Fabricating Pyramidal Lattice Structures of 304 L Stainless Steel by Wire Arc Additive Manufacturing.

Lattice structures have drawn considerable attention due to their superior mechanical properties. However, the existing fabrication methods for lattice structures require complex procedures, as they have low material utilization and lead to unreliable node connections, which greatly restricts their application. In this work, wire arc additive manufacturing is used to fabricate large-scale lattice structures efficiently, without any air holes between rods and panels. The principle and the process of fabricating the rods were analyzed systematically. The influence of the two most important parameters, including heat input and preset layer height, is disclosed. Through optical microscopy, the microstructure of the fabricated steel rods is found to consist of dendritic austenite and skeletal ferrite. The tensile strength of the rods can reach 603 MPa, and their elongation reaches 77%. These experimental results demonstrated the feasibility of fabricating lattice structures using wire arc additive manufacturing.

Relevance of clinical features in the prognosis of bronchopulmonary dysplasia in premature infants.

The aim of this study is to determine the accuracy rate of bronchopulmonary dysplasia (BPD) diagnosis and risk factors of short-term poor prognosis for premature infants. This study analyzed the clinical data of 81 premature infants (<32 weeks gestational age) with BPD, who were on oxygen therapy >28 days, and survived >36 weeks (corrected age). Outcome measures included treatments, conditions on the 28th day after birth, oxygen therapy conditions at the 36th week, occurrence of any serious complications during hospital stay. The major risk factors affecting prognosis were ventilation duration, duration of oxygen therapy, application of steroids, hypothyroidism and severity of BPD (all P<0.05). Interventions for complications (n=53) resulted in ceased inhalation of oxygen in 12 infants, improvement of symptoms in 26 infants, and were ineffective in 15 infants. BPD prognosis can be improved by shortening the duration of invasive ventilation and correcting thyroid function.

[Clinical and imaging features of premature infants with different degrees of bronchopulmonary dysplasia].

OBJECTIVE: To study the clinical and imaging features of premature infants with different degrees of bronchopulmonary dysplasia (BPD). METHODS: A prospective study was performed on the clinical data of 59 premature infants (gestational age <32 weeks) with BPD. Among the 59 premature infants, 37 cases had mild BPD and the other 22 cases had moderate to severe BPD. The clinical and imaging data were compared between these premature infants with different degrees of BPD. RESULTS: The durations of mechanical ventilation, oxygen therapy, antibiotic therapy, parenteral nutrition, and hospitalization in the moderate to severe group were significantly longer than those in the mild group (P<0.05). The incidence of nosocomial infection and number of times of red blood cell transfusion in the moderate to severe group were significantly higher than that in the mild group. The rates of X-ray changes, including grade I respiratory distress syndrome (1 day after birth) and hypolucency of lungs (4-10 days and ≥ 28 days after birth) were significantly higher in the mild group than in the moderate to severe group. The rates of X-ray changes in classical BPD stage III (4-10 days after birth) and IV (≥ 28 days after birth) were significantly higher in the moderate to severe group than in the mild group. CONCLUSIONS: The durations of mechanical ventilation, oxygen therapy, and antibiotic therapy and the incidence of nosocomial infection are correlated with the severity of BPD. The premature infants with severer BPD need a longer duration of parenteral nutrition and more times of red blood cell transfusion and have more typical imaging changes of BPD. Imaging examination has a predictive value for the severity of BPD.

Diagnosis of neonatal transient tachypnea and its differentiation from respiratory distress syndrome using lung ultrasound.

Transient tachypnea of the newborn (TTN) is one of the most common causes of perinatal dyspnea and is traditionally diagnosed by chest x-ray. This study aimed to explore the diagnostic value of lung ultrasonography (LUS) for TTN as well as differentiate it from respiratory distress syndrome (RDS) by using LUS. From January 2013 to February 2014, 60 infants who were diagnosed with TTN based on medical history, clinical manifestations, arterial blood gas analysis, and chest radiography were recruited to the study group. During the same period, 40 hospitalized neonates with nonlung diseases and 20 patients with RDS were recruited to the control group. In a quiet state, infants were placed in the supine, lateral, or prone position for the examination. Each lung of every infant was divided into 3 regions: the anterior, lateral, and posterior regions as bordered by the anterior axillary and posterior axillary lines. The probe was placed perpendicular to the ribs. Each region of both the lungs was carefully scanned.The common ultrasonographic manifestations of TTN were double-lung point (DLP), interstitial syndromes or white lungs, pleural line abnormalities, and A-line disappearance. A small number of infants (20%) with TTN exhibited pleural effusions, whereas the main ultrasonographic manifestation of RDS was lung consolidation with air bronchograms, which does not occur in TTN. The sensitivity and specificity of DLP for the diagnosis of TTN were 76.7% and 100%, respectively. LUS can accurately and reliably diagnose TTN. The DLP and lung consolidation possess great value in the diagnosis and differential diagnosis of TTN with RDS. Thus, we believe that LUS can be widely used in neonatal intensive care units.

BPD, Not BPD, or iatrogenic BPD: findings of lung ultrasound examinations.

Lung ultrasound has been extensively used to diagnose many types of lung disease. This study aimed to evaluate the pulmonary reasons for long-term oxygen dependence (LTOD) in premature infants using lung ultrasound.Lung ultrasound was routinely performed in 50 premature infants clinically diagnosed with bronchopulmonary dysplasia (BPD).Among the 50 patients studied, there were 9 cases of atelectasis, 4 cases of pneumonia, 2 cases of severe pulmonary edema, and 3 cases of pulmonary edema and consolidation that coexisted with BPD. The oxygen dependence of the babies either completely resolved or significantly decreased following appropriate treatments.More than one-third of the cases of LTOD in premature babies were caused by either BPD alone or diseases other than BPD. Lung ultrasound plays an important role in differentiating pulmonary causes of LTOD in patients with BPD, and the results of our study suggest that modifying the diagnostic criteria for BPD may be necessary.

[Therapeutic effect of Ommaya reservoir implantation on hydrocephalus in premature infants following intraventricular hemorrhage and factors associted with the therapeutic effect].

OBJECTIVE: To observe the therapeutic effect of Ommaya reservoir implantation on hydrocephalus in premature infants following intraventricular hemorrhage (IVH) and to investigate factors influencing the therapeutic effect. METHODS: An ambispective cohort study was conducted on the clinical and follow-up data of 20 premature infants (gestational age <32 weeks, birth weight <1500 g) who received Ommaya reservoir implantation because of hydrocephalus following IVH. The therapeutic effect of Ommaya reservoir implantation was observed. These patients were divided into cure and treatment failure groups according to their treatment outcomes. The factors influencing therapeutic effects were investigated by univariate analysis. RESULTS: Hydrocephalus was relieved significantly at 30 days after Ommaya reservoir implantation. However, some patients showed significantly decreased therapeutic effects since 3 months after operation: during 3-6 months after operation, 7 cases underwent ventriculoperitoneal shunt, 4 cases discontinued treatment because of economic reasons, and 1 case underwent endoscopic third ventriculostomy due to scalp hematoma with skin necrosis. The ventricles of the remaining 8 cases returned to normal size at 12-18 months after operation. As for postoperative complications, secondary IVH was seen in 8 cases, intracranial infection in 2 cases, and scalp hematoma with skin necrosis in 1 case. The univariate analysis revealed significant differences in gestational age, birth weight and duration of hydrocephalus before Ommaya reservoir implantation between the cure and the treatment failure groups (P<0.05). CONCLUSIONS: Ommaya reservoir implantation has a remarkable short-term therapeutic effect on hydrocephalus in premature infants following IVH, but later the effect decreases in some patients. Low gestational age, low birth weight and long duration of hydrocephalus may be the main factors influencing therapeutic effects of Ommaya reservoir implantation.

[Bedside diode laser photocoagulation for 103 cases with serious retinopathy of prematurity in NICU].

OBJECTIVE: To evaluate the efficacy and safety of the bedside diode laser photocoagulation for severe retinopathy of prematurity in neonatal intensive care unit (NICU). METHOD: Data of 103 patients with prethreshold or threshold retinopathy of prematurity (ROP), treated with diode laser photoablation after vecuronium-induced anesthesia and mechanical ventilation from March 2009 to July 2011 in NICU of Bayi Children's Hospital. RESULT: Totally 199 eyes in 103 patients received laser therapy with at least 5 months follow up. Among these eyes, zone I disease was found in 76 eyes (38.2%) of 39 infants, zone II disease was found in 123 eyes (61.8%)of 64 infants and additional disease was found in 180 eyes of 91 infants. After treatment 191 (96.0%) of 199 eyes had favorable outcomes and 8 developed to partial retinal detachment. The rate of favorable outcomes in zone I diseases and zone 2 diseases were 89.5% and 100% respectively. The laser therapy was undertaken in all patients safely and the use of ventilator was stopped quickly [after a mean of (6.7 ± 1.3) h]. CONCLUSION: Bedside laser photocoagulation in NICU is a safe and effective treatment mode for severe ROP and should be used widely.

[Retinopathy of prematurity screening in 2185 premature infants].

OBJECTIVE: To determine the incidence and risk factors of retinopathy of prematurity (ROP) among premature infants. METHODS: The fundus examination data of 2185 cases of premature infants [birth body weight ≤ 2000 g or gestational age (GA) ≤ 34 weeks] in neonatal intensive care unit of Bayi Children's Hospitals in Beijing between January 2009 and December 2010 were collected and retrospectively analyzed. RESULTS: Of 2185 cases of premature infants (1571 had used supplemental oxygen) received RetCam-II ophthalmoscopy screening, 287 cases developed ROP with the incidence of 13.1% according to the international classification of ROP (ICROP), including 34 cases (11.9%) suffering from zone I, 147 cases (51.2%) from zone II, and 106 cases (36.9%) from zone III. Stage 1, 2 and 3 lesions were 117 cases, 142 cases and 28 cases, accounting for 40.8%, 49.5% and 9.7%, respectively, while stage 4 and stage 5 lesions were not found. Thirty-six cases developed plus disease, accounting for 12.5%. Between ROP and Non-ROP groups, there were significant differences in birth weight (1269.9 ± 380.0) g vs (1479.7 ± 359.3) g vs (1633.9 ± 352.3) g, gestational age (30.6 ± 2.0) g vs (32.4 ± 1.8) W and time of supplemental oxygen [Median 10 d (0 to 71 d) vs 2 d (0 to 36 d)]. Among zone I, II and III groups, there were significant differences in birth weight (1269.9 ± 380.0) g vs (1479.7 ± 359.3) g vs (1633.9 ± 352.3) g, gestational age (29.3 ± 2.2) W vs (30.5 ± 1.9) W vs (31.2 ± 1.8) W and time of supplemental oxygen[Median 14 d (0 to 52 d)vs 10 d (0 to 71 d) vs 8 d (0 to 52 d)] (χ(2) = 257.5, 371.7, 6.695; P < 0.05), while among stage 1, 2 and 3 groups, there were also significant differences in birth weight (1593.3 ± 413.7) g vs (1481.3 ± 336.7) g vs (1325.3 ± 313.7) g, gestational age (30.9 ± 2.0) W vs (30.6 ± 1.9) W vs (29.5 ± 1.7) W and time of supplemental oxygen [Median 8 d (0 to 52 d) vs 11 d (0 to 65 d) vs 12 d (0 to 71 d)] (χ(2) = 230.8, 273.5, 6.695; P < 0.05). In 1004 cases admitted in 2009, 150 developed ROP with the incidence of 14.9%; while in 1181 cases admitted in 2010, 137 developed ROP with the incidence of 11.6%. There was significant differences in the incidence of ROP between these two years (χ(2) = 5.305, P < 0.05). Thirty-eight infants (1.7%) received laser therapy and only 3 infants progressed to stage 4 after laser therapy. Three infants with laser failed stopped progress after vasectomy. Finally, all patients were cured without blindness. CONCLUSIONS: Less birth weight, shorter GA and time of supplemental oxygen are close related to the development of ROP. It is necessary to pay high attention to the screen on premature infants with smaller gestation age, lower birth weight or using oxygen for the reduction or even avoid of blindness.

[Influence of premature rupture of membranes on neonatal health].

OBJECTIVE: To observe the influence of premature rupture of membranes (PROM) on neonatal health. METHOD: A retrospective cohort study was conducted among 3320 in-patient newborns of Bayi Children's Hospital from October 2006 to March 2008. One hundred term newborns and one hundred preterm newborns with PROM were chosen to be compared with fifty normal term newborns and preterm newborns respectively. The data were analyzed with Minitab 12.0 software. RESULT: Of the 3320 newborns, 711 (21.4%) were complicated with PROM. The morbidity of PROM was 21.4% (711/3320), among whom 9.69% (196/2022) were term newborns, 39.68% (515/1298) were preterm newborns, the differences between the term and the preterm newborns were statistically significant (P<0.001). Preterm newborns with PROM accounted for 72.43% of all PROM newborns (515/711). However, preterm infants only accounted for 30.01% of the newborns without PROM. Sixty-nine newborns with PROM had neonatal respiratory distress syndrome (RDS), incidence of which was 9.7% (69/711): 10 (5.1%) term newborns and 59 (11.5%) preterm newborns, of whom 3 developed broncho-pulmonary dysplasia Among all patients with PROM, 25% (178/711) newborns had different infectious diseases: 92 (12.9%) had pneumonia and 63 (8.9%) had septicemia, which totally accounted for 87.1% of the patients with infectious diseases, 23 (3.2%) newborns had other infectious diseases including peritonitis, purulent meningitis, urinary system infection, skin infection, perianal infection and conjunctivitis, which accounted for 12.9% of the patients with infectious diseases. Blood culture was performed for 163 newborns with PROM, the positive rate of the culture was 38.7% (63/163). The main pathogenic bacteria detected in blood culture were Gram-positive cocci (45.9%) and Gram-negative rods (54.1%). Gram-positive cocci mainly included Staphylococcus haemolyticus and Staphylococcus epidermidis (16/63). Gram-negative rods included K. pneumoniae (19/63) and Escherichia coli (9/63). Fungi were detected in two preterm infants (3.2%). There was no significant difference in the level of total serum bilirubin between term newborns and preterm newborns with PROM (P>0.05). Total serum bilirubin level of 37.1% of total preterm newborns with PROM exceeded 220 micromol/L, while it was 29.1% in term newborns with PROM (P<0.05). There was a significant decrease of blood platelet count (P<0.01) between the PROM group and the normal group. The myocardial enzymes including lactate dehydrogenases, aspartate aminotransferase, creatine kinase, MB isoenzyme of creatine kinase of PROM group were significantly higher than those of the normal group (P<0.05). Compared with the normal group, the average hospital stay of term newborns with PROM and preterm newborns with PROM were prolonged by 20.0% and 25.1% respectively, the average cost of hospitalization of them were increased 30.5% and 60.0% respectively. CONCLUSION: PROM is harmful to newborns health in many ways. Studies on PROM should be enhanced.