Experimental and simulation data of hole bearing type connections.

This paper presents a comprehensive dataset comprising experimental test data and numerical simulations of hole bearing tests involving 32 single-bolt, 20 two-bolt, and 20 four-bolt specimens. The dataset encompasses load-deformation curves obtained from experimental tests and displacement data acquired via the Digital Image Correlation (DIC) system, which covers specific regions of the specimens. Additionally, the dataset incorporates force-deformation curves derived from corresponding numerical simulations. The numerical simulation procedure is outlined, involving a simplified model employing solid elements for the specimen and rigid shell elements for the bolts. A "hard-contact" is employed to define the normal behavior of surface-to-surface contact between the specimen and the bolts. Material behavior modeling utilizes true stress-strain curves obtained from experimental tensile tests, encompassing both material properties extracted from these tests and the ensuing input parameters for numerical simulations. Furthermore, the DIC-system measurements provide data on displacements and strain distributions across various regions of the specimens. These strain measurements are meticulously evaluated and presented. The validation of the numerical simulations against experimental results substantiates the robustness of the numerical methodology, instilling confidence in its application for simulating bearing-type connections. Moreover, this dataset serves as a valuable resource for comparative analysis, enhancing the comprehension of these connections, and providing reference points for further numerical simulations.

A multi-technique study of corrosion products at the steel-concrete interface under two exposure conditions.

Steel corrosion can cause serious damage to reinforced concrete structures. This study employed multiple techniques, including SEM/BSE, EDX and Raman spectroscopy, to analyse the distribution and mineral composition of corrosion products (rusts) in corroded reinforced cementitious materials under two conditions, namely, chloride-induced corrosion and accelerated corrosion in carbonated mortar. Results showed that corrosion products tend to precipitate in large pore spaces close to the steel bar, such as the bleed water zones and voids. Corrosion products initially grew on the walls of these large pores and then the interior was filled with needle-like products gradually. In carbonated mortar, the length of some corrosion layers matches well the size of the coarse aggregate close to the steel. The main phases that were identified based on Roman spectra are magnetite and maghemite (after samples were exposed to atmosphere). Siderite was observed in carbonated mortars, which is not commonly found under natural conditions.

Acetabular avascular necrosis following high-dose steroid treatment and chemotherapy for leukemia : Computer tomography analysis of treatment with impaction bone grafting.

Avascular necrosis (AVN) of the bone is thought to be a serious complication of treatment for acute lymphoblastic leukemia (ALL). The acetabulum is an unusual area to be affected by AVN, and there are currently no reports of successful joint salvage procedures found in the literature. We present a case of a 20-year-old man with ALL who was diagnosed with debilitating AVN of both acetabula 2 years following initial diagnosis of ALL and treatment with a multi-agent chemotherapy regimen including high-dose corticosteroids. After unsuccessful treatment with bisphosphonate therapy, the acetabular AVN underwent bilateral curettage and impaction bone grafting to prevent collapse of subchondral fractures with the hope of salvaging both hip joints. Computer tomography (CT) of the AVN affected areas, pre- and post-bone impaction grafting, demonstrated healing of the subchondral fractures and a doubling of bone density that was maintained at 2 years after surgery. The patient resumed full weight-bearing at 3 months after first surgery, continues to ambulate unrestricted, and remains pain free 3 years post-surgery.

Minimally invasive anterior muscle-sparing versus a transgluteal approach for hemiarthroplasty in femoral neck fractures-a prospective randomised controlled trial including 190 elderly patients.

BACKGROUND: The relevance of femoral neck fractures (FNFs) increases with the ageing of numerous societies, injury-related decline is observed in many patients. Treatment strategies have evolved towards primary joint replacement, but the impact of different approaches remains a matter of debate. The aim of this trial was to evaluate the benefit of an anterior minimally-invasive (AMIS) compared to a lateral Hardinge (LAT) approach for hemiarthroplasty in these oftentimes frail patients. METHODS: Four hundred thirty-nine patients were screened during the 44-months trial, aiming at the evaluation of 150 patients > 60 yrs. of age. Eligible patients were randomised using an online-tool with completely random assignment. As primary endpoint, early mobility, a predictor for long-term outcomes, was evaluated at 3 weeks via the "Timed up and go" test (TUG). Secondary endpoints included the Functional Independence Measure (FIM), pain, complications, one-year mobility and mortality. RESULTS: A total of 190 patients were randomised; both groups were comparable at baseline, with a predominance for frailty-associated factors in the AMIS-group. At 3 weeks, 146 patients were assessed for the primary outcome. There was a reduction in the median duration of TUG performance of 21.5% (CI [- 41.2,4.7], p = 0.104) in the AMIS-arm (i.e., improved mobility). This reduction was more pronounced in patients with signs of frailty or cognitive impairment. FIM scores increased on average by 6.7 points (CI [0.5-12.8], p = 0.037), pain measured on a 10-point visual analogue scale decreased on average by 0.7 points (CI: [- 1.4,0.0], p = 0.064). The requirement for blood transfusion was lower in the AMIS- group, the rate of complications comparable, with a higher rate of soft tissue complications in the LAT-group. The mortality was higher in the AMIS-group. CONCLUSION: These results, similar to previous reports, support the concept that in elderly patients at risk of frailty, the AMIS approach for hemiarthroplasty can be beneficial, since early mobilisation and pain reduction potentially reduce deconditioning, morbidity and loss of independence. The results are, however, influenced by a plethora of factors. Only improvements in every aspect of the therapeutic chain can lead to optimisation of treatment and improve outcomes in this growing patient population. TRIAL REGISTRATION: www.clinicaltrials.gov : NCT01408693 (registered August 3rd 2011).

Cross-genus rebooting of custom-made, synthetic bacteriophage genomes in L-form bacteria.

Engineered bacteriophages provide powerful tools for biotechnology, diagnostics, pathogen control, and therapy. However, current techniques for phage editing are experimentally challenging and limited to few phages and host organisms. Viruses that target Gram-positive bacteria are particularly difficult to modify. Here, we present a platform technology that enables rapid, accurate, and selection-free construction of synthetic, tailor-made phages that infect Gram-positive bacteria. To this end, custom-designed, synthetic phage genomes were assembled in vitro from smaller DNA fragments. We show that replicating, cell wall-deficient Listeria monocytogenes L-form bacteria can reboot synthetic phage genomes upon transfection, i.e., produce virus particles from naked, synthetic DNA. Surprisingly, Listeria L-form cells not only support rebooting of native and synthetic Listeria phage genomes but also enable cross-genus reactivation of Bacillus and Staphylococcus phages from their DNA, thereby broadening the approach to phages that infect other important Gram-positive pathogens. We then used this platform to generate virulent phages by targeted modification of temperate phage genomes and demonstrated their superior killing efficacy. These synthetic, virulent phages were further armed by incorporation of enzybiotics into their genomes as a genetic payload, which allowed targeting of phage-resistant bystander cells. In conclusion, this straightforward and robust synthetic biology approach redefines the possibilities for the development of improved and completely new phage applications, including phage therapy.

Proliferation of Listeria monocytogenes L-form cells by formation of internal and external vesicles.

L-forms are cell wall-deficient bacteria that divide through unusual mechanisms, involving dynamic perturbations of the cellular shape and generation of vesicles, independently of the cell-division protein FtsZ. Here we describe FtsZ-independent mechanisms, involving internal and external vesicles, by which Listeria monocytogenes L-forms proliferate. Using micromanipulation of single cells and vesicles, we show that small vesicles are formed by invagination within larger intracellular vesicles, receive cytoplasmic content, and represent viable progeny. In addition, the L-forms can reproduce by pearling, that is, generation of extracellular vesicles that remain transiently linked to their mother cell via elastic membranous tubes. Using photobleaching and fluorescence recovery, we demonstrate cytoplasmic continuity and transfer through these membranous tubes. Our findings indicate that L-forms' polyploidy and extended interconnectivity through membranous tubes contribute to the generation of viable progeny independently of dedicated division machinery, and further support L-forms as models for studies of potential multiplication mechanisms of hypothetical primitive cells.

Implantation of Stromal Vascular Fraction Progenitors at Bone Fracture Sites: From a Rat Model to a First-in-Man Study.

Stromal Vascular Fraction (SVF) cells freshly isolated from adipose tissue include osteogenic- and vascular-progenitors, yet their relevance in bone fracture healing is currently unknown. Here, we investigated whether human SVF cells directly contribute to the repair of experimental fractures in nude rats, and explored the feasibility/safety of their clinical use for augmentation of upper arm fractures in elderly individuals. Human SVF cells were loaded onto ceramic granules within fibrin gel and implanted in critical nude rat femoral fractures after locking-plate osteosynthesis, with cell-free grafts as control. After 8 weeks, only SVF-treated fractures did not fail mechanically and displayed formation of ossicles at the repair site, with vascular and bone structures formed by human cells. The same materials combined with autologous SVF cells were then used to treat low-energy proximal humeral fractures in 8 patients (64-84 years old) along with standard open reduction and internal fixation. Graft manufacturing and implantation were compatible with intraoperative settings and led to no adverse reactions, thereby verifying feasibility/safety. Biopsies of the repair tissue after up to 12 months, upon plate revision or removal, demonstrated formation of bone ossicles, structurally disconnected and morphologically distinct from osteoconducted bone, suggesting the osteogenic nature of implanted SVF cells. We demonstrate that SVF cells, without expansion or exogenous priming, can spontaneously form bone tissue and vessel structures within a fracture-microenvironment. The gained clinical insights into the biological functionality of the grafts, combined with their facile, intra-operative manufacturing modality, warrant further tests of effectiveness in larger, controlled trials. Stem Cells 2016;34:2956-2966.

Versatility of an Extended Posterior Approach for the Treatment of Acetabular Fractures With Reference to the Superior Gluteal Neurovascular Bundle.

The superior gluteal neurovascular bundle is at risk of injury in certain types of acetabular fractures and the associated surgery. This article describes the versatility of an extended posterior approach, previously described for complex revision total hip replacement (the Adelaide approach) and for the treatment of acetabular fractures that allows a wide exposure of the ilium through identification, protection, and mobilization of the superior gluteal neurovascular bundle.

The Absence of a Mature Cell Wall Sacculus in Stable Listeria monocytogenes L-Form Cells Is Independent of Peptidoglycan Synthesis.

L-forms are cell wall-deficient variants of otherwise walled bacteria that maintain the ability to survive and proliferate in absence of the surrounding peptidoglycan sacculus. While transient or unstable L-forms can revert to the walled state and may still rely on residual peptidoglycan synthesis for multiplication, stable L-forms cannot revert to the walled form and are believed to propagate in the complete absence of peptidoglycan. L-forms are increasingly studied as a fundamental biological model system for cell wall synthesis. Here, we show that a stable L-form of the intracellular pathogen Listeria monocytogenes features a surprisingly intact peptidoglycan synthesis pathway including glycosyl transfer, in spite of the accumulation of multiple mutations during prolonged passage in the cell wall-deficient state. Microscopic and biochemical analysis revealed the presence of peptidoglycan precursors and functional glycosyl transferases, resulting in the formation of peptidoglycan polymers but without the synthesis of a mature cell wall sacculus. In conclusion, we found that stable, non-reverting L-forms, which do not require active PG synthesis for proliferation, may still continue to produce aberrant peptidoglycan.

Displaced trochanteric fragments lead to poor functional outcome in pertrochanteric fractures treated by cephalomedullary nails.

BACKGROUND: The importance of the greater trochanter and its attached abductor muscles for physiological gait is well accepted. However the influence of a displaced greater trochanter fracture after a pertrochanteric fracture is unknown. The aim of this study is to determine if there is an association between the greater trochanter position and the level of patient mobility following internal fixation of pertrochanteric fractures. METHODS: One hundred and thirty-three consecutive elderly patients with a median age of 85 (interquartile range [IQR] 79-91) years, who were treated for pertrochanteric fractures at a level I trauma centre, were recruited. AO 31 A3.1 and A3.2 fracture types were excluded from the statistical analysis. Patient mobility was prospectively assessed before the fracture and one year following fracture treatment using the Parker mobility score. In a multivariable analysis, the influence of a displaced greater trochanter on patient mobility at one-year follow-up was assessed. The analysis was adjusted for age, gender, body mass index, Charlson comorbidity index, AO fracture classification, varus-/valgus malposition of the neck-shaft fragments, and Parker mobility score before fracture. RESULTS: Post-operative X-rays were available in 125 patients, out of which 66 (53%) patients were identified with a displaced or migrated greater trochanter. One year mortality rate was 22% (n=27). In the 82 patients who had functional assessment one year post-operatively, the median Parker mobility score before fracture and at one-year follow-up was 7 (IQR 4-9) and 7 (IQR 3-9) in patients without, and 7 (IQR 4-9) and 3 (IQR 2-5) in patients with a displaced greater trochanter. In multivariable analysis, a displaced greater trochanter was significantly associated with a lower Parker mobility score (-1.74, 95% confidence interval -2.37, -1.12, p<0.01). CONCLUSION: Greater trochanter displacement following internal fixation of extracapsular hip fractures with a cephalomedullary nail is associated with a poor functional outcome. Greater attention to achieve adequate reduction and stabilisation of this fragment during internal fixation of pertrochanteric hip fractures should be aimed for despite the inability of current cephalomedullary implants to do so. LEVEL OF EVIDENCE: III prognostic and epidemiological study.

Does cup-cage reconstruction with oversized cups provide initial stability in THA for osteoporotic acetabular fractures?

BACKGROUND: The incidence of acetabular fractures in osteoporotic patients is increasing. Immediate total hip arthroplasty (THA) has potential advantages, but achieving acetabular component stability is challenging and, at early followup, reported revision rates for loosening are high. QUESTIONS/PURPOSES: This study measured acetabular component stability and the initial surface contact achieved between the acetabular component and unfractured region of the pelvis after THA using an oversized acetabular component and cup-cage reconstruction. METHODS: Between November 2011 and November 2013, we treated 40 acute acetabular fractures in patients older than 70 years of age. Of these, 12 (30%) underwent immediate THA using an oversized acetabular component with screws inserted only into the ilium and a cup-cage construct. Postoperatively all patients were mobilized without weightbearing restrictions. Indications for immediate THA after acetabular fractures were displaced articular comminution deemed unreducible. Eleven of the 12 were prospectively studied to evaluate the initial stability of the reconstructions using radiostereometric analysis. One of the patients died of a pulmonary embolism after surgery, and the remaining 10 (median age, 81 years; range, 72-86 years) were studied. Of these, five were analyzed at 1 year and five were analyzed at 2 years. Acetabular component migration was defined as acceptable if less than the limits for primary THA that predict later loosening (1.76 mm of proximal migration and 2.53° of sagittal rotation). The contact surface between the acetabular component and ilium in direct continuity with the sacroiliac joint, and the ischium and pubis in direct continuity with the symphysis pubis, was measured on postoperative CT scans. RESULTS: At 1 year the median proximal migration was 0.83 mm (range, 0.09-5.13 mm) and sagittal rotation was 1.3° (range, 0.1°-7.4°). Three of the 10 components had migration above the suggested limits for primary THA at 1 year postoperatively. The contact surface achieved at surgery between the acetabular component and pelvis ranged from 11 to 17 cm(2) (15%-27% of each component). CONCLUSIONS: The majority of acetabular components in this cohort were stable despite the small contact surface achieved between the component and pelvic bone. Three of 10 migrated in excess of the limits that predict later loosening in primary THA but it remains to be seen whether these limits apply to this selected group of frail osteoporotic patients. We continue to use this technique routinely to treat patients with the same indications, but since the analysis of these data we have added screw fixation of the acetabular component to the ischial tuberosity and the superior pubic ramus. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Beyond the matrix-assisted laser desorption ionization (MALDI) biotyping workflow: in search of microorganism-specific tryptic peptides enabling discrimination of subspecies.

A well-accepted method for identification of microorganisms uses matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) coupled to analysis software which identifies and classifies the organism according to its ribosomal protein spectral profile. The method, called MALDI biotyping, is widely used in clinical diagnostics and has partly replaced conventional microbiological techniques such as biochemical identification due to its shorter time to result (minutes for MALDI biotyping versus hours or days for classical phenotypic or genotypic identification). Besides its utility for identifying bacteria, MS-based identification has been shown to be applicable also to yeasts and molds. A limitation to this method, however, is that accurate identification is most reliably achieved on the species level on the basis of reference mass spectra, making further phylogenetic classification unreliable. Here, it is shown that combining tryptic digestion of the acid/organic solvent extracted (classical biotyping preparation) and resolubilized proteins, nano-liquid chromatography (nano-LC), and subsequent identification of the peptides by MALDI-tandem TOF (MALDI-TOF/TOF) mass spectrometry increases the discrimination power to the level of subspecies. As a proof of concept, using this targeted proteomics workflow, we have identified subspecies-specific biomarker peptides for three Salmonella subspecies, resulting in an extension of the mass range and type of proteins investigated compared to classical MALDI biotyping. This method therefore offers rapid and cost-effective identification and classification of microorganisms at a deeper taxonomic level.

Pubic rami fractures in the elderly--a neglected injury?

OBJECTIVE: To evaluate the patient characteristics and natural history of pubic rami fractures in geriatric patients, with a special focus on the frequency of concomitant posterior pelvic ring lesions and the percentage of secondarily operated patients as a result of conservative treatment failure. STUDY DESIGN: Retrospective cohort study. Patients were treated in a university hospital that is equivalent to a level I Trauma centre. PATIENTS AND METHODS: We analysed 132 consecutive patients (113 women, 19 men), >65 years old, presenting with low energy-trauma pubic rami fractures at our emergency department from January 2009 to December 2011. RESULTS: Mean age of patients was 84 years (range 66-100). Women were affected six times more frequently than men. Almost 30% of patients lost their previous independence permanently owing to the injury. Ninety eight percent of previously independent patients (community dwellers) required temporary hospital care for a median duration of 39 days (interquartile range [IQR] 28-52). One-year mortality was 18.5%. A concomitant posterior pelvic ring lesion was identified by computed tomography in 54% of patients. In 4% of the patients secondary operative fracture stabilisation was performed. DISCUSSION: Pubic rami fractures are frequently associated with concomitant posterior pelvic ring injuries, making these injuries more unstable than generally assumed. Based on this fact and the long duration of hospital stay, more aggressive management of these injuries may be considered. The principle aims in this patient population are satisfying pain management, early mobilisation, conservation of independence and return to previous place of residence.

Associated lesions in posterior wall acetabular fractures: not a valid predictor of failure.

BACKGROUND: The general outcome of posterior wall acetabular fractures is still the source of discussion. Posterior wall fractures are recognized throughout the literature as being difficult to treat. The aim of the present study was to analyze in our own patients the relevance of the classical prognostic criteria for the outcome of isolated posterior wall fractures and those with associated lesions. MATERIALS AND METHODS: A prospective cohort of 33 consecutive patients treated operatively between 1996 and 2006 in a single level 1 trauma center for a posterior wall fracture of the acetabulum was analyzed retrospectively. Included were posterior wall acetabular fractures or associated posterior wall fractures, such as the combinations of posterior column with posterior wall, transverse with posterior wall, or T-shaped fracture with posterior wall fracture. Outcome measurement of the postoperative survival of the hip joints until the primary outcome reoperation (total hip replacement or fusion) and secondary outcome diagnosis of symptomatic osteoarthritis were performed. RESULTS: Twenty-six of the 33 patients with posterior wall fractures also had a dislocated joint. Twelve had isolated and 21 associated fractures. Six patients were reoperated with a THA (four patients within 2 years and one after 10 years), and one arthrodesis was done to treat a hematogenous septic arthritis in a degenerative hip joint. Secondary arthritis was observed in 10 patients. CONCLUSIONS: No difference was found between the outcome in cases of isolated posterior wall acetabular fracture and the outcome in those with associated lesions. The classical prognostic criteria were not found to be relevant to the outcome for our group.

Evaluation of aerated steam treatment of alfalfa and mung bean seeds to eliminate high levels of Escherichia coli O157:H7 and O178:H12, Salmonella enterica, and Listeria monocytogenes.

Sprouts contaminated with human pathogens are able to cause food-borne diseases due to the favorable growth conditions for bacteria during germination and because of minimal processing steps prior to consumption. We have investigated the potential of hot humid air, i.e., aerated steam, to treat alfalfa and mung bean seeds which have been artificially contaminated with Escherichia coli O157:H7, Salmonella enterica subsp. enterica serovar Weltevreden, and Listeria monocytogenes Scott A. In addition, a recently collected E. coli O178:H12 isolate, characterized by a reduced heat sensitivity, was exposed to the treatment described. Populations of E. coli O157:H7 and S. enterica on alfalfa and mung bean seeds could be completely eliminated by a 300-s treatment with steam at 70 ± 1°C as revealed by enrichment studies. L. monocytogenes and E. coli O178:H12 could not be completely eliminated from artificially inoculated seeds. However, bacterial populations were reduced by more than 5 log CFU/g on alfalfa and by more than 4 log CFU/g on mung bean seeds. The germination rate of mung beans was not affected by the 300-s treatment compared to the germination rate of untreated seeds whereas that of alfalfa seeds was significantly lower by 11.9%. This chemical-free method is an effective alternative to the 20,000-ppm hypochlorite treatment presently recommended by the U.S. Food and Drug Administration (FDA).

[Postoperative course following open reduction and internal fixation of fractures]. / Postoperative Betreuung nach operativer Frakturbehandlung.

The postoperative management after open reduction and internal fixation (ORIF) of fractures is addressed with this article. The topics selected focus on topics that are of relevance for the family practitioner. Because of large differences in the treatment of adult - and geriatric fracture patients these two groups are separately looked at in Part 1 and Part 2 of the article. Fractures in children or fractures of the growing skeleton are not addressed. In the early postoperative phase, the fracture patient might seek for advice in case of complications, such as wound infection or complex regional pain syndrome (CRPS). After fracture healing, the decision on implant removal has to be made. Geriatric fracture patients mostly cannot return back home directly from the hospital. Instead they are transferred to a rehabilitation center. In these patients secondary fracture prevention should be in the focus of the family practitioner. This means osteoporosis diagnostics and treatment shall be initiated, if not done before. Another important task is to guarantee for compliance with the therapy once it is initiated.