Influencing factors of ocular pain in dry eye disease patients at high altitude

AIM:To quantify the severity and frequency of ocular pain in Tibetan plateau patients with dry eye,and to evaluate the related factors affecting ocular pain.METHODS:A retrospective study included 160 cases of dry eye disease(DED)patients who were treated from July 2022 to June 2023.Age,gender,occupation,illness course,anxiety,plateau duration,plateau protection,ocular surface disease index scale(OSDI),break-up time(BUT),Schirmer I test(SIT),conjunctivitis,history of ophthalmic medication,autoimmune disease,the workload of daily near vision range,smoking and overnight stay were obtained via comprehensive ophthalmic assessment,and their duration was followed up.Logistic regression analysis was used to determine the related factors affecting ocular pain.RESULTS:Totally 77.5%(124/160)of DED patients had ocular pain,of which the severity of ocular pain was mild,moderate,and severe in 30.0%,36.3%,and 11.3%of patients,respectively.Frequency of ocular pain was reported occasional,half the time,frequent,and persistent pain in 19.4%,36.9%,16.9%,and 4.4%.OSDI score was 19.67±5.70(13 to 36),and the level of pain was lowly correlated with OSDI(rs=0.316,P<0.001).Logistic regression showed that in plateau DED patients,increased anxiety led to increased severity and frequency of ocular pain[odds ratio(OR)=3.662,5.613,2.387,and 4.870;all P<0.05],professional eye protection and improvement of daily sleep quantity decreased pain(OR=0.307,0.572,0.418,and 0.789;all P<0.05),while smoking and general protection of plateau did not affect the severity and frequency of ocular pain(all P>0.05).CONCLUSION:Ocular pain is a common complaint in high-altitude DED patients during the pandemic.Anxiety,eye protection,and adequate sleep during the epidemic period are significantly associated with the severity and frequency of ocular pain in patients with plateau DED,while symptoms of DED have relatively little influence on them.

Mitochondrial genome sequences of Artemia tibetiana and Artemia urmiana:assessing molecular changes for high plateau adaptation

Brine shrimps,Artemia(Crustacea,Anostraca),inhabit hypersaline environments and have a broad geographical distribution from sea level to high plateaus.Artemia therefore possess significant genetic diversity,which gives them their outstanding adaptability.To understand this remarkable plasticity,we sequenced the mitochondrial genomes of two Artemia tibetiana isolates from the Tibetan Plateau in China and one Artemia urmiana isolate from Lake Urmia in Iran and compared them with the genome of a low-altitude Artemia,A.franciscana.We compared the ratio of the rate of nonsynonymous(Ka) and synonymous(Ks) substitutions(Ka/Ks ratio) in the mitochondrial protein-coding gene sequences and found that atp8 had the highest Ka/Ks ratios in comparisons of A.franciscana with either A.tibetiana or A.urmiana and that atp6 had the highest Ka/Ks ratio between A.tibetiana and A.urmiana.Atp6 may have experienced strong selective pressure for high-altitude adaptation because although A.tibetiana and A.urmiana are closely related they live at different altitudes.We identified two extended termination-associated sequences and three conserved sequence blocks in the D-loop region of the mitochondrial genomes.We propose that sequence variations in the D-loop region and in the subunits of the respiratory chain complexes independently or collectively contribute to the adaptation of Artemia to different altitudes.

Yak rumen microbiome elevates fiber degradation ability and alters rumen fermentation pattern to increase feed efficiency

Rumen microbes play an important role in ruminant energy supply and animal performance.Previous studies showed that yak(Bos grunniens)rumen microbiome and fermentation differ from other ruminants.However,little is understood about the features of the rumen microbiome that make yak adapted to their unique environmental and dietary conditions.This study was to investigate the rumen microbiome and metabolome to understand how yak adapt to the coarse forage and harsh environment in the Qinghai-Tibetan plateau.Nine female Qaidam yellow cattle(Bos taurus),9 dzomo(hybrids of cattle and yak)and 9 female plateau yak(B.grunniens),about 5 to 6 years old,were used in this study.Rumen fermentation parameters,fibrolytic enzyme activities,and rumen metataxonomic were determined.Then 18(6 samples per group)were selected for rumen metagenomic and metabolome analysis.Metataxonomic analysis revealed that the rumen microbiota was significantly different among plateau yak,Qaidam yellow cattle,and dzomo(P<0.05).Metagenomic analysis displayed a larger gene pool encoding a richer repertoire of carbohydrate-active enzymes in the rumen microbiome of plateau yak and dzomo than Qaidam yellow cattle(P<0.05).Some of the genes encoding glycoside hydrolases that mediate the digestion of cellulose and hemicellulose were significantly enriched in the rumen of plateau yak than Qaidam yellow cattle,but glycoside hydrolase 57 that primarily includes amylases was abundant in Qaidam yellow cattle(P<0.05).The rumen fermentation profile differed also,Qaidam yellow cattle having a higher molar proportion of acetate but a lower molar proportion of propionate than dzomo and plateau yak(P<0.05).Based on metabolomic analysis,rumen microbial metabolic pathways and metabolites were different.Differential metabolites are mainly amino acids,carboxylic acids,sugars,and bile acids.Changes in rumen microbial composition could explain the above results.The present study showed that the rumen microbiome of plateau yak helps its host to adapt to the Qinghai-Tibetan plateau.In particular,the plateau yak rumen microbiome has more enzymes genes involved in cellulase and hemicellulase than that of cattle,resulting higher fibrolytic enzyme activities inyak,further providing stronger fiber degradation function.

Evaluation of the Trend Uncertainty in Summer Ozone Valley over the Tibetan Plateau in Three Reanalysis Datasets

Trend uncertainty in the ozone valley over the Tibetan Plateau（OVTP）and the South Asian high（SAH）during1979–2009 in ERA-Interim（interim reanalysis data from the ECMWF）,JRA-55（55-yr reanalysis data from the Japan Meteorological Agency）,and NCEP-CFSR（Climate Forecast System Reanalysis）datasets was evaluated.The results showed that the NCEP-CFSR OVTP became strong in the summers of 1979–2009,whereas it became weak according to ERA-Interim and JRA-55.Satellite data merged with TOMS（Total Ozone Mapping Spectrometer）and OMI（Ozone Monitoring Instrument）agreed with the OVTP trend of NCEP-CFSR.The OVTP strengthening in NCEP-CFSR may have been caused by SAH intensification,a rising tropopause,and increasing ozone over non-TP（non-Tibetan Plateau）areas（27°–37°N,〈75°E and〉105°E）.Analogously,the OVTP weakening in ERA-Interim and JRA-55 may have been affected by weakening SAH,descending tropopause,and decreasing non-TP ozone.

Electrical conductivities of two granite samples in southern Tibet and their geophysical implications

There are clear differences in the electrical conductivities of the crustal granites of the Qinghai-Tibet Plateau.Because these granites are among the major rock types on the Qinghai-Tibet Plateau, it is very important to detect the electrical conductivity of granites under high temperatures and pressures to study the electrical conductivity structure of this area. Using impedance spectroscopy at a frequency range of 10.1–106 Hz, the electrical conductivity of the muscovite-granite collected from Yadong was investigated at a confining pressure of 1.0 GPa and temperatures ranging from 577 to 996 K, while the electrical conductivity of the biotite-granite collected from Lhasa was investigated at a pressure of 1.0 GPa and temperatures ranging from587 to 1382 K. The calculated activation enthalpies of the Yadong muscovite-granite sample is 0.92 eV in the low-temperature range(577–919 K) and 2.16 eV in the high-temperature range(919–996 K). The activation enthalpies of the Lhasa biotite-granite sample is 0.48 eV in the low-temperature range(587–990 K) and 2.06 eV in the high-temperature range(990–1382 K). The change in the activation enthalpies of the granites at different temperature ranges may be associated with the dehydration of the two samples. The electrical conductivities of the granite samples obtained in the laboratory using impedance spectroscopy correspond well with field observations conducted near the sampling points, both in terms of the actual conductivity values and the observed variations between the low-temperature and high-temperature regimes. This correlation of laboratory and field conductivities indicates that the conductivities of the crustal rocks in the two regions closely correspond to granite conductivities.We calculated the electrical conductivities of muscovite-granite and biotite-granite samples using the effective medium and HS boundary models. When applied to the crustal rocks of southern Tibet, the results of the geophysical conductivity profiles lie within the range of laboratory data. Thus, the electrical characteristics of the crustal rocks underlying the southern Qinghai-Tibet Plateau can largely be attributed to granites, with the large changes to high conductivities at increasing depths resulting from the dehydration of crustal rocks with granitic compositions.