Variability and Determinants of Occupational Noise Exposure Among Iron and Steel Factory Workers in Tanzania

Abstract

Background

Machines, processes, and tasks in the iron and steel factories may produce noise levels that are harmful to hearing if not properly controlled. Studies documenting noise exposure levels and related determinants in sub-Saharan Africa, including Tanzania are lacking. The aim of this study was to document noise exposure and to identify determinants of noise exposure with a view to establishing an effective hearing conservation programme.

Methods

A walk-through survey was conducted to describe the working environment in terms of noise sources in four metal factories (A–D) in Tanzania. Noise measurements were conducted by both personal, full-shift noise measurements (8 h) using dosimeters and area measurements (10-s measurements) using a sound level meter. A total of 163 participants had repeated personal noise measurements (Factory A: 46 participants, B: 43, C: 34, and D: 40). Workers were randomly selected and categorized into 13 exposure groups according to their job. Linear mixed effects models were used to identify significant determinants of noise exposure in the furnace section and the rolling mill section.

Results

The average personal noise exposure in the four factories was 92.0 dB(A) (range of job group means; 85.4–96.2 dB(A)) (n = 326). Personal exposure was significantly higher in the rolling mill section (93.0 dB(A)) than in the furnace section (89.6 dB(A)). Among the job groups, the cutters located in the rolling mill section had the highest noise exposure (96.2 dB(A)). In the furnace section, furnace installation (below the ground floor), manual handling of raw materials/billets/crowbars, and billet weighing/transfer were significant determinants explaining 40% of the total variance in personal noise exposure. In the rolling mill section, the size of the cutting machine, steel billet weight and feeding re-heating furnace explained 46% of the total variance in personal noise exposure. The mean noise level of the area measurements was 90.5 dB(A) (n = 376).

Conclusion

Workers in the four iron and steel factories in Tanzania were exposed to average noise of 92.0 dB(A), without using hearing protection, implying a high risk of developing hearing loss. Task and factory level determinants were identified in the furnace and the rolling mill sections of the plant, which can inform noise control in factories with similar characteristics.

21st Century Biological Nomenclature—the Enduring Power of Names

Synopsis

Nomenclature and taxonomy are complementary and distinct aspects of the study of biodiversity, but the two are often confused even by biologists. Taxonomy is the part of the science of systematics that deals with identifying, describing, and categorizing organisms from species to higher taxa. Nomenclature is a system of giving names to organisms based on rules established for the process. Adoption of a system of binomial nomenclature by end of the 18th century helped standardize the process of naming the wealth of new organisms collected during the Age of Exploration, but before the middle of the 19th century, the turmoil resulting from differences in procedures and philosophies among practicing taxonomists necessitated the development of codes of nomenclature to regulate naming. By the early 20th century, codified sets of rules for the names of both plants and animals, nowadays usually abbreviated as ICBN (Botanical Code) and ICZN (Zoological Code), were in place internationally. These codes worked reasonably well through most of the 20th century, under the aegis of various international bodies, in part because procedures exist to bypass them when their provisions threaten nomenclatural stability. They also inspired the development of other nomenclatural codes for specific groups of organisms like bacteria, and, alternatively, the proposal of unified codes for all organisms. The rapid development of electronic communications and various means of electronic publication at the end of the 20th century, combined with what may be the advent of a new age of biological extinction, resulted in pressure to revise the codes to allow at least some degree of electronic publication and speedier description of new taxa in the 21st century. Consistent and unambiguous names are the platforms on which biological research and conservation practices are built. As we pursue the goals of documenting and conserving biodiversity, for which a stable nomenclature is essential, we must do so without restricting the freedom of the science of systematics.

Mitochondrial dynamics (fission and fusion) and collagen production in a rat model of diabetic wound healing treated by photobiomodulation: comparison of 904 nm laser and 850 nm light-emitting diode (LED)

Publication date: Available online 3 August 2018

Source: Journal of Photochemistry and Photobiology B: Biology

Author(s): José Carlos Tatmatsu-Rocha, Carla Roberta Tim, Lucimar Avo, Rubens Bernardes Filho, Patricia Brassolati, Hueliton Wilian Kido, Michael R. Hamblin, Nivaldo Antonio Parizotto

Abstract

Objective

Mitochondrial dysfunction has been associated with the development of diabetes mellitus which is characterized by disorders of collagen production and impaired wound healing. This study analyzed the effects of photobiomodulation (PBM) mediated by laser and light-emitting diode (LED) on the production and organization of collagen fibers in an excisional wound in an animal model of diabetes, and the correlation with inflammation and mitochondrial dynamics.

Methods

Twenty Wistar rats were randomized into 4 groups of 5 animals. Groups: (SHAM) a control non-diabetic wounded group with no treatment; (DC) a diabetic wounded group with no treatment; (DLASER) a diabetic wounded group irradiated by 904 nm pulsed laser (40 mW, 9500 Hz, 1 min, 2.4 J); (DLED) a diabetic wounded group irradiated by continuous wave LED 850 nm (48 mW, 22 s, 1.0 J). Diabetes was induced by injection with streptozotocin (70 mg/kg). PBM was carried out daily for 5 days followed by sacrifice and tissue removal.

Results

Collagen fibers in diabetic wounded skin were increased by DLASER but not by DLED. Both groups showed increased blood vessels by atomic force microscopy. Vascular endothelial growth factor (VEGF) was higher and cyclooxygenase (COX2) was lower in the DLED group. Mitochondrial fusion was higher and mitochondrial fusion was lower in DLED compared to DLASER.

Conclusion

Differences observed between DLASER and DLED may be due to the pulsed laser and CW LED, and to the higher dose of laser. Regulation of mitochondrial homeostasis may be an important mechanism for PBM effects in diabetes.

Visible light responsive flower-like ZnO in photocatalytic antibacterial mechanism towards Enterococcus faecalis and Micrococcus luteus

Publication date: Available online 3 August 2018

Source: Journal of Photochemistry and Photobiology B: Biology

Author(s): Jian-Ai Quek, Sze-Mun Lam, Jin-Chung Sin, Abdul Rahman Mohamed

Abstract

Flower-like ZnO micro/nanostructures were successfully fabricated via a surfactant-free co-precipitation method. The as-synthesized product was characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and photoluminescence (PL) analyses. In the presence of visible light irradiation, the as-synthesized flower-like ZnO showed higher antibacterial activities against Enterococcus faecalis (E. faecalis) and Micrococcus luteus (M. luteus) than that of commercial ZnO. The excellent antibacterial performance of synthesized flower-like ZnO was also observed via the bacterial morphological change, K⁺ ions leakage and protein leakage in extracellular suspension. In addition, the FTIR investigation on both treated bacteria further confirmed the bacterial membrane damage via cellular substance alteration. The enhancement of the antibacterial activity of synthesized ZnO can be attributed to the unique flower-like morphology which can increase the surface OH⁻ groups and the quantity of photogenerated electron-hole pair available to participate in the photocatalytic reaction. The reactive oxidizing species (ROS) scavengers experiments showed that H₂O₂ played a main role in the photocatalytic antibacterial process. Our study showed that the synthesized flower-like ZnO micro/nanostructures can act as efficient antibacterial agents in the photocatalytic antibacterial process under visible light irradiation.

An analysis of the cosmetic surgery experience acquired through UK Plastic Surgery training

Publication date: Available online 3 August 2018

Source: Journal of Plastic, Reconstructive & Aesthetic Surgery

Author(s): Pantelides NM, Highton L, Lamb A, Foden P, Winterton RIS

ABSTRACT

Aims: Cosmetic surgery is an essential component of Plastic Surgery training. Our study demonstrates the average cosmetic surgery experience of UK Plastic Surgery registrars over their 6-year training scheme. Comparison is made with the operative requirements for the Certificate of Completion of Training (CCT) and the Royal College of Surgeons Cosmetic Certification scheme.

Methods: Using the web-based eLogbook, we analysed all of the cosmetic surgery operations recorded by Plastic Surgery Registrars during their specialist training. The weighted mean average number of procedures was calculated for different areas of cosmetic surgery practice, according to the level of supervision.

The number of RCS cosmetic credits acquired for eight domains of cosmetic surgery was calculated, enabling comparison with the operative requirements for certification.

Results: eLogbook data was collated for 454 Registrars from 2010-2016 inclusive. Trainees participated in a mean of 122 cosmetic operations during their training (50% as an assistant), which satisfies the requirement of 100 procedures for CCT. The majority of trainee involvement (66%) was with cosmetic breast and body contouring cases.

Comparison with the criteria for Cosmetic Certification reveals that, on average, trainees could certify in cosmetic breast and body contouring surgery but would be unable to accredit in other areas of practice.

Conclusions: Current UK training affords sufficient cosmetic surgery exposure for CCT but offers a limited breadth of exposure. Trainees wishing to certify in cosmetic surgery of the head and neck region will likely be required to seek additional experience outside their deanery training programme.

6-mT 0–120-Hz magnetic fields differentially affect cellular ATP levels

Abstract

Adenosine triphosphate (ATP), an indispensable molecule that provides energy for essentially all cellular processes, has been shown to be affected by some magnetic fields (MFs). Although people are frequently exposed to various static and power frequency MFs in their daily lives, the exact effects of these MFs of different frequencies have not been systematically investigated. Here, we tested 6-mT MFs with 0, 50, and 120 Hz for their effects on cellular ATP levels in 11 different cell lines. We found that the 6-mT static magnetic field (SMF) either does not affect or increase cellular ATP levels, while 6-mT 50-Hz MF either does not affect or decrease cellular ATP levels. In contrast, 6-mT 120-Hz MF has variable effects. We examined the mitochondrial membrane potential (MMP) as well as reactive oxygen species (ROS) in four different cell lines, but did not find their direct correlation with ATP levels. Although none of the ATP level changes induced by these three different frequencies of 6-mT MFs are dramatic, these results may be used to explain some differential cellular responses of various cell lines to different frequency MFs.

Use of statistical experimental methods for optimization of collagenolytic protease production by Bacillus cereus strain SUK grown on fish scales

Abstract

In this study, novel and cheap sources like fish scales and molasses were used for the production of collagenolytic protease. Statistical optimization of different parameters for the production of collagenolytic protease by Bacillus cereus strain SUK has been carried out using response surface methodology (RSM). Three most significant medium components identified by Plackett-Burman (PB) were fish scales, molasses, and incubation time, which were further optimized using central composite design (CCD). The medium having fish scales 9.38 g l⁻¹, molasses 2.42 g l⁻¹, and incubation time of 67.34 h was found to be optimum for maximum collagenolytic protease production. B. cereus strain SUK has shown multiple plant growth-promoting traits, whereas degraded fish scale hydrolysates (FSHs) were having antimicrobial as well as plant growth-promoting abilities. The collagenolytic efficiency of this isolate can be exploited in an eco-friendly process of bioconversion of fish waste, representing an alternative way of waste management that could be used to produce various value-added products, such as collagenolytic protease, microbial biomass, amino acids, protein hydrolysates, and collagen peptides.

Inoculation of plant growth-promoting bacteria Bacillus sp. YM-1 alleviates the toxicity of Pb to pakchoi

Abstract

Heavy metal accumulation in plants may imperil human health. Inoculation of plant growth-promoting bacteria can alleviate the toxicity of heavy metal and promote plant growth. In this study, Bacillus sp. YM-1, a heavy metal resistant and plant growth-promoting bacterium, was immobilized with spent substrate of mushroom and applied to alleviate the toxicity of Pb to pakchoi. The results indicated that the biomass of pakchoi in inoculation group was increased by 17.45 to 27.05% compared with that in non-inoculated group (p < 0.05). The root and shoot were lengthened by 13.45% to 39.17% and 20.23% to 42.36%, respectively. The content of Pb in root and shoot obviously reduced and that in edible part (shoot) was less than 0.2 mg kg⁻¹ in the low concentration of Pb. Other indicators such as superoxide dismutase (SOD), peroxidase (POD), chlorophyll, and protein all testified that YM-1 inoculation was conducive to the alleviation of Pb toxicity to pakchoi.

Correction to: Indoor and outdoor concentrations of BTEX and formaldehyde in Tehran, Iran: effects of building characteristics and health risk assessment

The original publication of this paper contains a mistake. The correct name and affiliation of the 3rd Author is presented in this paper.

MR Imaging Features of Adult-Onset Neuronal Intranuclear Inclusion Disease May Be Indistinguishable from Fragile X-Associated Tremor/Ataxia Syndrome [LETTERS]

Reply: [LETTERS]

Arterial Spin-Labeling in Children with Brain Tumor: A Meta-Analysis [PEDIATRICS]

BACKGROUND:

The value of arterial spin-labeling in a pediatric population has not been assessed in a meta-analysis.

PURPOSE:

Our aim was to assess the diagnostic accuracy of arterial spin-labeling–derived cerebral blood flow to discriminate low- and high-grade tumors.

DATA SOURCES:

MEDLINE, EMBASE, the Web of Science Core Collection, and the Cochrane Library were used.

STUDY SELECTION:

Pediatric patients with arterial spin-labeling MR imaging with verified neuropathologic diagnoses were included.

DATA ANALYSIS:

Relative CBF and absolute CBF and tumor grade were extracted, including sequence-specific information. Mean differences in CBF between low- and high-grade tumors were calculated. Study quality was assessed.

DATA SYNTHESIS:

Data were aggregated using the bivariate summary receiver operating characteristic curve model. Heterogeneity was explored with meta-regression and subgroup analyses. The study protocol was published at PROSPERO (CRD42017075055). Eight studies encompassing 286 pediatric patients were included. The mean differences in absolute CBF were 29.62 mL/min/100 g (95% CI, 10.43–48.82 mL/min/100 g), I² = 74, P = .002, and 1.34 mL/min/100 g (95% CI, 0.95–1.74 mL/min/100 g), P < .001, I² = 38 for relative CBF. Pooled sensitivity for relative CBF ranged from 0.75 to 0.90, and specificity, from 0.77 to 0.92 with an area under curve = 0.92. Meta-regression showed no moderating effect of sequence parameters TE, TR, acquisition time, or ROI method.

LIMITATIONS:

Included tumor types, analysis method, and original data varied among included studies.

CONCLUSIONS:

Arterial spin-labeling–derived CBF measures showed high diagnostic accuracy for discriminating low- and high-grade tumors in pediatric patients with brain tumors. The relative CBF showed less variation among studies than the absolute CBF.

Feasibility of a Synthetic MR Imaging Sequence for Spine Imaging [SPINE]

BACKGROUND AND PURPOSE:

Synthetic MR imaging is a method that can produce multiple contrasts from a single sequence, as well as quantitative maps. Our aim was to determine the feasibility of a synthetic MR image for spine imaging.

MATERIALS AND METHODS:

Thirty-eight patients with clinical indications of infectious, degenerative, and neoplastic disease underwent an MR imaging of the spine (11 cervical, 8 dorsal, and 19 lumbosacral MR imaging studies). The SyntAc sequence, with an acquisition time of 5 minutes 40 seconds, was added to the usual imaging protocol consisting of conventional sagittal T1 TSE, T2 TSE, and STIR TSE.

RESULTS:

Synthetic T1-weighted, T2-weighted, and STIR images were of adequate quality, and the acquisition time was 53% less than with conventional MR imaging. The image quality was rated as "good" for both synthetic and conventional images. Interreader agreement concerning lesion conspicuity was good with a Cohen of 0.737. Artifacts consisting of white pixels/spike noise across contrast views, as well as flow artifacts, were more common in the synthetic sequences, particularly in synthetic STIR. There were no statistically significant differences between readers concerning the scores assigned for image quality or lesion conspicuity.

CONCLUSIONS:

Our study shows that synthetic MR imaging is feasible in spine imaging and produces, in general, good image quality and diagnostic confidence. Furthermore, the non-negligible time savings and the ability to obtain quantitative measurements as well as to generate several contrasts with a single acquisition should promise a bright future for synthetic MR imaging in clinical routine.

Medullary Edema and Enhancement with a Straight Upper Border in Cases of Dural Arteriovenous Fistulas [LETTERS]

To stock or not to stock? Implementation of epinephrine autoinjectors in food establishments

Publication date: Available online 2 August 2018

Source: The Journal of Allergy and Clinical Immunology: In Practice

Author(s): Susan Waserman, Ernie Avilla, Laurie Harada, Wanrudee Isaranuwatchai, Johnna Perdrizet, Monika Kastner

A CdSe/ZnS quantum dot-based platform for the delivery of aluminum phthalocyanines to bacterial cells

Publication date: Available online 2 August 2018

Source: Journal of Photochemistry and Photobiology B: Biology

Author(s): D.A. Gvozdev, E.G. Maksimov, M.G. Strakhovskaya, A.M. Moisenovich, A.A. Ramonova, M.M. Moisenovich, S.N. Goryachev, V.Z. Paschenko, A.B. Rubin

Abstract

Enhancement of optical properties of photosensitizers by additional light-harvesting antennas is promising for the improvement of the photodynamic therapy. However, large number of parameters determine interactions of nanoparticles and photosensitizers in complex and, thus the photodynamic efficacy of the hybrid structure. In order to achieve high efficiency of energetic coupling and photodynamic activity of such complexes it is important to know the location of the photosensitizer molecule on the nanoparticle, because it affects the spectral properties of the photosensitizer and the stability of the hybrid complex in vitro/in vivo. In this work complexes of polycationic aluminum phthalocyanines and CdSe/ZnS quantum dots were obtained. We used quantum dots which outer shell consists of polymer with carboxyl groups and provides water solubility and the negative charge of the nanoparticle. We found that phthalocyanine molecules could penetrate deeply into the polymer shell of quantum dot, leading thereby to significant changes in the spectral and photodynamic properties of phthalocyanines. We also showed that noncovalent interactions between phthalocyanine and quantum dot provide possibility for a release of the phthalocyanine from the hybrid complex and its binding to both Gram-positive and Gram-negative bacterial cells. Also, detailed characterization of the nanoparticle core and shell sizes was carried out.

Ten years of myocutaneous flaps for pressure ulcers in patients with spinal lesions: analysis of complications in the framework of a specialised medical-surgical pathway

Publication date: Available online 2 August 2018

Source: Journal of Plastic, Reconstructive & Aesthetic Surgery

Author(s): C. Lefèvre, F. Bellier-Waast, F. Lejeune, F. Duteille, P. Kieny, M. Le Fort, B. Perrouin-Verbe

Abstract

Introduction: The objective of the study is to analyse complications associated with surgery for pelvic pressure ulcers: their frequency, nature and rate of surgical revisions. The secondary aims are to analyse the rate of recurrence, length of stay and time to healing, and to determine factors associated with complications and recurrence.

Methods: It is a single-centre, retrospective cohort study with a 10 year follow-up, setting in Nantes University Hospital, France, a specialist centre for Spinal Cord Injury (SCI).

All patients who were admitted to the Neurological Physical Medicine and Rehabilitation (PMR) department for surgery (flap coverage) for pelvic pressure ulcers between 1st of January 2004 and 30th September 2014 were included. The main outcome measures were the rate of complications, rate of recurrence, length of stay and time to healing, as well as factors associated with complications and recurrence.

Results: One hundred and sixty-six patients underwent 252 flap procedures during 239 operations. The majority of patients had spinal cord injury (78.3%). The ulcer sites were mainly ischial (67%), sacral (20%) and trochanteric (12%). Gluteus maximus was used most often (75.3% of flaps) (ischial and sacral ulcers), followed by tensor fascia lata (16.2%) (trochanteric ulcers). The rate of complications that delayed return to wheelchair at 6 weeks was 34.5%. The factors associated with complications were more than one surgical ulcer and drainage time greater than 10 days. The rate of recurrence was 20.04%. Factors related to recurrence were young age, scoliosis and an oblique pelvis.

Conclusions: Management within a specialised medical-surgical pathway limited post-operative complications and recurrences in this sample of subjects who mostly had SCI.

Diagnostic value of fluorine-18 deoxyglucose positron emission tomography/computed tomography in deep sternal wound infection

Publication date: Available online 2 August 2018

Source: Journal of Plastic, Reconstructive & Aesthetic Surgery

Author(s): Ru-fan Zhang, Zi-hao Feng, Yong Zhang, Hui Tan, Jian Wang, Fa-zhi Qi

Abstract

Objectives

Deep sternal wound infection (DSWI) is a refractory complication after heart surgery, and debridement is the first-line treatment. The accurate identification of the extent of the infection is the key to successful debridement. The present study assessed the diagnostic accuracy of fluorine-18 deoxyglucose (¹⁸F-FDG) positron emission tomography/ computed tomography (PET/CT) for identifying the infected area of DSWI.

Methods

Between February 2015 and May 2017, 73 consecutive patients with suspected DSWI received ¹⁸F-FDG PET/CT examinations before their operation. The PET/CT and extracted CT images were analyzed by nuclear medicine physicians and radiologists to determine whether the sternum, mediastinum, vascular prosthesis and each costal cartilage were infected. All the patients received debridement and chest wall reconstruction within 1 week following the PET scan. The final diagnosis was based on surgical, microbiological and histopathologic findings.

Results

Of the 73 patients, 64, 54, 28 and 6 were diagnosed with sternal osteomyelitis, mediastinitis, costal chondritis and vascular graft infection, respectively. The sensitivities of PET/CT for diagnosing sternal osteomyelitis, mediastinitis, and costal chondritis were 98.4%, 77.8% and 100.0%, respectively, and the corresponding specificities were 94.7%, 82.1% and 100.0%. PET/CT correctly diagnosed all 6 cases of vascular graft infection. There were 65 infected costal cartilages in the patients with costal chondritis. The sensitivity, specificity and accuracy of PET/CT for locating infected costal cartilages were 81.5%, 99.8% and 98.6%, respectively.

Conclusions

PET/CT proved to be a useful tool for determining the depth of DSWI and for locating infected costal cartilage; therefore, this tool can help guide debridement.

“Silicone Breast Prostheses; a cohort study of complaints, complications and explantations between 2003 and 2015.”

Publication date: Available online 2 August 2018

Source: Journal of Plastic, Reconstructive & Aesthetic Surgery

Author(s): Shariselle M.W. Pool, Roos Wolthuizen, Chantal M. Mouës-Vink

Abstract

Background

Complications after silicone implantation, with silicone extravasation being the most severe, remain a safety issue in breast implantation surgery. The purpose of our study was to determine the incidence of medium and long-term postoperative complaints and complications, and indications for explantation in patients with a silicone breast implant.

Methods

This is a retrospective cohort study consisting of all patients receiving silicone breast implants of the fourth or fifth generation between 2003 and 2015. Long-term outcomes (>3 months after initial placement) were derived from medical records. The association with indication of breast surgery, method of placement and type of reconstruction was tested.

Results

In total 448 patients (n=738 silicone breast implants) met the inclusion criteria with a median follow-up of 330 days. Overall, 18% of the implants resulted in postoperative complaints, with discomfort or pain being the most common complaint (12%), significantly more frequent in reconstructive cases and significantly associated with subglandular placement in cosmetically augmented breasts. Physical examination revealed in 14% one or more postoperative complications, with capsular contracture being the most common complication. A total of 12% of the implants were eventually explanted within a median time of 568 days. Predominant reasons were cosmetic dissatisfaction, capsular contracture and pain (respectively in 37%, 21% and 15%). Macroscopic leakage was demonstrated in 3% of the explanted prostheses.

Conclusions

Explantation of breast implants occurs in 12%, within a median time of 1.6 years, wherein macroscopic leakage was rarely seen. Cosmetic dissatisfaction, capsular contracture and pain are the most common indications.

Ten years of myocutaneous flaps for pressure ulcers in patients with spinal lesions: analysis of complications in the framework of a specialised medical-surgical pathway

Introduction: The objective of the study is to analyse complications associated with surgery for pelvic pressure ulcers: their frequency, nature and rate of surgical revisions. The secondary aims are to analyse the rate of recurrence, length of stay and time to healing, and to determine factors associated with complications and recurrence.Methods: It is a single-centre, retrospective cohort study with a 10 year follow-up, setting in Nantes University Hospital, France, a specialist centre for Spinal Cord Injury (SCI).