Water for agriculture: more crop per drop.

Global crop production in agriculture depends on water availability. Future scenarios predict increasing occurrence of flash floods and rapidly developing droughts accompanied by heatwaves in humid regions that rely on rain-fed agriculture. It is challenging to maintain high crop yields, even in arid and drought-prone regions that depend on irrigation. The average water demand of crops varies significantly, depending on plant species, development stage, and climate. Most crops, such as maize and wheat, require relatively more water during the vegetative phase compared to the ripening phase. In this review, we explain WUE and options to improve water use and thus crop yield. Nutrient management might represent another possibility to manipulate water uptake and use by plants. An emerging topic involves agroforest co-cultivation, where trees in the system facilitate water transfer through hydraulic lift, benefiting neighbouring crops. Other options to enhance crop yield per water use are discussed.

Metformin shows anti-neoplastic properties by inhibition of oxidative phosphorylation and glycolysis in epidermolysis bullosa-associated aggressive cutaneous squamous cell carcinoma.

BACKGROUND: While most cutaneous squamous cell carcinomas (cSCCs) are treatable, certain high-risk cSCCs, such as those in recessive dystrophic epidermolysis bullosa (RDEB) patients, are particularly aggressive. Owing to repeated wounding, inflammation and unproductive healing, RDEB patients have a 68% cumulative risk of developing life-threatening cSCCs by the age of 35, and a 70% risk of death by the age of 45. Despite aggressive treatment, cSCC represents the leading cause of premature mortality in these patients, highlighting an unmet clinical need. Increasing evidence points to a role of altered metabolism in the initiation and maintenance of cSCC, making metabolism a potential therapeutic target. OBJECTIVES: We sought to determine the feasibility of targeting tumour cell energetics as a strategy to selectively hinder the growth advantage of aggressive cSCC. METHODS: We evaluated the cell energetics profiles of RDEB-SCC cells by analysing available gene expression data against multiple gene signatures and single-gene targets linked to metabolic reprogramming. Additionally, we employed real-time metabolic profiling to measure glycolysis and respiration in these cells. Furthermore, we investigated the anti-neoplastic properties of the metformin against human and murine high-risk cSCCs in vitro and in vivo. RESULTS: Gene expression analyses highlighted a divergence in cell energetics profiles between RDEB-SCC and non-malignant RDEB keratinocytes, with tumour cells demonstrating enhanced respiration and glycolysis scores. Real-time metabolic profiling supported these data and additionally highlighted a metabolic plasticity of RDEB-SCC cells. Against this background, metformin exerted an anti-neoplastic potential by hampering both respiration and glycolysis, and by inhibiting proliferation in vitro. Metformin treatment in an analogous model of fast-growing murine cSCC resulted in delayed tumour onset and slower tumour growth, translating to a 29% increase in median overall survival. CONCLUSIONS: Our data indicate that metformin exerts anti-neoplastic properties in aggressive cSCCs that exhibit high-risk features by interfering with respiration and glycolytic processes.

Precomputed Radiative Heat Transport for Efficient Thermal Simulation.

Architectural design and urban planning are complex design tasks. Predicting the thermal impact of design choices at interactive rates enhances the ability of designers to improve energy efficiency and avoid problematic heat islands while maintaining design quality. We show how to use and adapt methods from computer graphics to efficiently simulate heat transfer via thermal radiation, thereby improving user guidance in the early design phase of large-scale construction projects and helping to increase energy efficiency and outdoor comfort. Our method combines a hardware-accelerated photon tracing approach with a carefully selected finite element discretization, inspired by precomputed radiance transfer. This combination allows us to precompute a radiative transport operator, which we then use to rapidly solve either steady-state or transient heat transport throughout the entire scene. Our formulation integrates time-dependent solar irradiation data without requiring changes in the transport operator, allowing us to quickly analyze many different scenarios such as common weather patterns, monthly or yearly averages, or transient simulations spanning multiple days or weeks. We show how our approach can be used for interactive design workflows such as city planning via fast feedback in the early design phase.

Litigations in orthopedics and trauma surgery: reasons, dynamics, and profiles.

BACKGROUND: In recent literature, the increasing number of medical litigations, both in terms of the number of cases being filed and the substantive costs associated with lawsuits, has been described. This study aims to provide an overview of the profile of litigation for orthopedic and trauma surgery to describe the differences and the development of the number of cases over time. PATIENTS AND MATERIALS: A retrospective review of all litigations between 2000 and 2017 was conducted using the institutional legal database. The causes of litigation were documented and classified into seven major categories. In addition to plaintiff characteristics, the litigation outcomes and the differences between emergency and elective surgery were analyzed. RESULTS: A total of 230 cases were evaluated. The mean age of the plaintiffs was 44.6 ± 20.1 years, and 56.8% were female. The main reasons for litigation were claimed inappropriate management (46.1%), misdiagnosis (22.6), and poor nursing care (8.3%). Significantly more litigations were filed against surgeons of the orthopedic subspecialty compared with trauma surgeons (78%; p ≤ 0.0001). There were significantly fewer litigations per 1000 cases filed overall in 2009-2017 (65% less; p = 0.003) than in 2000-2008. CONCLUSION: Our results could not confirm the often-stated trend of having more litigations against orthopedic and trauma surgeons. Although the absolute numbers increased, the number of litigations per 1000 patients treated declined. Patients who underwent elective surgery were more likely to file complaints than emergency patients.

Fretting-corrosion of CoCr-alloys against TiAl6V4: The importance of molybdenum in oxidative biological environments.

Periprosthetic fluids often contain reactive oxygen species, including H2O2, that are generated during inflammatory processes. Here, we investigated the fretting-corrosion behavior of CoCrX-alloys (X = Mo, Fe) in a complex protein-containing lubricant, with and without the addition of H2O2. Given the known protective role of molybdenum as an alloying element in metal degradation, we considered its effects by designing a two-way factorial experiment. The aim of the study was to investigate tribocorrosive mechanisms in modular joints of knee and hip prostheses. A previously described test-rig was used to run fretting corrosion tests of CoCrX-alloys with (X=Mo) and without (X=Fe) molybdenum against TiAl6V4 in bovine calf serum (BCS) with and without a physiological relevant H2O2 level (3 mM) in gross slip mode (4 Hz, ±50 µm, pmax=0.18 GPa, 37 °C, 50,000 cycles). Two CoCr-pins were pressed against a cylindrical TiAl6V4-rod, forming a line contact. Normal and frictional forces, the displacement, and the open circuit potential (OCP) were measured and recorded continuously. The dissipated frictional work was independent of alloy composition. The addition of H2O2 lowered the dissipated frictional work and increased wear, and this was significant in the absence of Mo. The mean OCP value was lower with Mo-containing than with Mo-free alloy in both pure BCS (p = .042), and BCS ± H2O2 (p < .0005). The wear scar was deeper for the Mo-free alloy, and this was significant (p = .013) in the presence of H2O2. These findings suggest a marked weakening of the passive film in the presence of H2O2, which is mitigated by the availability of Mo.

Therapeutic assessment of N-formyl-methionyl-leucyl-phenylalanine (fMLP) in reducing periprosthetic joint infection.

Despite many preventive measures, including prophylactic antibiotics, periprosthetic joint infection (PJI) remains a devastating complication following arthroplasty, leading to pain, suffering, morbidity and substantial economic burden. Humans have a powerful innate immune system that can effectively control infections, if alerted quickly. Unfortunately, pathogens use many mechanisms to dampen innate immune responses. The study hypothesis was that immunomodulators that can jumpstart and direct innate immune responses (particularly neutrophils) at the surgical site of implant placement would boost immune responses and reduce PJI, even in the absence of antibiotics. To test this hypothesis, N-formyl-methionyl-leucyl-phenylalanine (fMLP) (a potent chemoattractant for phagocytic leukocytes including neutrophils) was used in a mouse model of PJI with Staphylococcus aureus (S. aureus). Mice receiving intramedullary femoral implants were divided into three groups: i) implant alone; ii) implant + S. aureus; iii) implant + fMLP + S. aureus. fMLP treatment reduced S. aureus infection levels by ~ 2-Log orders at day 3. Moreover, fMLP therapy reduced infection-induced peri-implant periosteal reaction, focal cortical loss and areas of inflammatory infiltrate in mice distal femora at day 10. Finally, fMLP treatment reduced pain behaviour and increased weight-bearing at the implant leg in infected mice at day 10. Data indicated that fMLP therapy is a promising novel approach for reducing PJI, if administered locally at surgical sites. Future work will be toward further enhancement and optimisation of an fMLP-based therapeutic approach through combination with antibiotics and/or implant coating with fMLP.

Microindentation of cartilage before and after articular loading in a bioreactor: assessment of length-scale dependency using two analysis methods.

Background: Microindentation is a technique with high sensitivity and spatial resolution, allowing for measurements at small-scale indentation depths. Various methods of indentation analysis to determine output properties exist. Objective: Here, the Oliver-Pharr Method and Hertzian Method were compared for stiffness analyses of articular cartilage at varying length-scales before and after bioreactor loading. Methods: Using three different conospherical tips with varying radii (20, 100, 793.75 µm), a bioreactor-indenter workflow was performed on cartilage explants to assess changes in stiffness due to articular loading. For all data, both the Oliver-Pharr Method and Hertzian Method were applied for indentation analysis. Results: The reduced moduli calculated by the Hertzian Method were found to be similar to those of the Oliver-Pharr Method when the 20 µm tip size was used. The reduced moduli calculated using the Hertzian Method were found to be consistent across the varying length-scales, whereas for the Oliver-Pharr Method, adhesion/suction led to the largest tip exhibiting an increased average reduced modulus compared to the two smaller tips. Loading induced stiffening of articular cartilage was observed consistently, regardless of tip size or indentation analysis applied. Conclusions: Overall, geometric linearity is preserved across all tip sizes for the Hertzian Method and may be assumed for the two smaller tip sizes using the Oliver-Pharr Method. These findings further validate the previously described stiffening response of the superficial zone of cartilage after articular loading and demonstrate that the finding is length-scale independent.

The effect of albumin and γ-globulin on synovial fluid lubrication: Implication for knee joint replacements.

Total knee arthroplasty has become a routine procedure for patients suffering from joint diseases. Although the number of operations continuously increases, a limited service-life of implants represents a persisting challenge for scientists. Understanding of lubrication may help to suitably explain tribological processes on the way to replacements that become durable well into the third decade of service. The aim of the present study is to assess the formation of protein lubricating film in the knee implant. A developed knee simulator was used to observe the contact of real femoral and transparent polymer tibial component using fluorescent microscopy. The contact was lubricated by various protein solutions with attention to the behaviour of albumin and γ-globulin. In order to suitably mimic a human synovial fluid, hyaluronic acid and phospholipids were subsequently added to the solutions. Further, the change in shape and the migration of the contact zone were studied. The results showed considerable appearance differences of the contact over the swing phase of the simplified gait cycle. Regarding film formation, a strong interaction of the various molecules of synovial fluid was observed. It was found that the thickness of the lubricating layer stabilizes within around 50 s. Throughout the contact zone, protein agglomerations were present and could be clearly visualised using the applied optical technique.

In-vitro studies on cells and tissues in tribocorrosion processes: A systematic scoping review.

Tribocorrosion of implants has been widely addressed in the orthopedic and dental research fields. This study is a systematic scoping review about research methods that combine tribocorrosion tests with cells/tissues cultures, aimed to identify related current problems and future challenges. We used 4 different databases to identify 1022 records responding to an articulated keywords search-strategy. After removing the duplicates and the articles that didn't meet the search-criteria, we assessed 20 full-text articles for eligibility. Of the 20 eligible articles, we charted 8 records on cell cultures combined with tribocorrosion tests on implant materials (titanium, CoCrMo, and/or stainless steel). The year of publication ranged from 1991 to 2019. The cell line used was mostly murine. Two records used fretting tests, while 6 used reciprocating sliding with pin-on-disc tribometers. An electrochemical three-electrode setup was used in 4 records. We identified overall two experimental approaches: cells cultured on the metal (5 records), and cells cultured near the metal (3 records). Research activities on tribocorrosion processes in the presence of cells have been undertaken worldwide by a few groups. After a limited initial interest on this topic in the 1990's, research activities have restarted in the last decade, renewing the topic with technologically more advanced setups and analytical tools. We identified the main problems to be the lack of test reproducibility and wear particle characterization. We believe that the main challenges lay in the interdisciplinary approach, the inter-laboratory validation of experiments, and the interpretation of results, particularly in relation to potential clinical significance.

[Treatment-process analysis of orthopaedic trauma surgery patients at an outpatient setting in a university hospital]. / Prozessanalyse der ambulanten Behandlung unfallchirurgischer Patienten an einer universitären Poliklinik.

BACKGROUND: The cost pressure in a competitive environment forces hospitals and physicians to optimize clinical processes. In order to secure competitive advantages, a continuous evaluation of relevant processes is necessary. OBJECTIVE: Administrative and medical processes in a university outpatient department for orthopedics and traumatology were evaluated using the lean method in order to reduce patient waiting times. MATERIAL AND METHODS: Over a period of 2 weeks all patients who were treated in the department for orthopedic and trauma surgery on an outpatient basis were included in the assessment of the process. Personnel in the policlinic were prepared and trained to record times for appointments made by telephone, arrival time at the hospital, first contact, administrative procedure, first contact with the doctor, length of stay in the radiology and anesthesiology departments and completion of treatment. In addition, potential inefficiencies were identified through patient flow analysis and personal interviews with personnel in the administration and outpatient departments as well as residents and senior physicians. RESULTS: A total of 126 patients were enrolled in the study. The average length of stay of patients in the outpatient clinic was 144 min (range 30-371 min). A necessary imaging examination increased the length of stay by an average of 53 min and a necessary premedication by an average of 78 min compared to patients with no further consultations. CONCLUSION: By analyzing the pathways and times of patients, various reasons for waiting times in the university outpatient clinic could be shown. This study shows that a structured application of lean management and a dedicated analysis create added value for patients by reducing waiting times.

[Process optimization in the operating room area]. / Prozessoptimierung im operativen Bereich.

BACKGROUND: The operating room (OR) accounts for the highest fraction of hospital costs and also has the largest proportion of revenue. Classical goals of optimizing OR efficiency are to increase the quality of treatment and economic success. As the reduction of qualified personnel as the largest cost factor was favored for many years, nowadays a shortage of nursing personnel is threatening the surgery departments in many German hospitals. OBJECTIVE: Which improvements are possible while the OR already suffers from restrictions? What are critical resources, what are the critical burdens and how can they be optimized? MATERIAL AND METHODS: An analysis of the OR organization of an orthopedic and traumatology department with reduced OR capacity due to a shortage of OR and anesthesia nursing personnel was performed. This was followed by the evaluation of possible alterations with the corresponding advantages and disadvantages. After selection and implementation, the qualitative and quantitative differences were examined before and after the alterations. RESULTS: Multifaceted problem areas could be identified. The establishment of a fast track OR with concentration of additional resources on many fast points in an OR instead of on a few complex cases was selected and implemented. The installation of a holding area for patients waiting for surgery eliminated transportation delays almost entirely. Alterations in the OR planning and capacity distribution reduced nocturnal operating times. Despite reduction of the OR capacity both the number of operations performed and the incision to suture times could be increased. CONCLUSION: Optimization of the processes in the OR is possible and necessary, despite the lack of personnel. Even only a few structural changes can eliminate bottlenecks, resulting in qualitative and quantitative improvements.

[Medical service providers as bottleneck in orthopedics and trauma surgery : Problems and solution strategies in interdisciplinary collaboration]. / Medizinische Dienstleister als Nadelöhr in Orthopädie und Unfallchirurgie : Probleme und Lösungsstrategien in der interdisziplinären Zusammenarbeit.

BACKGROUND: Due to limited financial and human resources, efficient planning of patient flows, operation preparations and perioperative diagnostics are of great importance. In the present study potential problems and solution strategies in the interdisciplinary collaboration between orthopedic surgeons, trauma surgeons and colleagues in anesthesiology and radiology departments are presented. MATERIAL AND METHODS: After implementation of a process management system, the data were collated and the number of patients, the utilization of external departments in the consultation, waiting times and patient adherence to appointments were analyzed. Patient satisfaction was determined using a questionnaire. In addition, the current literature was searched regarding the topic of process optimization and interdisciplinary cooperation. RESULTS: The waiting time for an appointment in the outpatient clinic consultation in orthopedics and trauma at the University Hospital Bonn was between 9.15 and 11.23 days. Of the patients 10-20% from the consultation presented in the premedication outpatient department. Radiological imaging was performed in 22-28% of the cases. Patient satisfaction was recorded using a questionnaire gathering information on medical treatment, organization and infrastructure as well as treatment success. The importance of an efficient and digitally organized cooperation is generally promoted in the literature; however, there is insufficient data on the subject of process organization and economic interdisciplinary cooperation. CONCLUSION: By implementing a process management, deficiencies in the workflow and interdisciplinary collaboration can be identified and optimized in a structured manner. This also improves patient and employee satisfaction and the quality of treatment.

[Modular arthrodesis system TITAN (KAM-TITAN) after failed revision total knee arthroplasty : Operative technique and clinical experience]. / Modulares Kniearthrodesesystem TITAN (KAM-TITAN) nach fehlgeschlagener Knieendoprothetik : Operative Technik und klinische Ergebnisse.

OBJECTIVE: Restoration of a painless, weight-bearing extremity with a modular knee arthrodesis system based on a cementless modular revision stem for rotationally stable, diaphyseal anchorage. INDICATIONS: Severe bone loss and compromised soft tissue after failed total knee arthroplasty, two-stage revisions and non-reconstructible knee extensor mechanism deficiency. CONTRAINDICATIONS: Extensive osteolysis preventing diaphyseal anchorage of the prosthesis. Contralateral arthrodesis of the knee joint and/or ipsilateral arthrodesis of the hip joint and contralateral lower extremity amputation. SURGICAL TECHNIQUE: In revision cases, removal of the total knee arthroplasty, spacer, the bone cement and all intramedullary granulation tissue. Reaming the medullary cavity with intramedullary reamers to cortical contact. Restoring leg length and rotation with trial implants. After implantation of the femoral and tibial stems, placing and tensioning of the rotationally aligned coupling elements. POSTOPERATIVE MANAGEMENT: Mobilization on two forearm crutches from postoperative day 1. Removal of the Redon drains after 48 h. Partial weight bearing of 20 kg for 6 weeks postoperatively. If plain radiographs show unchanged seating of the prosthesis after 6 weeks, loading can be increased by 10 kg per week until full weight bearing is achieved. RESULTS: Between 2007 and 2012 clinical data were collected and analyzed retrospectively. A total of 27 patients had been treated within a two-stage exchange procedure with implantation of a modular intramedullary arthodesis nail TITAN (KAM-TITAN). The mean follow-up was 30.9 ± 12.0 months. A functional evaluation was performed using the Oxford Knee Score (OKS). The analyzed patients showed a mean score of 39.2 ± 8.3. To determine the pain level the Visual Analog Scale (VAS) for pain was used and showed a mean score of 2.9 ± 1.3. The rate of definitely free of infection (using Laffer criteria) at last follow-up was 85.2%.

Effects of bovine serum albumin and hyaluronic acid on the electrochemical response of a CoCrMo alloy to cathodic and anodic excursions.

The problem of wear and corrosion of CoCrMo-implant surfaces in the human body following total joint replacement has been commonly investigated with tribocorrosion tests, using different lubricants meant to simulate the pseudo-synovial fluid. While results considering the synovial fluid components separately have highlighted their individual influence on the tribological performance of CoCrMo-alloy, an understanding about the influence of the synovial fluid components under the electrochemical point of view is missing. This work aims to investigate the effect of bovine serum albumin (BSA) and hyaluronic acid (HA) on electrochemical potential variations of CoCrMo alloys tested in a model synovial fluid. To simulate the environment inside the synovial capsule, the tests were performed inside a CO2 incubator at 37°C. Open circuit potential, electrochemical impedance spectroscopy, cathodic and anodic potentiodynamic measurements were performed with different electrolytes, prepared with cell culture medium (RMPI-1640), BSA and HA. The final CoCrMo-surface was analyzed by SEM/EDS and infrared spectroscopy. The influence of HA on the corrosion of the CoCrMo-alloy depended on the presence of BSA proteins adsorbed on the CoCrMo-surface: EIS and anodic polarization results showed a corrosive action of HA in the absence of adsorbed proteins. In the presence of both BSA and HA, organometallic precipitates were found on the CoCrMo surface following reverse anodic polarization, which remind of corrosion products found in-vivo. These results indicate that HA affects the interaction of CoCrMo implant alloys with protein-containing model synovial fluids, and suggest that HA needs to be considered in tribocorrosion studies for more clinically relevant outcomes.

The effect of hyaluronic acid on the corrosion of an orthopedic CoCrMo-alloy in simulated inflammatory conditions.

During joint inflammation, various reactive oxygen species (ROS) are present in the surrounding tissue and joint fluid. In the laboratory, hydrogen peroxide (H2O2) is typically used to simulate inflammatory conditions, and media containing proteins and hyaluronic acid (HA) are employed to simulate joint synovial fluid. Electrochemical interactions between H2O2 and HA in the presence of a CoCrMo surface are expected, since HA molecules contain redox-active moieties. We hypothesized that any redox reactions of these moieties with ROS will mitigate the oxidizing effect of H2O2 on the CoCrMo surface, limiting the corrosion rate of the metal. Non-destructive electrochemical measurements (open circuit potential, linear polarization resistance and electrochemical impedance spectroscopy) were used to investigate the corrosion response of CoCrMo in synovial model fluid containing physiologically relevant concentrations of albumin proteins and hyaluronic acid, with and without H2O2. Two different molarities of H2O2, 3 mM and 30 mM, were tested. While both molarities are within physiological limits, 3mM is well within the range HA could mitigate, whereas 30 mM is not. Contrary to our hypothesis, HA did not alleviate corrosion in 3 mM H2O2 and even caused a corrosion increase in the case of 30 mM H2O2. The decrease in corrosion resistance of the alloy may be attributed to the complexation of degenerated HA molecular chains with chromium ions released from the metallic surface, which are necessary to build a protective oxide film. This finding has clinical implications, suggesting that HA accelerates corrosion of CoCrMo implants in the presence of strong inflammation.

Investigation of CoCrMo material loss in a novel bio-tribometer designed to study direct cell reaction to wear and corrosion products.

Wear and corrosion in total hip replacement negatively impact implant service-life and patient well-being. The aim of this study was to generate a statistical response surface of material loss using an apparatus, capable of testing the effect of wear and corrosion products in situ on cells, such as macrophages. The test chamber of a ball-on-flat tribometer operating inside a CO2 incubator was integrated with an electrochemical setup and adapted for cell culture work. A 20-test series, following a 2-level 3-factor design of experiments, was performed with a ceramic head in reciprocating rotational motion against a CoCrMo-alloy disc, under constant load. The lubricant was cell culture medium (RPMI-1640+10vol% bovine serum). Response surfaces were generated, which statistically showed the influence of motion amplitude, load, and potential on the total mass loss and wear scar volume of the metallic discs. Potential had the highest impact on the total mass loss, while motion amplitude and load significantly influenced the wear scar volume. The concentrations of the alloy elements found in the lubricants reflected the bulk-alloy stoichiometry. The total concentration of Co released into the lubricant (2.3-63 ppm by total mass loss, 1.5 to 62 ppm by ICP-MS) corresponded well with the known range to trigger cell response. Tribocorrosion tests in the presence of cells and tissues, such as macrophages, lymphocytes and/or synovium, will be carried out in the future.

Staphylococcus aureus versus Staphylococcus epidermidis in periprosthetic joint infection-Outcome analysis of methicillin-resistant versus methicillin-susceptible strains.

Periprosthetic joint infections (PJIs) are a major complication in total joint arthroplasty. Staphylococcus aureus and coagulase-negative staphylococci are known to cause the majority of all PJIs. This study aimed to analyze the eradication rates of S. aureus and S. epidermidis with methicillin susceptibility and methicillin resistance in a 2-stage therapy algorithm. Seventy-four patients with PJI caused by methicillin-resistant S. aureus (MRSA), methicillin-resistant coagulase-negative staphylococci (MRSE), methicillin-susceptible S. aureus (MSSA), and methicillin-susceptible coagulase-negative staphylococci (MSSE) were included, and the outcome was analyzed retrospectively. After a minimal follow-up of 2 years, n = 56 patients (75.7%) were definitively free of infection. The analysis revealed significant differences between the groups, with eradication rates as follows: MSSA (92.6%), MSSE (95.2%), MRSA (80%), and MRSE (54.2%). MRSE showed a significantly lower rate of patients graded as "definitively free of infection" as compared to patients with infections caused by MSSA, MSSE, and MRSA.

Fluid collection bags pose a threat for bacterial contamination in primary total hip arthroplasty: a prospective, internally controlled, non-blinded trial.

INTRODUCTION: Surgical equipment, and especially the so-called 'splash basins' that are used intraoperatively, are a potential source of bacterial contamination in primary total hip arthroplasty (THA). With this risk in mind, many commercially available draping kits include plastic bags that can be used to collect fluid or to temporarily store instruments. Following this rationale, we hypothesised that first: the fluid collection bags are a potential reservoir of bacteria and second: there is a time dependency for bacterial contamination. MATERIALS AND METHODS: After ethics approval, we investigated in a prospective, internally controlled, non-blinded trial 43 patients who received primary THA. At the beginning of the surgery, we took deep, representative, intracapsular tissue samples, which served as negative controls. At the end of surgery, tissue samples were taken from the bottom of the 'fluid collection bag' for microbiological analysis. RESULTS: All 86 control samples were negative. Out of the samples taken from the bags, a pathogen could be detected in four patients (9.3%). All pathogens were detected after a surgery time lasting longer than 90 min. CONCLUSION: We were able to show that fluid collection bags are a potential reservoir for bacteria in THA when surgery time was greater than a 90-min threshold. Our data suggest that the risks from fluid collection bags outweigh the advantages of using them. Therefore, we recommend against the use of fluid collection bags intraoperatively in primary THA.

Conductance through a helical state in an Indium antimonide nanowire.

The motion of an electron and its spin are generally not coupled. However in a one-dimensional material with strong spin-orbit interaction (SOI) a helical state may emerge at finite magnetic fields, where electrons of opposite spin will have opposite momentum. The existence of this helical state has applications for spin filtering and cooper pair splitter devices and is an essential ingredient for realizing topologically protected quantum computing using Majorana zero modes. Here, we report measurements of a quantum point contact in an indium antimonide nanowire. At magnetic fields exceeding 3 T, the 2 e 2/h conductance plateau shows a re-entrant feature toward 1 e 2/h which increases linearly in width with magnetic field. Rotating the magnetic field clearly attributes this experimental signature to SOI and by comparing our observations with a numerical model we extract a spin-orbit energy of approximately 6.5 meV, which is stronger than the spin-orbit energy obtained by other methods.Indium antimonide nanowires have large spin-orbit coupling, which can give rise to helical states that are an important part of proposals for topological quantum computing. Here the authors measure conductance through the helical states and extract a larger spin-orbit energy than obtained before.

In-situ Generated Tribomaterial in Metal/Metal Contacts: current understanding and future implications for implants.

Artificial hip joints operate in aqueous biofluids that are highly reactive towards metallic surfaces. The reactivity at the metal interface is enhanced by mechanical interaction due to friction, which can change the near-surface structure of the metal and surface chemistry. There are now several reports in the literature about the in-situ generation of reaction films and tribo-metallurgical transformations on metal-on-metal hip joints. This paper summarizes current knowledge and provides a mechanistic interpretation of the surface chemical and metallurgical phenomena. Basic concepts of corrosion and wear are illustrated and used to interpret available literature on in-vitro and in-vivo studies of metal-on-metal hip joints. Based on this review, three forms of tribomaterial, characterized by different combinations of oxide films and organic layers, can be determined. It is shown that the generation of these tribofilms can be related to specific electrochemical and mechanical phenomena in the metal interface. It is suggested that the generation of this surface reaction layer constitutes a way to minimize (mechanical) wear of MoM hip implants.