The macrocyclic ligand calix4arene (
L1
) and its sulphur-containing analogue thia4calixarene (
L2
) are promising precursors for functional molecular materials as they offer rational ...functionalization with various organic groups. Here, we present the first example of lanthanide-based coordination polymers built from the macrocyclic thiacalix4arene backbone bearing four carboxylic moieties, namely, ligand
H
4
L3
. The combination of
H
4
L3
with the Tb
3+
and Dy
3+
cations led to the formation of 1D ladder-type coordination polymers with the formula Ln
III
HL3
DMF
3
·(DMF) (where DMF = dimethylformamide and Ln = Tb or Dy, denoted as
HL3-Tb
and
HL3-Dy
), which resulted from the coordination of the lanthanide cations with the partially deprotonated ligand
HL3
3−
that behaved as a T-shape connector. The coordination sphere around the metal was completed by the coordinated DMF solvent molecules. By combining both Tb
3+
and Dy
3+
cations, isostructural heterobimetallic solid solutions
HL3-Tb
1−
x
Dy
x
were also prepared.
HL3-Tb
and
HL3-Dy
showed visible light photoluminescence originating from the f-f electronic transitions of pale green emissive Tb
3+
and pale yellow emissive Dy
3+
with efficient sensitization by the functionalized thia4calixarene ligand
HL3
. In the
HL3-Tb
1−
x
Dy
x
solid solutions, the Tb/Dy ratio governed both the emission colour as well as the emission quantum yield, which reached even 28% at room temperature for
HL3-Tb
. Moreover,
HL3-Dy
exhibited a slow magnetic relaxation effect related to the magnetic anisotropy of the dodecahedral Dy
3+
complexes, which were well isolated in the crystal lattice by expanded organic spacers.
The single crystals of the two isostructural Tb
3+
- and Dy
3+
-based coordination polymers (
HL3-Tb
and
HL3-Dy
) were structurally characterized, and their photophysical properties were investigated, together with their corresponding solid solutions.
Mounting evidence indicates increased risk of COVID-19 among healthcare personnel, but the evidence on risks in other occupations is limited. In this study, we quantify the occupational risk of ...COVID-19-related hospital admission in Denmark during 2020-2021.
The source population included 2.4 million employees age 20-69 years. All information was retrieved from public registers. The risk of COVID-19 related hospital admission was examined in 155 occupations with at least 2000 employees (at-risk, N=1 620 231) referenced to a group of mainly office workers defined by a COVID-19 job exposure matrix (N=369 341). Incidence rate ratios (IRR) were computed by Poisson regression.
During 186 million person-weeks of follow-up, we observed 2944 COVID-19 related hospital admissions in at-risk occupations and 559 in referents. Adjusted risk of such admission was elevated in several occupations within healthcare (including health care assistants, nurses, medical practitioners and laboratory technicians but not physiotherapists or midwives), social care (daycare assistants for children aged 4-7, and nursing aides in institutions and private homes, but not family daycare workers) and transportation (bus drivers, but not lorry drivers). Most IRR in these at-risk occupations were in the range of 1.5-3. Employees in education, retail sales and various service occupations seemed not to be at risk.
Employees in several occupations within and outside healthcare are at substantially increased risk of COVID-19. There is a need to revisit safety measures and precautions to mitigate viral transmission in the workplace during the current and forthcoming pandemics.
The anomalous variations of a very low frequency (VLF) signal recorded after the eruption of the Hunga-Tonga-Hunga-Ha’apai volcano on January 15, 2022, have been investigated. It is shown that the ...intensification of the phase and amplitude variations of the VLF signal was caused by the crossing of radio paths by the atmospheric Lamb wave and the tsunami propagating after the volcanic eruption.
Heat-induced solid-state decarboxylation of tetra(malonatemethylene) based cyclophane leads to its tetra(2-carboxyethyl) derivative in quantitative yield. This reaction provides more thermostable ...substance compared to the product of the same cyclophane decarboxylation in solution. The studied cyclophanes have been characterized by means of simultaneous thermal analysis involving thermogravimetry, differential scanning calorimetry, and mass spectrometry of evolved gases as well as fast scanning calorimetry, a method preferable to investigate the compounds with relatively low thermal stability.
The aim of the present study was to investigate the impact of endogenous and exogenous factors for the expression of the daily rhythms of body temperature (BT), blood pressure (BP) and heart rate ...(HR). One hundred and seventy-three young adults (YA), 17-24 years old (y.o.), of both genders were studied under a modified constant-routine (CR) protocol for 26 h. Participants were assigned randomly to groups with different lighting regimens: CR-LD, n = 77, lights (>400 l×) on from 09:00 to 17:00 h and off (<10 l×) from 17:00 to 09:00 next morning; CR-LL, n = 81, lights on (>400 l×) during the whole experimental session; CR-DD, n = 15, constant dim light (<10 l×) during the whole experiment. Systolic (SBP) and diastolic (DBP) BP, HR and BT were measured every 2 h. For comparison, the results of the former studies performed under conditions of regular life with an activity period from 07:00 to 23:00 h and sleep from 23:00 till 07:00 h (Control) were reanalyzed. Seven-day Ambulatory Blood Pressure Monitoring (ABPM) records from 27 YA (16-38 y.o.) and BT self-measurement data from 70 YA (17-30 y.o.) taken on ≥ 3 successive days at 08:00, 11:00, 14:00, 17:00, 20:00, 23:00 and 03:00 were available.
The obtained daily patterns were different between Control and CR-DD groups, due to effects of activity, sleep and light. The comparison of Control and CR-LD groups allowed the effects of sleep and activity to be estimated since the lighting conditions were similar. The activity level substantially elevated SBP, but not DBP. Sleep, on the other hand, lowered the nighttime DBP, but has no effect on SBP. HR was affected both by activity and sleep. In accordance with previous studies, these results confirm that the steep BP increase in the morning is not driven by the circadian clock, but rather by sympathoadrenal factors related to awakening and corresponding anticipatory mechanisms. The effect on BT was not significant.
To investigate the impact of light during the former dark time and darkness during the former light time, the CR-LL and CR-DD groups were each compared with the CR-LD group. Light delayed the evening decrease of BT, most likely via a suppression of the melatonin rise. Besides, it had a prominent arousal effect on SBP both in the former light and dark phases, a moderate effect on DBP and no effect on HR. Darkness induced decline in BT. BP values were decreased during the former light time. No effects on HR were found. Altogether, the results of the present paper show that BT, BP and HR are affected by exogenous factors differently. Moreover, the effect was gender-specific. Especially, the response of BT and BP to ambient light was evident only in females.
We suppose that the distinct, gender-specific responses of SBP, DBP and HR to activity, sleep and ambient light do reflect fundamental differences in the circadian control of various cardiovascular functions. Furthermore, the presented data are important for the elaboration of updated reference standards, the interpretation of rhythm disorders and for personalized chronotherapeutic approaches to prevent adverse cardiovascular events more effectively.
Calix4arene derivatives containing two or four
O
-propargyl moieties are capable of undergoing reductive depropargylation in the presence of hydrazine hydrate. The propargyl groups are removed in the ...form of 4,5-dihydro-1
H
-pyrazoles, which allowed proposing a reasonable mechanism for the depropargylation. The propargyl group can be used as the protection for the selective nitration at the distal positions of the upper rim of di-
O
-propargyl-substituted calix4arene and
p
-
tert
-butylcalix4arene. The reduction of nitro group at the upper rim proceeds along with the depropargylation upon the addition of a nickel catalyst to the reaction mixture with hydrazine hydrate, which leads to calixarenamines containing free hydroxy groups.
The efficiency of polyethylene glycol methyl ether 350 (PEG ME-350) in the process of extracting thiophene from model motor fuel has been studied experimentally. The influence of the contact time of ...the phases, the composition of the extractant, the initial concentration of thiophene, and the volume ratio of the extractant and model fuel on the extraction of thiophene has been investigated. It is found that PEG ME-350 exhibits effective extraction properties with respect to thiophene, extracting it up to 81.58% in one extraction stage. The results can be further used in the development of the extraction purification of liquid motor fuels from sulfur-containing compounds.
To study the association between overweight and lumbar disc degeneration.
Population-based 4-y follow-up magnetic resonance imaging (MRI) study.
The subjects were 129 working middle-aged men selected ...to the baseline magnetic resonance imaging (MRI) study from a cohort of 1832 men representing three occupations: machine drivers, construction carpenters, and office workers. The selection was based on the paticipants' age (40-45 y) and place of residence. MR images of the lumbar spines were obtained at baseline and at 4-y follow-up.
Signal intensity of the nucleus pulposus of the discs L2/L3-L4/L5 was visually assessed by two readers using the adjacent cerebrospinal fluid as an intensity reference. The weight (at age 25 and 40-45 y) and height of the subjects, history of car driving, smoking, and back injuries were assessed by questionnaire.
Multiple regression analyses allowing for occupation, history of car driving, smoking, and back injuries showed that persistent overweight (body mass index (BMI) > or =25 kg/m(2) at both ages) associated strongly with an increased risk of the number of lumbar discs with decreased signal intensity of nucleus pulposus at follow-up, adjusted odds ratio (OR) being 4.3 (95% confidence intervals (95% CIs) 1.3-14.3). Overweight at young age (risk ratio (RR) 3.8; 95% CI 1.4-10.4) was a stronger predictor of an increase in the number of degenerated discs during follow-up than overweight in middle age (RR 1.3; 95% CI 0.7-2.7).
The study provides evidence that the BMI above 25 kg/m(2) increases the risk of lumbar disc degeneration. Overweight at young age seems to be particularly detrimental.
A questionnaire-based follow-up study of 150 Finnish patients with coagulation disorders was conducted to evaluate the changes in clinical manifestation of the disease, pain intensity, functional ...disability and patient's health-related quality of life, occurring during a 3-year period. Health-related quality of life was assessed using the MOS-36 health survey. The clinical severity of the disease manifestation was estimated using the frequency of bleeding episodes into joints and soft tissue during the previous 12 months. Severity of musculoskeletal morbidity, which reflects simultaneous presence of pain and disability, was estimated using intensity of pain and level of disability. Results showed that clinical severity of the disease remained unchanged during the 3-year period for the majority of patients. Nonetheless, the annual number of bleeds in patients with severe or moderately severe haemophilia was still disconcertingly high and the number of bleeding episodes into soft tissue had increased. The clinical severity of the disease manifestation, rather than the severity of the disease based on molecular classification, was a factor that negatively influenced the intensity of pain (both acute and chronic), as well as level of disability. Severity of musculoskeletal morbidity at time 1 and changes in severity of musculoskeletal morbidity over time were found to be significant predictors of physical role, bodily pain, vitality and social functioning. In conclusion, the disease can be relatively well controlled by the availability of coagulation products, thus stabilizing the clinical severity of the disease manifestation during the 3-year period studied. The findings stress the importance of preventing haemorrhages to avoid resulting permanent joint impairment and disability.
The review considers in detail methods of synthesis of thiazolo3,2-
a
pyrimidines, synthesis and chemical properties of their 2-substituted derivatives, and crystal structures of ...2-(arylmethylidene)1,3thiazolo3,2-
a
pyrimidines. High antitumor, antibacterial, and anti-inflammatory activities of these compounds have been demonstrated.
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