Efficacy of cryoablation versus antiarrhythmic therapy for treatment of atrial fibrillation: a systematic review and meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Introduction

Atrial fibrillation (AF) is a common arrhythmia that causes various complications if left untreated. Current primary care guidelines recommend administration of antiarrhythmic drugs (AAD) as the preferred treatment regimen for first diagnosed AF and considers ablation if there is failure of therapy. However, recent studies show the benefit of cryoablation on the initial treatment of AF.

Purpose

The primary objective of this study is to determine the efficacy and the safety of cryoablation therapy over AAD as treatment regimen for atrial fibrillation.

Methods

A comprehensive and relevant search of randomized controlled trials (RCT) was conducted examining the use of cryoablation as initial treatment of AF compared to AAD. Outcome measures for recurrence of atrial arrhythmias and serious adverse effects (SAEs) were extracted and analyzed using Review Manager 5.4. Fixed effects model was used initially for both outcomes; however, if there was substantial heterogeneity (I² > 50%), random effects model was then used.

Results

Four studies were included in the meta-analysis with a total of 969 subjects analyzed. Initially, a fixed effect model was used to compute for the Risk Ratio (RR) which yielded RR of 0.55 [95% CI: 0.49-0.63], I²=93, p < 0.0001. Since there was substantial heterogeneity among the four RCTs, a random effects model was then used. The heterogeneity may be attributed to the difference in study designs as some of the studies involved a cross-over design. Using the random effects model, the computed RR was 0.50 [95% CI: 0.33-0.85], I²=93, p = 0.01. Hence, cryoballoon therapy is found to be more beneficial in preventing recurrence of atrial arrhythmias. This result can be interpreted as statistically significant given that the p value is < 0.05.

On the other hand, the fixed effects model revealed there was no significant difference between cryoballoon therapy and AAD in terms of SAE (RR 0.80 [95%CI: 0.58-1.10], I²=0, p=0.17). SAEs included in the studies included the following but not limited to death, stroke, acute coronary syndrome, syncope, pulmonary embolism, etc.

Conclusion

Cryoablation therapy is more beneficial in preventing atrial arrhythmias compared to AADs. The rate of serious adverse event is similar between cryoablation therapy and AAD.

Laminar Mixing in Corotating Disk Processors

Qualitative and quantitative studies of laminar mixing in a corotating disk processor chamber were carried out experimentally and theoretically. Theoretical study of the flow field in a parallel chamber indicates the presence of an orthogonal circulation flow pattern with a double circulation pattern at constant radii. A color tracer was used for studying experimentally the laminar mixing. The experiments verified the theoretically predicted flow fields and showed that the two orthogonal flow patterns bring about a composition randomization throughout the volume. Quantitative measurement of interfacial area evolution helped in characterizing the laminar mixing behaviour of such a configuration.

A Dispersive Mixing Testing Apparatus

The dispersion process of agglomerated soldis, such as carbon-black, into rubbers and plastics is still not understood to a satisfactory extent. Dispersive mixing is commonly carried out in roll mills, internal mixers and continuous intensive mixers. It is accomplished by repeated passage of the mixture, through converging-tight clearance high stress regions, of the mixers. The key design and operational variables are the geometry of this region, the stress history of the fluid element, and the passage distribution function. A laboratory apparatus was designed and built to enable a systematic study of the effect of these variables on mixing. The apparatus, and experimental results are described. Results verify that the number of passages is a dominant variable in dispersive mixing, and proves the utility of the apparatus to study the dispersive mixing process.

127 Optimum Treatment for Sigmoid Volvulus Remains Elusive but Surgery May Provide Considerable Benefit: Results of a 5-Year Audit

Background

Sigmoid volvulus is a surgical emergency and patients are often elderly with significant comorbidities. Whilst endoscopic decompression is easy and effective in the short-term, recurrence and repeated admissions are common with surgery generally being reserved for non-resolution or complications. Consensus an optimum management is lacking.

Method

A retrospective audit of all patients admitted with sigmoid volvulus to a DGH General Surgery service between 01/01/2015-20/10/2020 was undertaken. Patient demographics, comorbidities, clinical findings, investigations, and treatment were recorded.

Results

Sixty-three patients were identified (median age 71.5 years; 58.7% male]. Some 50.8% had more than one previous presentation (range 1–6), 19% presented after 3 days of symptoms and 3.2% presented with perforation. Plain radiography and CT scanning was undertaken in 90.5% and 54%, respectively.

Endoscopic detorsion was performed in 77.77% and repeated in the same admission for 33.3% of cases. Flatus tubes and rigid sigmoidoscopy was used in 47.6% with a 59.6% success rate. Seventeen patients (27%) underwent sigmoid resection, 14 having open surgery and 3 laparoscopic. Primary anastomosis was undertaken in 64.7% (11 patients), with only one anastomotic leak; the remaining 6 patients had a colostomy. The re-admission rate was 30.1% (19% non-operated patients, 11.1% operated patients).

Conclusions

Most patients with sigmoid volvulus are managed non-operatively with endoscopic detorsion which may be associated with a considerable healthcare burden and high readmission rates. Selective resection can be associated with low morbidity and good outcomes. Clinicians could reasonably adopt a lower threshold for surgical intervention, particularly for recurrent volvulus.

1073 Synchronous Cholecystitis and Appendicitis: A Case Report Highlighting Learning Points on Medical Imaging and Consent

Laparoscopic appendicectomy and laparoscopic cholecystectomy are separately two of the most common emergency surgical procedures carried out in the UK. Only a small number of synchronous presentations of acute appendicitis and acute cholecystitis have been reported in surgical literature and this rare co-existent pathology gives rise to several valuable learning points with regards to laparoscopy, medical imaging interpretation and the consent process.

Our case report involves a 58-year-old female patient presenting with both RUQ and RIF pain and positive Murphy’s sign on clinical examination. US scan demonstrated several gallstones within a thin-walled gallbladder. Subsequent CT scan reported acute appendicitis which was treated definitively with laparoscopic surgery. Intraoperatively a perforated gangrenous gallbladder containing multiple calculi was discovered, and the decision was made to perform a double procedure of laparoscopic appendicectomy and cholecystectomy. Histopathology confirmed synchronous pathology of appendicitis with faecolith and calculus cholecystitis.

This case demonstrates the importance of considering multiple pathologies when assessing a patient with ambiguous and migratory abdominal pain. It reinforces the importance of diagnostic laparoscopy to rule out multiple pathologies. This acts as a cautionary case against over-reliance on medical imaging and reminds surgeons of their obligation to maintain competence in CT interpretation plus correlation of imaging with clinical assessment of the patient. Readers should also be reminded that the consent process for surgical interventions should be undertaken meticulously in patients with ambiguous abdominal pain.

[What follow-up after pediatric cancer ? The SALTO consultation experience]

During the past 50 years, the mortality due to childhood cancers decreased dramatically thanks to improvements in supportive care and the use of multimodal approaches. In this context, the long-term follow up after childhood cancer has become a main concern for pediatric oncologists. The SALTO programme was developed in 2012 at the CHR Citadelle in Liège in order to organize a multidisciplinary long-term follow-up for the patients previously treated in our department for a childhood cancer. The aim of the present study was to review, for the most frequent childhood cancers, the long-term sequellae and the second cancers developed by the patients participating to the SALTO programme in order to define the follow-up needed. Our data confirm the importance of a multidisciplinary long-term follow-up, based on the treatments received and following international guidelines.

Photodynamic inactivation of Lasiodiplodia theobromae: lighting the way towards an environmentally friendly phytosanitary treatment

The fungus Lasiodiplodia theobromae is one of the main causal agents of trunk canker and dieback of grapevine. The objective of this work was to evaluate the efficiency of photodynamic inactivation (PDI) of L. theobromae with synthetic and natural photosensitizers and irradiation with either sunlight or artificial photosynthetically active radiation. Although the growth of the mycelium could not be completely prevented with natural sunlight irradiation, phenothiazine dyes (methylene blue, MB; toluidine blue O, TBO), riboflavin and a cationic porphyrin (Tetra-Py⁺-Me) caused complete inhibition under continuous irradiation with artificial light. Free radicals were the main cytotoxic agents in the PDI with MB, indicating the predominance of the type I mechanism. PDI with MB or Tetra-Py⁺-Me may represent a promising approach for the sanitation of vine material in greenhouse nurseries, in order to reduce the risk of infection upon grafting.

Volumetry of Mesiotemporal Structures Reflects Serostatus in Patients with Limbic Encephalitis

BACKGROUND AND PURPOSE

Limbic encephalitis is an autoimmune disease. A variety of autoantibodies have been associated with different subtypes of limbic encephalitis, whereas its MR imaging signature is uniformly characterized by mesiotemporal abnormalities across subtypes. Here, we hypothesized that patients with limbic encephalitis would show subtype-specific mesiotemporal structural correlates, which could be classified by supervised machine learning on an individual level.

MATERIALS AND METHODS

T1WI MPRAGE scans from 46 patients with antibodies against glutamic acid decarboxylase and 34 patients with antibodies against the voltage-gated potassium channel complex (including 10 patients with leucine-rich glioma-inactivated 1 autoantibodies) and 48 healthy controls were retrospectively ascertained. Parcellation of the amygdala, hippocampus, and hippocampal subfields was performed using FreeSurfer. Volumes were extracted and compared between groups using unpaired, 2-tailed t tests. The volumes of hippocampal subfields were analyzed using a multivariate linear model and a binary decision tree classifier.

RESULTS

Temporomesial volume alterations were most pronounced in an early stage and in the affected hemispheric side of patients. Statistical analysis revealed antibody-specific hippocampal fingerprints with a higher volume of CA1 in patients with glutamic acid decarboxylase-associated limbic encephalitis (P = .02), compared with controls, whereas CA1 did not differ from that in controls in patients with voltage-gated potassium channel complex autoantibodies. The classifier could successfully distinguish between patients with autoantibodies against leucine-rich glioma-inactivated 1 and glutamic acid decarboxylase with a specificity of 87% and a sensitivity of 80%.

CONCLUSIONS

Our results suggest stage-, side- and antibody-specific structural correlates of limbic encephalitis; thus, they create a perspective toward an MR imaging-based diagnosis.

Associations among gait score, production data, abattoir registrations, and postmortem tibia measurements in broiler chickens

Lameness and impaired walking ability in rapidly growing meat-type broiler chickens are major welfare issues that cause economic losses. This study analyzed the prevalence of impaired walking and its associations with production data, abattoir registrations, and postmortem tibia measurements in Norwegian broiler chickens. Gait score (GS) was used to assess walking ability in 59 different commercial broiler flocks (Ross 308) close to the slaughter d, 5,900 broilers in total, in 3 different geographical regions. In each flock, 100 arbitrary broilers were gait scored and 10 random broilers were culled to harvest tibias. Abattoir registrations on flock level were collected after slaughter. A total of 24.6% of the broilers had moderate to severe gait impairment. The broilers were sampled in 2 stages, first slaughterhouse/region, and then owner/flock. The final models showed that impaired gait is associated with first-week mortality (P < 0.05), region (P < 0.001), height of tibias mid-shaft (P < 0.05), and calcium content in the tibia ash (P < 0.05), and negatively associated with DOA (P < 0.05). The prevalence of impaired gait indicates that this is a common problem in the broiler industry in Norway, although the mean slaughter age is only 31 d and the maximum allowed animal density is relatively low. Impaired walking ability could not be predicted by the welfare indicators footpad lesion score, total on-farm mortality, and decreasing DOA prevalence. Further studies are needed to explore the relationship between first-week mortality and gait score.

Complex history of dog (Canis familiaris) origins and translocations in the Pacific revealed by ancient mitogenomes

Archaeological evidence suggests that dogs were introduced to the islands of Oceania via Island Southeast Asia around 3,300 years ago, and reached the eastern islands of Polynesia by the fourteenth century AD. This dispersal is intimately tied to human expansion, but the involvement of dogs in Pacific migrations is not well understood. Our analyses of seven new complete ancient mitogenomes and five partial mtDNA sequences from archaeological dog specimens from Mainland and Island Southeast Asia and the Pacific suggests at least three dog dispersal events into the region, in addition to the introduction of dingoes to Australia. We see an early introduction of dogs to Island Southeast Asia, which does not appear to extend into the islands of Oceania. A shared haplogroup identified between Iron Age Taiwanese dogs, terminal-Lapita and post-Lapita dogs suggests that at least one dog lineage was introduced to Near Oceania by or as the result of interactions with Austronesian language speakers associated with the Lapita Cultural Complex. We did not find any evidence that these dogs were successfully transported beyond New Guinea. Finally, we identify a widespread dog clade found across the Pacific, including the islands of Polynesia, which likely suggests a post-Lapita dog introduction from southern Island Southeast Asia.

Influence of macroporosity on NIH/3T3 adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 over bio-functionalized highly porous titanium implant material

Highly porous Ti implant materials are being used in order to overcome the stress shielding effect on orthopedic implants. However, the lack of bioactivity on Ti surfaces is still a major concern regarding the osseointegration process. It is known that the rapid recruitment of osteoblasts in bone defects is an essential prerequisite for efficient bone repair. Conventionally, osteoblast recruitment to bone defects and subsequent bone repair has been achieved using growth factors. Thus, in this study highly porous Ti samples were processed by powder metallurgy using space holder technique followed by the bio-functionalization through microarc oxidation using a Ca- and P-rich electrolyte. The biological response in terms of early cell response, namely, adhesion, spreading, viability, and proliferation of the novel biofunctionalized highly porous Ti was carried out with NIH/3T3 fibroblasts and MC3T3-E1 preosteoblasts in terms of viability, adhesion, proliferation, and alkaline phosphatase activity. Results showed that bio-functionalization did not affect the cell viability. However, bio-functionalized highly porous Ti (22% porosity) enhanced the cell proliferation and activity. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 73-85, 2019.

Mass Transfers in a Fluidized Bed Bioreactor using Alginate Beads for a Future Bioartificial Liver

Fluidized bed bioreactor with alginate beads may be an alternative to hollow fiber cartridge to host hepatocytes for bioartificial liver purposes. After the bioreactor design and the characterization of fluid mechanics, the present study was aimed at analyzing bi-directional mass transfers of calibrated species between external fluid and empty beads. Static (batch) and dynamic (fluidized bed bioreactor) experimental conditions were analyzed. A simple modelling approach permitted the definition of mass transfer coefficients.

The motion of beads within the bioreactor clearly enhanced mass transfer kinetics, but did not alter the amount exchanged. The shear enhanced diffusion coefficient for VitB12 was 20 times higher in the fluidized bed bioreactor than under batch conditions, proving the efficiency of such a device.

[Radiation-induced carotid stenosis: A personnalized approach]

INTRODUCTION

Surgical treatment of radio-induced carotid stenosis (RICS) is challenging and burdened by an elevated risk of local complications. Carotid artery stenting (CAS) may be a suitable alternative. The best approach is yet to be defined. We reviewed the results of both techniques following selection based on better-suitability characteristics (anatomic and clinical).

METHODS

We retrospectively reviewed 38 patients treated for 43 RICS from a group of 1230 patients who had carotid interventions between 2008 and 2015 (5 bilateral). Primary endpoints were morbidity and mortality at 30 days (transient ischemic attack, stroke, myocardial infarction, or death). Secondary endpoints were technical success, wound complications, cranial nerve injury (CNI), restenosis (≥50%) and recurrent symptoms.

RESULTS

RICS was symptomatic in 6 patients in the OR group and 3 in the CAS group. Lesions in the OR group were longer (P=0.02) and more calcified (P=0.08). Technical success rate was 100%. Cranial nerve injury rate was 14.2% (3/21). All injuries were completely resolved within several weeks. In the CAS group, technical success rate was 95% (21/22) with the one failure due to a residual stenosis exceeding 30%. Periprocedural stroke rates were 0% and 4.5% in the OR and CAS groups respectively (0/21 vs 1/22, P=0.32). There were no early deaths. Mean follow-up was 19.1 months (3-75). The restenosis rate was 9.5% (2/21) in the OR group and 9% (2/22) in the CAS group.

CONCLUSION

Our results do not support a preferred treatment strategy. The choice of treatment should be considered on an individual basis.

Steroids, steroid precursors, and neuroactive steroids in critically ill equine neonates

Hypothalamic-pituitary-adrenal axis (HPAA) dysfunction has been associated with sepsis and mortality in foals. Most studies have focused on cortisol, while other steroids have not been investigated. The objectives of this study were to characterise the adrenal steroid and steroid precursor response to disease and to determine their association with the HPAA response to illness, disease severity, and mortality in hospitalised foals. All foals (n=326) were classified by two scoring systems into three categories: based on the sepsis score (septic, sick non-septic [SNS] and healthy) and the foal survival score (Group 1: 3-18%; Group 2: 38-62%; Group 3: 82-97% likelihood of survival). Blood concentrations of adrenocorticotropic hormone (ACTH) and steroids were determined by immunoassays. ACTH-cortisol imbalance (ACI) was defined as a high ACTH/cortisol ratio. Septic foals had higher ACTH, cortisol, progesterone, 17α-OH-progesterone, pregnenolone, and androstenedione concentrations as well as higher ACTH/cortisol, ACTH/progesterone, ACTH/aldosterone, and ACTH/DHEAS ratios than SNS and healthy foals (P<0.01). Foals with DHEAS of 0.4-5.4ng/mL were more likely to have ACI (OR=2.5). Foals in Group 1 had higher ACTH, aldosterone, progesterone, and cortisol concentrations as well as ACTH/cortisol, ACTH/progesterone, and ACTH/DHEAS ratios than foals in Groups 2 and 3 (P<0.01). High progesterone concentrations were associated with non-survival and the cutoff value below which survival could be predicted was 23.5ng/mL, with 75% sensitivity and 72% specificity. In addition to cortisol, the response to the stress of illness in foals is characterised by the release of multiple adrenal steroids. DHEAS and progesterone were good predictors of HPAA dysfunction and outcome in hospitalised foals.

Quality in Community-Based day Center Services for People with Psychiatric Disabilities from the Attendees’ Perspective

Community-based day centers in Sweden are well-established arenas for psychiatric rehabilitation. Little is, however, known of the attendees’ perception of the quality of the service provided. Therefore, the aim of the study was to describe and investigate the quality of community-based day center services for people with psychiatric disabilities. A sample of 218 attendees (44% females) between 18 and 71 years old in 14 community-based day center services in Sweden completed the quality in psychiatric care–daily activities (QPC-DA) instrument. The results showed that people with psychiatric disabilities perceived the quality of community-based day center services as high and 87% perceived the overall quality as satisfactory. The highest ratings were found in encounter followed by support, daily activity-specific, secure environment, participation, and the lowest quality was found in secluded environment dimensions of the QPC-DA. Most notably, quality of service was rated higher by those with lower educational level, had waited shorter time to attend the center, and had better mental and physical health. However, particularly aspects of a secluded environment and participation (information) may be areas with potential for improvement. In conclusion, the results adhere to the importance of occupational balance, with periods of rest/privacy during the time at the center.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

The glassy behaviour of poorly crystalline Fe2O3 nanorods obtained by thermal decomposition of ferrous oxalate

Nanorod ferrous oxalate dihydrate (FeC2O4 × 2H2O) which had been synthesized by the microemulsion method, was used as a precursor in the thermal decomposition process performed in air atmosphere. The formation of nanocrystalline hematite as the final product was preceded by the appearence of an intermediate product. Comprehensive study comprising several complementary techniques (x-ray diffraction, transmission electron microscopy, selected area electron diffraction, thermogravimetric/differential thermal analyses and SQUID magnetometry) confirmed that the intermediate product corresponds to the poorly crystalline Fe2O3. Due to the specific nanorod shape and poorly crystalline structure, the investigated Fe2O3 showed high coercive field value of ~0.5 T at 5 K. Special attention in this study was devoted to the peculiar magnetic properties of poorly crystalline Fe2O3, which were thoroughly investigated by employing sophisticated experimental procedures such as relaxation of thermoremanent magnetization for different cooling fields, zero field and field cooled memory effects as well as aging experiments for different waiting times. At low temperatures and weak applied magnetic fields, the investigated system behaves similarly to spin glasses, manifesting slow, collective relaxation dynamics of magnetic moments through memory, rejuvenation and aging effects.

Gold(iii) compounds containing a chelating, dicarbanionic ligand derived from 4,4′-di-tert-butylbiphenyl

Various gold(iii)heterocycles were prepared and their structures and photophysical properties were examined.

Heterogeneous phase formation in diluted magnetic semiconducting Zn1−x−yCoxAlyO (CAZO) nanoparticles

This article reports a systematic investigation of the synthesis and structural characterization of composite CAZO [(Zn_1−x−yCo_xAl_yO; x = 0.04, 0.03, 0.02; y = 0.01, 0.02, 0.03)] nanoparticles from combustion.

Étude de l’utilisation optimisée de la rispéridone à libération prolongée par un programme d’accompagnement des patients

Contexte et objectif

La non-observance des traitements représente un risque d’exacerbation chez les patients schizophrènes [1,2,3]. L’objectif était d’évaluer l’impact d’un programme d’accompagnement des patients recevant la rispéridone à libération prolongée (RLP) sur le taux d’hospitalisation psychiatrique.

Méthodes

Une cohorte de 506 patients schizophrènes traités par RLP a été recrutée dans 36 centres et suivie 12 mois. Le programme d’accompagnement consistait en un rappel téléphonique 48 heures avant la date prévue de l’injection et dans les trois jours suivants, au besoin. Les centres observants étaient ceux ayant appliqué le programme pour 50 % ou plus des injections prévues. Les patients observants étaient ceux qui s’étaient présentés dans les cinq jours de la date prévue de l’injection pour au moins 80 % des injections. L’effet de l’observance (centre, patient, ou les deux combinés) sur le taux d’hospitalisation a été estimé par un modèle de Poisson avec appariement, ajusté sur un score de propension résumant les facteurs de risque.

Résultats

Environ 75 % des patients ont été observants et leur taux d’hospitalisation était similaire aux non-observants (32,8 et 31,7 par 100 patients-années [PA], respectivement). Les centres observants traitaient des patients moins sévères (hospitalisation dans l’année précédente [64,2 vs. 44,1 %] et meilleurs scores sur les échelles psychiatriques [CGI maximum, BPRS, EGF]). L’observance des centres avait un effet moins important sur le taux d’hospitalisation des patients observants (28,2/100 PA pour les centres observants vs 38,3/100 PA pour les centres non observants) que chez les patients non observants (11,7/100 PA vs 41,0/100 PA, respectivement). L’effet chez les patients non observants était maintenu dans les analyses ajustées.

Conclusion

Le taux d’hospitalisation chez les patients traités par RLP était comparable entre les patients observants et non observants, mais ce taux était amélioré dans les centres observants au programme d’accompagnement des patients à observance faible.

Oxinium femoral head damage generated by a metallic foreign body within the polyethylene cup following recurrent dislocation episodes

Oxinium femoral heads are supposed to be more scratch-resistant thanks to their oxidized layer. However, damages to this thin layer can jeopardize implant's properties. Following revision total hip arthroplasty performed for recurrent posterior dislocations, the Oxinium femoral head initially implanted was observed to be dramatically damaged. A metallic foreign body from a trochanteric fixation wire was found within the polyethylene cup. Only few cases of damaged Oxinium femoral heads have been reported and all were related to either dislocation or reduction of THA. The aim of this report is to describe a non-reported mechanism of damaged Oxinium femoral head due to a broken trochanteric fixation wire device. Any broken metallic wire from a transtrochanteric approach should be carefully followed to detect migration within the polyethylene cup. If such a migration occurs, revision surgery should be rapidly scheduled.

Modelling Twin Rotor Mixers and Extruders

A mathematical model for simulating flow in batch and continuous twin rotor mixers and extruders is presented. The model is a lumped parameter model based on the Flow Analysis Network (FAN) method.

A Dispersive Mixing Testing Apparatus

The dispersion process of agglomerated soldis, such as carbon-black, into rubbers and plastics is still not understood to a satisfactory extent. Dispersive mixing is commonly carried out in roll mills, internal mixers and continuous intensive mixers. It is accomplished by repeated passage of the mixture, through converging-tight clearance high stress regions, of the mixers. The key design and operational variables are the geometry of this region, the stress history of the fluid element, and the passage distribution function. A laboratory apparatus was designed and built to enable a systematic study of the effect of these variables on mixing. The apparatus, and experimental results are described. Results verify that the number of passages is a dominant variable in dispersive mixing, and proves the utility of the apparatus to study the dispersive mixing process.

Modelling Twin Rotor Mixers and Extruders

An improved flow model for simulating flow in batch and continuous twin rotor mixers and extruders is presented. The model adopts an Eulerian point of view from the stationary barrel surface. It incorporates Couette flow analysis, which accounts for the curvature effects in the non-intermeshing region, and correction factors for treatment of flow near the bounding sidewalls of a batch mixer. A method for tracking the motion of fluid particles is presented.

Gamma-Fe2O3 nanopowders synthesized in microwave plasma and extraordinarily strong temperature influence on their Mössbauer spectra

The article reports on two nanopowders synthesized in microwave plasma: the first sample was synthesized in a torch discharge at 1 bar and the second sample was synthesized in low-pressure plasma at 40 mbar. Morphology, composition and properties of the powders were studied by TEM, XRD, Raman and Mössbauer spectroscopies, and magnetic measurements. In the XRD patterns of the samples only gamma-Fe2O3 was identified (mean crystallite size d(XRD) was 24 nm for the first sample and 13 nm for the second sample). Based on the Mössbauer spectra measured at 5 K, the presence of other iron oxide phases was excluded in both samples. Unusually strong temperature dependence of the Lamb-Mössbauer factor was observed: I(SA)(5 K)/I(SA)(293 K) = 6 in the case of the first sample and I(SA)(5 K)/I(SA)(293 K) = 22 for the second sample (I(SA) denotes integral spectrum area). This effect is explained as the consequence of the reduced agglomeration of electrically charged nanoparticles in the plasma, i.e., particles can either move at 293 K (when they are free) or tilt (if they are a part of a chain). Superparamagnetic phase was not observed in the room-temperature Mössbauer spectra of both samples.

Survival and function of mesenchymal stem cells (MSCs) depend on glucose to overcome exposure to long-term, severe and continuous hypoxia

Use of mesenchymal stem cells (MSCs) has emerged as a potential new treatment for various diseases but has generated marginally successful results. A consistent finding of most studies is massive death of transplanted cells. The present study examined the respective roles of glucose and continuous severe hypoxia on MSC viability and function with respect to bone tissue engineering. We hereby demonstrate for the first time that MSCs survive exposure to long-term (12 days), severe (pO₂ < 1.5 mmHg) hypoxia, provided glucose is available. To this end, an in vitro model that mimics the hypoxic environment and cell-driven metabolic changes encountered by grafted sheep cells was established. In this model, the hallmarks of hypoxia (low pO₂, hypoxia inducible factor-1α expression and anaerobic metabolism) were present. When conditions switched from hypoxic (low pO₂) to ischemic (low pO₂ and glucose depletion), MSCs exhibited shrinking, decreased cell viability and ATP content due to complete exhaustion of glucose at day 6; these results provided evidence that ischemia led to the observed massive cell death. Moreover, MSCs exposed to severe, continuous hypoxia, but without any glucose shortage, remained viable and maintained both their in vitro proliferative ability after simulation with blood reperfusion at day 12 and their in vivo osteogenic ability. These findings challenge the traditional view according to which severe hypoxia per se is responsible for the massive MSC death observed upon transplantation of these cells and provide evidence that MSCs are able to withstand exposure to severe, continuous hypoxia provided that a glucose supply is available.

Bacterial osteomyelitis in a 3-week-old broiler chicken associated with Enterococcus hirae

Enterococcus hirae infections are reported to cause growth depression, encephalomalacia, endocarditis, and septicemia in chickens. This report describes osteomyelitis in the proximal femur of a 3-week-old broiler chicken that also suffered from valvular endocarditis and liver necrosis. Histologically, clusters of gram-positive coccoid bacteria were found in many organs, including bone lesions. In tissues from 5 of 6 examined chickens from the same flock, E hirae was isolated in large numbers. To the authors' knowledge, this is the first report of spontaneous bacterial osteomyelitis where E hirae was cultured from bone and where coccoid bacteria consistent with Enterococcus spp were simultaneously demonstrated within bone lesions.

Inventory management

A critical aspect of blood transfusion is the timely provision of high quality blood products. This task remains a significant challenge for many blood services and blood systems reflecting the difficulty of balancing the recruitment of sufficient donors, the optimal utilization of the donor's gift, the increasing safety related restrictions on blood donation, a growing menu of specialized blood products and an ever-growing imperative to increase the efficiency of blood product provision from a cost perspective. As our industry now faces questions about our standard practices including whether or not the age of blood has a negative impact on recipients, it is timely to take a look at our collective inventory management practices. This International Forum represents an effort to get a snap shot of inventory management practices around the world, and to understand the range of different products provided for patients. In addition to sharing current inventory management practices, this Forum is intended to foster an exchange of ideas around where we see our field moving with respect to various issues including specialty products, new technologies, and reducing recipient risk from blood transfusion products.