Extending the Shelf Life of Atlantic Salmon (Salmo salar) with Sub-Chilled Storage and Modified Atmosphere Packaging in Recyclable Mono-Material Trays

This study investigated the effect of sub-chilling whole gutted salmon and sub-chilled storage at -1 °C in modified-atmosphere packaging in two recyclable mono-material trays (CPET, HDPE). Quality parameters were measured, including water-holding properties, salt content, color, texture, lipid oxidation, and sensory and microbiological shelf life. The oxygen transmission rate was measured for the packages. Compared to traditional fish storage on ice, sub-chilling gave a 0.4% weight gain, better water-holding capacity, and higher salt content. The sub-chilled fish gave a significantly better sensory quality and microbiological shelf life of up to 49 days. Photobacterium was the dominating bacteria during storage. Salmon packaged in CPET trays had a higher drip loss than HDPE trays, but a lower rate of lipid oxidation (1-penten-3-ol). Our results showed the feasibility of significantly extending shelf life with sub-chilling, removing the need for ice. Moreover, using recyclable trays for packaging contributes to a circular economy without compromising food quality.

Pre-Slaughter Stunning of Farmed Atlantic Halibut in CO2-Saturated Seawater: Assessment of Unconsciousness by Electroencephalography (EEG)

As fish welfare becomes a growing concern, it is important to ensure humane treatment during slaughter. This study aimed to assess the onset of unconsciousness in Atlantic halibut immersed in CO₂-saturated seawater through electroencephalography (EEG). Of the 29 fish studied, 10 exhibited escape attempts, indicating aversion to CO₂-saturated water despite its oxygenation. EEG signals showed four distinct phases: transitional, excitation (high amplitude-high frequency), suppressed, and iso-electric phases. The onset of the suppressed phase, indicative of unconsciousness, occurred on average 258.8 ± 46.2 s after immersion. The spectral analysis of the EEG signals showed a progressive decrease in median frequency, spectral edge frequency, and high frequency contribution, which corresponded to the gradual loss of consciousness. The study concludes that CO₂-saturated water is not recommended for pre-slaughter handling of halibut due to the extended time required for the onset of unconsciousness and the observed aversive behaviour. Ensuring humane treatment during slaughter is important for addressing public concern and safeguarding fish welfare in all stages of production.

Effects of capture-related stress and pre-freezing holding in refrigerated sea water (RSW) on the muscle quality and storage stability of Atlantic mackerel (Scomber scombrus) during subsequent frozen storage

Crowded (stressed) and unstressed Atlantic mackerel with or without pre-freezing holding in refrigerated sea water (RSW) were stored at -19 °C for ∼12 months and analysed for nucleotide degradation (K value), muscle pH, water holding capacity (WHC), fillet firmness, cathepsin B/L like activity, lipid oxidation and fillet colour. The frozen storage showed the largest and most consistent direct effects on the quality metrics leading to increased lipid oxidation, discolouration (yellowing) and reduction on WHC and cathepsin activity. RSW treatment promoted nucleotide degradation and reduced WHC and fillet firmness in interaction with frozen storage and affected fillet colour lightness and saturation. Although showing only marginal main effects, crowding stress modified WHC, cathepsin activity and fillet firmness and colour through significant interactions with the frozen storage and RSW treatment. Further studies with larger sample sizes would be needed to elucidate their complex effects and interactions on the quality and storage stability of mackerel.

Multicentre randomised trial of invasive and less invasive surfactant delivery methods showed similar spirometry results at 5-9 years of age

AIM

We explored whether subnormal forced expiratory volume within one second (FEV₁ ) at 5-9 years of age was lower in children born preterm who received less invasive surfactant administration (LISA) rather than surfactant via an endotracheal tube.

METHODS

The multicentre, randomised Nonintubated Surfactant Application trial enrolled 211 preterm infants born at 23-26 weeks of gestation from 13 level III neonatal intensive care units from April 2009 to March 2012. They received surfactant via LISA (n=107) or after conventional endotracheal intubation (n=104). The follow-up assessments were carried out by a single team blinded to the group assignments. The main outcome was FEV₁ <80% of predicted values.

RESULTS

Spirometry was successful in 102/121 children. The other children died or were lost to follow up. Median FEV₁ was 93% (interquartile range 80-113%) of predicted values in the LISA group and 86% (interquartile range 77-102%) in the control group (p=0.685). Rates of FEV₁ < 80% were 11/57 (19%) and 15/45 (33 %) respectively, which was an absolute risk reduction of 14% (95% confidence interval -3.1% to 31.2%, p=0.235). There were no differences in other outcome measures.

CONCLUSION

The proportion of children aged 5-9 years with subnormal FEV₁ was not significantly different between the groups.

The benefit of adopting Microultrasound in the prostate cancer imaging pathway: A lesion-by-lesion analysis: Biopsies prostatiques guidée par micro-échographie, quel bénéfice ? Une analyse lésion par lésion

INTRODUCTION

- Microultrasound (MicroUS) is a novel imaging modality relying on a high-frequency transducer which confers a three-fold improvement in spatial resolution as compared with conventional transrectal ultrasound. We evaluated the diagnostic value of MRI-MicroUS fusion biopsy and determined the additional benefit of employing MicroUS.

METHODS

- Retrospective analysis of consecutive treatment-naïve men undergoing MRI-MicroUS fusion biopsy between May 2018 and March 2019. Pre-biopsy MRI was systematically reviewed in a dedicated meeting where suspicious lesions PIRADS ≥ 3 were registered and uploaded in the ExactVu MicroUS device. MRI and MicroUS lesions were individually marked in a PIRADS v2 scheme. The biopsy protocol included MRI-MicroUS fusion and MicroUS targeted biopsies; systematic biopsies were performed at clinician's discretion. The diagnostic value was evaluated in terms of detection rate of clinically significant prostate cancer, defined as Gleason pattern ≥ 4 at histology.

RESULTS

- In all, 148 patients with a median age of 69 years (IQR 63-74) and median PSA density of 0.16 ng/ml/cc (0.10-0.23) were included. Clinically significant cancer was detected in 42.5% (63/148) patients. MRI detected 89 lesions in the peripheral zone; 73% (65/89) were visible on MicroUS. Clinically significant cancer was detected in 46.1% (30/65) MRI and MicroUS visible lesions, and in 4.2% (1/24) lesions only visible on mpMRI. MicroUS additionally identified 35 suspicious lesions non-visible on MRI of which clinically significant cancer was present in 25.7% (9/35).

CONCLUSION

- Adding MicroUS to the conventional pathway seems to increase the detection rate of clinically significant disease in unselected men undergoing biopsy. © 2022 Elsevier Masson SAS. All rights reserved.

WITHDRAWN: The benefit of adopting Microultrasound in the prostate cancer imaging pathway : A lesion-by-lesion analysis

INTRODUCTION

Microultrasound (MicroUS) is a novel imaging modality relying on a high-frequency transducer which confers a three-fold improvement in spatial resolution as compared with conventional transrectal ultrasound. We evaluated the diagnostic value of MRI-MicroUS fusion biopsy and determined the additional benefit of employing MicroUS.

METHODS

Retrospective analysis of consecutive treatment-naïve men undergoing MRI-MicroUS fusion biopsy between May 2018 and March 2019. Pre-biopsy MRI was systematically reviewed in a dedicated meeting where suspicious lesions PIRADS≥3 were registered and uploaded in the ExactVu MicroUS device. MRI and MicroUS lesions were individually marked in a PIRADS v2 scheme. The biopsy protocol included MRI-MicroUS fusion and MicroUS targeted biopsies; systematic biopsies were performed at clinician's discretion. The diagnostic value was evaluated in terms of detection rate of clinically significant prostate cancer, defined as Gleason pattern≥4 at histology.

RESULTS

In all, 148 patients with a median age of 69 years (IQR 63-74) and median PSA density of 0.16ng/ml/cc (0.10-0.23) were included. Clinically significant cancer was detected in 42.5% (63/148) patients. MRI detected 89 lesions in the peripheral zone; 73% (65/89) were visible on MicroUS. Clinically significant cancer was detected in 46.1% (30/65) MRI and MicroUS visible lesions, and in 4.2% (1/24) lesions only visible on mpMRI. MicroUS additionally identified 35 suspicious lesions non-visible on MRI of which clinically significant cancer was present in 25.7% (9/35).

CONCLUSION

Adding MicroUS to the conventional pathway seems to increase the detection rate of clinically significant disease in unselected men undergoing biopsy.

Water holding properties of Atlantic salmon

With global seafood production increasing to feed the rising population, there is a need to produce fish and fishery products of high quality and freshness. Water holding properties, including drip loss (DL) and water holding capacity (WHC), are important parameters in determining fish quality as they affect functional properties of muscles such as juiciness and texture. This review focuses on the water holding properties of Atlantic salmon and evaluates the methods used to measure them. The pre- and postmortem factors and how processing and preservation methods influence water holding properties and their correlations to other quality parameters are reviewed. In addition, the possibility of using modelling is explained. Several methods are available to measure WHC. The most prevalent method is the centrifugation method, but other non-invasive and cost-effective approaches are increasingly preferred. The advantages and disadvantages of these methods and future trends are evaluated. Due to the diversity of methods, results from previous research are relative and cannot be directly compared unless the same method is used with the same conditions.

Physiological response and survival of Atlantic mackerel exposed to simulated purse seine crowding and release

Understanding how animals physiologically respond to capture and release from wild capture fishing is fundamental for developing practices that enhance their welfare and survival. As part of purse seine fishing for small pelagic fish in northern European waters, excess and/or unwanted catches are routinely released from the net in a process called slipping. Due to excessive crowding in the net prior to release, post-slipping mortality rates can be unacceptably high. Atlantic mackerel (Scomber scombrus) support large and economically important purse seine fisheries but are known to be particularly vulnerable to such crowding-induced mortality. Developing management advice to promote post-slipping survival for this species is currently challenging, due to a lack of understanding of how crowding influences their physiology. Here we examine the physiological response, recovery and survival of wild caught mackerel exposed to various degrees and durations of simulated crowding stress in a series of sea cage trials. The magnitude of the physiological response and its time to recovery was positively correlated with crowding density and duration and was characterized by cortisol elevation, energy mobilization and anaerobic metabolite accumulation. There were also indications of osmoregulatory disturbance. Skin injury and mortality rates showed a similar positive relationship to crowding density. The physiological disturbance was recoverable for most fish. Instead, the rate at which mortalities developed and the physiological profile of moribund fish indicated that skin injury, likely arising from abrasive contact with netting and other fish during crowding, was the probable cause of mortality. Injured fish also exhibited a loss of allometric condition relative to non-injured survivors. Crowding treatments were potentially confounded by differences in ambient oxygen reduction, water temperature and pre-treatment fish condition between trials, and densities were replicated only once. These results contribute to the development of welfare conscious fishing practices that aim to reduce post-slipping mortality.

[Prioritization of intensive medical treatment places - Concept proposal]

In the situation of a shortage of ventilation beds, ethically justifiable, transparent and comprehensible decisions must be made. This concept proposes that all patients are first intubated depending on necessity and then assessed by a triage team afterwards. In this situation newly admitted COVID patients compete with newly admitted Non-COVID patients as well as patients already treated in intensive care units for a ventilator. The combination of short-term and long-term prognoses should enable the interprofessional triage team to make comprehensible decisions. The aim of the prioritization concept is to save as many human lives as possible and to relieve the treatment team of the difficult decision on prioritization.

Surgical site infections: guidance for elective surgery during the SARS-CoV-2 pandemic - international recommendations and clinical experience

BACKGROUND

The COVID-19 pandemic not only had an impact on public life and healthcare facilities in general, but also affected established surgical workflows for elective procedures. The strategy to protect patients and healthcare workers from infection by SARS-CoV-2 in surgical departments has needed step-by-step development. Based on the evaluation of international recommendations and guidelines, as well as personal experiences in a clinical 'hot spot' and in a 450-bed surgical clinic, an adapted surgical site infection (SSI) prevention checklist was needed to develop concise instructions, which described roles and responsibilities of healthcare professionals that could be used for wider guidance in pandemic conditions.

METHOD

Publications of COVID-19-related recommendations and guidelines, produced by health authorities and organizations, such as WHO, US-CDC, ECDC, the American College of Surgery and the Robert Koch Institute, were retrieved, assessed and referenced up to 31st January 2020. Additionally, clinical personal experiences in Germany were evaluated and considered.

RESULTS

Part 1 of this guidance summarizes the experience of a tertiary care, surgical centre which utilized redundant hospital buildings for immediate spatial separation in a 'hot spot' COVID-19 area. Part 2 outlines the successful screening and isolation strategy in a surgical clinic in a region of Germany with outbreaks in surrounding medical centres. Part 3 provides the synopsis of personal experiences and international recommendations suggested for implementation during the COVID-19 pandemic.

CONCLUSION

Understanding of COVID-19, and SARS-CoV-2-related epidemiology, is constantly and rapidly changing, requiring continuous adaptation and re-evaluation of recommendations. Established national and local guidelines for continuation of surgical services and prevention of SSI require ongoing scrutiny and focused implementation. This manuscript presents a core facility checklist to support medical institutions to continue their clinical and surgical work during the COVID-19 pandemic.

Descriptive study of young disabled children aged 2-6, enrolled in mainstream schools, and benefiting from special needs assistants in the Bouches-du-Rhône in 2014

BACKGROUND

Since the law of February 11, 2005, in France, the number of children with disabilities enrolled in ordinary schools has increased steadily. As a result, the amount of personal support provided by a special needs assistant (personal support) is also increasing. The aim of the study was to describe the diseases and impairments of disabled children aged 2-6, enrolled in mainstream schools and benefiting from personal support for schooling by special needs assistants in the Bouches-du-Rhône (France) in 2014.

METHODS

A cross-sectional descriptive study was performed. Children included were benefiting from either an individual or shared personal support. Physicians from the territorial organization in charge of disability coded diseases and deficiencies using the International Classification of Diseases, 10th revision, and nomenclature inspired by the International Classification of Functioning, Disability and Health.

RESULTS

Medical data were coded for 990 children out of 1260 of the total population. These young disabled children were most frequently children with pervasive developmental disorders (23.3%), lack of expected normal physiological development (19.9%), or mixed specific developmental disorders (13.5%), and most often had behavioral, personality, and relational skills disorders (61.8%), psychomotor function impairments (51.9%), or written or oral language learning impairment (43.2%). Finally, the two main types of impairments most represented among these children were psychological impairments (86.7%) and language and speech impairments (79.8%). The children were most often supported by an individual personal support (for one child only) than by a shared personal support (60% vs. 40%). They were mainly boys (almost 75%).

CONCLUSION

This study provides working guidelines for the management of health policies relating to disability at the territorial or even national level.

A comparative study of Atlantic salmon chilled in refrigerated seawater versus on ice: from whole fish to cold-smoked fillets

Water and salt uptake, and water holding capacity (WHC) of whole gutted Atlantic salmon superchilled at sub-zero temperatures in refrigerated seawater (RSW) were compared to traditional ice storage. Following the entire value chain, the whole salmon was further processed, and fillets were either chilled on ice or dry salted and cold-smoked. Changes in quality parameters including colour, texture, enzyme activity and microbial counts were also analyzed for 3 weeks. Our results showed that when fish were removed from the RSW tank after 4 days and further chilled for 3 days, an overall weight gain of 0.7%, salt uptake of 0.3% and higher WHC were observed. In contrast, ice-stored fish had a total weight loss of 1% and steady salt uptake of 0.1%. After filleting, raw fillets from whole fish initially immersed in RSW had better gaping occurrence, softer texture, lower cathepsin B + L activity but higher microbiological growth. Otherwise, there were no differences in drip loss nor colour (L*a*b*) on both raw and smoked fillets from RSW and iced fish. Storage duration significantly affected quality parameters including drip loss, colour, texture, enzyme activity and microbial counts in raw fillets and drip loss, WHC, redness and yellowness in smoked fillets.

Physiological and flesh quality consequences of pre-mortem crowding stress in Atlantic mackerel (Scomber scombrus)

In commercial wild capture pelagic fisheries it is common practice to crowd catches to high densities to allow efficient pumping onboard. Crowding during the final stages of purse seine capture for small pelagic species often results in intense and sustained behavioural escape responses. Such a response may trigger a shift in energy production from aerobic to anaerobic pathways and result in metabolic acid accumulation and exhaustion of intracellular reserves of ATP. Where there is insufficient time or opportunity to recover to physiological equilibrium before death, pre-mortem stress may be an important determinant of fillet quality, as has been shown for a variety of farmed fish species. However, there is currently a lack of knowledge related to the flesh quality implications of capture stress for wild captured species in European waters. Here we show that crowding results in a physiological stress response that has consequences for flesh quality in the wild captured species Atlantic mackerel (Scomber scombrus). Using small schools in tanks and aquaculture net pens in three separate experiments, we found crowding results in physiological changes in mackerel consistent with an acute stress response and anaerobic metabolism. Consequently, we found crowded fish had more acidic pre- and post-mortem muscle pH as well as indications of faster onset and strength of rigor mortis and increased cathepsin B & L activity. We examined fillet flesh quality after two and seven days of ice storage and found reduced green colouration, increased gaping (separation of muscle myotomes) and reduced textural firmness associated with fish which had been crowded. However, the effects on quality were dependant on experiment and/or storage time. These results indicate the potential of crowding capture stress to influence the flesh quality of an economically important species and may have important implications for the wild capture pelagic fishing industry.

Assessing the effectiveness of an electrical stunning and chilling protocol for the slaughter of Atlantic mackerel (Scomber scombrus)

Inducing unconsciousness in fish using electrical stunning prior to slaughter may improve fish welfare and fillet quality if such practises can be disseminated into wild capture fisheries. The objectives of this study were to: 1) evaluate if an established slaughter protocol consisting of dry electrical stunning (using a coupled AC/DC current at ≈ 110 Vrms) followed by chilling could be used to stun the wild captured species Atlantic mackerel (Scomber scombrus) unconscious within 0.5 s; 2) determine if death could be induced without consciousness recovery by longer duration stunning (5 s) combined with chilling in an ice/water slurry for 6 min; and 3) examine the extent of quality defects arising from the applied slaughter protocol. We determined consciousness by examination of behavioural responses in a standardised vitality assessment. Out of a sample of 10 mackerel, 9 were assumed to be rendered unconscious by the 0.5 s stun, as determined by the presence of tonic and/or clonic muscle cramping consistent with a general epileptic insult. Assumed unconsciousness was maintained throughout chilling treatment in all fish (n = 25) following a full stun of 5 s. All fish were assumed to have died as a result of the protocol. There was no evidence of spinal damage or haematoma quality defects post filleting. These results suggest that the examined protocol is effective at slaughtering mackerel in a manner consistent with good welfare and without inducing quality defects, but further research is required to verify the unconscious condition via electroencephalogram (EEG) and before the procedure can be applied in wild capture fisheries.

Influence of the Mold Temperature and Part Thickness on the Replication Quality and Molecular Orientation in Compression Injection Molding of Polystyrene

It is well known that the process of injection molding with dynamic mold temperature control leads to a good replication quality of high aspect ratio microstructures. However, the inhomogeneous pressure distribution during the holding pressure phase results in an anisotropy of the component properties, low dimensional accuracy and, especially with optical polymers, in undesired stress birefringence. The anisotropy is based on the orientation of the molecular chains in the flow direction, which can be reduced by an injection-compression molding (ICM) process. In order to use the synergy from both processes, an injection-compression molding process with dynamic mold temperature control can be utilized. Within the scope of this investigation, the new process was reproduced by an ICM process at elevated mold temperature (ICM_EMT) and compared with injection molding (IM) with regard to molding accuracy and optical properties in dependence of component thickness and mold temperature. In order to evaluate the molding accuracy, the roughness of a wire-eroded microstructure on the cavity surface was measured. To determine the degree of orientation, the optical properties considered were the transmission and the path difference. It was shown that the adapted ICM process was able to achieve a high degree of replication accuracy with a low degree of orientation, especially for thin-walled components. ICM at elevated mold temperature reduced the path difference in the components with the lowest wall thickness by a factor of two while at the same time optimizing the replication of the microstructure. This could also be confirmed by transmission measurements.

Optoacoustic inversion via convolution kernel reconstruction in the paraxial approximation and beyond

In this article we address the numeric inversion of optoacoustic signals to initial stress profiles. Therefore we study a Volterra integral equation of the second kind that describes the shape transformation of propagating stress waves in the paraxial approximation of the underlying wave-equation. Expanding the optoacoustic convolution kernel in terms of a Fourier-series, a best fit to a pair of observed near-field and far-field signals allows to obtain a sequence of expansion coefficients that describe a given "apparative" setup. The resulting effective kernel is used to solve the optoacoustic source reconstruction problem using a Picard-Lindelöf correction scheme. We verify the validity of the proposed inversion protocol for synthetic input signals and explore the feasibility of our approach to also account for the shape transformation of signals beyond the paraxial approximation including the inversion of experimental data stemming from measurements on melanin doped PVA hydrogel tissue phantoms.

[Instillation therapies for urothelial carcinoma of the upper urinary tract]

Traditionally, urothelial carcinoma of the upper urinary tract was a clear indication for radical nephroureterectomy with bladder cuff excision. It has been shown that in well-selected patients and depending on tumor stage, a kidney-sparing approach can be pursued with good oncological outcome and equivalent to the radical approach. The prevention of local and bladder recurrences is an important factor. Instillation therapies with bacillus Calmette-Guérin and/or mitomycin C have been successfully used to this end. Due to the low incidence of upper tract urothelial cancer and due to the usually retrospective nature of existing literature, however, data is limited. In this article, we provide a review of the indication, technical execution and results of instillation therapies of the upper urinary tract.

Direct Text Entry in Electronic Progress Notes

Objectives: It is not uncommon that the introduction of a new technology fixes old problems while introducing new ones. The Veterans Administration recently implemented a comprehensive electronic medical record system (CPRS) to support provider order entry. Progress notes are entered directly by clinicians, primarily through keyboard input. Due to concerns that there may be significant, invisible disruptions to information flow, this study was conducted to formally examine the incidence and characteristics of input errors in the electronic patient record.

Methods: Sixty patient charts were randomly selected from all 2,301 inpatient admissions during a 5-month period. A panel of clinicians with informatics backgrounds developed the review criteria. After establishing inter-rater reliability, two raters independently reviewed 1,891 notes for copying, copying errors, inconsistent text, inappropriate object insertion and signature issues.

Results: Overall, 60% of patients reviewed had one or more input-related errors averaging 7.8 errors per patient. About 20% of notes showed evidence of copying, with an average of 1.01 error per copied note. Copying another clinician’s note and making changes had the highest risk of error. Templating resulted in large amounts of blank spaces. Overall, MDs make more errors than other clinicians even after controlling for the number of notes.

Conclusions: Moving towards a more progressive model for the electronic medical record, where actions are recorded only once, history and physical information is encoded for use later, and note generation is organized around problems, would greatly minimize the potential for error.

Development of a combined OCT-Raman probe for the prospective in vivo clinical melanoma skin cancer screening

A combined optical coherence tomography (OCT)-Raman probe was designed and built into a spectral domain OCT head, and its performance was evaluated and compared to the most common Raman probe setups, based on a fiber bundle and confocal free space optics. Due to the use of the full field of view of an OCT scanning lens, the combined probe has a superior performance within maximum permissible exposure limits, compared to the other two probes. Skin Raman spectra, recorded in vivo, further prove the feasibility of the OCT-Raman probe for the future in vivo clinical applications in skin cancer screening.

Effective one-dimensional approach to the source reconstruction problem of three-dimensional inverse optoacoustics

The direct problem of optoacoustic signal generation in biological media consists of solving an inhomogeneous three-dimensional (3D) wave equation for an initial acoustic stress profile. In contrast, the more defiant inverse problem requires the reconstruction of the initial stress profile from a proper set of observed signals. In this article, we consider an effectively 1D approach, based on the assumption of a Gaussian transverse irradiation source profile and plane acoustic waves, in which the effects of acoustic diffraction are described in terms of a linear integral equation. The respective inverse problem along the beam axis can be cast into a Volterra integral equation of the second kind for which we explore here efficient numerical schemes in order to reconstruct initial stress profiles from observed signals, constituting a methodical progress of computational aspects of optoacoustics. In this regard, we explore the validity as well as the limits of the inversion scheme via numerical experiments, with parameters geared toward actual optoacoustic problem instances. The considered inversion input consists of synthetic data, obtained in terms of the effectively 1D approach, and, more generally, a solution of the 3D optoacoustic wave equation. Finally, we also analyze the effect of noise and different detector-to-sample distances on the optoacoustic signal and the reconstructed pressure profiles.

Effect of antiseptic irrigation on infection rates of traumatic soft tissue wounds: a longitudinal cohort study

OBJECTIVE

Acute traumatic wounds are contaminated with bacteria and therefore an infection risk. Antiseptic wound irrigation before surgical intervention is routinely performed for contaminated wounds. However, a broad variety of different irrigation solutions are in use. The aim of this retrospective, non-randomised, controlled longitudinal cohort study was to assess the preventive effect of four different irrigation solutions before surgical treatment, on wound infection in traumatic soft tissue wounds.

METHOD

Over a period of three decades, the prophylactic application of wound irrigation was studied in patients with contaminated traumatic wounds requiring surgical treatment, with or without primary wound closure. The main outcome measure was development of wound infection. From 1974-1983, either 0.04 % polihexanide (PHMB), 1 % povidone-iodine (PVP-I), 4 % hydrogen peroxide, or undiluted Ringer's solution were concurrently in use. From 1984-1996, only 0.04 % PHMB or 1 % PVP-I were applied. From 1997, 0.04 % PHMB was used until the end of the study period in 2005.

RESULTS

The combined rate for superficial and deep wound infection was 1.7 % in the 0.04 % PHMB group (n=3264), 4.8 % in the 1 % PVP-I group (n=2552), 5.9 % in the Ringer's group (n=645), and 11.7 % in the 4 % hydrogen peroxide group (n=643). Compared with all other treatment arms, PHMB showed the highest efficacy in preventing infection in traumatic soft tissue wounds (p<0.001). However, compared with PVP-I, the difference was only significant for superficial infections.

CONCLUSION

The large patient numbers in this study demonstrated a robust superiority of 0.04 % PHMB to prevent infection in traumatic soft tissue wounds. These retrospective results may further provide important information as the basis for power calculations for the urgently needed prospective clinical trials in the evolving field of wound antisepsis.

Detection, numerical simulation and approximate inversion of optoacoustic signals generated in multi-layered PVA hydrogel based tissue phantoms

Optoacoustic (OA) measurements can not only be used for imaging purposes but as a more general tool to "sense" physical characteristics of biological tissue, such as geometric features and intrinsic optical properties. In order to pave the way for a systematic model-guided analysis of complex objects we devised numerical simulations in accordance with the experimental measurements. We validate our computational approach with experimental results observed for layered polyvinyl alcohol hydrogel samples, using melanin as the absorbing agent. Experimentally, we characterize the acoustic signal observed by a piezoelectric detector in the acoustic far-field in backward mode and we discuss the implication of acoustic diffraction on our measurements. We further attempt an inversion of an OA signal in the far-field approximation.

Synthesis of Control Systems for Manipulators Using Multivariable Robust Servomechanism Theory

This paper describes a framework for synthesizing control laws for manipulators based on robust servomechanism theory for multivariable linear systems. This framework takes into account the coupled and nonlinear nature of the differen tial equations describing the manipulator as well as the fact that the inputs and outputs are subject to large excursions.

The robust servomechanism theory is applied to the linear system that results when the overall, nonlinear, dynamic system is split, in the standard manner, into a nominal sys tem and a (linear) system linearized about the nominal. A control law for the linear system is then derived on the basis of linear quadratic regulator theory. To ensure good dynamic response, the implicit model-following technique is used to choose the weights in the resulting performance index.

The theory is then applied to design a control law for a two-degree-of-freedom spatial manipulator following a pre scribed trajectory. The effect of changing the speed and iner tias of the manipulator on the gains prescribed by the control law is also discussed.