Blue emitting exciplex for yellow and white organic light-emitting diodes

White organic light-emitting diodes (WOLEDs) have several desirable features, but their commercialization is hindered by the poor stability of blue light emitters and high production costs due to complicated device structures. Herein, we investigate a standard blue emitting hole transporting material (HTM) N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine (NPB) and its exciplex emission upon combining with a suitable electron transporting material (ETM), 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ). Blue and yellow OLEDs with simple device structures are developed by using a blend layer, NPB:TAZ, as a blue emitter as well as a host for yellow phosphorescent dopant iridium (III) bis(4-phenylthieno[3,2-c]pyridinato-N,C2')acetylacetonate (PO-01). Strategic device design then exploits the ambipolar charge transport properties of tetracene as a spacer layer to connect these blue and yellow emitting units. The tetracene-linked device demonstrates more promising results compared to those using a conventional charge generation layer (CGL). Judicious choice of the spacer prevents exciton diffusion from the blue emitter unit, yet facilitates charge carrier transport to the yellow emitter unit to enable additional exciplex formation. This complementary behavior of the spacer improves the blue emission properties concomitantly yielding reasonable yellow emission. The overall white light emission properties are enhanced, achieving CIE coordinates (0.36, 0.39) and color temperature (4643 K) similar to daylight. Employing intermolecular exciplex emission in OLEDs simplifies the device architecture via its dual functionality as a host and as an emitter.

[Structured approach for infected prosthesis]

BACKGROUND

Endoprosthesis infections represent a major challenge for doctors and patients. Due to the increase in endoprosthesis implantation because of the increasing life expectancy, an increase in endoprosthesis infections is to be expected. In addition to infection prophylaxis, methods of infection control become highly relevant, especially in the group of geriatric and multimorbid patients. The aim is to reduce the high 1‑year mortality from prosthesis infections through a structured algorithm.

ALGORITHM FOR PROSTHESIS INFECTIONS

Prosthesis infections can basically be divided into early and late infections. According to the criteria of the International Consensus Meeting, a late infection is defined as the occurrence more than 30 days after implantation. With respect to the planned approach, the (p)TNM classification offers an orientation. In the early postoperative interval the clinical appearance is crucial as in this phase neither laboratory parameters nor an analysis of synovial fluid show a high sensitivity. It is fundamental that, apart from patients with sepsis, environment diagnostics should be initiated. If a late infection is suspected, in addition to radiological diagnostics (X-ray, skeletal scintigraphy and if necessary, computed tomography, CT), laboratory (C-reactive protein, CRP, leukocytes, blood sedimentation, and if necessary, interleukin‑6, procalcitonin) and microbiological diagnostics (arthrocentesis with synovial analysis and microbiology) are indicated; however, in addition to the arthrocentesis result, the clinical appearance is crucial in cases where an exclusion cannot be confirmed by laboratory parameters. If an infection is confirmed, the treatment depends on the spectrum of pathogens, the soft tissue situation and the comorbidities, including a multistage procedure with temporary explantation and, if necessary, implantation of an antibiotic-containing spacer is necessary. A prosthesis preservation using the debridement, antibiotics and implant retention (DAIR) regimen is only appropriate in an acute infection situation. Basically, radical surgical debridement should be carried out to reduce the pathogen load and treatment of a possible biofilm formation for both early and late infections. The subsequent antibiotic treatment (short or long interval) should be coordinated with the infectious disease specialists.

CONCLUSION

A structured approach for prosthesis infections oriented to an evidence-based algorithm provides a sufficient possibility of healing. An interdisciplinary approach involving cooperation between orthopedic and infectious disease specialists has proven to be beneficial. Surgical treatment with the aim of reducing the bacterial load by removing the biofilm with subsequent antibiotic treatment is of intrinsic importance.

Novel, static, permanent spacers to treat chronic knee periprosthetic joint infections

PURPOSE

To discuss a static and permanent spacer in the treatment of chronic periprosthetic knee infection. Methods In this study, patients who were diagonised with chronic periprosthetic knee infection and not appropriate to undergo revision operations were included and were treated with static and permanent spacers. Infection recurrence rate was recorded, Visual Analogue Scale (VAS) score and Knee Society Score (KSS) were used to record patients' pain and knee function before the operation and at the final follow-up (minimum 24 months).

RESULTS

Fifteen patients were identified for this study. Pain and function were significantly improved at the latest follow-up evaluation. One patient had a recurrent infection and underwent amputation. No patients had signs of residual instability at the final follow-up evaluation, and no breakage or subsidence of the antibiotic spacer were identified at the final radiographic follow-up evaluation.

CONCLUSION

Our study provided evidence that the static and permanent spacer was a reliable salvage procedure to treat periprosthetic knee infection in compromised patients.

Antimicrobials in polymethylmethacrylate: from prevention to prosthetic joint infection treatment: basic principles and risk of resistance

BACKGROUND

Excellent revisions about antibiotic-loaded bone cement (ALBC) have been recently published. In the present article, we review the principles and limitations of local antibiotic delivery in the context of recent advances in the pathogenesis of prosthetic joint infections (PJI), with particular attention paid to the potential association between ALBC and antimicrobial resistance.

MAIN BODY

Recalcitrance of PJI is related to the ability of pathogens to adapt to particular environments present in bone tissue and protect themselves from host immunity in different ways. Accordingly, delivery of high local antimicrobial concentrations using ALBC is needed. Most relevant clinical data showing the efficacy of ALBC for PJI prophylaxis and treatment are reviewed, and we dissected the limitations on the basis of the recent findings from animal models and suggested that aminoglycosides, in particular, could not be the best option. One of the major concerns associated with ALBC is the emergence of resistance because of theoretical prolonged exposure to low antibiotic concentrations. We summarize the mechanisms for the selection of resistant microorganisms, and we critically reviewed the evidence from animal models and clinical data from observational and registry studies and concluded that there is no evidence to support this association.

CONCLUSION

While waiting for better evidence from well-designed clinical trials, ALBC shows a beneficial effect as a prophylaxis in arthroplasty, and to avoid the colonization of spacers used for two-stage revision in patients with PJI. Experimental models and clinical evidence suggest the need to achieve high local antimicrobial concentrations to obtain the highest prophylactic and therapeutic effect. The current evidence does not support the risk of increasing resistance with use of ALBC. In the future, it is necessary to evaluate new carriers and different antimicrobials to improve clinical outcomes.

A review on spacers and membranes: Conventional or hybrid additive manufacturing?

Over the past decade, 3D printing or additive manufacturing (AM) technology has seen great advancement in many aspects such as printing resolution, speed and cost. Membranes for water treatment experienced significant breakthroughs owing to the unique benefits of additive manufacturing. In particular, 3D printing's high degree of freedom in various aspects such as material and prototype design has helped to fabricate innovative spacers and membranes. However, there were conflicting reports on the feasibility of 3D printing, especially for membranes. Some research groups stated that technology limitations today made it impossible to 3D print membranes, but others showed that it was possible by successfully fabricating prototypes. This paper will provide a critical and comprehensive discussion on 3D printing specifically for spacers and membranes. Various 3D printing techniques will be introduced, and their suitability for membrane and spacer fabrication will be discussed. It will be followed by a review of past studies associated with 3D-printed spacers and membranes. A new category of additive manufacturing in the membrane water industry will be introduced here, known as hybrid additive manufacturing, to address the controversies of 3D printing for membrane. As AM technology continues to advance, its possibilities in the water treatment is limitless. Some insightful future trends will be provided at the end of the paper.

How I do it: 1st stage revision TKA

This article covers the key steps and decisions that we make when performing a 1st-stage revision Total Knee Arthroplasty (TKA) at the Avon Orthopaedic Centre and includes more detailed technique and tips regarding how we make our spacers. The first stage of a two-stage protocol should be done in a stable patient with information about the organism, and with the option of plastic surgery flap coverage if required. It should ideally be performed in the unit that is going to perform the second stage, and the operation note should document the soft-tissues, bone loss and extensor mechanism issues that will influence planning for the second stage. Nothing will make up for a bad debridement, so we focus on this as the key step for infection clearance. Infection clearance is equivalent between mobile and static spacers, but patients generally prefer having the better mobility and function of a mobile spacer. We recommend a mobile spacer, unless there is compromise to ligaments or extensor mechanism, or if bone loss is large. Whichever spacer you use, it should aim to: deliver appropriate antibiotics; allow stability, pain relief and some function and weight-bearing prior to the second stage. Doing a good technical job with the spacer is important because you do not want complications with the spacer to cause harm or necessitate a return to theatre or re-operation sooner than planned. Ideally the second stage should be performed when the surgeon & MDT team deem it appropriate clinically and when the patient is fit and ready for further surgery.

Comparing the use of preformed vs hand-made antibiotic spacer cement in two stages revision of hip periprosthetic infection

BACKGROUND

The number of periprosthetic joint infections (PJI) is continuously increasing because of the increasing number of arthroprostheses performed every year. Two-stage revision, using antibiotic-loaded spacers, remains the gold standard for their treatment. The aim of our study is to compare the use of preformed vs hand-made spacers in hip arthroplasty infections evaluating infection eradication, bone loss and clinical/functional outcomes.

METHODS

From January 2010 to December 2017 we performed a prospective nonrandomized study. We pooled 50 patients affected by infected hip joint replacements, and divided them in 2 groups, one receiving commercially preformed spacers and the other receiving hand-made spacers. The study endpoint was set at 12 months. Intra-operative and peri-operative complications, Harris Hip Score (HHS), Short Form 12 Health Survey, intra-operative and radiological evaluation of bone loss were collected. Data were analyzed using descriptive statistics, T-test and Fisher Exact test.

RESULTS

We found a statistically significant differences (p < 0.05) between the two groups in favour of the VancogenX group for the following variables: surgical time, first and second stage intraoperative complication rates, infection eradication. Moreover, the preformed-spacers group had better results in the preservation of bone stock, even though the difference was not statistically significant (p > 0.05).

CONCLUSION

Our results support the use of preformed antibiotic spacers, even though more studies are needed.

CRISPR-Cas bioinformatics

Clustered regularly interspaced short palindromic repeats (CRISPR) and their associated proteins (Cas) are essential genetic elements in many archaeal and bacterial genomes, playing a key role in a prokaryote adaptive immune system against invasive foreign elements. In recent years, the CRISPR-Cas system has also been engineered to facilitate target gene editing in eukaryotic genomes. Bioinformatics played an essential role in the detection and analysis of CRISPR systems and here we review the bioinformatics-based efforts that pushed the field of CRISPR-Cas research further. We discuss the bioinformatics tools that have been published over the last few years and, finally, present the most popular tools for the design of CRISPR-Cas9 guides.

Development of anti-biofouling feed spacers to improve performance of reverse osmosis modules

This study investigates the biofouling resistance of modified reverse osmosis (RO) feed spacers. Control spacers (made of polypropylene) were functionalized with a biocidal coating (silver), hydrophilic (SiO₂ nanoparticles) or superhydrophobic (TMPSi-TiO₂ nanoparticles) anti-adhesive coatings, or a hybrid hydrophilic-biocidal coating (graphene oxide). Performance was measured by adhesion assays, viability tests, and permeate flow decline in a bench scale RO system. The control spacers proved to be one of the better performing materials based on bacterial deposition and dynamic RO fouling experiments. The good anti-adhesive properties of the control can be explained by its near ideal surface free energy (SFE). The only surface modification that significantly reduced biofouling compared to the control was the biocidal silver coating, which outperformed the other spacers by all measured indicators. Therefore, future efforts to improve spacer materials for biofouling control should focus on engineering biocidal coatings, rather than anti-adhesive ones.

A Retrospective Study of the Effectiveness of the AeroChamber Plus® Flow-Vu® Antistatic Valved Holding Chamber for Asthma Control

Introduction

Electrostatic charge in valved holding chambers (VHCs) may lead to inconsistent metered-dose inhaler (MDI) asthma drug delivery. We compared the AeroChamber Plus^® Flow Vu^® Antistatic Valved Holding Chamber (AC⁺FV AVHC) with non-antistatic control VHCs in terms of asthma exacerbations, resource use, and cost in an asthma population.

Methods

Patients included in an adjudicated claims database with AC⁺FV AVHC or non-antistatic VHC (control VHC) use between 1/2010 and 8/2015 (index) who were treated with an inhaled corticosteroid (ICS) or a combination of an ICS and a long-acting β2 agonist MDI within 60 days before or after the index date, were diagnosed with asthma, and had ≥12 months of pre- and ≥30 days of post-index health plan enrollment were included. Cohorts were matched 1:1 using propensity scores. We compared incidence rates (IR) of exacerbation, time to first exacerbation using Kaplan–Meier survival analysis, occurrence of exacerbations, and healthcare resource use and costs using generalized linear models.

Results

9325 patients in each cohort were identified. The IR of exacerbations per 100 person-days (95% CI) was significantly higher in the control VHC cohort than the AC⁺FV AVHC cohort [0.161 (0.150–0.172) vs. 0.137 (0.128–0.147)]. A higher proportion of exacerbation-free patients was observed in the AC⁺FV AVHC cohort. Among the 4293 patients in each cohort with ≥12 months of follow-up, AC⁺FV AVHC patients were found to be 10–12% less likely than control VHC patients to experience an exacerbation throughout the study period. A lower proportion of the AC⁺FV AVHC patients had an ED visit compared to the control VHC patients (10.8% vs. 12.4%). Exacerbation-related costs for the AC⁺FV AVHC cohort were 23%, 25%, 20%, and 12% lower than those for the control VHC cohort at 1, 6, 9, and 12 months, respectively.

Conclusions

The AC⁺FV AVHC was associated with lower exacerbation rates, delayed time to first exacerbation, and lower exacerbation-related costs when compared to control non-antistatic VHCs.

Investigation of multiphase multicomponent aerosol flow dictating pMDI-spacer interactions

The use of Pressurized metered dose inhalers (pMDIs) for the treatment of asthma and other chronic obstructive pulmonary diseases is frequently associated with breath-actuation synchronization problems and poor pulmonary delivery, particularly amongst the pediatric and geriatric population groups. Spacers, or Valved Holding Chambers (VHCs), are frequently used to address these problems. However, the performance of spacers with different pMDIs is also highly variable and needs to be investigated. The purpose of the current study is to develop a computational fluid dynamics (CFD) model which can characterize multiphase multicomponent aerosol flow issuing from a commercial suspension-based pMDI into a spacer. The CFD model was initially calibrated against published experimental measurements in order to appropriately model the spray characteristics. This model was subsequently used to examine several combinations of inhaler, spacer and USP Throat geometries under different discharge rates of coflow air. The CFD model predictions compared favorably with experimental measurements. In particular, the predictions show, in accordance with experimental determinations, a decrease of drug retained by the spacers with increasing coflow air. The recirculation observed near the obstructions in axial path of the spray within either spacer is considered to be central for increasing spray retention and drug deposition behavior. Fluid flow patterns within the spacers were correlated with drug deposition behavior through a dimensionless variable, the Recirculation index (RCI). Bigger particles were found to be selectively retained within the spacer.

Home-made spacer as an auxiliary device in administration of beclomethasone via pressurized metered dose inhaler for asthma control. A randomized controlled pragmatic trial

BACKGROUND

Holding chambers or spacers can enhance the efficacy of pressurized metered dose inhalers (pMDI) in delivering inhaled medications, as they reduce the need for hand-breath coordination and improve lower airways deposition. Nevertheless, their cost can be high for patients in low-income countries.

OBJECTIVE

To compare asthma control achieved with beclomethasone-dipropionate administered through a hydrofluoroalkane-driven pMDI (BDp-pMDI) coupled to a home-made spacer (HmS) or to a valved commercial spacer (VCS) as auxiliary devices.

METHODS

Sixty-three patients with poorly controlled asthma that had a BDp-pMDI prescription were randomized to use the inhaler coupled to a HmS made of 500 ml plastic bottles (Group HmS, n = 32) or to a VCS (Group VCS, n = 31) for 60 days. All were given training sessions. Asthma control was assessed through the Asthma Control Test (ACT) and forced expiratory volume in the first second (FEV1), both measured before, and 30 and 60 days after treatment began.

RESULTS

Both groups showed significant improvement in ACT scores after 30 and 60 days compared to baseline values (an increase of 7 and 7.8 points for the HmS group and 5.9 and 7.0 points for the VCS group, respectively, p < 0.001). There was no statistically significant difference in ACT scores between groups at any observation time (P = 0.261). FEV1 showed the same behavior.

CONCLUSIONS

A similar level of asthma control was achieved with beclomethasone-dipropionate administered through a pMDI whether the inhaler was coupled to the HmS or VCS. These results are significant for asthma control planning strategies in low-income communities. (Trial Register Number: RBR-5x4dc9).

Structure and variation of CRISPR and CRISPR-flanking regions in deleted-direct repeat region Mycobacterium tuberculosis complex strains

Background

CRISPR and CRISPR-flanking genomic regions are important for molecular epidemiology of Mycobacterium tuberculosis complex (MTBC) strains, and potentially for adaptive immunity to phage and plasmid DNA, and endogenous roles in the bacterium. Genotyping in the Israel National Mycobacterium Reference Center Tel-Aviv of over 1500 MTBC strains from 2008–2013 showed three strains with validated negative 43-spacer spoligotypes, that is, with putatively deleted direct repeat regions (deleted-DR/CRISPR regions). Two isolates of each of three negative spoligotype MTBC (a total of 6 isolates) were subjected to Next Generation Sequencing (NGS). As positive controls, NGS was performed for three intact-DR isolates belonging to T3_Eth, the largest multiple-drug-resistant (MDR)-containing African-origin cluster in Israel. Other controls consisted of NGS reads and complete whole genome sequences from GenBank for 20 intact-DR MTBC and for 1 deleted-DR MTBC strain recognized as CAS by its defining RD deletion.

Results

NGS reads from negative spoligotype MTBC mapped to reference H37Rv NC_000962.3 suggested that the DR/CRISPR regions were completely deleted except for retention of the middle IS6110 mobile element. Clonally specific deletion of CRISPR-flanking genes also was observed, including deletion of at least cas2 and cas1 genes. Genomic RD deletions defined lineages corresponding to the major spoligotype families Beijing, EAI, and Haarlem, consistent with 24 loci MIRU-VNTR profiles. Analysis of NGS reads, and analysis of contigs obtained by manual PCR confirmed that all 43 gold standard DR/CRISPR spacers were missing in the deleted-DR genomes.

Conclusions

Although many negative spoligotype strains are recorded as spoligotype-international-type (SIT) 2669 in the SITVIT international database, this is the first time to our knowledge that it has been shown that negative spoligotype strains are found in at least 4 different 24 loci MIRU-VNTR and RD deletion families. We report for the first time negative spoligotype-associated total loss of CRISPR region spacers and repeats, with accompanying clonally specific loss of flanking genes, including at least CRISPR-associated genes cas2 and cas1. Since cas1 deleted E.coli shows increased sensitivity to DNA damage and impaired chromosomal segregation, we discussed the possibility of a similar phenotype in the deleted-DR strains and Beijing family strains as both lack the cas1 gene.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3560-6) contains supplementary material, which is available to authorized users.

[Augmentation with antibiotic-impregnated spacers in sepsis revision surgery]

BACKGROUND

The development of antibiotic-impregnated polymethyl methacrylate (PMMA) spacers is based on clinical experience and the use of antibiotic-loaded PMMA beads in septic bone surgery as well as antibiotic-loaded bone cement in arthroplasty beginning in the 1970s.

MATERIAL AND METHODS

In the meantime hand-formed and prefabricated spacers are implanted in cases of sepsis to achieve high local antibiotic concentrations and bactericidal effects to eradicate the infection. Preformed spacers with gentamicin are commercially available and furthermore, clindamycin-loaded PMMA bone cement can also be used. In principle, all thermostable antibiotics can be mixed with PMMA cement.

SIGNIFICANCE

Spacers permit bridging of bone defects originating from trauma or septic bone segment resection. After joint resection spacers allow a certain degree of articulation and inhibit shortening of the extremity which has a positive effect on the soft tissue covering and its perfusion.

CONCLUSION

The functional outcome after secondary arthroplasty is better if a spacer has been implanted compared to long-term immobilization without spacers. Nevertheless, spacers can also cause serious complications, such as dislocations and fractures. Antibiotic-loaded spacers have therefore widened the therapeutic options in sepsis surgery.

Evaluating the technique of using inhalation device in COPD and bronchial asthma patients

BACKGROUND

In asthma management, poor handling of inhalation devices and wrong inhalation technique are associated with decreased medication delivery and poor disease control. The key to overcome the drawbacks in inhalation technique is to make patients familiar with issues related to correct use and performance of these medical devices. The objective of this study was to evaluate and analyse technique of use of the inhalation device used by patients of COPD and Bronchial Asthma.

METHODS

A total of 300 cases of BA or COPD patients using different types of inhalation devices were included in this observational study. Data were captured using a proforma and were analysed using SPSS version 15.0.

RESULT

Out of total 300 enrolled patients, 247 (82.3%) made at least one error. Maximum errors observed in subjects using MDI (94.3%), followed by DPI (82.3%), MDI with Spacer (78%) while Nebulizer users (70%) made least number of errors (p = 0.005). Illiterate patients showed 95.2% error while post-graduate and professionals showed 33.3%. This difference was statistically significant (p < 0.001). Self-educated patients committed 100% error, while those trained by a doctor made 56.3% error.

CONCLUSION

Majority of patients using inhalation devices made errors while using the device. Proper education to patients on correct usage may not only improve control of the symptoms of the disease but might also allow dose reduction in long term.