For mines with poor ore bodies and surrounding rocks,the general mining method does not allow the ore to be extracted from underground safely and efficiently.For these mines,the downward layered filling mining techniq...For mines with poor ore bodies and surrounding rocks,the general mining method does not allow the ore to be extracted from underground safely and efficiently.For these mines,the downward layered filling mining technique is undoubtedly the most suitable mining method.The downward filling mining technique may eliminate the troubles relating to poor ore deposit conditions,such as production safety,ore loss rate,and depletion rate.However,in this technique,the safety of the artificial roof of the next stratum is of paramount importance.Cementitious tailings backfilling(CTB)that is not sufficiently cemented and causes collapses could threaten ore production.This paper explores a diamond-shaped composite structure to mimic the stability of a glued false roof in an actual infill mine based on the recently emerged three-dimensional(3D)printing technology.Experimental means such as three-point bending and digital image correlation(DIC)techniques were used to explore the flexural characteristics of 3D construction specimens and CTB combinations with different cement/tailings weight ratios at diverse layer heights.The results show that the 3D structure with a 14-mm ply height and CTB has strong flexural characteristics,with a maximum deflection value of 30.1 mm,while the 3D-printed rhomboid polymer(3D-PRP)structure with a 26-mm ply height is slightly worse in terms of flexural strength characteristics,but it has a higher maximum flexural strength of 2.83 MPa.A combination of 3D structure and CTB has more unique mechanical properties than CTB itself.This research work offers practical knowledge on the artificial roof performance of the downward layered filling mining technique and builds a scientific knowledge base regarding the successful application of CTB material in mines.展开更多
Two novel,supramolecular,multiferrocenyl rhomboids 5 and 6 have been successfully constructed from newly designed 60 ferrocenyl donor precursor 1 via coordination-driven self-assembly.The structures of all multiferroc...Two novel,supramolecular,multiferrocenyl rhomboids 5 and 6 have been successfully constructed from newly designed 60 ferrocenyl donor precursor 1 via coordination-driven self-assembly.The structures of all multiferrocenyl rhomboids were characterized by multinuclear NMR（~1H and ^（31）P）,CSI-TOF-MS, and PM6 semi-empirical molecular simulation,and their electrochemical behaviors have been investigated.展开更多
We adopted auricular pressure therapy to treat 32 cases with strain of rhomboidmuscle and achieved satisfactory results,namely,the cure rate was 46.87％,improved rate 40.67％,and the total effective rate 87.54％.
<b><span style="font-family:Verdana;">Background</span></b><span style="font-family:Verdana;"><strong></strong></span><strong><b><span...<b><span style="font-family:Verdana;">Background</span></b><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"></span></strong><span style="font-family:Verdana;"> Pilonidal disease is a chronic inflammatory disease of the sacrococcygeal region that mainly affects young people. Its incidence is 26 cases per 100,000 persons. Although many techniques have been described, there is no consensus on the treatment of pilonidal sinus disease (PSD). </span><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">Materials</span></b><span style="font-family:Verdana;"></span></strong><b><span style="font-family:;" "=""> </span></b><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">and</span></b><span style="font-family:Verdana;"></span></strong><span style="font-family:;" "=""> </span><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">Methods</span></b><span style="font-family:Verdana;"></span></strong><strong><b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"></span></strong><b><span style="font-family:;" "=""> </span></b><span style="font-family:Verdana;">This study included 30 patients with PSD who were treated between May 2014 and September 2017. All cases underwent excision and flap reconstruction. The operative time, postoperative complications, the length of hospital stay, painless sitting and walking time, patient satisfaction and recurrence were evaluated prospectively. </span><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">Results</span></b><span style="font-family:Verdana;"></span></strong><strong><b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"></span></strong><b><span style="font-family:;" "=""> </span></b><span style="font-family:Verdana;">The results of this prospective, randomized and comparative study are based on experience of a single surgical centre. All patients were followed up 18 months after discharge from the hospital. There is a difference in surgery durations (minutes) between the two groups (33.86 ± 2.89 min. in “keystone” flap vs. 41.26 ± 4.19 in the “rhombic” flap group) (p = 0.001). There were no significant differences in the length of hospital stay, painless sitting and walking time or patient satisfaction. The total complication rate was 66.6% after rhomboid flap compared with 6.6% after keystone flap. There was no flap necrosis. </span><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">Conclusions</span></b><span style="font-family:Verdana;"></span></strong><strong><b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"></span></strong><span style="font-family:Verdana;"> Both of these methods have shown to be successful in treatment of PSD. The KPIF is associated with the advantages of very simple design, abundant blood supply from the perforator vessels and lower rate of complication.</span>展开更多
Background: Prolonged pressure on the skin known as pressure sores, can cause frequent injuries to the skin and underlying tissues. However, several prevention approaches, including non-surgical and surgical managemen...Background: Prolonged pressure on the skin known as pressure sores, can cause frequent injuries to the skin and underlying tissues. However, several prevention approaches, including non-surgical and surgical management,are available. In flap surgery for pressure sores, a variety of flap types may be used;each offers certain benefits and some incidences of complications and recurrence. This study evaluated the versatility of the perforatorenhanced rhomboid flap technique for ischial sore construction.Methods: This prospective study was conducted in the Plastic Surgery Department of Fayoum University Hospital.The perforator-enhanced rhomboid flap technique was employed in 20 patients with ischial pressure sores who failed to respond to conservative treatment. A proper history was obtained and a preoperative arterial duplex was performed to determine the site of the prominent perforators for their preservation at the base of the flap.Postoperative follow-ups and evaluations were performed.Results: The mean age of the study group was 43.7 ± 13.1, ranging from 19 to 65 years. Moreover, 80% of the participants were males while 20% were female. The main etiology of the sores was paraplegia in 45% of cases.The mean surface area of sores was 24.8 ± 6.3 cm2. In 75% of cases, the color match of the flap was rated as excellent. Similarly, 70% of the patients rated flap thickness as excellent. In 55% of the cases, the scar appearance was deemed excellent. Overall satisfaction was reported as excellent by 40% of the patients, while only 5% reported poor satisfaction. Approximately, 10% of the cases were identified with seroma, and 30% had wound dehiscence of a mean size of 1.33 ± 0.98 cm and required around 6.8 ± 1.9 weeks to heal.Conclusion: The perforator-enhanced rhomboid flap technique is a versatile method for reconstructing ischial pressure sores owing to its technical ease, short operative time, reliable vascularity, aesthetic outcome, matching skin color, and short recovery time. The main limitations include large defects with large surface areas, lack of a nearby donor site for a rhomboid flap, and scarring from prior procedures around the sore.展开更多
The design and self-assembly of pyrene-modified rhomboidal metallodendrimers R1--R6 via directional metal-ligand bonding approach is described. By employing pyrene-containing 120° di-Pt（II） acceptor and appropr...The design and self-assembly of pyrene-modified rhomboidal metallodendrimers R1--R6 via directional metal-ligand bonding approach is described. By employing pyrene-containing 120° di-Pt（II） acceptor and appropri- ate 60° dendritic dipyridyl donors, a variety of [G-1]--[G-3] pyrene-modified rhomboidal metallodendrimers with well-defined shape and size were prepared under mild conditions in high yields. The supramolecular dendrimers were characterized with multinuclear NMR （1H and 31p） and mass spectrometry （CSI-TOF-MS）. lsotopically re- solved mass spectrometry data support the existence of the pyrene-modified dendrimers with rhomboidal cavities, and NMR data were consistent with the formation of all ensembles. The shape and size of all rhomboidal den- drimers were investigated with the PM6 semiempirical molecular orbital method. Their primary photochemical properties were studied as well.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2022YFC2905004)the National Natural Science Foundation of China(No.51804017)。
文摘For mines with poor ore bodies and surrounding rocks,the general mining method does not allow the ore to be extracted from underground safely and efficiently.For these mines,the downward layered filling mining technique is undoubtedly the most suitable mining method.The downward filling mining technique may eliminate the troubles relating to poor ore deposit conditions,such as production safety,ore loss rate,and depletion rate.However,in this technique,the safety of the artificial roof of the next stratum is of paramount importance.Cementitious tailings backfilling(CTB)that is not sufficiently cemented and causes collapses could threaten ore production.This paper explores a diamond-shaped composite structure to mimic the stability of a glued false roof in an actual infill mine based on the recently emerged three-dimensional(3D)printing technology.Experimental means such as three-point bending and digital image correlation(DIC)techniques were used to explore the flexural characteristics of 3D construction specimens and CTB combinations with different cement/tailings weight ratios at diverse layer heights.The results show that the 3D structure with a 14-mm ply height and CTB has strong flexural characteristics,with a maximum deflection value of 30.1 mm,while the 3D-printed rhomboid polymer(3D-PRP)structure with a 26-mm ply height is slightly worse in terms of flexural strength characteristics,but it has a higher maximum flexural strength of 2.83 MPa.A combination of 3D structure and CTB has more unique mechanical properties than CTB itself.This research work offers practical knowledge on the artificial roof performance of the downward layered filling mining technique and builds a scientific knowledge base regarding the successful application of CTB material in mines.
基金financially supported by NSFC(Nos.21132005 and 91027005)
文摘Two novel,supramolecular,multiferrocenyl rhomboids 5 and 6 have been successfully constructed from newly designed 60 ferrocenyl donor precursor 1 via coordination-driven self-assembly.The structures of all multiferrocenyl rhomboids were characterized by multinuclear NMR（~1H and ^（31）P）,CSI-TOF-MS, and PM6 semi-empirical molecular simulation,and their electrochemical behaviors have been investigated.
文摘We adopted auricular pressure therapy to treat 32 cases with strain of rhomboidmuscle and achieved satisfactory results,namely,the cure rate was 46.87％,improved rate 40.67％,and the total effective rate 87.54％.
文摘<b><span style="font-family:Verdana;">Background</span></b><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"></span></strong><span style="font-family:Verdana;"> Pilonidal disease is a chronic inflammatory disease of the sacrococcygeal region that mainly affects young people. Its incidence is 26 cases per 100,000 persons. Although many techniques have been described, there is no consensus on the treatment of pilonidal sinus disease (PSD). </span><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">Materials</span></b><span style="font-family:Verdana;"></span></strong><b><span style="font-family:;" "=""> </span></b><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">and</span></b><span style="font-family:Verdana;"></span></strong><span style="font-family:;" "=""> </span><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">Methods</span></b><span style="font-family:Verdana;"></span></strong><strong><b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"></span></strong><b><span style="font-family:;" "=""> </span></b><span style="font-family:Verdana;">This study included 30 patients with PSD who were treated between May 2014 and September 2017. All cases underwent excision and flap reconstruction. The operative time, postoperative complications, the length of hospital stay, painless sitting and walking time, patient satisfaction and recurrence were evaluated prospectively. </span><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">Results</span></b><span style="font-family:Verdana;"></span></strong><strong><b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"></span></strong><b><span style="font-family:;" "=""> </span></b><span style="font-family:Verdana;">The results of this prospective, randomized and comparative study are based on experience of a single surgical centre. All patients were followed up 18 months after discharge from the hospital. There is a difference in surgery durations (minutes) between the two groups (33.86 ± 2.89 min. in “keystone” flap vs. 41.26 ± 4.19 in the “rhombic” flap group) (p = 0.001). There were no significant differences in the length of hospital stay, painless sitting and walking time or patient satisfaction. The total complication rate was 66.6% after rhomboid flap compared with 6.6% after keystone flap. There was no flap necrosis. </span><span style="font-family:Verdana;"><strong></strong></span><strong><b><span style="font-family:Verdana;">Conclusions</span></b><span style="font-family:Verdana;"></span></strong><strong><b><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"></span></strong><span style="font-family:Verdana;"> Both of these methods have shown to be successful in treatment of PSD. The KPIF is associated with the advantages of very simple design, abundant blood supply from the perforator vessels and lower rate of complication.</span>
文摘Background: Prolonged pressure on the skin known as pressure sores, can cause frequent injuries to the skin and underlying tissues. However, several prevention approaches, including non-surgical and surgical management,are available. In flap surgery for pressure sores, a variety of flap types may be used;each offers certain benefits and some incidences of complications and recurrence. This study evaluated the versatility of the perforatorenhanced rhomboid flap technique for ischial sore construction.Methods: This prospective study was conducted in the Plastic Surgery Department of Fayoum University Hospital.The perforator-enhanced rhomboid flap technique was employed in 20 patients with ischial pressure sores who failed to respond to conservative treatment. A proper history was obtained and a preoperative arterial duplex was performed to determine the site of the prominent perforators for their preservation at the base of the flap.Postoperative follow-ups and evaluations were performed.Results: The mean age of the study group was 43.7 ± 13.1, ranging from 19 to 65 years. Moreover, 80% of the participants were males while 20% were female. The main etiology of the sores was paraplegia in 45% of cases.The mean surface area of sores was 24.8 ± 6.3 cm2. In 75% of cases, the color match of the flap was rated as excellent. Similarly, 70% of the patients rated flap thickness as excellent. In 55% of the cases, the scar appearance was deemed excellent. Overall satisfaction was reported as excellent by 40% of the patients, while only 5% reported poor satisfaction. Approximately, 10% of the cases were identified with seroma, and 30% had wound dehiscence of a mean size of 1.33 ± 0.98 cm and required around 6.8 ± 1.9 weeks to heal.Conclusion: The perforator-enhanced rhomboid flap technique is a versatile method for reconstructing ischial pressure sores owing to its technical ease, short operative time, reliable vascularity, aesthetic outcome, matching skin color, and short recovery time. The main limitations include large defects with large surface areas, lack of a nearby donor site for a rhomboid flap, and scarring from prior procedures around the sore.
文摘The design and self-assembly of pyrene-modified rhomboidal metallodendrimers R1--R6 via directional metal-ligand bonding approach is described. By employing pyrene-containing 120° di-Pt（II） acceptor and appropri- ate 60° dendritic dipyridyl donors, a variety of [G-1]--[G-3] pyrene-modified rhomboidal metallodendrimers with well-defined shape and size were prepared under mild conditions in high yields. The supramolecular dendrimers were characterized with multinuclear NMR （1H and 31p） and mass spectrometry （CSI-TOF-MS）. lsotopically re- solved mass spectrometry data support the existence of the pyrene-modified dendrimers with rhomboidal cavities, and NMR data were consistent with the formation of all ensembles. The shape and size of all rhomboidal den- drimers were investigated with the PM6 semiempirical molecular orbital method. Their primary photochemical properties were studied as well.
