Communication-efficient federated learning with stagewise training strategy.

The efficiency of communication across workers is a significant factor that affects the performance of federated learning. Though periodic communication strategy is applied to reduce communication rounds in training, the communication cost is still high when the training data distributions are not independently and identically distributed (non-IID) which is common in federated learning. Recently, some works introduce variance reduction to eliminate the effect caused by non-IID data among workers. Nevertheless the provable optimal communication complexity O(log(ST)) and convergence rate O(1/(ST)) cannot be achieved simultaneously, where S denotes the number of sampled workers in each round and T is the number of iterations. To deal with this dilemma, we propose an optimization algorithm SQUARFA that adopts stagewise training framework coupling with variance reduction and uses a quick-start phase in each loop. Theoretical results show that SQUARFA achieves both optimal convergence rate and communication complexity for both strongly convex objectives and non-convex objectives under PL condition, thus fills the gap mentioned above. Then, a variant of SQUARFA yields the optimal theoretical results for general non-convex objectives. We further extend the technique in SQUARFA to the large batch setting and achieve optimal communication complexity. Experimental results demonstrate the superiority of the proposed algorithms.

[Effect of hyperbaric oxygen on the expression of nitric oxide synthase mRNA in cortex after acute traumatic cerebral injury].

OBJECTIVE: To investigate the effect of hyperbaric oxygen (HBO) treatment on the expression of nitric oxide synthase (NOS) mRNA in cortex after acute traumatic cerebral injury, and to study the mechanism of HBO on brain injury. METHODS: Acute traumatic brain injury model was established with rest received free fall injury method in SD rats. 0.25 MPa HBO treatment was used 1 h or 12 h after brain injury and the cortex was isolated 6 h or 24 h after brain injury respectively. The expression of mRNA coding for nNOS, eNOS or iNOS were assayed using reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The expression of nNOS, eNOS and iNOS mRNA were significantly decreased in 0.25 MPa HBO treatment groups than those in acute cerebral injury groups (P < 0.01). The amount of nNOS, eNOS and iNOS mRNA was significantly lower in HBOT 24 h group than those in HBOT 6 h group (P < 0.05, P < 0.01). There was no significantly difference among nNOS, eNOS and iNOS mRNA in 0.25 MPa normoxic hyperbaric nitrogen groups and acute cerebral injury groups (P > 0.05). CONCLUSION: HBO may exert significant effects on the expression of nNOS mRNA/iNOS mRNA and protect cortical neuronal from traumatic cerebral injury.

Effects of hyperbaric oxygen on aggressive periodontitis and subgingival anaerobes in Chinese patients.

OBJECTIVE: To investigate the effects of hyperbaric oxygen (HBO2) on aggressive periodontitis (AgP), and subgingival obligate anaerobes in Chinese patients. MATERIALS AND METHODS: Sixty cases of Chinese patients with AgP were randomly divided into two groups -the HBO2 group (30 cases) and the control group (30 cases). Study teeth were divided into four groups -: the HBO2 therapy, the HBO2 + scaling scaling group, the scaling group and the control group. Subgingival anaerobic organisms were measured with anaerobic culture, and number of obligate anaerobes and facultative anaerobes and Bacteroides melaninogenicus was counted. Comparisons of changes in the clinical indices, and subgingival anaerobes were made between the groups. RESULTS: Highly significant differences in gingival index (GI), probing depth (PD), attachment loss (AL), and Plaque index (PLI), and tooth odontoseisis (TO) were seen in the HBO2, the HBO2 + scaling and the scaling groups when compared with the control group (P<0.01). The number of subgingival anaerobes as well as the types of obligate anaerobes and facultative anaerobes and the number of Bacteroides melaninogenicus were reduced markedly in these three treatment groups. Highly statistical differences in clinical indices, subgingival anaerobe number and types of obligate anaerobes and facultative anaerobes and Bacteroides melaninogenicus were found when comparisons were made between the HBO2 + scaling and the HBO2 groups, as well as between the HBO2 + scaling and the scaling groups. Clinical follow-ups indicated that the GI, PD, AL, TO, PLI and subgingival anaerobes number of the three therapeutic groups were reduced more severely than the control group. CONCLUSIONS: HBO2 had good therapeutic effects on Chinese patients with AgP. HBO2 therapy combined with scaling and root planing was the most beneficial in the treatment of AgP. The therapeutic effect of HBO2 on AgP is most likely through inhibition of the growth of subgingival anaerobes. Clinical follow-ups suggest that the effect could last more than 2 years.

[Octreotide induces apoptosis of human hepatoma cells by the mechanism of facilitating the Fas/FasL gene expression therein].

OBJECTIVE: To investigate the effects of octreotide on apoptosis of and Fas/FasL gene expression in human hepatoma cell mechanism of the suppression effect of liver cancer with e in order to offer the experimental foundation for clinic treatment. METHODS: Hyman hematoma cells of the line SMMC-7721 were cultured and divided into two groups: octreotide group, co-cultured with octreotide 4,7, and 10 microg/ml respectively for 24 h, 48 h, or 72 h, and control group. TUNEL was used to detect the apoptosis of the cells. Flow cytometry was used with terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) technique to detect the apoptosis of the cells. FC was used with direct labeling of monoclonal antibody (CD95/CD178) to detect the expression of Fas and FasL, and the Fas/FasL ratio. RESULTS: Octreotide increased the apoptotic rate of the cells dose- and time-dependently (all P < 0.05). Octreotide increased the Fas expression rate, FasL expression rate, and Fas/FasL ratio dose- and time-dependently (all P < 0.05). CONCLUSION: Octreotide induces the apoptosis of human hepatoma cells, possibly by the mechanism of facilitating the Fas/FasL gene expression.

[Changes of glycine uptake of synaptosomes of rat spinal cord in 0.7 MPa (7ATA) air pressure].

AIM: To study changes of function of transmitter glycine in nitrogen narcosis. METHODS: Synaptosomes of rat spinal cord were prepared. Glycine uptake of synaptosomes of rat spinal cord in 0.7 MPa (7ATA) hyperbaric air pressure was observed by the methods of isotope. RESULTS: Glycine uptake slowed down and took a longer period of time to reach saturation in 0.7 MPa (7ATA). The maximum glycine uptake was lessened. Vm was diminished, but Km was increased. Vm rose in 0.7 MPa (7ATA) when corticosterone was added. CONCLUSION: When nitrogen narcosis arose in 0.7 MPa (7ATA), the function of transporters of glycine re-uptake was reduced, the affinity of glycine for transporters subsided. Corticosterone was conductive to the recovery of the function of glycine transporters of high affinity.

[Effects and holding time of hyperbaric oxygen on human severe periodontitis].

OBJECTIVE: This paper studied the therapeutic effects and holding time of hyperbaric oxygen (HBO) on human severe periodontitis. METHODS: 30 cases with periodontitis were selected and randomly divided into 2 groups, i.e. the HBO group and control group. For HBO group, they were exposed to a pressure of 0.25 MPa. For control group, they were rinsed with gargle. Gingival indices (GI), sulcus bleeding indices (SBI), plaque index (PLI), probing depth (PD), attachment loss (AL) and gingival crevicular fluid (GCF) were measured during both the first and last clinical visits, and 1 year after HBO therapy. The gingival blood flow (GBF) were measured by Laser Doppler Flowmeter. RESULTS: HBO can decrease GI of patients with periodontitis by 1.1 decrease SBI by 1.2, lower PD and AL by 0.7 mm, decrease the volume of GCF by 2.0, and significant differences could be seen in the above indices between pre and post HBO therapy. The GBF had a 1.8 folds increase after HBO exposure. GI and SBI one year after HBO therapy were larger than that of the time after HBO therapy. There were no significant differences in the PLI, PD, AL, GCF, GBF between post HBO therapy and 1 year after HBO therapy. CONCLUSION: HBO had good therapeutic effects on human severe periodontitis, the effects can keep more than 1 year.

Effects and mechanism of hyperbaric oxygen on prostaglandins in alveolar bone and gingival of experimental periodontitis in animal.

OBJECTIVE: To study the effects and the therapeutic mechanism of hyperbaric oxygen (HBO) on prostaglandin E(2) (PGE(2)) in alveolar bone and gingiva of experimental periodontitis in animal. METHODS: Experimental periodontitis was produced by silk thread sutures combined with high content sugar diet. For HBO therapy, they were exposed to a pressure of 0.25 MPa (2.5ATA), breathing pure oxygen one session a day for 60 min. The treatment course was 2 weeks. The value of PGE(2) in gingiva and alveolar bone was analyzed by enzyme immunoassay (EIA). RESULTS: The value of PGE(2) in gingiva of control group was 3.21 ng/g, and that of PGE(2) in alveolar bone was 3.22 ng/g. The contents of PGE(2) in gingiva (13.96 ng/g) and alveolar bone (13.32 ng/g) of periodontitis group increased markedly than control group (P < 0.01). The contents of PGE(2) in gingiva (5.21 ng/g) of HBO group were 62.7% which was lower than that of periodontitis group, and the value of PGE(2) in alveolar bone (4.05 ng/g) were 69.6% lower than that of periodontitis group. The difference of PGE(2) in gingiva or alveolar bone was significant for the HBO group and periodontitis group (P < 0.01). CONCLUSIONS: The contents of PGE(2) in alveolar bone and gingiva increased markedly when experimental periodontitis has formed. The value of PGE(2) in alveolar bone and gingiva reduce markedly after HBO exposure, and the decreased rate of PGE(2) in alveolar bone is more evident than that of PGE(2) in gingiva after HBO therapy.

[Effects of fast decompression on prostaglandins content in cerebral tissue of guinea pigs].

Objective. To investigate the effect of fast decompression on prostaglandins in cerebral tissue. Method. 26 guinea pigs were divided into 2 groups randomly. The animals in group FDC (group 1) were treated with fast decompression and formed decompression sickness, but those in control group (group 2) were not treated with decompression. The contents of prostaglandin E2 (PGE2), 6-keto-prostaglandin F1a (6-K-PGF1a) and thromboxane B2 (TXB2) in cerebral tissue of the animals were determined by enzyme immunoassay. Result. The content of PGE2 in cerebral tissue of FDC animals was twice as much as that in control animals. The content of TXB2 in cerebral tissue of FDC animals was 3 times as high as that in control animals, and that of 6-K-PGF1a in cerebral tissue of FDC animals was 2.6 times as that in control animals. It showed very significant differences as compared with control group (P<0.01). Conclusion. The content of PGs in cerebral tissue increased markedly after fast decompression, and may cause cerebral injury.