Low loss silicon waveguides for the mid-infrared Mashanovich, Goran Z; Milošević, Milan M; Nedeljkovic, Milos ...
Optics express,
2011-Apr-11, 2011-04-11, 20110411, Letnik:
19, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Silicon-on-insulator (SOI) has been used as a platform for near-infrared photonic devices for more than twenty years. Longer wavelengths, however, may be problematic for SOI due to higher absorption ...loss in silicon dioxide. In this paper we report propagation loss measurements for the longest wavelength used so far on SOI platform. We show that propagation losses of 0.6-0.7 dB/cm can be achieved at a wavelength of 3.39 µm. We also report propagation loss measurements for silicon on porous silicon (SiPSi) waveguides at the same wavelength.
We introduce a hyperuniform-disordered platform for the realization of near-infrared photonic devices on a silicon-on-insulator platform, demonstrating the functionality of these structures in a ...flexible silicon photonics integrated circuit platform unconstrained by crystalline symmetries. The designs proposed advantageously leverage the large, complete, and isotropic photonic band gaps provided by hyperuniform disordered structures. An integrated design for a compact, sub-volt, sub-fJ/bit, hyperuniform-clad, electrically controlled resonant optical modulator suitable for fabrication in the silicon photonics ecosystem is presented along with simulation results. We also report results for passive device elements, including waveguides and resonators, which are seamlessly integrated with conventional silicon-on-insulator strip waveguides and vertical couplers. We show that the hyperuniform-disordered platform enables improved compactness, enhanced energy efficiency, and better temperature stability compared to the silicon photonics devices based on rib and strip waveguides.
One of the side-effects of the COVID-19 pandemic is a global change in work ergonomic patterns as millions of people replaced their usual work environment with home to limit the spread of the severe ...acute respiratory syndrome coronavirus 2 (SARS-COV-2) infection. The aim of our cross-sectional pilot study was to identify musculoskeletal pain that may have resulted from this change and included 232 telecommunications company workers of both genders 121 (52.2 %) men aged 23–62 (median 41; interquartile range 33–46 yrs.) and 111 (47.8 %) women aged 23–53 (median 40; interquartile range 33–44) who had been working from home for eight months (from 16 March to 4 December 2020) before they joined the study. The participants were asked to fill in our web-based questionnaire by self-assessing their experience of hand, lower back, and upper back/neck pain while working at home and by describing their work setting and physical activity. Compared to previous work at the office, 90 (39.1 %) participants reported stronger pain in the lower back, 105 (45.7 %) in the upper back/neck, and 63 (27.2 %) in their hands. Only one third did not report any musculoskeletal problems related to work from home. Significantly fewer men than women reported hand, lower back, and upper back/ neck pain (p=0.033, p=0.001 and p=0.013, respectively). Sixty-nine workers (29.9 %) reported to work in a separate room, 75 (32.4 %) worked in a separate section of a room with other household members, whereas 87 (37.7 %) had no separate work space, 30 of whom most often worked in the dining room. Ninety-five participants (40.9 %) had no office desk to work at, and only 75 (32.3 %) used an ergonomic chair. Of those who shared their household with others (N=164), 116 (70.7 %) complained about constant or occasional disturbances. Over a half of all participants (52 %) said that they worked longer hours from home than at work, predominantly women (p=0.05). Only 69 participants (29.9 %) were taking frequent breaks, predominantly older ones (p=0.006). Our findings clearly point to a need to inform home workers how to make more ergonomic use of non-ergonomic equipment, use breaks, and exercise and to inform employers how to better organise working hours to meet the needs of work from home.
Purpose
Acute hydrocephalus is a common complication after aneurysmal subarachnoid hemorrhage (aSAH). It can be self-limiting or require cerebrospinal fluid diversion. We aimed to determine the ...transient acute hydrocephalus (TAH) rate in patients with aSAH treated endovascularly and evaluate its predictive factors.
Methods
A retrospective review of 357 patients with aSAH who underwent endovascular treatment from March 2013 to December 2019 was performed. Clinical and radiographic data were analyzed and risk factors with potential significance for acute hydrocephalus were identified. We constructed a new risk score, the Drainage Or Transiency of Acute Hydrocephalus after Aneurysmal SAH (DOTAHAS) score, that may differentiate patients who would experience TAH from those needing surgical interventions.
Results
Acute hydrocephalus occurred in 129 patients (36%), out of whom in 66 patients (51%) it was self-limiting while 63 patients (49%) required external ventricular drainage placement. As independent risk factors for acute hydrocephalus, we identified older age, poor initial clinical condition, aSAH from posterior circulation, and the extent of cisternal and intraventricular hemorrhage. The following three factors were shown to predict acute hydrocephalus transiency and therefore included in the DOTAHAS score, ranging from 0 to 7 points: Hunt and Hess grade ≥ 3 (1 point), modified Fisher grade 4 (2 points), and Ventricular Hijdra Sum Score (vHSS) ≥ 6 (4 points). Patients scoring ≥ 3 points had significantly higher risk for EVD (
P
< 0.0001) than other patients.
Conclusion
The newly developed DOTAHAS score can be useful in identifying patients with transient acute hydrocephalus. Further score evaluation is needed.
Although the role of microbiota has been investigated in relation to different oral diseases, it is unknown if its composition has any effect on the course of recovery after third molar alveotomy. ...Our aim was to determine the influence of patient clinical characteristics as well as pericoronary microbiota composition on the course of recovery after a semi-impacted third molar alveotomy. Thirty-six patients were included and samples obtained with paper points, swabs, and tissue samples were analyzed using DNA hybridization and culture methods. Among the 295 organisms detected, the most frequent were
spp. (22.4%; 66/295) followed by
spp. (11.9%; 35/295), and
(9.1%; 27/295). A comparison of microbiota composition in patients with better and worse recovery did not show significant differences. Worse recovery outcomes were more frequent in patients with a grade 2 self-assessment of oral health (
= 0.040) and better recovery courses were observed in patients with a grade 4 self-assessment (
= 0.0200). A worse recovery course was statistically significant more frequently in patients with previous oral surgical procedures (
= 0.019). Although we demonstrate that worse recovery outcomes were more frequent when certain bacteria were detected, there was no statistically significant difference. Further research is needed to identify microbial profiles specific to the development of worse outcomes after a third molar alveotomy.
Typically, a healthcare intervention is evaluated by comparing data before and after its implementation using statistical tests. Comparing group means can miss underlying trends and lead to erroneous ...conclusions. Segmented linear regression can be used to reveal secular trends but is susceptible to outliers. We described a novel method using segmented robust regression techniques to evaluate the effect of introducing a dedicated hip fracture unit (HFU).
We retrospectively analysed patient outcomes from a total of 2777 patients sustaining proximal femoral fragility fractures over a 6-year period at a Level 1 Major Trauma Centre. We compared time to surgical intervention and length of hospital stay before and after the implementation of the HFU using group comparison tests, segmented ordinary regression and robust regression techniques to evaluate the effect of the intervention.
Group comparison tests did not identify a significant difference in time to surgery pre and post- HFU. Segmented regression revealed that there was a significant reduction in time to surgery but that this predated the introduction of the HFU. Group comparison tests did not identify a significant difference in length of stay pre and post-HFU. Ordinary segmented regression demonstrated that there was a constant reduction in length of stay, which accelerated after the introduction of the HFU. Robust regression identified that this change occurred prior to the HFU.
There was a significant decrease in time to surgical intervention during the study period that occurred long before the introduction of the HFU, and that cannot be attributed to the HFU itself. Length of stay started dropping early in the study period and was unrelated to the HFU. However, with robust regression we concluded that the HFU was effective in reducing relatively long hospital stays (outliers).
Several explanatory factors that may have affected the observed trends in time to surgery and length of stay were identified.
Robust regression is a useful adjunct to ordinary segmented linear regression techniques in modelling retrospective time-series and dealing with outliers. The changes observed in hip fracture patient outcomes over a 6-year period was likely multifactorial.
Healthcare workers (HCWs) are considered to run a higher occupational risk of becoming infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and develop coronavirus disease ...(COVID-19) than the rest of the population. The aim of this study was to describe and analyse the characteristics of work-related COVID-19 in Croatian HCWs. Study participants were HCWs who contacted their occupational physician between 1 May 2020 and 12 November 2020 with a request for the registration of COVID-19 as an occupational disease. All participants filled out our online Occupational COVID-19 in Healthcare Workers Questionnaire. The study included 59 HCWs (median age 45.0, interquartile range 36.0–56.0 years). Most (78 %) were nurses or laboratory technicians, and almost all (94.9 %) worked in hospitals. Hierarchical cluster analysis revealed three clusters of COVID-19-related symptoms: 1) elevated body temperature with general weakness and fatigue, 2) diarrhoea, and 3) headache, muscle and joint pain, anosmia, ageusia, and respiratory symptoms (nasal symptoms, burning throat, cough, dyspnoea, tachypnoea). Almost half (44.6 %) reported comorbidities. Only those with chronic pulmonary conditions were more often hospitalised than those without respiratory disorders (57.1 % vs. 2.5 %, respectively; P=0.001). Our findings suggest that work-related COVID-19 among Croatian HCWs is most common in hospital nurses/laboratory technicians and takes a mild form, with symptoms clustering around three clinical phenotypes: general symptoms of acute infection, specific symptoms including neurological (anosmia, ageusia) and respiratory symptoms, and diarrhoea as a separate symptom. They also support evidence from other studies that persons with chronic pulmonary conditions are at higher risk for developing severe forms of COVID-19.
Coronavirus disease 2019 (COVID-19) can be diagnosed as occupational disease by an occupational health physician (OHP), if supported by relevant work-related and medical documentation. The aim of ...this study was to analyse such documentation submitted by Croatian healthcare workers (HCWs) and discuss its relevance in view of European and Croatian guidelines. The study included 100 Croatian HCWs who were SARS-CoV-2-positive and requested that their infection be diagnosed as occupational disease by their OHPs from 1 May 2020 to 10 March 2021. As participants they were asked to fill out our online Occupational COVID-19 in Healthcare Workers Questionnaire. For the purpose of this study we analysed answers about the type of close contact at the workplace, COVID-19 symptoms, and enclosed work-related (job description, employer statement about exposure to SARS-CoV-2) and medical documentation (positive SARS-CoV-2 polymerase chain reaction test and patient history confirming the diagnosis of COVID-19). Most participants were working in hospitals (N=95), mostly nurses (N=75), who became infected by a patient (N=68) or colleague (N=31), and had at least one COVID-19 symptom (N=87). Eighty participants did not enclose obligatory documents, 41 of whom failed to submit job description and 31 both job description and employer statement. These findings confirm that the major risk of occupational COVID-19 in HCWs is close contact with patients and colleagues, and points out the need for better cooperation between OHPs, occupational safety experts, employers, and diseased workers.
Every procedure in healthcare carries a certain degree of inherent unsafety resulting from problems in practice, which might lead to a healthcare adverse event (HAE). It is very important, and even ...mandatory, to report HAE. The point of HAE reporting is not to blame the person, but to learn from the HAE in order to prevent future HAEs.
Our aim was to examine the prevalence and the impact of culture of blame on health workers' health.
A cross-sectional study on healthcare workers at two Croatian hospitals was conducted using the Hospital Survey on Patient Safety Culture (PSC).
: The majority of PSC dimensions in both hospitals were high. Among the dimensions, Hospital Handoffs and Transitions and Overall Perceptions of Safety had the highest values. The Nonpunitive Response to Error dimension had low values, indicating the ongoing culture of blame. The Staffing dimension had low values, indicating the ongoing shortage of doctors and nurses.
: We found inconsistencies between a single-item measure and PSC dimensions. It was expected that Frequency of Events Reported (PSC dimension) relates to Number of Events Reported (single-item measure). However, in our study, the relations between these pairs of measures were different between hospitals. Our results indicate the ongoing culture of blame. Healthcare workers do not report HAE because they fear they will be punished by management or by law.
PDF
