young adult lymphomas with respect to disease biology, clinical characteristics, treatment, and prognosis of this unique lymphoma population.
Bone Flap Technique With Piezosurgery for Impacted Teeth Extraction and Bone Cysts Removal Without Additional Fixation
Authors: Akçay Hüseyin , Tatar Birkan , Kuru Keremcan , Gözlüklü Özgür , Ulu Murat
Published: November 2018

To explore a new surgical approach for impacted teeth extraction and cystectomy using piezosurgery that provides proper bone healing in normal anatomical structure without additional fixation and graft materials.

In cases with intact and relatively thicker vestibular compact bone, a bone flap design was used with converging osteotomy lines made with piezosurgery tips which allow proper stabilization after enucleation or extraction.

Procedure was performed in 10 patients with 9 to 36 months follow-up resulted in satisfactory healing without any complications.

Comparing to traditional techniques, effective enucleation and accelerated bone regeneration are achieved, with reduced risk of complications, operation time, and costs.
Masseter-to-Facial Nerve Transfer for Reanimation of a Patient With Long-Term Facial Paralysis
Authors: Salmerón-González Enrique , Simón-Sanz Eduardo , García-Vilariño Elena , García-Sánchez Jose María , Ruiz-Cases Alberto
Published: November 2018

Facial paralysis is a condition caused by a wide variety of etiologies, including neurologic, congenital, infectious, neoplastic, systemic, and iatrogenic causes. A patient suffering from long-term facial paralysis, with minimal innervation detected through electroneurography, who was successfully reanimated by performing a masseter-to-facial nerve transfer, was presented in this study. Facial paralysis had been caused after resection of an acquired middle ear cholesteatoma more than 5 years before.
Comparison of the Clinical Outcomes of Buccal Advancement Flap Versus Platelet-Rich Fibrin Application for the Immediate Closure of Acute Oroantral Communications
Authors: Bilginaylar Kani
Published: November 2018

The aim of this study was to compare the clinical outcomes of buccal advancement flap surgery to platelet-rich fibrin (PRF) application for the closure of acute oroantral communications (AOACs). In 36 patients, following the extractions of posterior maxillary teeth, AOACs which were larger than 3 mm diameter were detected. In group A, PRF clots were used in 21 patients and group B, classic buccal advancement flap was used in 15 patients. Baseline variables such as pain, the analgesic doses are taken, and swelling was assessed preoperatively. These were also examined on postoperative days 1, 2, 3, and 7, and patients were seen again in the 3rd week. In group A, statistically significant reduction was examined (P < 0.05) in pain and the analgesic doses are taken (sum of 1st, 2nd, 3rd, and 7th days on days 1 and 2) (PRF). The swelling was also significantly less in group A (P < 0.05). The mean duration did not differ between the groups (P > 0.05). In conclusion, both methods were successful for the immediate closure of AOACs. However, a lesser amount of pain and no swelling observed with the use of PRF clots for the immediate closure of AOACs compared to buccal advancement flap surgery.
Tympanogram Findings in Hemodialysis Patients
Authors: Aksit Ates Mehmet , Pektas Emel , Kalcioglu Mahmut Tayyar , Ozkok Abdullah , Tuysuz Ozan , Tekin Muhammet
Published: November 2018

Background:

The aim of this study is to investigate whether changes in cerebrospinal fluid (CSF) pressure during the hemodialysis (HD) treatment are reflected on tympanometric measurements.

Methods:

The study was performed on 24 HD patients. The static compliance and absorbance values of the patients before and after HD were measured using a wideband tympanometry. The tympanogram tests were performed immediately before and at the end of the HD session.

Results:

The static compliance values of the patients after HD were significantly lower than those before HD. This decrease significantly correlated with the adequacy of dialysis determined by urea reduction rate and Kt/V. The absorbance values showed a decrease in the band 343 and 727 Hz, but no significant difference was found in other frequencies. The static admittance and absorbance values were influenced by the HD process.

Discussion:

This influence might be due to the increase in CSF pressure as a result of the removal of urea from blood during HD session.
Distraction Osteogenesis of Fibula Graft for Mandibular Reconstruction Following Ameloblastoma Ablation
Authors: Xu Luchen , Li Chunjie , Wang Hongning , Zhu Songsong , Li Yunfeng
Published: November 2018

Background:

Resection of maxillofacial may cause a series of complications such as loss of facial deformity, dysfunction, and psychological distress. Mandibular reconstruction following resection still remains difficult.

Methods:

A 18-year-old male patient with mandibular ameloblastoma was admitted in the hospital of stomatology. The tumor was dissected and the defect was reconstructed using vascularized fibula graft. One year later, distraction osteogenesis (DO) was performed on the fibula graft to augment the alveolar bone for dental implants. Panoramic radiographs, computed tomography, and clinical photographs were taken. Five months after completion of distraction, the distraction device was removed.

Results:

Panoramic radiographs, computed tomography, and clinical photographs showed the good healing after fibula graft for mandibular reconstruction following ameloblastoma ablation and satisfied alveolar bone with good width and height for dental implants after DO.

Conclusions:

This report suggests that DO of fibula graft following mandibular reconstruction was an efficient method to augment the alveolar bone for dental implants.
A Step-by-Step Procedure for Bone Regeneration Using Calcium Phosphate Scaffolds: From Site Preparation to Graft Placement
Authors: Messina Antonello Maria , Marini Luca , Oh Daniel S. , Marini Ettore
Published: November 2018

Hydroxyapatite (HA) is the main mineral component of bone and teeth. HA is often used as a bone substitute and especially in its granular form it is osteoconductive and osseointegrating as shown by many investigations in animals and humans. HA granules are used for filling bone defects, but they have poor handling qualities and retention at the surgical site, leading to graft voids between the granules and bone tissue and resulting in mechanical instability. Furthermore HA implantation is not constantly followed by favorable results, especially when it is carried out for augmentation of the alveolar ridge. This article offers a protocol for bone reconstruction and predictable implant treatment outcomes. We provide a step-by-step description of both the recipient site and composite graft preparations using coralline HA granules (CHAG) and homologous fibrin glue (HFG). In the present study, 20 randomly selected patients (12 women and 8 men) underwent bone regeneration using CHAG-HFG before a dental implant procedure. Radiographic imaging, physical examination, and histological analysis were performed during a 2-year period. Biopsies were obtained at second-stage surgery before implant insertion using a 2.8-mm trephine bur. A morphological study of 20 bioptic human specimens was performed. Our results demonstrate that this surgical protocol for the preparation of the recipient site associated with a mixture of coralline HA granules with homologous fibrin glue provides reliable bone regeneration, thus reducing failures and minimizing risks of postoperative morbidity.
Examining the Complicated Relationship Between Depressive Symptoms and Cognitive Impairment in Preclinical Alzheimer Disease
Authors: Javaherian Kavon , Newman Brianne M. , Weng Hua , Hassenstab Jason , Xiong Chengjie , Coble Dean , Fagan Anne M. , Benzinger Tammie , Morris John C.
Published: November 2018

Introduction:

The relationships between Alzheimer disease (AD), cognitive performance, and depression are poorly understood. It is unclear whether depressive features are a prodrome of AD. In addition, some studies of aging exclude depressed individuals, which may inappropriately limit generalizability. The aim of the present study was to determine whether depressive symptoms affect cognitive function in the context of preclinical AD.

Methods:

Cross-sectional multivariate analysis of participants in a longitudinal study of aging (n=356) that evaluates the influence of depressive symptoms on cognitive function in cognitively normal adults.

Results:

There is no relationship between the presence of depressive symptoms and cognitive function in those with either no evidence of preclinical AD or biomarker evidence of early-stage preclinical AD. However, in later stages of preclinical AD, the presence of depressive symptoms demonstrated interactive effects, including in episodic memory (0.96; 95% confidence interval, 0.31-1.62) and global cognitive function (0.46; 95% confidence interval, 0.028-0.89).

Conclusions:

The presence of depressive symptoms may be a late prodrome of AD. In addition, studies investigating cognitive function in older adults may not need to exclude participants with depressive symptomology, but may still consider depressive symptoms as a potential confounder in the context of more extensive neuronal injury.
Crack growth in heterogeneous brittle solids: intermittency, crackling and induced seismicity
Authors: Barés Jonathan , Bonamy Daniel
Published: November 2018

Crack growth is the basic mechanism leading to the failure of brittle materials. Engineering addresses this problem within the framework of continuum mechanics, which links deterministically the crack motion to the applied loading. Such an idealization, however, fails in several situations and in particular cannot capture the highly erratic (earthquake-like) dynamics sometimes observed in slowly fracturing heterogeneous solids. Here, we examine this problem by means of innovative experiments of crack growth in artificial rocks of controlled microstructure. The dynamical events are analysed at both global and local scales, from the time fluctuation of the spatially averaged crack speed and the induced acoustic emission, respectively. Their statistics are characterized and compared with the predictions of a recent approach mapping fracture onset to the depinning of an elastic interface. Finally, the overall time–size organization of the events is characterized to shed light on the mechanisms underlying the scaling laws observed in seismology.

This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’.
Mapping heterogeneities through avalanche statistics
Authors: Biswas Soumyajyoti , Goehring Lucas
Published: November 2018

Avalanche statistics of various threshold-activated dynamical systems are known to depend on the magnitude of the drive, or stress, on the system. Such dependences exist for earthquake size distributions, in sheared granular avalanches, laboratory-scale fracture and also in the outage statistics of power grids. In this work, we model threshold-activated avalanche dynamics and investigate the time required to detect local variations in the ability of model elements to bear stress. We show that the detection time follows a scaling law where the scaling exponents depend on whether the feature that is sought is either weaker, or stronger, than its surroundings. We then look at earthquake data from Sumatra and California, demonstrate the trade-off between the spatial resolution of a map of earthquake exponents (i.e. theb-values of the Gutenberg–Richter Law) and the accuracy of those exponents, and suggest a means to maximize both.

This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’.
Geological implication of grain-size segregation in dense granular matter
Authors: Itoh Ryo , Hatano Takahiro
Published: November 2018

To the current common belief, grain size segregation in granular matter requires sufficient porosity. Therefore, grain size segregation found in a natural fault gouge could imply elevated fluid pressure and the reduced normal stress on fault, possibly caused by the frictional heat during an earthquake. To clarify whether fluidization is essential to grain size segregation, we conduct numerical simulation on a simple model of fault gouge in a plane shear geometry under constant volume condition: the volume fraction is fixed at 0.6, at which the granular system possesses yield stress. We observe apparent grain size segregation at this volume fraction, meaning that grain size segregation alone does not imply fluidization of granular matter. We also show that segregation is driven by the nonlinear velocity profile, and that the gravity is not essential to segregation. The physical condition tested here may be relevant to earthquake faults: the normal stress of 1 MPa, the sliding velocity of 1 m s
−1
, and the duration of 0.1 s.

This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’.
Nature of the high-speed rupture of the two-dimensional Burridge–Knopoff model of earthquakes
Authors: Kawamura Hikaru , Yoshimura Koji , Kakui Shingo
Published: November 2018

The nature of the high-speed rupture or the main shock of the Burridge–Knopoff spring-block model in two dimensions obeying the rate- and state-dependent friction law is studied by means of extensive computer simulations. It is found that the rupture propagation in larger events is highly anisotropic and irregular in shape on longer length scales, although the model is completely uniform and the emergent rupture-propagation velocity is nearly constant everywhere at the rupture front. The manner of the rupture propagation sometimes mimics the successive ruptures of neighbouring ‘asperities’ observed in real, large earthquakes. Large events tend to be unilateral, with its epicentre lying at the rim of its rupture zone. The epicentre site of a large event is also located next to the rim of the rupture zone of some past event. Event-size distributions are computed and discussed in comparison with those of the corresponding one-dimensional model. The magnitude distribution exhibits a power-law behaviour resembling the Gutenberg–Richter law for smaller magnitudes, which changes over to a more characteristic behaviour for larger magnitudes. For very large events, the rupture-length distribution exhibits mutually different behaviours in one dimension and in two dimensions, reflecting the difference in the underlying geometry.

This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’.
Similarities between mode III crack growth patterns and strike-slip faults
Authors: Cambonie T. , Klinger Y. , Lazarus V.
Published: November 2018

Why are strike slip faults not perfectly linear but made of successive segments? Are they reminiscences of the fracture of an initially sound crust by the bottom-up propagation of a crack subjected to mode III loading? The plausibility of this newly proposed scenario will be investigated here through model experiments and some theoretical explanations in the framework of brittle fracture.

This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’.
Mechanism of memory effect of paste which dominates desiccation crack patterns
Authors: Nakahara Akio , Hiraoka Tomoki , Hayashi Rokuya , Matsuo Yousuke , Kitsunezaki So
Published: November 2018

When a densely packed colloidal suspension, called a paste, behaves as plastic fluid, it can remember the direction of its motion it has experienced, such as vibrational motion and flow. These memories kept in paste can be visualized as the morphology of crack patterns that appear when the paste is dried. For example, when a paste remembers the direction of vibrational motion, all primary desiccation cracks propagate in the direction perpendicular to the direction of the vibrational motion that the paste has experienced. On the other hand, when a paste remembers the direction of flow motion, all primary cracks propagate along the flow direction. To find out the mechanism of memory effect of vibration, we perform experiments to rewrite memory in paste by applying additional vibration to the paste along a different direction before the paste is dried. By investigating the process of rewriting memory in paste, we find the competitive phenomena between quasi-linear effect and nonlinear effect, which were studied in each theoretical model based on residual tension theories. That is, at the initial stage of the memory-imprinting process of the vibrational motion, the mechanism predicted by the quasi-linear analysis based on residual tension theory holds, but, as the paste is vibrated repeatedly, the mechanism shown by the nonlinear analysis gradually come to play a dominant role in the memory effect.

This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’.
Statistical physics perspective of fracture in brittle and quasi-brittle materials
Authors: Ray Purusattam
Published: November 2018

We discuss the physics of fracture in terms of the statistical physics associated with the failure of elastic media under applied stresses in presence of quenched disorder. We show that the development and the propagation of fracture are largely determined by the strength of the disorder and the stress field around them. Disorder acts as nucleation centres for fracture. We discuss Griffith's law for a single crack-like defect as a source for fracture nucleation and subsequently consider two situations: (i) low disorder concentration of the defects, where the failure is determined by the extreme value statistics of the most vulnerable defect (nucleation regime) and (ii) high disorder concentration of the defects, where the scaling theory near percolation transition is applicable. In this regime, the development of fracture takes place through avalanches of a large number of tiny microfractures with universal statistical features. We discuss the transition from brittle to quasi-brittle behaviour of fracture with the strength of disorder in the mean-field fibre bundle model. We also discuss how the nucleation or percolation mode of growth of fracture depends on the stress distribution range around a defect. We discuss the corresponding numerical simulation results on random resistor and spring networks.

This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’.
Thermally activated crack fronts propagating in pinning disorder: simultaneous brittle/creep behaviour depending on scale
Authors: Cochard A. , Lengliné O. , Måløy K. J. , Toussaint R.
Published: November 2018

We study theoretically the propagation of a crack front in mode I along an interface in a disordered elastic medium, with a numerical model considering a thermally activated rheology, toughness disorder and long-range elastic interactions. This model reproduces not only the large-scale dynamics of the crack front position in fast or creep loading regimes, but also the small-scale self-affine behaviour of the front. Two different scaling laws are predicted for the front morphology, with a Hurst exponent of 0.5 at small scales and a logarithmic scaling law at large scales, consistently with experiments. The prefactor of these scaling laws is expressed as a function of the temperature, and of the quenched disorder characteristics. The cross-over between these regimes is expressed as a function of the quenched disorder amplitude, and is proportional to the average energy release rate, and to the inverse of temperature. This model captures as well the experimentally observed local velocity fluctuation probability distribution, with a high-velocity tail
P
(
v
)∼
v
−2.6
. This feature is shown to arise when the quenched disorder is sufficiently large, whereas smaller toughness fluctuations lead to a lognormal-like velocity distribution. Overall, the system is shown to obey a scaling determined by two distinct mechanisms as a function of scale: namely, the large scales display fluctuations similar to an elastic line in an annealed noise excited as the average front travels through the pinning landscape, while small scales display a balance between thresholds in possible elastic forces and quenched disorder.

This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’.
Statistical physics of fracture and earthquakes
Authors: Biswas Soumyajyoti , Goehring Lucas , Chakrabarti Bikas K.
Published: November 2018

Manifestations of emergent properties in stressed disordered materials are often the result of an interplay between strong perturbations in the stress field around defects. The collective response of a long-ranged correlated multi-component system is an ideal playing field for statistical physics. Hence, many aspects of such collective responses in widely spread length and energy scales can be addressed by the tools of statistical physics. In this theme issue, some of these aspects are treated from various angles of experiments, simulations and analytical methods, and connected together by their common base of complex-system dynamics.

This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’ .